Infection Disease Exam Master

A 17-year-old boy presents with a 5-day history of intermittent fever, joint pain, and redness and swelling of the joints. The patient gives a history of pain in the right knee and ankle. 3 days ago, he had pain and swelling in his left knee, but now it has improved. On examination, temperature is 102°F, pulse is 108/min, RR is 20/min, and BP is 110/80 mm Hg. The patient's right knee is swollen, tender, and warm. There is a limitation of range of motion due to pain. The right ankle appears swollen and warm. Other system exams are normal. Lab tests are ordered; during the follow-up exam, you note elevated erythrocyte sedimentation rate (ESR) and rising ASO titers. Question Highlights How long should the patient receive secondary prophylactic antibiotics? 1 10 days 2 1 month 3 6 months 4 1 year 5 5 years

Correct Answer: 5 years Rheumatic fever is an inflammatory condition precipitated by group A Streptococcal infection. It is more common in children, but it also occurs in adults. The clinical manifestations include arthritis, carditis, fever, subcutaneous nodules, erythema marginatum, and chorea. It is more commonly diagnosed in close living quarters, such as a dormitory. The diagnosis is established by finding antecedent Streptococcal infection (+ culture OR rising ASO or anti-DNAase titers), plus fulfillment of the modified Jones criteria. Modified Jones criteria: Must have 2 major findings, or 1 major and 2 minor findings. Major Findings: Polyarthritis Chorea Carditis Erythema maginatum Subcutaneous nodules Minor Findings: Fever Elevated erythrocyte sedimentation rate/CRP Prolonged PR interval on EKG Arthralgia (if arthritis not counted as a major finding) Supporting evidence of preceding group A streptococcal infection: positive throat culture rapid streptococcal antigen test elevated or rising streptococcal antibody titer This patient already meets the criteria to establish the diagnosis of rheumatic fever. Long-term antibiotic prophylaxis is indicated because recurrence of rheumatic fever is common, especially during the first 5 years. Adults with rheumatic fever usually receive at least 5 years of prophylactic antibiotics, usually administered as 1.2 million units of benzathine penicillin G IM each month, or penicillin VK 250 po bid. The prophylactic regimen is life-long for certain patients, such as those who already have pre-existing valvular heart disease.

A 17-year-old male football player is being evaluated for fatigue and a sore throat. He denies coughing or fevers. He does not smoke or drink. In addition, he denies blood in his stool or urine and any dysuric symptoms. He practices safe sexual intercourse with his girlfriend. Physical exam demonstrates a blood pressure of 130/65 mm Hg, a pulse of 72/minute, respirations of 16/minute, and a temperature of 98°F (36.6°C). Lung and heart sounds are normal. There is no cervical adenopathy. When you look at the pharynx, there is tonsillar enlargement with evidence of exudates. The abdominal exam demonstrates a spleen tip that is easily palpable 1.5 cm below the left costal margin. Results of a Monospot test are positive. Question Highlights What management scheme is best for this patient? 1 Empiric antibiotic treatment 2 Intravenous acyclovir therapy 3 Oral acyclovir therapy 4 Oral steroids for 5 days 5 Acetaminophen or NSAIDs

Correct Answer: Acetaminophen or NSAIDs Infectious mononucleosis is caused by double-stranded Epstein-Barr virus or EBV (part of the Herpesviridae family). The incidence is highest in young adults ages 15-35. Symptomatic infections are common, and most adults are seropositive to the EBV. Symptoms include fever, headache, generalized fatigue, and malaise. Signs include lymphadenopathy (posterior cervical chain), hepatosplenomegaly, jaundice, periorbital edema, exudative pharyngitis, palatine petechiae, and rash. There is lymphocytosis with 20% atypical lymphocyte, positive heterophile agglutination (Monospot test) after the second week of illness, and a heterophile titer greater than 1:56. Liver function tests are elevated. There is also granulocytopenia, thrombocytopenia, and hemolytic anemia. Treatment is for symptomatic improvement in mild cases such as NSAIDs or acetaminophen for sore throat or fever. Symptoms usually improve in 2-4 weeks. No contact sports should be carried out in view of the splenomegaly. Treatment with amoxicillin or ampicillin may lead to severe maculopapular rashes, and it should be avoided. Specific antiviral treatments (e.g., acyclovir) are not beneficial. In severe cases in which the pharyngitis may obstruct airway, a 5-day course of steroids may be needed

A 10-year-old boy presents with a 1-week history of progressing joint pain. The pain started in his ankles, and then progressed to his knees; his hips are now starting to hurt. His ankles feel slightly better. He had contact with someone who had strep throat within the past couple of weeks. The patient's heart rate is 130. On exam, there is erythema and edema over the knees and hips as well as minimal edema over the ankles. A high-pitched holosystolic murmur is noted over the apex and radiates to the axilla with a noted friction rub. Question Highlights Based on the above history and physical exam, what is the most likely diagnosis? 1 Juvenile idiopathic arthritis 2 Systemic lupus erythematosus 3 Acute rheumatic fever 4 Kawasaki disease 5 Septic arthritis

Correct Answer: Acute rheumatic fever Acute rheumatic fever is the correct response; the scenario identifies 2 major Jones criteria: migratory polyarthritis and carditis. Arthritis with acute rheumatic fever typically starts in the legs and then migrates; most commonly, it affects the large joints. The pain can subside within 1 - 2 days, and the arthritis starts affecting another joint. Swelling and redness are common over the joints involved. Typically, a mitral or aortic regurgitation murmur is noted on exam. A friction rub indicates involvement of the myocardium. Polyarthritis and carditis are the most common major Jones criteria for acute rheumatic fever. A confirmed group A Streptococcus test needs to be done, but with the sick contact, you can safely assume the patient has strep.

A 13-year-old girl presents to the emergency department with febrile episodes (Tmax 102°F), joint aches in her knees and wrists, chest pain, and a raised red rash. She denies sexual activity or intravenous drug use. Vital signs are BP 90/60 mm Hg, HR 115/min, T 101°F, RR 25/min. Physical exam is remarkable for diffuse scattered ring-shaped macules on her extremities, a III/VI systolic ejection murmur, and guarded passive range of motion in wrists and knees bilaterally with no apparent swelling. Laboratory findings: WBC 16,000 mcL, Hematocrit 35%, Platelets 350,000 mcL, ESR 65 mm/h, positive antistreptolysin O titer. Question What is the most likely diagnosis? 1 Systemic onset juvenile idiopathic arthritis 2 Acute rheumatic fever 3 Septic arthritis 4 Systemic lupus erythematosus 5 Lyme disease

Correct Answer: Acute rheumatic fever This patient demonstrates three major Jones criteria to support the diagnosis of acute rheumatic fever: polyarthritis, carditis, and erythema marginatum. She also has minor Jones criteria: fever and elevated ESR. Evidence of previous streptococcal infection is noted with a positive antistreptolysin O titer. Systemic onset juvenile idiopathic arthritis (Still's disease) is a diagnosis of exclusion, and the patient does not exhibit significant anemia. She also does not exhibit the type of rash that accompanies this disease. The rash is salmon-colored and presents on the chest and abdomen. Septic arthritis presents with swelling in the affected joint(s). No major risk factors for developing septic arthritis are identified in this patient. Systemic lupus erythematosus presents with a malar rash or discoid lesions. Even though she does exhibit some subjective problems that could be construed as SLE, more lab work must be drawn (autoantibodies) to diagnose SLE. Lyme disease presents with a characteristic bullseye rash (erythema migrans). Lyme disease is not associated with a murmur or a positive antistreptolysin O titer.

A 5-year-old Latino boy with acute lymphoblastic leukemia presents with fever and rash. He is currently on induction chemotherapy that includes dexamethasone. He was exposed to a friend with varicella 2 weeks ago; he has never had the varicella vaccination and his mother cannot recall that he ever had a varicella infection. Blood tests prior to initiation of chemotherapy showed the absence of antibody to the varicella virus. He now has 10 small vesicles and several red macules on his face and chest. Temperature is 38.5°C. Exam is otherwise normal. Question Highlights What is the most appropriate immediate treatment for this patient? 1 Acetaminophen as needed 2 Varicella-zoster immune globulin 125 units/10 kg IM 3 Varicella vaccine 0.5 mL IM 4 Acyclovir 500 mg/m2 IV every 8 hours 5 Acyclovir 200 mg/m2 PO 5 times a day

Correct Answer: Acyclovir 500 mg/m2 IV every 8 hours High doses of IV acyclovir (500 mg/m2 IV every 8 hours) should be administered to immunocompromised patients with primary varicella infections due to the high risk of disseminated disease and complications from infection.

A 25-year-old sexually active woman presents with a 2-day history of pain and swelling of her dorsal right wrist and fingers. For the past week, the pain and swelling have been in different joints of her body, including her left knee, left elbow, and right ankle. On exam, you note edema, effusion, and erythema over the dorsal right wrist with the wrist held in 15° of extension. It is very tender on palpation and has virtually no range of motion secondary to the pain. You aspirate synovial fluid for lab studies. The lab studies reveal the following information: Synovial fluid: WBCs - 57,000 cells/mcL Gram stain: too numerous to count WBCs with no bacteria seen Culture: pending Question Based on this history, physical, and lab findings thus far, what should be the initial treatment for this woman? 1 Prescribe oral doxycycline for 10 days. 2 Admit to the hospital for IV ceftriaxone. 3 Wait for the results of the synovial fluid culture. 4 Admit for immediate surgical arthroscopic irrigation. 5 Admit for IV penicillin.

Correct Answer: Admit to the hospital for IV ceftriaxone. This patient most likely has gonococcal septic arthritis, based on her age, history, and physical and lab findings. She should be admitted for IV ceftriaxone (Rocephin) until culture results return and have sensitivities determined. Oral treatment, especially with doxycycline, is ineffective in treating gonococcal septic arthritis. One should not wait for culture results to start treatment. Surgical arthroscopic irrigation may be needed if after 24-48 hours there is no improvement on the IV antibiotic treatment. 4-5% of gonococcal isolates produce a β-lactamase that confers penicillin resistance, so it is not first-line treatment.

A 32-year-old Latinx woman, previously in good health, was brought to the emergency department by paramedics after she was found unresponsive in her home. It is unknown if she had a seizure. Past medical history is not significant, and she has no known allergies. She is not on any medications and is Gravida 4, Para 4, Ab 0. She is married and recently emigrated to the US from Central America. Vital signs: temperature 100.4°F, pulse 112, respirations 24, blood pressure 110/62, O2 sat 96% on room air. Physical exam reveals a well-developed woman with obtunded mental status. Cardiac exam reveals normal S1 and S2 without rub, murmur, or gallop. Lungs are clear to auscultation and percussion. Spinal tap is thought to be contraindicated. The patient is admitted to the ICU. After consultation with specialists, a tentative diagnosis is made; the patient is treated with a therapeutic trial of medication. The following morning, the patient is found to be alert, oriented, and afebrile. Lab and imaging studies show: WBC 17.2 K/mcL ESR 25 mm/hr Hgb 12.4 gm/dL Electrolytes normal Hct 37% BUN 12 mg/dL Platelets 305 K/mcL Creatinine 1.2 mg/dL Neutrophils 68% Pregnancy test Negative Lymphocytes 20% HIV immunoassay Negative Monocytes 2% Blood cultures No growth (preliminary) Eosinophils 10% EKG NSR, 1 PAC Basophils 1% Transthoracic echocardiogram Normal heart size and structure. Chest X-ray Normal heart size. No infiltrates or edema. CT Brain without contrast Multiple cystic lesions. Cyst with dot sign noted. MRI Brain with contrast Multiple cystic lesions. Cyst with dot sign present. Question Highlights What is the treatment of choice (the successful therapeutic trial) for this patient's disease? 1 Albendazole with IV prednisolone 2 Heparin IV 3 Interferon alfa 2-b 4 Isoniazid, rifampin, pyrazinamide, and ethambutol 5 Pyrimethamine with sulfadiazine

Correct Answer: Albendazole with IV prednisolone Albendazole with concomitant steroid therapy (dexamethasone or prednisolone) is currently the treatment of choice for neurocysticercosis of the brain parenchyma due to active lesions caused by larval forms of the pork tapeworm Taenia solium. Neurocysticercosis, the most common parasitic disease of the brain worldwide, most commonly presents with seizure, but other neurologic manifestations may occur (double vision, stroke, neuropsychiatric syndrome, or hydrocephalus). CT and MRI of this patient's brain showed multiple cystic lesions with a "dot sign," which represents larval cysts with scolex ("head"). Albendazole is an antihelminthic drug that decreases glucose uptake and depletes glycogen storage of the parasite, resulting in its death. Possible adverse effects of albendazole can include bone marrow suppression, teratogenicity, hepatic effects, retinal damage in retinal neurocysticercosis, and unmasking of neurocysticercosis in patients with hydatid disease. Brain inflammation in neurocysticercosis may increase as the parasites die, so concomitant treatment with steroid therapy is recommended, as is treatment with antiepileptic drugs, especially if seizure activity has occurred. Prior to use of albendazole, a pregnancy test should be obtained in any woman of childbearing age; liver function tests must be monitored every 2 weeks during treatment. The most common side effects of albendazole are elevated liver function tests and GI symptoms such as abdominal pain, nausea, or vomiting.

You have been asked to do a house call on an 88-year-old woman who is bed-bound and lives at home with her private home health aide. She has had no medical follow-up for the past year. Approximately 3 weeks ago, she appeared to be having "headaches." 2 weeks ago, she developed a rash on the left of her forehead that developed into "little blisters that popped and crusted over." She has a history of coronary artery disease and was diagnosed with "senile dementia" 6 years ago. The home health aide says she is occasionally combative and resistant to care. On exam, she is awake and mumbles several words but is not responsive to verbal commands. BP is 118/68 mm Hg, P 84/min R 20/min. Skin exam reveals clusters of vesicles with crusts on her left forehead. There are no other significant lesions noted on the body. Question Highlights What is the most appropriate treatment? 1 Acyclovir ointment 2 Permethrin cream 3 Aluminum acetate solution 4 Capsaicin cream 5 Metronidazole lotion

Correct Answer: Aluminum acetate solution Herpes zoster (shingles) is a skin eruption caused by reactivation of latent varicella virus. Primary varicella eruption typically occurs in childhood (chickenpox). Once this resolves, the virus may remain dormant in the dorsal root ganglia. Immunosuppressed patients are at higher risk for developing zoster. The incidence of herpes zoster increases markedly with age. The rash usually involves one dermatome, and pain may occur before a rash erupts. It begins as a macular erythematous rash that progresses to clusters of vesicles over the next 12-24 hours; new vesicles can appear over the next 2 days. Vesicle fluid often appears purulent, then dries out. Crust forms by 10-12 days and falls off in 2-3 weeks. Local treatment of zoster rash should consist of cleaning with soap and water. Application of an astringent, like aluminum acetate solution (Burow's, Domeboro's) can be helpful in relieving local symptoms of pain and itching.

A 10-year-old girl presents with chest pain and joint aches. Her mother says that about 2 weeks ago, her daughter had a sore throat with fevers and pus around her tonsils. She was prescribed a 14-day course of penicillin on the initial visit, but her mother stopped the medications after 2 days because the fever subsided. She also experienced chest pain and recurrence of fever. Her vital signs: blood pressure 120/80 mm Hg, heart rate 110 beats/min, temperature 102.3°F. On physical examination, normal S1/S2 and a II/VI short mid-diastolic murmur are heard. Her EKG shows a sinus tachycardia with a prolonged PR interval. Question Highlights What would have been the best way to prevent this disease? 1 Steroid therapy 2 Saltwater gargles 3 Acetaminophen 4 Aspirin 5 Antibiotic compliance

Correct Answer: Antibiotic compliance The clinical picture is suggestive of acute rheumatic fever. Penicillin is prescribed to eliminate the streptococcal infection. Antibiotic compliance is an important part of prevention. In this case, not finishing the prescribed course of antibiotics did not eliminate the streptococcal infection and allowed the strep infection to progress to rheumatic fever. Repeated exposure and untreated strep infections lead to recurrent attacks of ARF.

During a routine X-ray examination for employment insurance purposes, the radiologist notices a rounded lesion in a pulmonary cavity on the right upper lobe of the pulmonary X-ray of a middle-aged man. The patient was treated for pulmonary cavitary tuberculosis (TB) 2 years ago; he has completed treatment, and he has not had any problems since. Question Highlights What late complication of TB is seen in this patient? 1 Fibrothorax 2 Aspergilloma 3 Broncholithiasis 4 Reactivation of TB 5 Bronchiectasis

Correct Answer: Aspergilloma Aspergilloma is a solid mycelial mass caused by the growth of Aspergillus species within a cavity, usually within the lung. This condition is most commonly a result of a previous tuberculous infection. Although the patient may be asymptomatic, cough is frequent, and a severe life-threatening hemoptysis may occur. Patients present with hemoptysis, or it can be an incidental diagnosis with a routine X-ray. Previous TB history and anti-TB treatment are helpful for the diagnosis. The diagnosis is confirmed by the demonstration of a mobile intracavitary mass on the radiograph and air-crescent sign around the mass. Although cultures are often negative, patients frequently have high titers of antibody to Aspergillus. If the patient is asymptomatic, the treatment is conservative. Surgical removal is the only reliable curative method indicated for uncontrollable hemoptysis. Spontaneous expectoration of the fungal mass may occur. Oral itraconazole results in partial or complete resolution of aspergillomas in 60% of patients.

A 28-year-old man presents with a 2-week history of a non-painful non-pruritic rash. He is negative for any other rashes, dysuria, urinary frequency, penile discharge, erectile dysfunction, diarrhea, constipation, change in stool, nausea, or vomiting. He does recall having had a penile "scab" approximately 4 weeks ago that healed; he never sought medical attention. He is not aware of having been exposed to anyone with any illnesses in the past few months. Social history is positive for unprotected anal sex with multiple male partners in the past 6 months, with the last sexual encounter occurring 4 days ago. He states that he has not engaged in any recreational drug use or cigarette smoking. Skin exam reveals a pink-red papulosquamous eruption with scattered discrete coppery papules on the palms of his hands. Question Highlights What treatment is the best choice for the patient's condition? 1 Ceftriaxone 150 mg IM once 2 Benzathine penicillin G 2.4 million units IM once 3 Azithromycin 250 mg daily for 7 days 4 Doxycycline 100 mg twice daily for 7 days 5 Ciprofloxacin 500 mg twice daily for 7 days

Correct Answer: Benzathine penicillin G 2.4 million units IM once Based on the clinical scenario, the most likely diagnosis is secondary syphilis. Secondary syphilis without CNS or ocular involvement is treated similarly to primary syphilis, with the preferred treatment of 2.4 million units of benzathine penicillin G. There is limited data on the use of ceftriaxone, and treatment specifics have not been defined. Azithromycin may be used as an alternative treatment, but there has recently been increased resistance questioning its efficacy. Doxycycline is a good alternative for penicillin-allergic patients, but it must be given for 2 weeks. Ciprofloxacin is not a recommended treatment for primary or secondary syphilis.

A nurse in your office may have been exposed to blood from a patient with AIDS. She was administering an antibiotic injection intramuscularly to an HIV-positive patient and accidentally sustained a needle prick injury. As part of her post-exposure prophylaxis therapy, you instruct her to begin daily tenofovir. Question What is the mode of action of this medication? 1 Cannot be phosphorylated by host cell enzymes 2 Inhibits the host cell RNA polymerase 3 Blocks the viral enzyme in reverse transcriptase 4 Incorporates into viral DNA as purine analog causing chain termination 5 Prevents the virus from entering the cells

Correct Answer: Blocks the viral enzyme in reverse transcriptase Tenofovir is categorized as a nucleoside analog reverse transcriptase inhibitor (NRTIs). An NRTI's mechanism of action is to block reverse transcriptase, an enzyme that enables the human immunodeficiency virus 1 (HIV-1) to flourish. This enzyme aids HIV in making a copy of DNA from the viral RNA, and this DNA is incorporated into the host genome. The effectiveness has been found in a review conducted by the Centers for Disease Control and Prevention to be so effective that "pre-exposure prophylaxis can potentially be a vital option for HIV prevention in patients at very high risk for infection, whether through sexual transmission or injecting drug use."

A healthy mother with no known medical illnesses presents her 6-month-old male infant due to a 1-day history of poor feeding, lethargy, and weak cry. At first, the infant had difficulty sucking and swallowing and was not opening his eyes. This was followed by loss of head control, weakness of the trunk, arms, and then legs. The infant is constipated and has had decreased tears and saliva since yesterday. The infant was healthy before the onset of these symptoms. There is no history of fever, vomiting, cough, seizures, or difficulty in breathing. The infant has weak gag and pupillary reflexes, generalized hypotonia, loss of head control, ptosis, and diminished deep tendon reflexes. Blood counts and CSF examination are within normal limits. Question Highlights What is the most likely diagnosis? 1 Myasthenia gravis 2 Spinal muscular atrophy 3 Guillain-Barré syndrome 4 Botulism 5 Tick paralysis

Correct Answer: Botulism The most likely diagnosis is infant botulism. The classic presentation is weak suck, ptosis, lethargy, and constipation. Blood counts and CSF were normal, which excludes sepsis. The clinical features of botulism are caused by a neurotoxin produced by Clostridium botulinum, a gram-positive anaerobe found in soil; it produces a toxin in the GI tract. Ingestion of honey is a risk factor.

A 23-year-old man presents with burning on urination and a light greenish-yellow penile discharge. He is afebrile but otherwise well. He admits to having unprotected anal sex with a man. Question According to the Centers for Disease Control, what treatment is most appropriate? 1 Ciprofloxacin 500 mg now and azithromycin 1 g now 2 Ciprofloxacin 500 mg now and doxycycline 100 mg every 12 hours for 7 days 3 Penicillin G 1.2 M Units IM now and azithromycin 1 g now 4 Ceftriaxone 250 mg IM once and azithromycin 1 g now 5 Ceftriaxone 125 mg IM now and penicillin G 1.2 M units IM now

Correct Answer: Ceftriaxone 250 mg IM once and azithromycin 1 g now The correct answer is ceftriaxone 250 mg IM now and azithromycin 1 g now. According to the Centers for Disease Control, the correct first-line treatment for uncomplicated gonococcal urethritis is ceftriaxone. There has been evidence of increasing resistance of gonococci strains against fluoroquinolones such as ciprofloxacin in the United States. In addition, when chlamydia status is unknown in a patient with gonorrhea, it is appropriate to treat for suspected chlamydia infection with either azithromycin 1 g once or doxycycline 100 mg 2 times daily for 7 days.

A 23-year-old man presents with a 2-day history of burning urine. He also reports a slight purulent urethral discharge. He denies any fever, malaise, or chills. He smokes 1 pack of cigarettes daily and drinks socially; he has multiple sexual partners. On exam, his vitals are normal and lungs are clear; abdominal exam is unremarkable, without any renal angle or suprapubic tenderness, and external genitals reveal only slight urethral discharge. Labs show WBC of 6500/uL, and urinalysis has 5-10 WBC and 0 RBC. Gram stain of the urethral discharge shows neutrophils and intracellular gram-negative diplococci. Question Highlights What is the best treatment regimen for this patient? 1 Ceftriaxone 250 mg IM plus azithromycin 1g PO each single dose 2 Ofloxacin 400 mg BID for 7 days 3 Trimethoprim-sulfamethoxazole for 3 days 4 Doxycycline 100 mg daily for 7 days 5 Ceftriaxone 125 mg IM single dose

Correct Answer: Ceftriaxone 250 mg IM plus azithromycin 1g PO each single dose The correct response is ceftriaxone 250 mg IM plus azithromycin 1g PO each single dose. This patient has gonococcal urethritis, evidenced by the diplococci in the urethral discharge. The causative organism of gonorrhea is Neisseria gonorrhoeae, which is a gram-negative intracellular diplococcus. Gonorrhea treatment is complicated by the ability of N. gonorrhoeae to develop resistance to antimicrobials. A theoretical basis exists for combination therapy using two antimicrobials with different mechanisms of action (e.g., a cephalosporin plus azithromycin) to improve treatment efficacy and potentially slow the emergence and spread of resistance to cephalosporins. In addition, clinical trials have demonstrated the efficacy of azithromycin 1 g for the treatment of uncomplicated urogenital gonorrhea. Furthermore, those infected with N. gonorrhoeae frequently are coinfected with Chlamydia trachomatis; this finding has led to the long-standing recommendation that persons treated for gonococcal infection also be treated with a regimen that is effective against uncomplicated genital C. trachomatis infection, further supporting the use of dual therapy that includes azithromycin. Therefore, the use of ceftriaxone alone is not the best choice for treatment.

A 30-year-old woman presents because she recently had a PPD skin test; the transverse diameter of the induration was 14 mm. The patient denies ever having tuberculosis and she is asymptomatic now, but she expresses some anxiety about the result of the skin test. For the last 6 months, she has worked as a nurse for a long-term care facility. Her patient is a vent-dependent tetraplegic. On clinical examination, there are no abnormalities. Question What is the most appropriate next step? 1 Chest X-ray 2 Isoniazid prophylaxis 3 Reassurance 4 Respiratory isolation 5 Sputum examination

Correct Answer: Chest X-ray Any PPD skin test should be performed and interpreted only in healthy asymptomatic individuals with a negative chest X-ray for active tuberculosis (TB). A positive result is considered if the transverse diameter of the induration is >15 mm for low-risk individuals, >10 mm for high-risk individuals, and >5 mm for HIV-positive individuals or close contacts of patients with active TB. A healthcare worker is considered a high-risk individual if exposed to patients with known TB or when working in congregate facilities. In this case, the next step in the management is performing a chest X-ray to look for old or active TB lesions since she is a high-risk healthcare worker showing no symptoms of active TB with an induration >10mm (a positive result in this patient). She would then get prophylaxis.

A 2-month-old girl presents with rapid breathing and a staccato cough, appearing otherwise well; she is afebrile. Physical examination detects fine rales over the lungs and a thickened red tympanic membrane. A chest X-ray shows bilateral patchy interstitial infiltrates. Laboratory studies indicate eosinophilia. Her mother received limited prenatal care. What is the likely causative organism? 1 Haemophilus influenzae 2 Escherichia coli 3 Streptococcus pneumoniae 4 Mycobacterium tuberculosis 5 Chlamydia trachomatis

Correct Answer: Chlamydia trachomatis This clinical picture is highly suggestive of Chlamydia trachomatis pneumonia: staccato cough, afebrile, and eosinophilia. Chlamydia trachomatis is the most common sexually transmitted disease in the US. Infants born to mothers with active infection are prone to develop infections or pneumonia. Staining a smear of a nasopharyngeal specimen with fluorescein-conjugated monoclonal antibody can establish the diagnosis. The specimen for this commercially available test must be evaluated within 30 minutes. The early onset of this form of pneumonia suggests infection through direct contact during the birth process. H. influenzae and S. pneumoniae typically have a more acute onset. Fever is usually present. E. coli is a rare cause of pneumonia in infants that usually has a more abrupt onset with fever. M. tuberculosis is uncommon in children not from endemic areas and does not typically present as patchy infiltrates.

A 9-year-old boy presents with burning during urination and a creamy white penile discharge. The grandmother is concerned about sexual abuse by a female caregiver. Question What is the most likely diagnosis? 1 Candidal urethritis 2 Chlamydia urethritis 3 Glans-Balanitis 4 Gonococcal urethritis 5 Human papillomavirus

Correct Answer: Chlamydia urethritis Chlamydia is one of the most common sexually transmitted diseases; it would be the most appropriate response in this case. Male patients may be asymptomatic or they may have a white penile discharge.

A 52-year-old man stepped on a piece of glassyesterday. On exam, his wound appears clean, and it is not infected. He has never had the primary series of tetanus immunization. The patient asks if he needs tetanus immunization. Question Highlights What should you recommend? 1 No tetanus immunization needed 2 Tetanus booster 3 Complete tetanus immunizations plus TIG 4 Check in 24 hours to determine if immunization 5 Adult tetanus and diphtheria toxoid

Correct Answer: Complete tetanus immunizations plus TIG If there is a doubt about the completion of the original series of three tetanus immunizations, then the person should receive tetanus immunoglobulin plus a complete series of tetanus immunization. The complete series is comprised of three doses; the initial two doses are administered 4-6 weeks apart, and the third dose 6-12 months after the second with a one-time dose of Tdap substituted for one of the doses of Td.

A 3-year-old boy is admitted to the emergency room in acute respiratory distress. The patient has a body temperature of 40°C, a respiratory rate of 70/min, and a pulse of 130/min. Auscultations of the lungs are unremarkable. An examination of the throat reveals an exudate in the posterior pharynx that is yellowish and membranous. Bleeding occurrs when it is scraped and removed. The parents of the child reveal that the child has no prior immunizations. A throat culture was ordered and worked up specifically for an organism that selectively grows on cystine tellurite agar. Question Highlights What organism is causing this child's disease? 1 Respiratory syncytial virus 2 Bordetella pertussis 3 Haemophilus influenzae Type b 4 Streptococcus pyogenes 5 Corynebacterium diphtheriae

Correct Answer: Corynebacterium diphtheriae Corynebacterium diphtheriae is an aerobic club-shaped gram-positive rod that causes diphtheria. Selective media (cystine tellurite agar) is used for the isolation and identification of the bacteria; the organism produces black colonies. The organism produces a toxin (diphtheria toxin) that is the major virulence factor; it enters the circulation and inhibits protein synthesis in a variety of tissues (the heart, nerves, and kidneys are particularly targeted). The disease will usually occur in individuals that have not been properly immunized (especially children). On physical examination, the patient will have a pseudomembrane formed at the back of the throat. This pseudomembrane is composed of bacteria, fibrin, dead epithelial cells, and red and white blood cells. Aspiration of this pseudomembrane can cause death by suffocation. In unvaccinated children, the mortality rate is approximately 20%. Treatment is usually with both antibiotics and diphtheria antitoxin.

A 15-year-old girl presents with a 2-day history of excessive vaginal discharge. She had unprotected sex with a boyfriend 4 days ago, and he later informed her that he has gonorrhea. On speculum exam, the girl is found to have a moderate amount of off-white and frothy vaginal secretions. The appearance of the cervix is normal. A cervical swab reveals copious gram-negative intracellular diplococci. Question Highlights What should be the first step in the management of this patient? 1 Obtain written or oral parental consent to treat. 2 Ask the patient to return with a parent or adult guardian. 3 Request permission to treat from the Department of Health. 4 Counsel the patient about safer sex and treat. 5 Ask the patient to provide a list of sexual contacts.

Correct Answer: Counsel the patient about safer sex and treat. The patient should be provided counseling on the role of safer sex practices, condom use, the risks of sexually transmitted infections, and HIV transmission. Counseling skills characterized by respect, compassion, and a non-judgmental attitude towards all patients are essential in obtaining a thorough sexual history and for delivering effective prevention messages. For uncomplicated gonococcal infections, the preferred treatment is ceftriaxone 125 mg IM as a single dose to treat the gonococcal infection and azithromycin 1 g orally single dose to treat possible chlamydia infection.

A 15-year-old girl presents due to a rash. She does not take any over-the-counter or prescription medications and she does not have any pertinent medical history or drug allergies. She denies known exposure to any sick contacts in the last several days, but she admits to traveling to Tennessee and hiking in the Smoky Mountains last week. Further questioning reveals that the patient admits to feeling feverish (although the patient has not formally taken her temperature), headache, lack of appetite, and muscle pain. Physical examination reveals a rash on her bilateral wrists, forearms, and bilateral ankles; it consists of numerous small flat pink macules that are non-pruritic and non-scaly. Question Highlights What treatment regimen is most appropriate for this patient? 1 Amoxicillin 2 Amoxicillin/clavulanic acid 3 Azithromycin 4 Doxycycline 5 Sulfamethoxazole/trimethoprim

Correct Answer: Doxycycline The patient case scenario results in a diagnosis of Rocky Mountain Spotted Fever (RMSF), spread via an infected tick. Despite its namesake, diagnosis of this has been highest in Arkansas, Delaware, Missouri, North Carolina, Oklahoma, and Tennessee. Incidence of RMSF is highest during the summer months, specifically June and July. Symptoms of RMSF typically begin 2-14 days after the bite of the tick. Various symptoms include fever, rash, headache, nausea, vomiting, abdominal pain, muscle pain, lack of appetite, or conjunctival injection. The classic rash of RMSF first appears 2-5 days after onset of a fever and will be small flat pink non-pruritic macules on the wrists, forearms, and ankles, spreading to the trunk and potentially the palms and soles. A more red-purple-colored petechial rash is typically present after the sixth day of symptoms. Treatment should be initiated as soon as diagnosis is made. Doxycycline is the first-line treatment for adults and children of all ages and should be initiated immediately whenever RMSF is suspected. Chloramphenicol may also be considered.

A 25-year-old Caucasian male landscaper presents with a 2-week history of generalized malaise and an "unusual rash" on his right thigh. The patient reports that this rash has been widening, but he denies any pruritus or pain in association with his complaints. In the past week, he has also noticed a constant headache and mild fever. The past medical history is unremarkable. The physical exam reveals vital signs within the normal limits, enlarged non-tender diffuse lymph nodes in cervical and inguinal areas, and an erythematous rash with central clearing and few satellite lesions. Question Highlights Given this patient's diagnosis, how would this patient's clinical stage be defined? 1 Early disseminated 2 Latent 3 Early localized 4 Late 5 Tertiary

Correct Answer: Early localized This specific patient is at risk for contracting Lyme disease since he works outdoors and is at higher risk for insect bites (e.g., a tick bite). The rash, characteristically referred to as erythema migrans, is highly suggestive of Lyme disease. This disease occurs more commonly during the summer months and is caused by the spirochete Borrelia burgdorferi. The clinical presentation of Lyme disease has been divided into three phases. The first phase (early localized) is characterized by malaise and myalgias, with an enlarging erythematous rash at the site of the tick bite carrying the spirochete. Lyme disease progresses to an early disseminated disease state. This involves the myocardium, causing conduction abnormalities and arrhythmias; it can involve the nervous system either centrally or peripherally. Late or persistent lyme disease consists of mild neuropsychiatric disturbances and/or multiple-joint arthritic involvement.

Your patient is a 1-day-old "floppy baby"; he was born full term by normal vaginal delivery in the hospital. Birth weight was 2.4 kg; Apgar scores were 6 (1 min), 8 (5 min), and 8 (10 min). His mother had a normal pregnancy, except for an episode of a mononucleosis-like illness, but her heterophile antibodies were negative. On examination today, the patient is febrile, with a heart rate of 130/min, shallow breathing, and bilateral fine crepitations. You notice petechial purpura. He has hepatosplenomegaly and generalized lymphadenopathy (cervical, axillary, and inguinal). Neurological examination reveals hypotonia and bulging anterior fontanelles; there are no meningeal signs. Ophthalmological examination reveals multiple foci of chorioretinitis on both eyes. He is polypneic and hypoxic; nasal oxygen therapy and wide-spectrum antibiotic therapy is introduced (ampicillin, gentamycin, and cefotaxime). Labs are listed below. Value Finding Normal for 12-24 hr old, full term Hb (g/L) 95 184 WBC x 109/L 29 18.9 (9.4-34) Neutro x 109/L 16 11.5 (5-21) Lymph x 109/L 12.9 5.8 (2-11.5) Platelets103/mm3 120 150-350 Cerebrospinal fluid (CSF) Value Finding Normal for 12-24 hr old, full term WBC (mm3) 10 5 (0 - 30) RBC (mm3) 10 9 (0 - 50) Protein (g/L) 8 0.6 (0.3 - 2.5) Glucose (millimol/L) 45 (blood sugar 48 mg/dL) >2/3 of the blood sugar level The rest of his laboratory values, including liver function tests, are normal. Chest X-ray reveals interstitial pneumonia. CT shows intracranial diffuse calcifications. Question Highlights What behavior should you ask the mother about? 1 Eating undercooked meat during the pregnancy 2 Being in contact with febrile children during the pregnancy 3 Having unprotected sex during the pregnancy 4 Drinking alcohol during the pregnancy 5 Receiving rubella vaccine before the pregnancy

Correct Answer: Eating undercooked meat during the pregnancy In the view of hepatosplenomegaly, generalized lymphadenopathy, raised intracranial tension, diffuse pattern of intracranial calcifications, chorioretinitis, and elevated CSF proteins, you should consider congenital infection, specifically toxoplasmosis. Maternal infection is most commonly acquired through the ingestion of undercooked meat and meat products, fruits and vegetables that have been contaminated with soil, and unfiltered contaminated water. Another common cause is contact with parasites while handling and cleaning cat litterboxes. The acute infection in the mother is either asymptomatic or non-specific. Pregnant women with a monoucleois-like illness and negative heterophile antibodies should undergo toxoplasmosis testing.

A 26-year-old HIV-positive man presents after a series of strange dreams and lack of concentration. He started on antiretrovirals 1 week ago. For his HIV infection, he takes zidovudine, lamivudine, and efavirenz. For pneumocystosis prophylaxis, he takes trimethoprim/sulfamethoxazole. He also takes a multivitamin. Question Highlights What medication is probably causing the patient's symptoms? 1 Zidovudine 2 Lamivudine 3 Efavirenz 4 Multivitamin 5 Trimethoprim/sulfamethoxazole

Correct Answer: Efavirenz Efavirenz is a non-nucleoside reverse transcriptase inhibitor likely causing the side effects this patient is experiencing. The side effects of this medication are primarily neurologic, and patients will often present with strange dreams, lack of concentration, and occasionally delusions and mania. These effects typically wane over time, usually in a month.

A 10-year-old boy presents with swelling on his face that has been progressively increasing in size. He is an immigrant from East Africa. On examination, he has mild pallor and large swelling involving his right maxilla. A biopsy taken reveals a starry sky pattern of lymphocytes. 1 Hepatitis B virus 2 Human papilloma virus 3 Schistosoma hematobium 4 Epstein Barr virus (EBV) 5 Human T-cell lymphotropic virus type 1

Correct Answer: Epstein Barr virus (EBV) The clinical presentation is suggestive of Burkitt's lymphoma, a highly malignant form of non-Hodgkin's lymphoma associated with the Epstein-Barr virus (EBV). It is common in children in Central and East Africa. Patients may present with a rapidly enlarging jaw or abdominal mass. Histology reveals a "starry sky pattern" of rapidly proliferating malignant lymphocytes. Cerebrospinal fluid cytology should be included as part of the initial evaluation, as it has a high propensity to metastasize to the central nervous system. Treatment is by combination chemotherapy with meningeal prophylaxis.

A 30-year-old man presents with a 2-month history of coughing and a 2-day history of coughing blood. He has been losing weight and sweating at night. On physical examination, the patient appears wasted and tachypneic with bronchial breath sounds in the right upper lobe and crepitations in the left upper lobe and right mid-zone. His direct sputum result comes back positive for acid-fast bacilli with Ziehl-Neelsen stain. His sputum is sent for culture and treatment is started for his condition. After starting the medication, he notices he is unable to distinguish between red and green colors. Question Highlights What treatment medication for his condition would cause this? 1 Isoniazid 2 Rifampin 3 Pyrazinamide 4 Streptomycin 5 Ethambutol

Correct Answer: Ethambutol The correct response is ethambutol. This patient has all the signs and symptoms of pulmonary tuberculosis (TB). Direct sputum examination by Ziehl-Nielsen stain also helps the diagnosis, but it is still not confirmatory. Sputum needs to be cultured to check what kind of mycobacterium is causing this disease. It is important to start the treatment as soon as the culture is sent.

A 24-year-old man is brought to the emergency room in shock. A quick history from his girlfriend reveals that he has had a "blister on his left foot" for the past couple of days. According to the girlfriend, the patient developed a fever earlier in the day; he felt weak and eventually collapsed. He last passed urine the evening prior to presentation. On examination, his BP is 70/40 and pulse is 130/minute; his hands feel cold and clammy. Except for a swollen left foot, systemic examination is normal. His lab values are as follows: Total WBC count: 21,000/mm3 Neutrophils: 55% Lymphocytes: 25% Hemoglobin: 11.0 g/dL CRP: 165 mg/L Serum Creatinine: 2.3 mg/dL Urine Myoglobin: positive Serum K: 5.9 Meq/dL Serum Na: 133 Meq/dL ECG: sinus tachycardia Question What is the critical component in management of this patient? 1 Administration of IV calcium gluconate 2 Low-dose dopamine infusion 3 Broad-spectrum antibiotics 4 Tetanus prophylaxis with immunoglobulin administration 5 Extensive early surgical debridement

Correct Answer: Extensive early surgical debridement The history, clinical picture, and lab values point to a diagnosis of necrotizing fasciitis, which is one of the most devastating surgically managed infections. The infection is most commonly polymicrobial, (Type I); occasionally, it is monopathogenic (Type II). Causative agents include Group A Streptococcus, Staphylococcus aureus, Clostridium perfringens, Bacteroides fragilis, and Aeromonas hydrophila. Small, seemingly insignificant trauma may be the inciting factor. Predisposing conditions include immunocompromised patients, diabetes, malnutrition, and recent surgery. The diagnosis is enhanced by the use of the LRINEC score, developed from a retrospective database. The scoring criteria are as follows: CRP (mg/L) ≥150: 4 points WBC count (×103/mm3) <15: 0 points 15-25: 1 point >25: 2 points Hemoglobin (g/dL) >13.5: 0 points 11-13.5: 1 point <11: 2 points Sodium (mmol/L) <135: 2 points Creatinine (umol/L) >141: 2 points Glucose (mmol/L) >10: 1 point A value of over 6 indicates the possibility of necrotizing fasciitis. Surgical debridement is the treatment of choice, and it must be done aggressively and early in the course of the disease. Patient outcomes depend on the speed with which the debridement is done.

An 8-year-old girl presents with a 3-day history of fever, generalized muscle weakness, bilateral knee pain, and chest pain. You suspect acute rheumatic fever (ARF). Question What illness, contracted about 1 month ago, would support your suspicion? 1 Proteus mirabilis infection 2 Group A Streptococcus infection 3 Helicobacter pylori infection 4 Haemophilus influenza infection 5 E. coli infection

Correct Answer: Group A Streptococcus infection The correct answer is group A Streptococcus infection, as this type of infection is a prerequisite to the development of ARF. Patients typically experience pharyngitis about 2-4 weeks earlier than the onset of symptoms associated with ARF. In addition to the preceding infection, there are other criteria (Jones criteria) required to diagnose a patient with ARF. The major Jones criteria include carditis, erythema marginatum, subcutaneous nodules, chorea, and arthritis. The minor Jones criteria include fever, polyarthralgias, reversible prolongation of the PR interval on EKG, history of rheumatic fever, rapid erythrocyte sedimentation rate, and a history of streptococcal infection. Either 2 of the major criteria or 1 major and 2 minor criteria are required for the diagnosis of ARF.

A 30-year-old immigrant worker presented 4 weeks ago with a chronic cough, blood-stained sputum, and night sweats. His PPD was 15 mm and pulmonary tuberculosis was diagnosed. Treatment was started at that time and today he is back for a checkup with the complaint of "pins and needles" sensation in his hands. Question Highlights What drug is causing this type of side effect? 1 Pyrazinamide 2 Ethambutol 3 Rifampicin 4 Streptomycin 5 Isoniazid

Correct Answer: Isoniazid The correct response is isoniazid. This patient has typical symptoms of peripheral neuropathy. Important side effects of tuberculosis drugs are: Isoniazid: Hepatitis, peripheral neuropathy (pyridoxine is the treatment for peripheral neuropathy) Rifampicin: Hepatotoxic, hypersensitivity reactions, red coloring of the urine and other secretions (saliva, tears, stool) Pyrazinamide: Hepatotoxic (rare), hyperuricemia Ethambutol: Optic neuritis, difficulty distinguishing between blue and green Streptomycin: Ototoxic, nephrotoxic

A 33-year-old woman comes to your office after a 6-month sabbatical working in caves in the eastern part of the South America. Upon questioning, the patient reports fever, chills, productive cough, and joint stiffness that started 1 month before her return. Physical exam reveals 3 ulcerated lesions on her inner cheek. Question What is your treatment recommendation? 1 Corticosteroid 2 Itraconazole 3 Penicillin 4 Amphotericin B 5 Supportive treatment

Correct Answer: Itraconazole The correct response is itraconazole. Histoplasmosis is a chronic respiratory infection caused by inhaling the spores of the fungus Histoplasma capsulatum found in bird and bat droppings common along river valleys. Most cases are mild or asymptomatic. Risk factors include travel or residence in central/eastern United States or South America, environmental or occupational exposure to droppings of chickens, bats, or blackbirds, pre-existing COPD (chronic obstructive pulmonary disease), and immunocompromised people. Symptoms include fever, chills, cough (with mucus or pus), skin lesions, and joint stiffness. The associated skin lesion usually presents as a lesion on the mouth or inner cheek as a papule; it may ulcerate. First line treatment is Itraconazole 200 mg 3 times daily for 3 days and then 200 mg once or twice daily for 6-12 weeks for patients who continue to have symptoms for 11 months.

A 2-year-old boy presents to your office. He is from a poor rural family and has not had regular healthcare since birth. He is experiencing a childhood exanthematous disease that involves a maculopapular rash and a fever. It started 7 days ago. He now has corneal ulcers and pneumonia. Question What are the classic prodromal signs of his suspected diagnosis? 1 Fever, barky cough, otalgia, conjunctivitis, and maculopapular rash 2 Rash on hands and feet, sore throat, coryza, fever, and cough 3 Koplik's spots, coryza, fever, cough, and conjunctivitis 4 Herald's patch, fever, hematuria, pruritic rash, and conjunctivitis 5 Slapped cheek appearance, coryza, fever, malaise, and maculopapular rash

Correct Answer: Koplik's spots, coryza, fever, cough, and conjunctivitis Not having the immunizations properly, living in a low socioeconomic area, and having a maculopapular rash with corneal ulcers and pneumonia as complications indicate this child has measles. The other pyrexial exanthematous diseases will not cause corneal ulcers as a complication. The measles (rubeola) virus is in the Paramyxovirus family, transmitted by respiratory droplets produced by coughing and sneezing both during the prodromal period and a few days after the rash appears. After an incubation period of 10-14 days, the classic prodromal phase for measles is characterized by fever, Koplik's spots (bright red lesions with a white central dot that are located on the buccal mucosa), and the 3 Cs (conjunctivitis, coryza, cough). All of the prodromal signs should be present and should be followed by a typical maculopapular rash to be able to diagnose measles clinically. Rash appears at the exanthematic stage and lasts approximately 5 days.

A 17-year-old girl presents with a sore throat and weakness; she has a fever of 100°F. There is cervical lymphadenopathy on physical exam, and the Monospot test is positive. After 14 days, the patient develops acute abdominal pain. During the abdominal examination, guarding is noted in the upper left quadrant. The patient is becoming increasingly pale, sweaty, and cold. Question What is the proper management in this case? 1 Intravenous fluids and observation 2 Urgent gastroscopy 3 Laparotomy 4 Colonoscopy 5 Double-contrast barium enema

Correct Answer: Laparotomy Sore throat, fever, lymphadenopathy, and a positive Monospot test confirm the diagnosis of infectious mononucleosis, an acute infection caused by EBV. Splenomegaly often occurs and predisposes the patient to rupture of the spleen. An urgent laparotomy is indicated in this case because splenic rupture can cause shock with internal hemorrhage. IV fluids and observation would not be indicated, as the patient appears unstable. Double contrast barium enema and colonoscopy would be utilized to evaluate the colon or rectum for polyps or cancer. Gastroscopy would be utilized if the patient was presenting with symptoms of a gastroesophageal tear.

A 17-year-old boy presents with pain in his wrists, elbows, and knees bilaterally. He has felt fatigued, and he has been unable to work his summer job as a cashier and bagger in his family's community grocery store for the past 2 weeks. He also reports intermittent fevers and a large rash on his back in the area of his right shoulder. All of these symptoms have emerged in the last 4 weeks after a week-long backpacking trip in upper state New York. He has no significant past medical history. His only medication is acetaminophen daily for joint pain. He does not use tobacco, alcohol, or illicit drugs. He has no known allergies. Physical examination reveals a thin male adolescent in no acute distress. Temp 99.1°F, P 100 bpm, RR 14, BP 120/70 mm Hg. Small non-tender mobile lymph nodes are palpable in the neck and axilla bilaterally. There is a large warm erythematous patch with central clearing at the patient's posterior right shoulder region; it extends across the arm and axilla and measures approximately 25 cm in diameter. There is limited range of motion in his right wrist and left elbow. There were no gross focal neurologic deficits. Question Highlights What is the most likely cause of these symptoms? 1 Lyme disease 2 Pityriasis rosea 3 Pityriasis versicolor 4 Rocky Mountain spotted fever 5 Secondary syphilis

Correct Answer: Lyme disease Lyme disease is the most likely diagnosis, given the arthritic clinical picture and history of backpacking in an endemic area. 90% of Lyme disease in the United States occurs in the Northeast or upper Midwest (New York, New Jersey, Connecticut, Rhode Island, Massachusetts, Pennsylvania, Wisconsin, and Minnesota). Classically, Lyme disease consists of three stages, although not all cases follow this sequence. Stage 1 features flulike symptoms (arthralgia, headache, malaise, and weakness) and the typical single skin lesion of erythema migrans (EM) or "bullseye" rash at the site of the tick bite. Stage 2, after a latent period, features a rash similar to the one described here and systemic symptoms similar to those of stage 1. Stage 3, after a varying prolonged asymptomatic period that ranges from months to years, features synovitis, arthritis, central nervous system impairment, dermatitis, keratitis, and neurologic and myocardial abnormalities.

A 49-year-old man presents with chronic fatigue, headache, fevers, and muscle and joint pain. He describes the initial rash occurred on his arm with a red circular rash with central clearing. He describes transient "reddish spots" that can be quite large and have appeared on his skin then faded away. His symptoms developed about 4 months ago with no apparent cause; they have gradually gotten worse with the recent addition of the musculoskeletal pains. He is married and monogamous, and he lives in a small rural community; nevertheless, he is concerned that he may have somehow contracted a communicable STD. Question Highlights What condition is causing the patient's symptoms? 1 Acute rheumatic fever 2 Alcoholic cirrhosis 3 Lyme disease 4 Malaria 5 Polymyalgia rheumatica

Correct Answer: Lyme disease The pathogenic agent of Lyme disease is the spirochete bacterium Borrelia burgdorferi passed to humans by the bite of the hard-shelled ticks of the Ixodes genus. Several days to a month after infection, a rash develops at the sight of the bite. Known as erythema migrans (EM), this erythematous lesion appears with a circular red flat rash with central clearing. This often expands over the course of several weeks. The ECM lesion gradually fades over several weeks, but new transient lesions may subsequently appear in various areas. Early signs and symptoms include general malaise and severe fatigue with fevers and chills. Headache, musculoskeletal pains, myalgias, and lymphadenopathy are common. If untreated, later phases may include neurological symptoms, cardiac dysfunction, and an asymmetrical pattern of arthralgias and arthritis that may resemble early rheumatoid arthritis.

A 3-year-old girl tells her parents that she has itching in what seems to be the perianal area. The itching is something that wakes her at night, and this is when she has complained most to her parents. Her pediatrician performs an anal swab, and microscopic examination reveals ova. Question Highlights What is the most likely recommended treatment for this patient? 1 Cefdinir (Omnicef) 2 Miconazole (Oravig) 3 Doxycycline (Vibramycin) 4 Mebendazole (Vermox) 5 Metronidazole (Flagyl)

Correct Answer: Mebendazole (Vermox) This patient has an intestinal infection with Enterobium vermicularis, commonly known as pinworms. This most commonly occurs in children, and the possible symptoms include perianal or perineal itching, dysuria, insomnia, restless sleep, and vulvovaginitis. Children complain about the symptoms—especially the itching—more during the night. The physical examination should include inspection of the perianal area, and may even include a digital rectal examination or an anal swab. Microscopic examination will reveal ova, but the female worm may also be visualized. Parents can test at home by placing clear tape over the child's perianal skin during the early morning. The treatment for pinworms should include either mebendazole (Vermox), albendazole, or pyrantel pamoate, which are all antiworm medications.

A 38-year-old male patient with HIV develops diabetes; he takes stavudine. What diabetes medication is most likely to exacerbate potential acid-base disorders of his antiviral therapy? 1 Metformin 2 Glyburide 3 Glipizide 4 Exenatide 5 Insulin

Correct Answer: Metformin Lactic acidosis is a serious and potential complication of both metformin and stavudine use. Lactic acidosis is a form of elevated anion gap metabolic acidosis. Patients with nucleotide/nucleoside reverse transcriptase inhibitor (NRTI)-induced lactic acidosis may range from having asymptomatic mild and chronically elevated lactate levels to life-threatening acute elevations with associated cardiac and hemodynamic complications. Hyperventilation, abdominal pain, change in consciousness, leukocytosis, hyperphosphatemia, and hyperuricemia may also accompany lactic acidosis. Metformin use may also be complicated by lactic acidosis, and patients taking both stavudine and metformin who develop elevated anion gap acidosis should be evaluated for lactic acidosis.

A 24-year-old man with HIV-positive status for 2 years presents due to an ongoing chronic cough for the past 8 months. He admits to a mild fever that comes and goes during that period. A 5 lb unintentional weight loss is also discovered since his last visit to your office, which was approximately 9 months ago. He states he has noted an increased amount of breathlessness with simple activities that were never bothersome before the cough began. The patient denies smoking, and his TB test is negative. Question What organism is most likely causing this patient's signs and symptoms? 1 Mycobacterium avium complex 2 Mycobacterium bovis 3 Mycobacterium chelonae 4 Mycobacterium haemophilum 5 Mycobacterium leprae

Correct Answer: Mycobacterium avium complex This patient is most likely has a pulmonary infection secondary to Mycobacterium avium complex (MAC). This type of infection is almost indistinguishable from tuberculosis, but it causes a chronic, slowly progressive pulmonary infection in both immunocompromised and immunocompetent patients. When symptoms present, they are less severe and more chronic than a Mycobacterium tuberculosis infection. Symptoms most commonly seen include: cough, sputum production, weight loss, breathlessness, chest pain, hemoptysis, and fever or night sweats. Mycobacterium leprae leads to Hansen disease (leprosy). This disease state is rarely seen in the United States, but it is endemic in tropical and subtropical Asia, Africa, and Central/South America. Signs and symptoms are pale macular/nodular and erythematous skin lesions and superficial nerve thickening, associated anesthesia, and motor abnormalities. Bilateral ulnar neuropathy is highly suggestive of this diagnosis. Mycobacterium haemophilum, Mycobacterium bovis, and Mycobacterium chelonae are all potential causes of lymphadenitis (scrofula). These organisms are much more prevalent in Northern Europe.

A 24-year-old man presents with a 2-day history of skin rash on his back. He notes pain in his joints and tiredness. He has just returned from a camping trip. Vital signs are normal. Examination reveals an expanding lesion with a concentric circle of erythema. Question Highlights If left untreated, what is a complication of early dissemination of this condition? 1 Endocarditis 2 Myocarditis 3 Restrictive cardiomyopathy 4 Fibromyalgia 5 Endarteritis obliterans

Correct Answer: Myocarditis This patient's history and clinical picture are suggestive of Lyme disease. Lyme disease is an inflammatory disease characterized by a skin rash, joint inflammation, and flu-like symptoms; it is caused by the bacterium Borrelia burgdorferi and is transmitted by the bite of a deer tick. Early disseminated infection may cause secondary erythema migrans, disease of the nervous system (facial palsy or other cranial neuropathies, meningitis, and radiculoneuritis), musculoskeletal disease (arthralgia), and myocarditis (inflammation of the cardiac muscle) that may lead to transient atrioventricular block. If untreated, Lyme disease can cause late disseminated manifestations weeks to months after infection, including arthritis, polyneuropathy, and encephalopathy.

A 32-year-old Latinx woman, previously in good health, was brought to the emergency department by paramedics after she was found unresponsive in her home. It is unknown if she had a seizure. Past medical history is not significant, and she has no known allergies. She is not on any medications and is gravida 4, para 4, Ab 0. She is married and recently emigrated to the US from Central America. Vital signs: temperature 100.4°F, pulse 112, respirations 24, blood pressure 110/62, O2 sat 96% on room air. Physical exam reveals a well-developed woman with obtunded mental status. Cardiac exam reveals normal S1 and S2 without rub, murmur, or gallop. Lungs are clear to auscultation and percussion. Spinal tap is thought to be contraindicated. Patient is admitted to the ICU. After consultation with specialists, a tentative diagnosis is made; the patient is treated with a therapeutic trial of medication. The following morning, the patient is found to be alert, oriented, and afebrile. Lab and imaging studies show: WBC 17.2 K/mcL ESR 25 mm/hr Hgb 12.4 gm/dL Electrolytes normal Hct 37% BUN 12 mg/dL Platelets 305 K/mcL Creatinine 1.2 mg/dL Neutrophils 68% Pregnancy test Negative Lymphocytes 20% HIV immunoassay Negative Monocytes 2% Blood cultures No growth (preliminary) Eosinophils 10% EKG NSR, 1 PAC Basophils 1% Transthoracic echocardiogram Normal heart size and structure. Chest X-ray Normal heart size. No infiltrates or edema. CT brain without contrast Multiple cystic lesions. Cyst with dot sign noted. MRI brain with contrast Multiple cystic lesions. Cyst with dot sign present. Question What is the primary diagnosis? 1 CVA secondary to embolic shower 2 Metastatic cancer with multiple brain metastases 3 Neurocysticercosis 4 Toxoplasmosis 5 Tuberculous meningitis

Correct Answer: Neurocysticercosis Neurocysticercosis is the most common parasitic brain disease worldwide, and it commonly affects US immigrants. It is caused by ingestion of eggs from the pork tapeworm Taenia solis via oral-fecal contamination from infected humans. Eggs hatch in the small intestine, invade the intestinal wall, and travel to various tissues of the body where they form cysts. Neurocysticercosis refers to these cysts in the brain. The peak severity of symptoms is approximately 3-5 years following initial infection and commonly occurs as the cysts start to degenerate. Patients with neurocysticercosis can be asymptomatic or have vague symptoms such as headache or nausea. Seizure is the most common presentation. Neuroimaging studies are crucial for the diagnosis of neurocysticercosis, while clinical, epidemiologic, and lab studies provide supportive evidence. The presence of 1-2 enhancing cysts, usually 5-20 mm in diameter, and an eccentric dot representing the scolex ("head") are pathognomic. Treatment is focused on anti-epileptic medication and eradication of viable parasites.

A 50-year-old man presents for the evaluation of a 1-year history of progressive cognitive, motor, and behavioral problems. He complains of inattention, reduced concentration, slowing of processing, and difficulty changing mental sets. What started as slow movements now is clumsiness and problems with coordination. His friend states that the patient is "not himself anymore" and has become apathetic, non-communicative, and "down." He is HIV-positive and was diagnosed with AIDS 2 years ago because of the presence of Pneumocystis carinii with CD4 of 100. He had an excellent response to antiretroviral therapy, however, and his last CD4+ lymphocyte counts were normal and viral load undetectable. On examination, you find an apathetic male in mild distress. Neurological exam shows loss of coordination, unsteadiness, generalized weakness (more pronounced in legs), ataxia, and tremor. Question Highlights What should be the next diagnostic step in this patient? 1 Neuropsychological testing 2 Neuroimaging methods 3 Electroencephalography 4 Cerebrospinal fluid examination 5 CD4+ lymphocyte counts

Correct Answer: Neuroimaging methods Progressive cognitive, motor, and behavioral problems in an HIV-infected patient points to the diagnosis of AIDS dementia complex. Brain imaging is essential in the evaluation of patients with AIDS dementia complex, not only for the confirmation of the diagnosis, but also to exclude opportunistic infections (progressive multifocal leukoencephalopathy, toxoplasmosis, tuberculosis, cryptococcosis), tumors, primary CNS lymphoma, and/or the ependymal changes consistent with cytomegalovirus encephalitis. Neuroimaging in AIDS dementia complex will show cerebral—often basal—ganglia atrophy, and white-matter abnormalities (described as "fluffy," "ground-glass," or even diffuse).

A 55-year-old male firefighter suddenly develops fever, palpitations, and shortness of breath 7 days after skin transplant for severe facial burns. He also has fever resistant to intravenous antibiotics therapy introduced at the onset of fever. Because of oropharyngeal lesions, he is on parenteral nutrition. On examination, transplant shows neither signs of infections nor signs of rejection. Patient appears lethargic, with a blood pressure of 80/40, pulse rate of 120, respiratory rate of 18, and temperature of 103.4°F. Stat CBC shows neutropenia and eosinophilia. Question Highlights Why would you order a blood culture for systemic fungal infection? 1 Neutropenia 2 Intravenous antibiotics 3 Parenteral nutrition 4 Facial surgery 5 Age

Correct Answer: Neutropenia In a patient with antibiotic-resistant fevers and signs and symptoms of systemic infection, including tachycardia, dyspnea, and hypotension, you should think about systemic mycosis due to cell-mediated immune deficiency presented as neutropenia. Fever resistant to antibiotics indicates that there is inflammation; neutropenia indicates cell-mediated immune deficiency; and the presence of certain predisposing factors (severe burns, impairment of oropharyngeal mucosa, parental nutrition, use of antibacterial drugs, surgery) raises the probability of fungal infection. Most probably, blood culture will reveal the presence of Candida. Also, infectious diseases associated with eosinophilia typically include parasitic (both protozoan and metazoan infestations) and fungal diseases. Patients are at risk of fungal infections when they are on long-term antibiotic therapy, wherein antibiotics disturb the balance between microorganisms, allowing the overgrowth of fungi. Fever resistant to antibiotics should prompt you to think about causes other than bacterial infection, particularly when the wound shows no signs of inflammation.

A 43-year-old man visits the internal medicine clinic of a university hospital presenting with a 3-week history of shortness of breath, fever, and chills. Examination shows a temperature of 38.0°C. Laboratory results suggest hypoxemia with PO2 of 74. Previous history shows the patient has been HIV-1 positive for 4 years and presently has a CD4+ T-cell count of 50/mm3. A presumptive diagnosis of Pneumocystis carinii pneumonia (PCP) is made, which is confirmed by bronchoalveolar lavage. Question What would be expected from chest auscultation in this patient? 1 No findings 2 Tactile fremitus 3 Bilateral rales 4 Egophony 5 Prolonged expiration

Correct Answer: No findings The correct response is no findings. Pneumocystis carinii pneumonia (PCP) is an important opportunistic infection in patients with HIV-1 infection and CD4+ T-cell counts <200/mm3. Despite frequent radiographic findings typical of pulmonary edema and bilateral interstitial infiltrates, auscultation is usually completely normal. Diagnosis of PCP is difficult, as manifestations are often subtle and sometimes exclude respiratory symptoms. Induced sputum results are variable, with sensitivity for P. carinii detection of 30-90%. Bronchial lavage is 98-100% sensitive for P. carinii detection in persons with AIDS, and lung biopsy is seldom necessary.

A 31-year-old man presents with a tick bite. He describes locating a tick in the left axillary area while showering in the evening, and he denies that the tick was present the previous evening. He removed the tick with forceps and cleaned the wound with alcohol. Examination of the bite shows local erythema and mild induration 3-5 mm diameter. The tick is identified as an adult female Ixodes scapularis. Question Highlights What is the recommended course of management for this patient? 1 No treatment needed 2 Test tick for Borrelia burgdorferi 3 Prophylaxis with doxycycline 4 Lyme disease serology 5 Urine antigen test

Correct Answer: No treatment needed The correct response is that no treatment is needed. Lyme disease is a spirochetal infection caused by Borrelia burgdorferi and transmitted by ticks of the genus Ixodes. Lyme disease is highly endemic in the northeastern and north-central states of the US. Infection is often accompanied by the development of an expanding annular lesion (erythema migrans, or EM) at the site of the tick bite. A small amount of induration at the site of tick extraction is normal and easily differentiated from EM.

A 9-month-old female infant presents with an acute onset of a rash on her trunk. She has a 4-day history of fever up to 104°F, but the mother states her daughter has no fever today. She has had some diarrheal stools, but no vomiting. No coughing or nasal congestion has been noted. The child has previously been well. Her past medical history is unremarkable, and she is up to date on her immunizations. She attends daycare, and her mother notes that some children have been ill with non-specific febrile illnesses over the past 2 weeks. Her only medication has been ibuprofen for the fever. Physical exam shows a temperature of 98.8°F, pulse of 124 bpm, and respiratory rate of 28/min. She is alert and shows no other abnormalities. Her exam shows normal tympanic membranes in the ear and normal conjunctivae in the eye. The neck shows some shotty anterior cervical adenopathy; a normal appearing pharynx, and the skin appears with an erythematous maculopapular rash most pronounced on the trunk. Her chest is clear to auscultation, heart rhythm is regular without murmurs, abdomen is soft and non-tender, and her neurological exam is normal. Question Highlights What is the most appropriate intervention for this patient? 1 Draw measles titers of acute and convalescent sera. 2 Administer oral acyclovir. 3 Observe the child and reassure the parent. 4 Draw a complete blood count and blood cultures. 5 Treat presumptively with oral antibiotics.

Correct Answer: Observe the child and reassure the parent. The clinical syndrome in this vignette is typical for roseola infantum. Typically, the patient will have a moderate-to-high fever for 3-5 days, followed by defervescence and the outbreak of an erythematous macular or maculopapular rash that usually begins on the trunk and neck, then spreads to extremities and face. The rash is usually gone within 1-2 days. Human herpesvirus 6 is the etiologic agent of the vast majority of cases. Once the rash has appeared and the child appears well, the only treatment is observation of the child and reassurance for the parents in regard to the benign nature of the condition.

A 32-year-old Hispanic woman presents with a 3-day history of vaginal pruritus. She is worried she has another infection. She was treated with penicillin 2 weeks ago for group A Streptococcus pharyngitis. The patient reports occasional sinus and urinary tract infections and always struggles with vaginal symptoms afterward. She has episodes of vaginal pruritus and thick white discharge approximately 3 times per year. She usually returns to her urgent care clinic for evaluation and treatment, then her symptoms resolve. She has no chronic medical conditions. She is non-obese and is not pregnant. On exam, the vaginal mucosa is inflamed and coated with thick clumpy white discharge. On a wet mount slide treated with potassium hydroxide, you see pseudohyphae. The patient would like treatment for her current vaginal symptoms and advice in preventing her symptoms in the future. Question Highlights What is the best intervention for prevention of the patient's current condition? 1 Advise the patient to drink cranberry juice. 2 Advise the patient to eat yogurt. 3 Avoid prescribing antibiotics for this patient in the future. 4 Offer fluconazole in combination with antibiotics if indicated. 5 Prescribe nitrofurantoin for use after intercourse.

Correct Answer: Offer fluconazole in combination with antibiotics if indicated. This patient has a vaginal yeast infection. It would be most reasonable to offer fluconazole (an antifungal) to be taken in combination with antibiotics if indicated in the future. Recent use of antibiotics is a risk factor for development of a vaginal yeast (usually Candida) infection because the normal protective flora is diminished. Increased duration of antibiotic use is another risk factor for vaginal candidiasis. Appropriate antibiotic prescribing guidelines should be followed. Several other conditions, such as AIDS, diabetes, and pregnancy, can predispose women to frequent vaginal yeast infections. This patient should be evaluated to ensure she does not have any of these other risk factors. If her symptoms do not resolve with treatment, she could be treated for chronic vaginal candidiasis with lengthier regimens of antifungals.

A 52-year-old man is hospitalized for a left lower lobe pneumonia. The patient is HIV positive with a CD4 count <100/uL and is known to be neutropenic. He also has type 2 diabetes mellitus and diabetic nephropathy. He is started on ciprofloxacin, ceftriaxone, and clindamycin. During treatment, the physician notes a white coating of the tonsils and oropharynx. The physician obtains scrapings of the white coating. The sample is observed microscopically and confirms the presence of fungal hyphae and budding. The physician suspects a candidal infection of the oropharynx. Question What is the next step in patient management? 1 Oral metronidazole 2 Oral amphotericin B 3 Oral fluconazole 4 Topical nystatin 5 Oral itraconazole

Correct Answer: Oral fluconazole This patient has a candidal infection. In an immunocompromised patient, oral fluconazole is the preferred choice. Topical nystatin, clotrimazole, or miconazole are commonly used to treat uncomplicated cases of oral candida infections. The morbidity rate of candidiasis with symptoms (once bloodborne) is high in hospitalized patients. This becomes more serious in the presence of an abdominal abscess, endocarditis, endophthalmitis (seen as cotton-wool exudates on funduscopic exam), myocarditis, esophagitis, pneumonia, peritonitis, and thrush. The presence of Candida in this patient cannot be ignored due to the potential for prolonged hospital stay and subsequent high health costs; there is rapid progression of the organism once bloodborne; there is also high mortality rate.

A 6-year-old boy presents with a 2-day history of fever followed by cough, coryza, and conjunctivitis. He has also developed a rash that started behind the ear and is starting to spread downwards towards the trunk. On examination, you notice erythematous maculopapular blanching rash with coalescence in some areas. The palm and soles are spared. On oral examination, you notice 1-3 mm bluish lesions surrounded by an erythematous base. He is not up to date with his immunizations. Question Highlights What virus is most likely responsible for this patient's condition? 1 Paramyxovirus 2 Togavirus 3 Human parvovirus B19 4 Human herpesvirus 6 5 Varicella virus

Correct Answer: Paramyxovirus The patient has rubeola/measles, which is caused by a paramyxovirus. It is characterized by truncal rash, centrally distributed, which usually starts at the hairline and moves down the body, sparing the palms and soles. It begins as discrete erythematous lesions that become confluent as the rash spreads. Koplik spots (1-3 mm white or blue lesions on an erythematous base on the buccal mucosa) are pathognomonic for measles and are generally seen during the first 2 days of infection. This patient has both the typical rash and Koplik spots, which help make the diagnosis of measles.

An 18-month-old infant presents with a 5-day history of fever of 104°F. On physical examination, you note a mildly irritable infant who has not been feeding well. There are no other clinically significant findings. You prescribe acetaminophen (Children's Tylenol) and tell the mother to monitor the infant's fever for the next few days; if the fever goes down, everything should be fine. The mother calls the next day and says that the fever has stopped, but a rash has developed, and she is concerned. The infant examination reveals a diffuse fine maculopapular rash. Presently, the child does not appear ill. Question What is the most likely diagnosis? 1 Rubella 2 Rubeola 3 Erythema infectiosum 4 Roseola 5 Chickenpox

Correct Answer: Roseola The clinical picture is suggestive of roseola. Roseola is a benign illness in humans caused largely by the human herpesvirus 6, but other viruses can also cause it. It is a major cause of acute febrile illness in young children. The most prominent feature is a fever lasting up to 3-5 days and often exceeding 39.5°C (103.1°F). The fever subsides abruptly, and a blanching rose-pink maculopapular rash appears for 1-2 days.

A 13-month-old boy presents with a rash. The mother reports that he has had high fevers over the past 4 days, but he has not had a fever for the past 24 hours. The rash began 6 hours ago, startingt on his chest and back, spreading to his neck, face, and arms. The child does not appear to be itchy, and he has been acting normally since the fever subsided. The mother denies cough, runny nose, vomiting, and diarrhea. The only medication that the child has taken is acetaminophen. On examination, the child is happy and playful. The only physical finding is a blanching macular rash noted on the mentioned areas. Question Highlights What is the most likely diagnosis? 1 Rubella 2 Roseola 3 Measles 4 Drug hypersensitivity 5 Varicella

Correct Answer: Roseola This child exhibits the typical rash of roseola. Roseola infantum (also called exanthem subitum) is caused by Human herpesvirus 6 and occurs almost exclusively during infancy. There is usually no prodromal period. The illness begins with high temperatures (averaging 103°F) for 3-5 days; the fever typically resolves abruptly. The rash appears 12-24 hours after fever resolution. The rash of roseola is rose-colored and begins as discrete small slightly raised pink lesions on the trunk and spreads to the neck, face, and proximal extremities. The rash is not pruritic, and no vesicles or pustules develop. Roseola is self-limited, and treatment is supportive only (e.g., antipyretics during the febrile phase).

A 27-year-old man presents with the "flu." He says that he has felt feverish, tired, and mildly nauseated for the past few weeks. He mentions a headache and non-pruritic rash. He denies any past medical history or medication use. On exam, he is afebrile. Examination reveals diffuse mild lymphadenopathy with mild hepatosplenomegaly; his soft palate has a few scattered shallow ulcerations. The palmar and plantar surfaces have a scattered papular rash that is copper colored, with a few papules on the flexor surfaces of the arms, legs, and trunk. Laboratory evaluation reveals hemoglobin of 12.8 g/dL, hematocrit of 38%, and white blood cell count of 11.1 x 103/ìL. Question What is the most likely diagnosis? 1 Influenza 2 Rocky Mountain spotted fever 3 Hand-foot-and-mouth disease 4 Secondary syphilis 5 Streptococcal pharyngitis

Correct Answer: Secondary syphilis Syphilis is a sexually transmitted disease caused by infection with the spirochete Treponema pallidum. Acquired syphilis begins as T. Pallidum enters through the mucous membranes, generally after sexual contact. The spirochete infects the regional lymph nodes and then rapidly spreads throughout the body. The primary stage of syphilis is characterized by a primary painless lesion known as the chancre with regional lymphadenopathy. This usually appears 3-4 weeks after initial exposure. Secondary syphilis is characterized by the development of cutaneous rashes and mild constitutional symptoms. The cutaneous manifestations typically include a symmetric papular non-pruritic rash along the flexor, palmar, and plantar surfaces. Mild anemia, hyperbilirubinemia, and albuminuria may be present, often with eroding lesions on the mucous membranes (mouth, vagina, penis, or rectum): grayish-white patches with a red center. The cutaneous rashes of secondary syphilis appear 3-6 weeks after the end of the primary stage, and they are most pronounced after 3-4 months. This stage will resolve spontaneously. Tertiary or late-stage syphilis may manifest years after initial infection and is characterized by involvement of the nervous and cardiovascular systems.

A 26-year-old woman presents with diagnosed with primary tuberculosis and wants to discuss treatment options. Initial labs come back with mild anemia, positive HCG, and elevated cholesterol. All other labs are within normal range. Question What drug should be avoided in this patient? 1 Isoniazid 2 Rifampin 3 Ethambutol 4 Streptomycin 5 Pyrazinamide

Correct Answer: Streptomycin Streptomycin is contraindicated in pregnancy because it may cause congenital defects. Isoniazid, rifampin, and ethambutol are considered safe to use during pregnancy.

You are covering a weekend shift at a local inner-city free clinic. A 41-year-old woman presents with what she describes as "a cough." The patient states that this cough will not go away and has been present for several months, to the point that the patient is coughing up blood for the last 4 days. She admits to unintentionally losing about 10 pounds in the last 2 months. Progressively worsening fatigue, night sweats, and chills are also present. She is a non-smoker and lives in a rent-controlled apartment with 3 adults and 4 kids. Question Given the most likely diagnosis and need for confirmation of the diagnosis, what laboratory study is viewed as the gold standard and most sensitive for confirming the diagnosis? 1 QuantiFERON-TB Gold 2 Tuberculin skin test 3 Chest radiograph 4 Acid-fast bacilli smear 5 TB culture

Correct Answer: TB culture Tuberculosis (TB) is a chronic mycobacterial infection that most commonly affects the lungs but can spread to other organs. TB is usually spread person to person via droplets after a cough or a sneeze. There are many groups of patient who have a higher risk of developing a TB infection, including those who live/work around people who have TB, medically underserved populations, and patients that reside in a group setting, such as a nursing home or jail. Symptoms of TB initially may be only a non-productive cough that progresses to hemoptysis (coughing up blood). Other signs and symptoms include chest pain, fatigue, loss of appetite, unintentional weight loss, fever, and chills or night sweats. To confirm the diagnosis of TB, a TB culture should be ordered and completed. An acid-fast bacilli (AFB) smear is usually completed to help support the diagnosis of TB, but it cannot indicate diagnosis itself. AFB smear may also be used to monitor treatment of TB once it has been initiated.

A 29-year-old man presents 1 hour after stepping on a sharp nail. The nail penetrated deep into his foot; his last tetanus immunization was at age 6. Question Highlights What treatment would be most appropriate? 1 Tetanus immunoglobulin only 2 Tetanus toxoid only 3 Tetanus immunoglobulin plus toxoid 4 Tdap vaccine plus antibiotics 5 Antibiotics only

Correct Answer: Tdap vaccine plus antibiotics This patient has not received a tetanus booster for over 10 years. Current immunization schedule includes a primary course of 3 doses of DTaP (diphtheria, tetanus inactivated toxoids, and acellular pertussis) given from 2 months to 5 years. A booster should be given 10 and 20 years after the primary course. If more than 5 years have elapsed since the last dose, a booster dose of Tdap (tetanus, diphtheria toxoid, acellular pertussis) is indicated. This vaccine is recommended for children over 7 and adults. Tdap is preferred to Td (tetanus and diphtheria toxoid only) because of the resurgence of pertussis infections due to waning immunity. In children under 7, DTaP or DT (if pertussis vaccine is contraindication or allergy is present) is the appropriate therapy.

A 27-year-old woman who is 18 weeks pregnant states that her 3-year-old daughter was just diagnosed with erythema infectiosum (Fifth disease). An antibody test is ordered, and the woman is found to be seronegative. She is healthy and has no signs or symptoms of parvoviral infection. 2 weeks later, the test is repeated and the patient is IgM-positive. Question What is the significance of this test result with regard to the patient's fetus? 1 The patient has developed protective immunity that will also protect the fetus. 2 There is a 75% chance the fetus has been or will become infected during pregnancy. 3 The patient should undergo amniocentesis to determine if the virus has crossed the placenta. 4 The patient should undergo serial fetal ultrasounds to monitor for signs of hydrops fetalis. 5 The fetus is not at risk of becoming infected because the virus cannot cross the placenta.

Correct Answer: The patient should undergo serial fetal ultrasounds to monitor for signs of hydrops fetalis. Erythema infectiosum/Fifth disease (FD) is a common childhood exanthem caused by parvovirus B19. FD is spread by respiratory secretions and often preceded by a prodrome of low-grade fever, malaise, pharyngitis, and coryza. FD is readily distinguished from other eruptions by a characteristic "slapped-cheek" rash. This presentation is notable for a bright red macular appearance that favors the malar surfaces sparing the bridge, orbits, and mouth. Within 1-2 days, another rash develops, characterized by symmetric eruptions and blotchy areas with a reticular or lacy pattern.

A 32-year-old woman is brought to the emergency room with sudden onset of fever, headache, sore throat, profuse watery diarrhea, vomiting, and lethargy; symptoms started in the morning. On physical examination, she is slightly confused; her temperature is 39°C (103°F), her blood pressure is 100/50 mm Hg, and she has diffuse sunburn like an erythematous rash. When the emergency doctor is trying to find out if she is pregnant, she mentions that her period started 2 days ago. Question Highlights What is the most likely diagnosis? 1 Scarlet fever 2 Rocky Mountain spotted fever 3 Meningococcemia 4 Toxic shock syndrome 5 Food poisoning

Correct Answer: Toxic shock syndrome This is a typical case presentation of toxic shock syndrome (TSS). The patient is a young woman; she is menstruating, and the disease had a sudden abrupt onset with rapid deterioration. TSS is caused by toxic shock syndrome toxin-1 (TSST-1) produced by Staphylococcus aureus. TSST-1 is a pyrogenic exotoxin, which causes fever, multiple organ dysfunction, rash, hypotension, syncope, and shock. TSS can be seen in menstruating women who use tampons, individuals with wound infections, or patients with nasal packing to stop bleeding from the nose.

A 54-year-old man presents after having a generalized seizure. The patient is HIV-positive, but he has been unable to afford antiretroviral therapy since losing his job 2 years ago. Other than cachexia, the physical exam is unremarkable. Upon further inquiry, the patient also notes that he has become short-tempered and hypercritical; at times he seems confused. An MRI of the brain is performed, and it reveals several cortical ring-enhancing lesions. Question What is the most likely diagnosis? 1 AIDS dementia complex 2 Cryptococcal meningitis 3 Cytomegalovirus encephalitis 4 Progressive multifocal leukoencephalopathy 5 Toxoplasma encephalitis

Correct Answer: Toxoplasma encephalitis The patient's symptoms and MRI findings are most consistent with the diagnosis of toxoplasmic encephalitis. Toxoplasmosis is the most common cerebral mass lesion among HIV-positive patients. Infection with the Toxoplasma gondii parasite is relatively common and usually asymptomatic. Reactivation occurs in HIV-positive patients due to failing cellular immunity, and it causes a multifocal necrotizing encephalitis. Seizures may be the initial manifestation of central nervous system (CNS) infection; other common clinical manifestations include focal neurologic deficits, e.g., impaired speech and hemiparesis. Personality change, lethargy, headache, and confusion are also observed. The MRI in patients with toxoplasma encephalitis characteristically reveals multiple, ring-enhancing lesions with surrounding edema; these lesions usually occur bilaterally in the frontal and parietal cortices.

A 20-year-old primigravida woman at 12 weeks gestation presents with a 2-day history of low-grade fever and swelling in her neck. She does not have any significant medical history and denies previous blood transfusion. On questioning, she states that she is not sexually promiscuous and that she is living with her husband and their pet cat. She is a homemaker and spends her free time gardening. She has received all immunizations, and they are up-to-date. She also states that she has abstained from sex since learning of her pregnancy 2 months ago. On examination, her vitals are temp 99°F, PR 88/min, BP 110/70 mm Hg, RR 20/min. She also has painless prominent cervical lymph nodes. Abdominal examination reveals a just-palpable uterus. Question Highlights The fetus is at increased susceptibility to what infection? 1 Treponema pallidum 2 Cytomegalovirus 3 Rubella 4 Toxoplasma gondii 5 Herpes simplex virus

Correct Answer: Toxoplasma gondii The patient's history (gardening and presence of cat) and the clinical presentation are indicative of toxoplasmosis in the mother. This specifies a higher fetal susceptibility to infection by T. gondii than infection by T. pallidum, Cytomegalovirus, rubella, or herpes simplex virus. Toxoplasma gondii is a protozoan parasite that causes toxoplasmosis. Infection mainly occurs by the ingestion of food or water contaminated with oocysts shed by cats or by eating undercooked or raw meat containing tissue cysts. Primary infection (toxoplasmosis) is usually subclinical, but it manifests in some as cervical lymphadenopathy with low-grade fever or ocular disease. Infection acquired during pregnancy may cause severe fetal damage. Congenital toxoplasmosis occurs by vertical transmission from a recently infected pregnant woman to the fetus. Severe fetal consequences can occur when the transmission is closer to conception. The clinical manifestations include the classic triad of chorioretinitis, hydrocephalus, and intracranial calcifications. Other manifestations include anemia, jaundice, thrombocytopenia, microcephaly, convulsions, spasticity and palsies, intellectual disability, and learning disabilities.

A 25-year-old man develops clinical signs of bacteremia in the hospital. Examination reveals erythema, tenderness, and a slight purulent discharge around the insertion site of a central venous catheter. Gram stain of discharge shows gram-positive cocci in grape-like clusters. Culture sensitivity of the fluid showed methicillin-resistant Staphylococcus epidermidis. Question What is the most appropriate antibiotic therapy? 1 Cloxacillin 2 Cefazolin 3 Sulfamethoxazole/trimethoprim 4 Vancomycin 5 Penicillin

Correct Answer: Vancomycin Staphylococcus epidermidis is a normal inhabitant of the skin, upper respiratory tract, and the gastrointestinal tract. It is an opportunistic pathogen; it requires a break in the skin or mucosal surfaces and the body defenses to establish infection. The skin penetration of these organisms is through artificial prostheses, IV lines, or through intraperitoneal catheters. It produces viscous slime that helps in the adherence to plastic and foreign surfaces. Infections due to contamination of the surgical site by skin organisms or an exogenous source (e.g., vascular access devices) with bacteremia are characteristic. Vancomycin is the drug of choice in methicillin-resistant S. epidermidis, and it is administered as 1 g or 15 mg/kg IV every 12 hours. Adverse reactions associated with vancomycin include fever, rash, phlebitis, neutropenia, nephrotoxicity, auditory toxicity, interstitial nephritis, and several infusion-related reactions.

An 18-month-old child presents with a 2-day history of fever that is currently 101°F rectally. You symptomatically treat the patient and ask the mother to return if the condition worsens. he mother returns 2 days later because the child has developed small red spots that became bumps and are now blisters. The mother also noted the child was scratching the lesions. Physical exam reveals macules, papules, and vesicles are on the face and thorax bilaterally. Each vesicle resides on its own erythematous base. Question What is the most likely diagnosis? 1 Shingles 2 Ramsey-Hunt syndrome 3 Erythema infectiosum 4 Primary herpes simplex 5 Varicella

Correct Answer: Varicella The clinical picture is suggestive of a varicella infection. Signs and symptoms include fever and malaise, which are mild in children. The rash usually begins on the face and trunk and then spreads to the extremities. The lesions are pruritic; they appear as maculopapular, then become vesicles, then pustular, and then they will crust over. All forms of the lesions can be seen at the same time. A classic description of primary varicella lesions is "dewdrop on a rose petal," indicating that each vesicle resides on an erythematous base.

A 21-year-old man presents with acute onset of pleuritic chest pain accompanied by 2-3 days of fever, chills, arthralgias, and myalgias. Upon further questioning, the patient notes that he had a severe sore throat and fever 4 weeks ago, but he was not evaluated for these symptoms. Physical examination reveals a febrile patient in mild distress. A systolic murmur is noted in the left fourth/fifth intercostal space that radiates to the left axilla. A friction rub is also appreciated on exam. Laboratory results reveal an elevated erythrocyte sedimentation rate (ESR) and antistreptolysin antibodies. Question What is the most appropriate initial management of this patient? 1 Tetracycline 2 Ciprofloxacin 3 Amantadine 4 Aspirin 5 Prednisone

Correct Answer: Aspirin This patient most likely has acute rheumatic fever, systemic immune process that is often a complication of undertreated b-hemolytic streptococcal infection of the throat, resulting in inflammatory changes in the heart, skin, joints, and other tissues. Clinical presentation of acute rheumatic fever is often an acute febrile illness and a migratory polyarthritis of the larger limb joints. Cardiac symptomatology is less common but can manifest as murmurs or a friction rub, indicating valvular and pericardial involvement, respectively. The diagnosis of acute rheumatic fever is based on clinical features plus evidence of a preceding streptococcal infection. The presence of two major criteria—or one major and two minor criteria—establishes the diagnosis. Major criteria include: Carditis—including evidence of pericarditis, cardiomegaly, congestive heart failure, or mitral/aortic valvular disease Erythema marginatum—a rash consisting of rapidly enlarging macules that assume a ring-like or crescent shape Subcutaneous nodules—palpable small firm non-tender nodules that present primarily over bony prominences, similar to rheumatoid nodules Sydenham chorea—involuntary choreiform movements of the face, tongue, and upper extremities Migratory polyarthritis (joint inflammation that changes in location) involving the large joints Minor criteria include fever, arthralgias/myalgias, previous diagnosis of rheumatic fever or rheumatic heart disease, evidence of systemic inflammation (elevated ESR or C-reactive protein), plus supporting confirmation of recent streptococcal infection (positive throat culture or elevated anti-streptococcal antibody titers). Treatment of acute rheumatic fever is primarily bedrest and supportive therapy. Salicylates (e.g., aspirin) are usually adequate to markedly reduce fever, joint pain, and swelling. Adults may require large doses of aspirin while children are treated with lower doses.

A 28-year-old woman presents with malaise. She is known to be HIV positive. Her CD4 count is unchanged at 350 cells/field, and her viral count is undetectable. She is afebrile and has a normal exam. She takes zidovudine, indinavir, potassium, hydrochlorothiazide, and glyburide. Workup shows: Serum bicarbonate 20 meq/L Serum sodium 140 meq/L Serum chloride 100 meq/L Serum lactate 6 mmol/L Serum potassium 4.2 meq/L Whole blood glucose 85 mg/dL HemoglobinA1C 6.2% Hemoglobin 13.5 g/dL( unchanged) Question Highlights What medication is likely causing her elevated lactate? 1 Hydrochlorothiazide 2 Glyburide 3 Indinavir 4 Zidovudine 5 Potassium

Correct Answer: Zidovudine Lactic acidosis is a known complication of zidovudine use. Zidovudine is a nucleoside analog reverse-transcriptase inhibitor (NRTI) used in the anti-retroviral treatment of AIDS and HIV. NRTI are thought to cause mitochondrial toxicity, leading to lactic acidosis. Lactic acidosis is a form of elevated anion gap metabolic acidosis. Patients with NRTI-induced lactic acidosis may range from having asymptomatic mild and chronically elevated lactate levels to life-threatening acute elevations (Berns) with associated cardiac and hemodynamic complications.

A 4-year-old boy presents with a 1-month history of weight loss, fevers, cough, and night sweats. He and his family moved to the United States from Africa 3 months ago. He is a thin pale boy in no acute distress. His heart rate and rhythm are regular, his lungs are clear to auscultation, and he has no organomegaly. Question Highlights What initial test would most likely have the most value? 1 Hepatitis B surface antigen 2 Tuberculin skin test 3 Serum blood culture 4 Rapid plasma reagin (RPR) 5 Schistomsoma serologic testing

This boy presents with classic symptoms of tuberculosis. Clinical manifestations often appear 1-6 months after infection, which corresponds to the timing of the child's recent emigration from a high-risk continent. The CDC suggests that TB diagnosis in the pediatric population is challenging, as children are less likely to have a positive result. They recommend using a combination of positive tuberculin skin test, chest X-ray, and clinical signs and symptoms for diagnosis. The tuberculin skin test consists of 5 tuberculin units of purified protein derivative injected intradermally into the forearm. Measurement of the resulting induration indicates the likelihood of tuberculosis infection.

A 31-year-old HIV-positive woman presents for ongoing care. She was diagnosed with HIV 2 years ago, and she began antiretroviral therapy. Her CD4 T cell count is 400 cells/mL, and she has a history of oral candidiasis. As part of her evaluation, a tuberculin skin test (TST) is performed using 5 TU of purified protein derivative (PPD). The test site is examined 48 hours later and the skin reaction is measured. Question Highlights What is the minimum diameter of induration at which this test result should be considered positive in this patient? 1 2 mm 2 5 mm 3 10 mm 4 15 mm 5 20 mm

Correct Answer: 5 mm Persons with HIV should be tested yearly for tuberculosis using the purified protein derivative (PPD) skin test (Mantoux test). In those with HIV, and in certain other cases (refer to the table), an induration ≥5 mm is considered positive. Preventive therapy should be prescribed for all patients having a positive PPD. Those with a positive skin test (or high-risk exposure) should undergo prophylaxis. A common regimen consists of isoniazid (INH) and pyridoxine daily, usually for at least 1 year. CDC recommends INH (300 mg/day) for a period of 12 months to any HIV-infected persons with positive TST (≥5 mm) and supplemental pyridoxine (25-50 mg/day) to prevent peripheral neuropathy. Both isoniazid-resistant and multidrug-resistant strains of Mycobacterium tuberculosis are becoming more prevalent. Classifying positive TST reactions: Interpretation of the tuberculin skin test*: Induration (dia.) Positive in persons with ≥5 mm - HIV infection - Persons with chest X-ray findings consistent with prior TB - Close contacts of a person with infectious TB - Patients with organ transplant and other immunosuppressed persons ≥10 mm - Medical risk factors such as chronic renal disease, diabetes, gastrectomy, and silicosis - Residents/employees of high-risk congregate settings (jails, nursing homes, hospitals, and other long-term facilities for elderly populations) - IV drug users - Mycobacteriology laboratory personnel ≥15 mm - Healthy persons without known risk factors * 5 TU PPD

A healthy couple presents for an evaluation before traveling to the Dominican Republic; they leave in 1 month and will stay for 4 weeks. The CDC lists the Dominican Republic as a malaria-endemic area, but it is not considered to have a resistant strain of Plasmodium falciparum. Question Highlights What is the best advice for this couple? 1 "You should both take chloroquine weekly starting 1 week before travel." 2 "If you get any mosquito bites, return to the US immediately for malaria treatment." 3 "Be aware that malaria typically causes a mild 3-4 day self-limiting diarrheal illness." 4 "If you take prophylactic medications for malaria, you can discontinue them upon arrival if you have no symptoms." 5 "You should both pack prescriptions of high-dose amoxicillin in case malarial symptoms begin."

Correct Answer: "You should both take chloroquine weekly starting 1 week before travel." When there is no drug resistance to Plasmodium falciparum (one of the Plasmodium protozoans that causes malaria), weekly chloroquine is the prophylactic drug of choice. It is well-tolerated and can be dosed once weekly rather than daily (hydroxychloroquine is similar for malaria prophylaxis). Travelers should be advised of the risk of malaria, chemoprophylaxis, and personal protection measures. The chloroquine should be dosed weekly starting 1-2 weeks prior to travel, continuing throughout travel, and discontinued 4 weeks after return from a malaria-endemic region. Atovaquone/proguanil, mefloquine, doxycycline, and primaquine can be considered for regions known to have resistant strains of P. falciparum.

A 6-month-old infant is brought in for routine vaccination. The mother saw information about a measles outbreak online. There is no known measles outbreak in the state. The mother is asking for more information about this vaccine. She would like her child to receive it now. Question What ages of administration are appropriate to advise the mother about for this vaccine? 1 6-8 months, 10 years 2 12-15 months, 4-6 years 3 1 month, 2 months, 6 months 4 11-12 months, 12-14 years 5 2 months, 4 months, 6 months

Correct Answer: 12-15 months, 4-6 years The MMR vaccine is a mixture of live attenuated viruses, administered for immunization against measles, mumps, and rubella. The current recommendation for MMR vaccine is that the first dose should be given at 12-15 months. The second dose of MMR is routinely recommended at age 4-6. It may be administered during any visit if at least 4 weeks have elapsed since the first dose and both doses are administered beginning at or after the age of 12 months. Those children who have not received the second dose at the recommended age should complete the schedule by age 11-12. The vaccine should not be given before 12 months of age because maternal antibody in the child can neutralize the virus, reducing the immune responses. Since immunity can wane, a booster dose at age 4-6 is recommended. Because it is a live vaccine, it should not be given to immunocompromised persons or pregnant women.

A 33-year-old man presents with a 2-day history of severe diarrhea and vomiting. He had been on a business trip to Asia 3 days ago, and he reports eating food bought from street vendors. He describes his stools as watery and not bloodstained. He is allergic to seafood, and he takes antacids for peptic ulcers. On examination, he is moderately dehydrated; temperature is 37°C, PR is 100, and BP is 120/60 mm Hg. Question What pathogenic organism is most likely causing his symptoms? 1 Staphylococcus aureus 2 Bacillus cereus 3 Escherichia coli serotype O157:H7 4 Vibrio cholera 5 Vibrio parahaemolyticus

Correct Answer: Vibrio cholera This clinical picture is suggestive of cholera caused by Vibrio cholerae, which is a small, gram-negative bacillus that produces an enterotoxin, stimulatating adenylate cyclase, resulting in increased secretion of fluids and electrolytes. Cholera is spread by ingestion of water, seafood, and other food contaminated by the feces of symptomatic or asymptomatic food handlers. It is endemic in parts of Asia, the Middle East, and Africa, but persons living in these areas gradually acquire a natural immunity. There is increased susceptibility to infection in persons with hypochlorhydria and achlorhydria or taking antacids, as the bacilli are sensitive to gastric acid. The incubation period is 1-3 days. Patients usually present with painless and profuse watery diarrhea and vomiting of sudden onset. The resultant severe water, sodium, chloride, bicarbonate, and potassium depletion, resulting in intense thirst, muscle cramps, hypovolemia, oliguria, and anuria with severe metabolic acidosis. If untreated, it can result in circulatory collapse. Uncomplicated cholera is self-limiting, and recovery occurs in 3-6 days. Severe cases have a high mortality rate, which is usually due to dehydration.

A 26-year-old woman presents for her second obstetric visit in the first trimester. Routine screening tests (blood typing, testing for syphilis, hepatitis, rubella immunity, and HIV) are performed; the test returns positive for HIV. She is counseled to start antiretroviral therapy and to have a cesarean delivery. Question To reduce the risk of mother-to-newborn transmission, the best drug treatment is a drug that prevents what mechanism of the infection? 1 Virus replication 2 Viral assembly 3 Fusion of virus with the host cell 4 Integration of HIV genetic material into the host chromosome 5 Binding of the HIV virion to the surface of the cells

Correct Answer: Virus replication All pregnant HIV-infected patients beyond 14 weeks' gestation should be on a highly active antiretroviral therapy (HART) regimen. With cesarean delivery and appropriate antiretroviral therapy, risk of transmission of HIV to the newborn is less than 1%; the risk would be 25% without such a treatment. Zidovudine is the only anti-HIV drug that is fully approved for use during pregnancy. It is inhibits HIV's reverse transcriptase and is placed within the viral DNA. When placed in the viral DNA by the reverse transcriptase, transcription of the viral genes is inhibited. This prevents virus replication. Other drugs that belong to this group (abacavir, emtricitabine, didanosine, zalcitabine, lamivudine, tenofovir, reverset, and stavudine) are not approved because of side effects.