ID: Exammaster

Your patent is a 1-day-old 'floppy baby'; he was born full term by normal vaginal delivery in the hospital. Birth weight was 2.4 kgs; Apgar scores were 6 (1st min), 8 (5 min), and 8 (10 min). His mother had a normal pregnancy, except for an episode of a monoucleois-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). His hemogram shows leukocytosis with anemia [Hb = 8.0 gm%, WBC = 28,200 cells/cu mm (51% polymorphs and 49% lymphocytes)]. Value Finding Normal for 12 - 24 hr old full term Hb (g/L) 95 184 WCC x 109/L 29.0 18.9 (9.4 - 34) Neutro x 109/L 16.0 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 WCC (mm3) 10 5 (0 - 30) RCC (mm3) 10 9 (0 - 50) Protein (g/L) 8.0 0.6 (0.3 - 2.5) Glucose (millimol/L) 45 (blood sugar 48 mg/dl) Greater than 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: Due to the mechanism of the disease, you ask if the mother did what? Answer Choices: A Ate undercooked meat during the pregnancy B Had contact with febrile children during the pregnancy C Had unprotected sex during the pregnancy D Consumed alcohol during the pregnancy E Received rubella vaccine prior to pregnancy

A

What body fluid is considered potentially infectious for HIV as well as hepatitis B and C? Answer Choices: A CSF (cerebral spinal fluid), non-bloody B Saliva (non-bloody) C Vomitus (non-bloody) D Sputum (non-bloody)

A

What trophozoite demonstrates "falling leaf" motility in the wet mount? Answer Choices: A Entamoeba histolytica B Endolimax nana C Giardia lamblia D Dientamoeba fragilis E Trichomonas vaginalis

C

A 35-year-old man has just returned to the United States from Thailand. He presents with a 3-day history of chills, fever, headache, myalgia, weakness, and loss of appetite. For the past 12 years he lived in Thailand, where he had 3 episodes of malaria. He gives a history of exploratory laparotomy and splenectomy following an auto accident in his 20's. Based on the above information, what is the most important diagnosis to consider? A Malaria B Schistosomiasis C Influenzal syndrome D Trypanosomiasis E Smallpox

A

A 25-year-old sexually active man presents with a 2-week history of a painless sore on his penis. On questioning, he denies any discharge or pain with urination. On physical examination, the sore is still present. He is afebrile and is found to have palpable inguinal lymph nodes. The lymph nodes are enlarged, but painless. Dark-field examination results are positive. Question: What is the most likely diagnosis? Answer Choices: A Syphilis B Condyloma acuminatum C Herpes genitalis D Chancroid E Gonorrhea

A

A 28-year-old woman presented to Accident and Emergency complaining of a 3-hour history of nausea, abdominal cramping, vomiting, and watery diarrhoea. She recounts her lunch approximately 8 hours ago, which consisted of a prawn salad and a diet fizzy drink. She denies any neurological or other symptoms. She also denies any similar problems prior to this episode and was feeling well just before this incident. She denies fever or recent travel. What is the most likely organism responsible for her symptoms? A Vibrio parahaemolyticus B Giardia Lamblia C Clostridium difficile D Clostridium perfringens E Campylobacter jejuni

A

A 26-year-old man, residing in Thailand, presents with a 7-day history of high-grade fever, dull, frontal headache, malaise, anorexia, and vague abdominal discomfort. He has mild diarrhea, dry cough, and myalgia. On examination, temperature is 39°C and pulse is 65 per minute. He has a coated tongue, tender abdomen, and a soft, palpable spleen. Clinical diagnosis is enteric fever. Appropriate clinical samples are sent for culture and serology. What laboratory data would be helpful in making a definitive diagnosis? Answer Choices: A Blood culture positive for S. typhi B Stool culture positive for S. typhi C Urine culture positive for S. typhi D Serum titer of S. typhi O agglutinins 1:80 E Serum titer of S. typhi H agglutinins 1:160

A

A 27-year-old man presents with a 4-day history of fever, chills, and a non-productive cough. He says he feels like he has the "flu" and complains of muscle and joint aches. Several of his friends have similar symptoms, and 1 of them is hospitalized. The group of friends took a road trip together 3 weeks ago through a variety of regions and terrains. What exposure would lead you to suspect infection with Histoplasmosis? A Bats B Fleas C Mosquitos D Parrots E Rabbits F Ticks

A

A 32-year-old woman returns from a 2-week camping trip along the Appalachian Trail in New York; she presents with a low-grade fever and a non-pruritic rash on her back and buttocks. Physical exam reveals 2 large 5 cm erythematous lesions, with central clearing on her low back and buttocks. There is no lymphadenopathy. CBC with differential and ESR are normal. What is the most likely diagnosis? Answer Choices: A Lyme disease B Rhus dermatitis C Pityriasis rubra pilaris D Erythema nodosum E Erythema multiforma

A

A 10-year old boy presents with blurred vision, difficulty of swallowing, and weakness. The symptoms evolved rapidly, and his speech became slurred. Pupils are dilated. There is ptosis and loss of accommodation. The muscle action potential is low, and there is an incremental response on rapid repetitive stimulation. What is the most likely causal organism? Answer Choices: A Clostridium botulinum B Campylobacter jejuni C Epstein-Barr virus D Poliovirus E Coxsackievirus

A

A 13-year-old boy goes camping with his Boy Scout troop over Memorial Day weekend. Unbeknownst to him, a tick attaches itself to his scalp. A few days after returning home, he suddenly develops a bad headache, nausea, and muscle aches accompanied by a high fever. 3 days later, a patchy rash develops on his wrists, hands, ankles, and feet. He also complains of joint pain. 3 days later, the rash spreads to his trunk. What is the classification of the agent that caused his disease? Answer Choices: A Rickettsia B Spirochete C Gram-negative rod D Chlamydia E Mycobacteria

A

A 13-year-old girl presents with a very itchy foot. Laboratory tests show a microcytic anemia. A fecal sample for ova and parasite shows that there are the microscopic hookworm eggs in her feces. Where does the causative agent reside? Answer Choices: A Small intestine B Colon C Lung D Liver E Blood

A

A 20-year-old college student spent his summer working in the forest on eastern shore of Maryland. A month after returning home to Virginia, he experienced a sudden onset of fever, nausea, muscle aches, and headaches. Blood and stool cultures were negative for obvious bacterial and parasitic pathogens. His symptoms subsided and he assumed he had recovered. Two weeks later, the symptoms reappeared, now accompanied by marked splenomegaly. He also noticed a single, spreading rash with a pale halo surrounding a brighter red rash (Figure K1.3) on the back of his right shoulder which increased in size and sensitivity. This time a blood smear showed the presence of spirochetes. The etiologic agent responsible for the infection was MOST likely acquired by which of the following methods? Answer Choices: A a tick bite B drinking contaminated water C sexual contact D consumption of contaminated foods E inhalation (Image of bulls eye rash)

A

A 20-year-old man presents with a 2-week history of fever. He states the fever has been as high as 104.5° and it goes down with acetaminophen (Tylenol). He has no other symptoms. His past medical history is noncontributory; family history and social history are noncontributory. He states that he has been with his friends (1 of whom has strep throat), but he does not have throat pain, headache, or stiff neck. He went hot tubbing with friends 7 days ago. His labs are all within normal range. What is the most likely diagnosis? Answer Choices: A FUO (fever of unknown origin) B Sinusitis C Measles D Infectious mononucleosis E Tuberculosis

A

A 22-year-old male off-shore medical student presents with a 2-day history of dysuria accompanied by a painful genital lesion that has formed into an ulcer. He also reports fever with a recorded oral temperature of 101°F, generalized malaise, myalgias, and headache. He denies lesion blistering, and there is no previous history of this condition. He has otherwise been in good general health. He is heterosexual and admits to multiple sexual partners in the recent past with inconsistent use of condoms. T=100.9°F; BP=130/80; P=70; RR=12. Pertinent findings on the physical examination are relegated to the genital exam. Exam reveals a non-circumcised penis with a non-indurated ulcer of the penile frenulum and foreskin, sharply defined borders, undermined edges, and purulent yellow-gray exudative discharge. There is bilaterally tender inguinal adenopathy. Testicles are descended bilaterally with no lesions or masses. Question: What is the most likely diagnosis? Answer Choices: A Chancroid B Granuloma inguinale C Herpes simplex infection D Lymphogranuloma venereum E Primary syphilis

A

A 24-year-old woman presents with dry mouth and blurred vision associated with nausea, malaise, and the recent onset of diplopia. You find out that 2 days ago she had been eating home-canned foods at her brother's house. Previously, she had been healthy and had no medical problems. On physical exam, you confirm slight ptosis and a slight disconjugate gaze. The latest lab work is as follows: Sodium 139 mmol/L Potassium 5.0 mmol/L Chloride 99 mmol/L Bicarbonate 24 mmol/L Blood Urea Nitrogen 7 mg/dL Creatinine 0.7 mg/dL Calcium 7.7 mg/dL What test would be appropriate in this case? A Detection of toxin of Clostridium botulism in the patient's serum B Doxycycline challenge for tick paralysis C Lumbar puncture to rule out a cerebrovascular event D MRI to rule-out Guillain-Barré syndrome E Psychiatric consult to evaluate hysteria

A

A 36-year-old male soybean farmer presents with the inability to walk. The patient reports having received a puncture wound on his left foot several days earlier; it became infected and bloated. Examination of the foot reveals a deep, highly purulent wound that has necrotized and produces a foul odor. The wound is drained and irrigated, and a wet mount of exudate is examined microscopically. Numerous motile rods containing terminal endospores with a 'tennis racket' appearance are seen. What organism is most likely responsible for the infection? Answer Choices: A Clostridium tetani B Clostridium perfringens C Clostridium difficile D Clostridium botulinum E Bacteroides fragilis

A

A 4-year-old boy, who is currently hospitalized with pneumonia, develops vomiting and stiff neck. The new symptoms are followed by a seizure. On physical examination, he is febrile and has signs of meningeal irritation. A lumbar puncture is done to determine if he has meningitis. The results are as follows: TEST RESULTS REFERENCE RANGE CSF pressure 238 mm H2O 70-80 mm H2O CSF leukocytes 8,200 cu mm 0-10 cu mm CSF glucose 26 mg/dL 45-80 mg/dL CSF protein 253 mg/dL 15-45 mg/dL CSF gram stain Pending What organism is probably causing his meningitis? Answer Choices: A Neisseria meningitidis B Staphylococcus epidermidis C Staphylococcus aureus D Streptococcus agalactiae E Listeria monocytogenes

A

A 42-year-old man presents with stumbling, memory loss, and confusion, which his girlfriend claims has been occurring for the past month. Additionally, he reportedly had a tonic-clonic seizure 1 week ago, for which he refused treatment. The patient's past medical history is significant for HIV infection/AIDS and he has been non-compliant with his HIV medication, with no medication use at all for at least 4 months. His CD4 count was 123 cells/mcL 6 months ago, and his HIV viral load was 926 copies/mL. A CT of his head shows multiple peripheral ring-enhancing lesions. Question: What is the most likely diagnosis? Answer Choices: A Toxoplasmosis B HIV dementia C Progressive multifocal leukoencephalopathy (PML) D CNS lymphoma E Cryptococcal meningitis

A

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, and laboratory results suggest hypoxia. 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. What physical finding in PCP would be expected from chest auscultation in this patient? Answer Choices: A No findings B Unilateral consolidation C Rales D Egophony E Infiltrates F Crepitation

A

A 5-week-old male infant presents with a 2-week history of prominent cough, nasal congestion, and wheezing. His symptoms have been getting progressively worse. Yesterday, the patient's mother took her son to her primary care doctor. The doctor started albuterol nebulizers every 4 hours and told her that the child had a viral infection and would get better. His mother is now particularly concerned that her child has had dry diapers for over 15 hours. The child has been irritable during this time. He has not had any fevers, vomiting, or diarrhea. The child is not tolerating breast-feeding or bottle-feeding well. The physical exam shows that the child is acyanotic and alert. The temperature is 97.8 Fahrenheit (36.5 Celsius), respirations are 40/minute, and the pulse is 119/minute. There are no lymph nodes observed, and his tympanic membranes appear normal. There are rales noted diffusely on auscultation. The mucous membranes are moist and the skin has good turgor. You also detect conjunctivitis. Blood work is obtained; including a set of blood cultures, and a urine culture. The following lab values return: Hemoglobin 12.6mg/dL Hematocrit 37.1% Platelet count 204 x 109 Eosinophilia count 6% The chest film demonstrates interstitial infiltrates and hyperinflation. What is the organism causing the infant's symptoms? A Chlamydia trachomatis B Human Parvovirus C Parainfluenza virus D Respiratory Syncytial Virus E Staphylococcal species

A

A 55-year-old male firefighter suddenly develops fever, palpitations, and shortness of breath seven 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. Stat CBC shows neutropenia and eosinophilia. Question: For what reason would you order a blood culture for systemic fungal infection? Answer Choices: A Neutropenia B Intravenous antibiotics C Parenteral nutrition D Facial surgery E Age

A

A local company arranged an outdoor end-of-the-summer luncheon for its coworkers. The food was prepared by a local caterer and included sandwiches, hot dogs, hamburgers, and a selection of cold salads. It was a beautiful, hot summer day and the party seemed to be going very well. However, about 30 minutes after lunch was served, several of the guests developed nausea and severe vomiting. The illness affected so many workers that the company was forced to shut down for the rest of the day. A food-borne illness was suspected, and the public health authorities were called to investigate. Based on the description of the event, what pathogen most likely caused this outbreak? Answer Choices: A Staphylococcus aureus B Bacillus cereus C Clostridium perfringens D Giardia lamblia E Entamoeba histolytica

A

A male infant presents for his 2-week physical exam. On exam, you notice white plaques on the buccal mucosa and palate. When you try to remove the plaques, there are small punctate areas of bleeding. What is the most likely diagnosis? Answer Choices: A Thrush B Epstein pearls C Bohn nodules D Milk residue E Aphthous ulcers

A

Herpes virus can be detected by the Tzanck smear of the skin lesion. This test stains for the presence of which one of the following? Answer Choices: A Multinucleated giant cells B Inclusion bodies C Dead cells D Herpes DNA E Herpes cell envelope

A

A 10-year-old boy presents with chest pain and joint swelling. His mother says about 3 weeks ago he had a sore throat with fevers and cervical lymphadenopathy. He was prescribed penicillin, but stopped taking it after a day because of nausea. His symptoms soon resolved. About a week ago, he complained of knee pain and swelling and later had elbow pain and swelling. He also experienced chest pain and recurrence of his fever. His mother is concerned. His vital signs are blood pressure 110/70 mm Hg, heart rate 120/min, temperature 100.1° F. On physical examination, normal S1/S2 and a II/VI holosystolic murmur is heard, and mild knee tenderness without swelling is present. Elbow still has swelling and pain. His EKG shows a sinus tachycardia with a prolonged PR interval. His chest X-ray is normal. Question: What is the most likely diagnosis? Answer Choices: A Infective endocarditis B Acute Rheumatic fever C Pericarditis D Kawasaki's Disease E Lyme Disease

B

A 13-year-old girl presents to the emergency department with complaints of 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 90/60mmHg, HR 115/min, T 101°F, RR 25/min. Her physical exam is remarkable for diffuse, scattered ring shaped macules on her extremities that is consistent with erythema marginatum, a III/VI systolic ejection murmur, and guarded passive range of motion in wrists and knees bilaterally with no apparent swelling. Laboratory findings are as follows; WBC 16,000mcL, Hematocrit 35%, Platelets 350,000mcL, ESR greater than 15mm/h and a positive antistreptolysin O titer. Question: What should you suspect as this patient's diagnosis? Answer Choices: A Still's Disease B Acute rheumatic fever C Septic arthritis D Systemic lupus erythematosus E Lyme Disease

B

A 14-year-old boy presents with a 1-week history of acute watery diarrhea with vague abdominal discomfort and vomiting. Now he has developed fever, malaise, facial and periobital edema, and myalgias. He is experiencing pain and swelling of the calf muscles. The patient gives history of consuming some delicacies prepared from pork and game meat in a restaurant about 3 - 4 weeks back. Blood examination shows moderate eosinophilia. Question: What is the most likely etiological agent responsible for the patient's illness? Answer Choices: A Ascaris lumbricoides B Trichinella Spiralis C Taena solium D Necator Americanus E Giardia lamblia

B

A 15-year-old girl with no record of any significant illness in the last 2 years presents after a 5-day history of fever. She has no cough, her lungs are clear, but she has a fever of 38.2°C. There is the presence of a significantly large circular rash on her abdomen. Her history is notable for having recently returned from spending the early summer at her grandparent's cottage on the shoreline of Connecticut. She spent most of her time hiking through the meadows and collecting photographs. She submits a jar containing an insect that she found feeding on her body. You analyze the insect microscopically (refer to the image). A CBC is ordered and the results are unremarkable. Based on the clinical history and presentation, you should order tests for what infection? Answer Choices: A Francisella tularensis B Borrelia burgdorferi C Rickettsia rickettsii D Ehrlichia chaffeensis E Babesia microti

B

A 21-year-old man presents with an acute onset of nausea and vomiting. He is a college student. The symptoms began in the middle of the night. He denies alcohol or other drug ingestion. When he returned from his evening class, he reheated some fried rice from yesterday's takeout, did a little reading, and went to bed. On physical exam, he appears pale and tired. The abdomen is mildly tender, but there is no guarding. He is afebrile, pulse is 103, and blood pressure is 100/70. Food-borne illness is suspected, and the patient is advised to drink fluids and return to the clinic the following day. As anticipated, at his next visit, the patient's symptoms have resolved completely. Based on the clinical scenario, what agent is most likely to have caused this patient's illness? Answer Choices: A Staphylococcus aureus B Bacillus cereus C Clostridium perfringens D Giardia lamblia E Entamoeba histolytica

B

A 24-year-old intravenous drug abuser who is HIV positive presents with a 4-week history of fever, dry cough, tachypnea, and dyspnea. There is a diffuse interstitial pattern on his X-ray (see image). What is the most likely cause of the patient's symptoms? Answer Choices: A Pulmonary emboli B Pneumocystis jiroveci C Kaposi's sarcoma D Legionnaire's disease E Lyme disease

B

A 24-year-old man recently returned to the United States from a South American vacation; he presents with an itchy, red, palpable, serpiginous lesion on the pretibial skin. The skin lesion has slowly lengthened during the past week. What is most consistent with this presentation? Answer Choices: A Bubonic plague B Cutaneous larva migrans C Lyme disease D Viral exanthem E Acute rheumatic fever

B

A 25-year-old man with no prior history of any significant illness comes to your office presenting with a wound infection to the hand; he acquired the wound 3 weeks ago, and it has been worsening. Physical examination of the hand is remarkable for the presence of an initial wound site that is ulcerated and surrounded with papules that are blue-purple in color. Nodules are present (of lymphatic origin) ascending from the wound site on the forearm. The patient acquired the initial wound while at work at a pet store, where he accidentally cut his hand while cleaning out an aquarium. Material for bacterial, fungal and mycobacterial culture is obtained from the wound site. Special instructions on incubation requirements are given for the mycobacterial culture. Bacterial and fungal cultures prove to be negative; however, at day 7 there is 4+-mycobacterial growth detected that produces the following characteristics: GROWTH RATE NIACIN NITRATE REDUCTION OPTIMUM TEMPERATURE TWEEN HYDROLYSIS UREASE 7 DAYS NEG NEG 32° C POS POS Based on the clinical and isolate characteristics, what is the infection in the hand of this patient? A Mycobacterium kansasii B Mycobacterium marinum C Mycobacterium gordonae D Mycobacterium avium-intracellulare E Mycobacterium tuberculosis F Mycobacterium bovis

B

A 25-year-old sexually active man presents with what he describes as an infection of his penis. His history is significant for having had sex with a prostitute in the past 2 months. He has no history of fever, chills, headache, joint pain, malaise, or anorexia. There is no history of drug use. Physically, he appears in very good shape and all vital signs are normal. Physical examination of the penis is significant for the presence of a chancre that is located on the glans penis. The base appears smooth with raised borders. Although painless, the chancre is sensitive to touch. There appears to be little to no exudate at the chancre. The patient also has the presence of regional lymphadenopathy, which is non-tender to the touch. The chancre is scraped for material to be examined. The scraped material is placed on a slide with sterile isotonic saline and coverslipped. It is observed under dark field microscopy and is reported by the laboratory as positive. What is the most likely diagnosis? Answer Choices: A Chancroid B Primary stage syphilis C Primary genital herpes D Localized candidiasis E Anogenital warts F Bacterial vaginosis

B

A 27-year-old man presents with burning pain during urination and a 5-day history of urethral discharge. He sees his family physician because of his complaints. Several laboratory tests are done, including a Gram stain and culture on a sample of the discharge. The results are negative, and gonorrhea is ruled out. What is the most common cause of his condition? Answer Choices: A Chlamydia psittaci B Chlamydia trachomatis C Mycoplasma genitalium D Trichomonas vaginalis E Mycoplasma hominis

B

A 30-year-old man presents to his primary care physician's office with a 3-day history of having an itchy scalp. He was recently on vacation and slept on the floor of a house with pets. Otherwise, nothing has changed recently in his daily living and he denies all other symptoms. His overall health is good. Which physical examination description is mostly closely associated with tinea capitis? A Round patches of hair loss with normal appearance of scalp B Erythematous, scaly patches associated with patchy hair loss C Group of 3-5 inflamed, tender nodules that have purulent drainage D Thick patchy areas with silvery scales attached to hair shafts E Erythematous, greasy skin covered in yellow scales

B

A 30-year-old woman presents with lower abdominal pain; she is thought to have pelvic inflammatory disease (PID). She admits to prostitution and illicit drug use. Labs on admission reveal blood glucose of 260 mg/dL, a positive HIV screen, and a non-reactive RPR. Aside from the abdominal/pelvic pain, the admitting physical is also notable for moderate obesity, the absence of pronounced lymphadenopathy, and an erythematous macerated rash in the intertriginous distribution. The patient reports her rash is "really itchy and wet all the time", and it began within the last 3 months; it is now at its worst. She also reports intense itching of the vulva over the last few weeks. The intertriginous rash is most likely a manifestation of what condition? Answer Choices: A Atopic dermatitis B Candidiasis C Lichen planus D Psoriasis E Secondary syphilis

B

A 36-year-old woman presents with a 24-hour history of sudden, severe diarrhea described as profuse, gray, cloudy, watery stools without blood or fecal odor. She was recently in Bangladesh for work and returned yesterday, when the diarrhea began. She complains of mildly elevated temperature with a very dry mouth, headache, and severe fatigue. Question: The most likely offending organism is: Answer Choices: A Enterotoxigenic E. coli B Vibrio cholerae C Norwalk virus D Shigella dysenteriae E Clostridium difficile

B

A 36-year-old woman returning from a conference in Indonesia presents with profuse watery diarrhea. She reports having consumed fried rice, iced tea, and fruit at a street market several hours before her flight to the United States. The patient has 4 - 6 bowel movements daily, and they are preceded by cramps and nausea. She also has overwhelming thirst. Examination reveals dehydration, diaphoresis, orthostatic hypotension, and abnormal laboratory values for potassium (2.8 mmol/L). No leukocytes are seen in stool specimens, and cultures yield an oxidase-positive curved Gram-negative rod on blood and TCBS agar. What is the most probable etiology of the patient's illness? Answer Choices: A Clostridium perfringens B Vibrio cholerae C Clostridium difficile D Campylobacter jejuni E Shigella sonnei

B

A 40-year-old male inmate, who was born in the United States, has been incarcerated for the past 20 years; he gets a required annual PPD. 2 days later, the nurse, who is a new graduate, reads his PPD at 11 mm; she verbally informs you of this result. However, all of his previous readings have been 0 mm, and he has not transferred to any other institution in the past 5 years. There are no known cases of active TB in your facility. Question: What should be your next step? Answer Choices: A Obtain a chest X-ray B Recheck his PPD C HIV screen D Obtain a Hepatic Panel/CBC E Obtain a Quantiferon-TB Gold test

B

A 43-year-old woman is admitted for nausea, emesis, ataxia, and dizziness. Previous medical history reveals HIV positive status for 4 years, with the most recent CD4 T-cell count of 100/mm3. Vital signs and neurologic exam are normal. An MRI shows 2 ring-enhancing lesions of the basal ganglia, each approximately 1 cm in diameter. The patient is treated with sulfadiazine plus pyrimethamine, and she is discharged following rehydration. Within 1 week, the patient's symptoms improve; a 2nd MRI 4 weeks later shows a significant reduction in the size of the lesions. What is the most likely diagnosis? Answer Choices: A Lymphoma B Toxoplasmosis C Mycobacterial abscess D CMV encephalitis E Fungal abscess F HIV encephalitis

B

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 a 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. However, he had an excellent response to antiretroviral therapy, 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: What should be the next diagnostic step in this patient? Answer Choices: A Neuropsychological testing B Neuroimaging methods C Electroencephalography D Cerebrospinal fluid examination E CD4+ lymphocyte counts

B

A 55-year-old African American woman presents to you with fatigue, non-productive cough, and hair loss as well as admitting to a 40 pack-year smoking history. You take a thorough history and perform an appropriate physical examination and you suspect Human Immunodeficiency Virus (HIV) infection. Which of the following physical exam findings is most specific for HIV infection? Answer Choices: A Basilar rales on lung auscultation B Oral hairy leukoplakia on tongue C Vitiligo D Alopecia areata E Clubbing

B

A woman comes to your office after a 6-month sabbatical during which she worked in caves in the eastern part of South America. The patient presents with fever, chills, productive cough, and joint stiffness that started 1 month before her return. Physical exam reveals 3 ulcerated lesions on her inner cheek. What is the diagnosis? Answer Choices: A Acute pulmonary eosinophilia B Histoplasmosis C Pulmonary actinomycosis D Acute coccidioidomycosis E Pulmonary asbestosis

B

An 18-year-old man presents with urethral discomfort and dysuria and urethral discharge. He notes no other symptoms. His temperature is normal, and physical exam is unremarkable. He is sexually active, heterosexual, and had sex with 3 different women in the last 2 weeks. He was not practicing safe sex. The urethral discharge was noted to be clear and slightly viscous in nature. The urethral discharge is Gram stained and examined. It is found to contain a few WBCs and no organisms. This presentation is most suggestive of what organism? Answer Choices: A Neisseria gonorrhoeae B Chlamydia trachomatis C Herpes simplex D Haemophilus ducreyi E Treponema pallidum

B

An 8-year-old girl presents with a 3-day history of fever, generalized muscle weakness, bilateral knee pain, and chest pain. What illness, contracted about 1 month ago, would support the diagnosis of Acute Rheumatic Fever (ARF)? A Proteus mirabilis infection of the urinary tract B Group A Streptococcus infection of the upper respiratory tract C Helicobacter pylori infection of the gastrointestinal tract D Haemophilus influenza infection of the upper respiratory tract E E. coli infection of the urinary tract

B

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: Based on the above history and physical exam, what is the most likely diagnosis? Answer Choices: A Juvenile Idiopathic Arthritis B Systemic Lupus Erythematosus C Acute Rheumatic Fever D Kawasaki Disease E Septic Arthritis

C

A 15-year-old male adolescent presents with a 1-week history of malaise, a low-grade fever, and a sore throat. On exam, you note pharyngeal erythema, scant yellow exudates, and enlarged posterior cervical lymph nodes. There are no current signs of airway compromise. There is no skin eruption noted, and the rapid strep screen is negative. What other physical examination finding is usually present with this condition? Answer Choices: A Sclera icterus B Pancreatitis C Splenomegaly D Hepatomegaly E Cullen sign

C

A 17-year-old boy presents to your office with a 2-week history of a red, itchy rash. The rash began on his feet, and over the last 2 weeks it appears to be migrating up his legs. The rash is intensely pruritic. There is no fever, vomiting, diarrhea, cough, weakness, or weight loss. The patient has no significant past medical history. He has just returned from a summer job in Georgia where he was working as a landscaper. There is no travel outside the United States. He denies the use of alcohol and intravenous drug use, but has smoked marijuana occasionally over the summer. On physical exam, there are serpiginous, raised, erythematous lesions streaking up both lower extremities. The rest of his exam is normal. What complications may occur as a result of this boy's infection? Answer Choices: A Meningitis B Peritonitis C Pneumonitis D Seizures E Decreased visual acuity

C

A 2-year-old boy is from a poor, rural family. He is experiencing a childhood exanthematous disease that involves a maculopapular rash and a fever. It started 7 days ago. He is now suffering from corneal ulcers and pneumonia. He was not given the childhood immunizations properly. Question: Refer to the image (same image as above) and case. What best describes the distribution of the rash? Answer Choices: A Faint rash begins on the cheeks and spreads to the trunk and extremities B Pruritic rash starts from trunk and spreads peripherally C Maculopapular rash starts behind the ears and spreads to the face and down to the trunk and the extremities D Diffuse erythema on mucous membranes, palms, and soles with polymorphous rash E Diffuse erythematous rash, more prominent on abdomen and cutaneous folds with circumoral pallor

C

A 2-year-old boy is from a poor, rural family. He is experiencing a childhood exanthematous disease that involves a maculopapular rash and a fever. It started 7 days ago. He is now suffering from corneal ulcers and pneumonia. He was not given the childhood immunizations properly. Question: Refer to the image and case. Which of the followings are the all-prodromal signs of this disease? Answer Choices: A Koplik's spots, fever, cough, conjunctivitis, and maculopapular rash B Koplik's spots, coryza, fever, and cough C Koplik's spots, coryza, fever, cough, and conjunctivitis D Coryza, fever, and conjunctivitis E Coryza, fever, and maculopapular rash

C

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 4 weeks ago he had a severe sore throat and fever but was not evaluated for these symptoms. Physical examination reveals a febrile patient in mild distress. A diastolic murmur is noted in the left 4th/5th 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 likely diagnosis for this patient's presentation? Answer Choices: A Pericarditis B Pleurisy C Acute Rheumatic Fever D Endocarditis E Influenza

C

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 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, as well as an erythematous rash with central clearing and few satellite lesions. If your diagnostic impression of Lyme disease were to be confirmed, how would this patient's disease stage be defined? Answer Choices: A Early-onset B Late-onset C 1st stage D 2nd stage E 3rd stage

C

A 27-year-old woman presents because she noticed some cobblestone changes in her genital area 1 month prior. She has no other symptoms. Her current sex partner has similar changes on the skin at the base of his penis. Examination of the genitalia reveals multiple dry small skin-colored, papular keratotic lesions in the skin of the perineal area. The rest of the examination is normal. You suspect the diagnosis of condyloma acuminata. Question: Which of the following is an appropriate next step in therapy? Answer Choices: A No further treatment is indicated B Topical fluorouracil C Podofilox 0.5% gel D Silver nitrate E Gardasil

C

A 27-year-old woman presents because she noticed some cobblestone changes in her genital area 1 month prior. She has no other symptoms. Her current sex partner has similar changes on the skin at the base of his penis. Her last Pap test, which was done about 2 years ago, was normal. She has been sexually active with both sexes since age 18, and she has had a total of 8 sex partners over her lifetime. For the last 2 years, she has been sexually active with 1 partner, and she uses oral contraceptives for birth control. She has no history of STDs. Examination of the genitalia reveals multiple dry small skin-colored, papular keratotic lesions in the skin of the perineal area. The rest of the examination is normal. Question: What should be your next step in order to make a diagnosis? Answer Choices: A VDRL testing B DNA polymerase C Pap smear D Biopsy of the lesion E HIV viral load

C

A 28-year-old man presents for evaluation of a rash. His trunk is covered with a pink-red papulosquamous eruption with scattered discrete coppery papules on the palms of his hands and a few lesions on the soles of his feet. He is afebrile and has not experienced any illness in the past month that he can recall. Skin exam reveals soft, flat, moist papules scattered on his perineum. Question: Which of following laboratory tests will yield the most information about the patient's condition? Answer Choices: A KOH prep B HIV antibody C VDRL D Peripheral blood smear E Tzanck smear

C

A 3-month-old infant is brought in by her parents because they are concerned about her health. They report that the infant has grown lethargic and weak. When they try to feed her, she is unresponsive to the presence of the baby bottle or breast-feeding. Physical examination is remarkable for hypotonia of the extremities and a flaccid neck. She has a poor gag and suck reflex. Her body temperature is normal, with a slightly decreased respiration rate. Further questioning of the parents reveals that the infant had been previously induced to bottle feed by coating the nipple with honey. Blood is drawn for toxin studies, and they come back positive. The honey is also examined for the presence of toxin, and it is also found to be positive. What organism is causing the infant's disease? Answer Choices: A Campylobacter jejuni B Bacillus cereus C Clostridium botulinum D Vibrio parahaemolyticus E Listeria monocytogenes

C

A 3-year-old boy is evaluated for a 24-hour history of diarrhea. His mother reports that he had 5 episodes of foul-smelling, watery diarrhea associated with decreased appetite. A few other children at the same day care center have also presented with the same problem. On physical examination, the child is well hydrated and his abdomen is tender. Stool microscopy shows the presence of motile trophozoites of the etiological agent. What is causing the patient's symptoms? Answer Choices: A Cryptosporidiosis B Cyclosporiasis C Giardiasis D Isosporiasis E Microsporidiosis

C

A 30-year-old Asian man develops fever, cough and expectoration. 2 days later, he presents with red tender nodules on his shins. He reveals that he returned 10 days ago from a vacation in California. While there, he went exploring the desert with his friends. He has no known allergies. An X-ray film of the chest shows a left pleural effusion. A dimorphic fungal infection endemic in the state of California is suspected as the cause of the patient's illness. What is the diagnosis? Answer Choices: A Aspergillosis B Blastomycosis C Coccidioidomycosis D Histoplasmosis E Paracoccidiomycosis

C

A 34-year-old man closely adhered to a personal policy of annual physical checkups and routinely received a clean bill of health. 3 weeks after returning from a business trip to California, he noticed a small circular lesion on tip of his penis. The area became more sensitive and began to ooze fluid. Medical examination revealed lymphocytes and plasma cells and no unexpected Gram-stainable bacteria. A serum sample showed a positive VDRL test with a titer of > 1:64. If the patient does not receive medical treatment, and the lesion clears, there remains the possibility of what condition? Answer Choices: A Nongonococcal urethritis B Primary syphilis C Secondary syphilis D Tertiary syphilis E Latent syphilis

C

A 35-year-old man is admitted to the hospital with progressive shortness of breath, fever, and worsening cough. The patient had been in good health until 2 months ago, when he began losing weight. This was associated with anorexia, intermittent diarrhea, night sweats, and then a nonproductive cough. He had lost more than 20 pounds by the time he was admitted to the hospital. His past medical history is unremarkable. He has been divorced for 5 years, and he has 1 child. He is employed as a medical equipment salesman, traveling extensively in the Midwest. He admits to drinking alcohol in large amounts on weekends, but he denies tobacco and intravenous drug use. He gives history of a previous homosexual encounter. Physical examination shows that the chest was normal to percussion and clear by auscultation, except for a few scattered ronchi. The heart is normal except for tachycardia. The abdomen is soft with normal bowel sounds. Genitalia are normal; however, there is a painful 2 cm ulceration at the anal verge. The neurologic exam is unremarkable. Chest radiological findings show diffuse bilateral interstitial infiltrates. Arterial blood gases on room air show pO2- 57mmHg, pCO2 31 mmHg, and pH 7.45. His alveolar-arterial O2 gradient is 55mmHg. Bronchoalveolar lavage fluid with lung biopsy shows the presence of cysts. Sputum cytology is negative for acid-fast bacilli. Question: What is the most likely diagnosis? Answer Choices: A AIDS-related tuberculosis B Secondary syphilis C Pneumocystis pneumonia D Lung cancer E Legionella pneumonia

C

A 35-year-old man presents with knee pain that makes him unable to move his knee. The pain began 3 days ago and has markedly increased. The knee pain was preceded by a flu-like illness 1 week ago. The illness was accompanied by a rash on his thigh that had red margins and a pale center. It started 2 weeks after he came back from a hiking trip last month. He denies any urinary or GIT symptoms. He has no other significant past history. What could be a complication of the patient's illness? Answer Choices: A Stroke B Heart failure C Bell's palsy D Chronic constipation E Renal failure

C

A 35-year-old patient is admitted to the ER presenting with a severe headache. The headache is now 1 week old and has progressively worsened to the point where the patient finds it difficult to tolerate. He has been experiencing photophobia, malaise, and fevers that have gone up to 40° C. His present temperature is 38.3° C. The patient appears confused and disoriented, and his response to questioning is delayed. He mentions a 3-year history of IV drug abuse. His vital signs are all within normal limits. A chest examination and radiograph is normal; a CT scan is normal. The patient's mental status continues to deteriorate, and he is admitted. A lumbar puncture is done, and the results can be found in the table. An India ink prep prepared by the microbiology laboratory produces the following (refer to the image), and a specific antigen test is positive. The organism is recovered from the CSF 48 hours later. What is the most likely organism causing the patient's illness? glucose - 22 Protein - 89 WBC - 32 diff - lymphocytes 89%, monocytes 11% RBC - 0 Answer Choices: A Neisseria meningitidis B Streptococcus pneumoniae C Cryptococcus neoformans D Haemophilus influenza E Listeria monocytogenes

C

A 45-year-old man presents with a 3-week history of fever, malaise, and cough. The illness began with low-grade fever, headache, sore throat, and non-productive cough. He tried symptomatic treatment with over-the-counter medicines and did not take any antibiotics. His condition worsened, and he developed expectoration of non-blood stained sputum, shortness of breath, and chest soreness. There was no history of exposure to birds or any new environment. Chest auscultation detected scattered rales and expiratory wheezes. Chest X-ray showed bilateral diffuse infiltrates and consolidation of right lower lobe. Gram-stain of sputum showed presence of leukocytes and normal flora. Routine culture for bacterial pathogens grew only normal flora. The microbiology laboratory was not equipped for isolation of fastidious organisms. Considering the presumptive clinical diagnosis of atypical pneumonia, a supportive non-specific serological test was done to detect cross-reacting antibodies to human erythrocytes. Test result showed significant titer of the antibodies. What is likely to be the causative agent in the above patient? A Chlamydia pneumoniae B Legionella pneumoniae C Mycoplasma pneumoniae D Coxiella burnetii E Chlamydia psittaci

C

A 49-year-old man presents with chronic fatigue, headache, fevers, and muscle and joint pain. He describes transient "reddish spots", which can be quite large, that have appeared on his skin and 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 lives in a small rural community; nevertheless, he is concerned that he may have somehow contracted a communicable STD. What condition is causing the patient's symptoms? Answer Choices: A Acute rheumatic fever B Alcoholic cirrhosis C Lyme disease D Malaria E Polymyalgia rheumatica

C

A 10-year-old boy presents after being bitten by his cat on the dorsum of his left hand several hours ago. He was playing with the cat, and she snapped and bit him on the hand; the bite drew blood. His mother immediately washed the bite out with soap and water, but it has gotten increasingly red and swollen over the past several hours. He is currently afebrile. The dorsum of his left hand reveals a 4 cm oval area of redness that is tender to the touch; there are 4 puncture wounds at the center without pus. You suspect the wound is infected, so a culture is taken. Question: What is the most likely isolate in this case? Answer Choices: A Pseudomonas sp. B Staphylococcus sp. C Streptococcus sp. D Pasteurella sp. E Bacterioides sp.

D

A 10-year-old boy presents with swelling on his face; it 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. What organism is associated with his condition? Answer Choices: A Hepatitis B virus B Human papilloma virus C Schistosoma hematobium D Epstein Barr virus (EBV) E Human T-cell lymphotrophic virus type 1

D

A 12-year-old boy eats hamburgers, hot-dogs, deviled eggs, macaroni salad, and potato salad at an Independence Day picnic. Approximately 3 hours after eating, he suddenly develops nausea, vomiting, and non-bloody diarrhea. His mother takes his temperature and is relieved to find that he does not have a fever. What caused the boy's food poisoning? Answer Choices: A Entamoeba histolytica B Shigella species C Campylobacter jejuni D Staphylococcus aureus E Yersinia enterocolitica

D

A 1-year-old child presents with acute watery diarrhea that was preceded by a low-grade fever and vomiting. What test could confirm the most likely cause of this disease? Answer Choices: A Serum antibody test B Stool culture C Abdominal x-ray D ELISA testing of stool E Throat culture

D

A 17-year-old boy presents for an annual physical exam prior to the start of college. For the last 3 weeks, he has been camping in Los Alamos. Although he and his friends brought bottled water on the trip, he says the rivers were so clean that they all ended up just drinking from them directly. On further questioning, the boy explains that while he has been in generally good health, over the past few weeks he has been suffering from loose bowel movements and excessive flatulence. In addition, he intermittently has mild nausea and chronic abdominal pain that is interfering with his appetite. He thinks he has lost a little weight. He reports no history of fever, vomiting, or other non-gastrointestinal complaints. What is the probable cause of the boy's infection? Answer Choices: A Staphylococcus aureus B Bacillus cereus C Clostridium perfringens D Giardia lamblia E Entamoeba histolytica

D

A 20-year-old male college student presents with fever, chills, malaise, headache, photophobia and confusion with numerous petechiae on his extremities and trunk. On examination, he has positive Brudzinski and Kernig signs. A CT scan of the head is within normal limits. A lumbar puncture reveals increased leukocytes particularly polymorphonuclear neutrophils, increased protein and decreased glucose levels. Gram staining of the CSF reveals Gram-negative cocci in pairs. Question: What is the most likely causative agent for the infection in this patient? Answer Choices: A Bordetella pertussis B Francisella tularensis C Haemophilus influenzae D Neisseria meningitidis E Yersinia pestis

D

A 20-year-old man spent his summer working in the forest on eastern shore of Maryland. A month after returning home to Virginia, he experienced a sudden onset of fever, nausea, muscle aches, and headaches. Blood and stool cultures were negative for obvious bacterial and parasitic pathogens. His symptoms subsided and he assumed he had recovered. 2 weeks later, the symptoms reappeared, now accompanied by marked splenomegaly. He also noticed a single, spreading rash with a pale halo surrounding a brighter red rash on the back of his right shoulder. It has been increasing in size and sensitivity. This time, a blood smear showed the presence of spirochetes. What is the MOST probable etiologic agent for the above illness? Answer Choices: A Spirocheta B Rickettsia C Treponema D Borrelia E Leptospira picture of a bullseye rash

D

A 20-year-old woman on the orthopedic floor develops redness and inflammation of a knee that had ACL repair done. The knee is inflamed and tender to the touch. The surgical sites are significant for a white, pus-like drainage. There is no significant odor present, which would be indicative of a possible anaerobic infection. Drainage material was collected for Gram stain and culture. The Gram stain result report had many neutrophils present and many Gram-positive cocci. The culture grew colonies on blood agar that were beta-hemolytic (refer to the image) and catalase/coagulase-positive. This patient has what infection? Answer Choices: A Escherichia coli B Pseudomonas aeruginosa C Streptococcus pyogenes D Staphylococcus aureus E Streptococcus pneumoniae

D

A 21-year-old man is a recent immigrant from Somalia; he presents with back pain. The patient reports a dull aching pain localized to the T9 - T10 vertebral region. He describes intermittent pain for 6 months, and an episode earlier in the week of severe pain following heavy lifting. Physical examination shows tenderness from T9 - T12 with point tenderness at T10. The patient has normal vital signs, and laboratory measures are within normal limits. He denies fever, chills, and parenteral drug use. A myelogram shows a nearly complete block at T9 - T10, and an MRI reveals erosion of T9 and T10 vertebral bodies; there is a large surrounding paraspinal abscess. A tissue specimen obtained by biopsy reveals granuloma with necrosis. Gram stains of abscess drainage are uninformative. Auramine O staining and culture results confirm the diagnosis. What pathogen is most likely responsible for the patient's symptoms? Answer Choices: A Brucella melitensis B Actinomyces israelii C Mycobacterium leprae D Mycobacterium tuberculosis E Calymmatobacterium granulomatis

D

A 21-year-old woman developed low-grade fever, sore throat, malaise, and fatigue that lasted several days. Physical examination revealed swollen lymph nodes and discomfort in the left upper quadrant of the abdomen. Examination of peripheral blood smear revealed 50% of atypical lymphocytes of the total white cells. Result for heterophile antibody test was positive. What is the most probable cause of infection? Answer Choices: A Cytomegalovirus B Respiratory syncytial virus C Influenza virus D Epstein-Barr virus E Varicella zoster virus

D

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. What is the most likely diagnosis? Answer Choices: A Influenza B Rocky Mountain spotted fever C Hand-foot-and-mouth disease D Secondary syphilis E Streptococcal pharyngitis

D

A 30-year-old white man complains of a 3-day history of fever with chills and severe weakness. There are no other complaints. The patient has had multiple sex partners in the past. He also gives history of travel to South America and consumption of street food while working there 1-month back. He admits to intravenous drug abuse and cocaine abuse (snorting) in his early 20s. He often ventures out into the woods and has been bitten by several insects in the recent past. Abdominal exam reveals mild hepatomegaly. You send for routine lab investigations including CBC, comprehensive panel, and serology of HIV and Hepatitis B and C. Liver enzymes are elevated, and anti-HCV comes back positive. Anti-HIV and HBV are negative. Question: Which of the following is the most likely mode by which this man acquired the hepatitis C infection? Answer Choices: A Sex with multiple partners B Consumption of street food C Cocaine abuse D Intravenous drug abuse E Tick bite

D

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 prior to presentation, 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. What pathogenic organism is most likely causing his symptoms? Answer Choices: A Staphylococcus aureus B Bacillus cereus C Escherichia coli, serotype O157:H7 D Vibrio cholera E Vibrio parahaemolyticus

D

A 34-year-old man presents with a 2-day history of right ankle pain and swelling. He reports experiencing discomfort with weight bearing, ambulation, and when driving an automobile. On further questioning, he denies experiencing a recent trauma, although he does recall spraining his ankle approximately 1 year ago. On physical examination, the patient's temperature is 99.9° F. His right ankle shows swelling, is warm to palpation, and reveals an effusion. With passive range of motion of the right ankle, significant pain is elicited. Question: What is the most appropriate next step in the management of this patient? Answer Choices: A Check the serum uric acid level; if elevated, initiate therapy with indomethacin and colchicine. B Obtain a plain radiograph of the right ankle to assess for chondrocalcinosis. C Obtain a plain radiograph of the right ankle to assess for structural damage. D Perform arthrocentesis of the right ankle with analysis of the synovial fluid. E Treat with ibuprofen and have the patient return to your office in 1 week for follow-up.

D

A 38-year-old HIV-positive man presents with fever, headache, right hemiparesis, and expressive aphasia. Recent CD4 count is 45, but he is not on any prophylactic medications. Computed tomography scan (CT) reveals multiple ring-enhancing lesions in the parietal and frontal lobes. What is the most likely cause? Answer Choices: A Cytomegalovirus (CMV) B HIV encephalopathy C Tuberculosis D Toxoplasmosis E Cryptococcosis

D

A 38-year-old male HIV positive patient with a history of IV drug abuse is brought to the emergency room complaining of severe headache and neck stiffness. The headache has been present for the last 3 days and has progressively worsened. The patient appears slightly disoriented and answers his questions slowly. A CBC is ordered, and the results come back unremarkable. Because of the patient's history and CNS symptoms, a lumbar puncture is performed. CSF is sent to the laboratory for examination and testing. While waiting for the results a quick test is done in the laboratory by the attending physician that confirms a diagnosis (refer to the image same one as above). What is the reagent used in this quick diagnostic test? Answer Choices: A Lactophenol Cotton Blue B Lugol's Iodine C Kinyoun Acid Fast Stain D India Ink E Gomori Methenamine Silver Stain (GMI)

D

A 38-year-old man presents with nausea, vomiting, diarrhea, and abdominal cramping for the past 2 hours. The patient reveals that he had consumed meat that had been left uncovered for a night. Laboratory examination revealed that the meat was contaminated with circular, clustered organisms, which were found on Gram staining to be Gram-positive. Fairly large, yellow colored colonies were formed when the organism was grown on mannitol agar media in a temperature range of 15 to 45°C. The organism showed positive results for coagulase enzyme activity and showed resistance to penicillin and methicillin antibiotics. Question: What organism was the causative agent of the food poisoning? Answer Choices: A Clostridium perfringens B Enterococcus faecalis C Escherichia coli D Staphylococcus aureus E Salmonella species

D

A 42-year-old homosexual male presents with rectal pain and mucopurulent discharge. The diagnosis of gonorrhea is made. In this patient diagnosed with rectal gonorrhea, which of the following treatment regimens is recommended? A Ciprofloxacin only B Ceftriaxone only C Ciprofloxacin and azithromycin D Ceftriaxone and azithromycin E Azithromycin and doxycycline

D

A 5-year-old boy presents with a 4-day history of bloody diarrhea. He has had fever up to 104 degrees F, abdominal pain, and painful defecation. His past medical history is unremarkable, and he has had no surgeries. He is on no medications and has no drug allergies. He attends a local daycare with 9 other children. On physical examination, his abdomen is tender with hyperactive bowel sounds. While in the emergency department, he has a 5-minute generalized seizure. What pathogen is the most likely cause of the patient's seizure? Answer Choices: A Campylobacter jejuni B Giardia lamblia C Rotavirus D Shigella sonnei E Salmonella typhimurium

D

A 75-year-old woman was hospitalized with a localized subcutaneous abscess at the site of a cat bite. Pus drained from the abscess was cultured in the microbiology laboratory. Colonies of small Gram-negative coccobacilli grew on chocolate agar incubated at 37°C for 24 hours. The bacterium was non-motile, oxidase and catalase positive, urease negative, and showed fermentative activity on carbohydrates. The isolate is most likely to be what zoonotic pathogen? Answer Choices: A Bartonella henselae B Ehrlichia chaffeensis C Coxiella burnetii D Pasteurella multocida E Bordetella bronchiseptica

D

A mother has brought her 6-month-old infant to your office for a 1-day history of poor feeding, lethargy, and weak cry. In the beginning, the infant had difficulty sucking and swallowing and was not opening his eyes. This was followed by loss of head control, weakness of the arms, trunk, and then legs. Infant is constipated and had drooling of saliva since yesterday. The infant was healthy before the onset of the above symptoms. There is no history of fever, vomiting, cough, seizures, or difficulty in breathing. The infant has weak gag and corneal reflexes, generalized hypotonia, loss of head control, ptosis, and diminished deep tendon reflexes. Blood counts and CSF examination are within normal limits. Question: What is the most likely clinical diagnosis? Answer Choices: A Myasthenia gravis B Spinal muscular atrophy C Guillain-Barre syndrome D Botulism E Tick paralysis

D

The newborn nursery calls you to see a 1-day-old male infant. He has developed a worsening mucocutaneous rash over his whole body, especially his palms and soles, which has begun to desquamate. He also has a runny nose. Worrying about possible syphilis, you inquire about the maternal history. What maternal risk factor is particularly associated with congenital syphilis? Answer Choices: A Young maternal age B Domestic violence C Alcohol abuse D Lack of prenatal care E Homelessness

D

What is a likely cause of chronic meningitis in a patient with AIDS? Answer Choices: A Candida B Mycobacterium avium C Cryptosporidium D Cryptococcus neoformans E Actinomyces

D

A 12-year-old girl presents because her joints are hurting. Her knees and ankles have been painful, warm, and swollen for several weeks now. It started in her left knee, then her left ankle became involved, and then her right knee was affected. Her left knee is 'almost back to normal now,' but the other involved joints are becoming more painful. She is a middle school student and has been unable to go to school or church for the past 3 days because of the pain. She is taking acetaminophen arthritis formula, but the pain continues to get worse. Her mother did not want to give her non-steroidal antiinflammatory medications because of her age. Review of systems (ROS) is positive for fever, chills, malaise, mild chest pain when lying down, moderate headaches, and weight loss. ROS is negative for sexually transmitted diseases, trauma to affected joints, tick exposure, and recent travel. What component of the physical exam would lead you to suspect acute rheumatic fever as the cause of her joint pain? A Erythema infectiosum B Erythema migrans C Fever above 100 degrees F D Jaundice E Mitral regurgitation

E

A 2-month-old infant presents with a 48-hour history of poor feeding, crying, limpness, and constipation. The doctor in charge asks the mother how she feeds the infant. The infant is given formula regularly, but the mother sometimes adds honey to make the formula sweeter. She keeps the honey in the kitchen cupboard. When the doctor examines her, she notices a very drowsy infant with flaccid paralysis. What is causing this infant's symptoms? Answer Choices: A Sepsis B Hypothyroidism C Congenital muscular dystrophy D Lactose intolerance E Botulism

E

A 20-year-old woman presents with a 5-day history vaginal discharge and vulvar itching. She has had unprotected sexual intercourse with a new partner for the last month. On clinical examination, there is vulvar erythema and edema. The vaginal discharge is noted to have an unpleasant odor, a white-gray color, and a frothy appearance. The upper vagina and the cervix have a strawberry appearance with multiple erythematous epithelial papillae. The vaginal pH is 6.5. What test is likely to give a positive diagnostic? Answer Choices: A Culture on Sabouraud agar B Dark field microscopy C Rapid plasma reagins D Tzanck smear E Wet vaginal prep

E

A 23-year-old woman visits a community clinic presenting with vaginal pain, itching, and odor. The patient reports that she was treated for gonorrhea 3 weeks earlier. Examination shows a white vaginal discharge. Cervical cultures are submitted for Neisseria gonorrhoeae and Chlamydia trachomatis. Gram stain reveals predominant, slender, Gram-positive rods with rare neutrophils. Wet mount of a cervical smear shows flagellate protozoa. What is the most likely cause of the presenting problem? Answer Choices: A Gardnerella vaginalis B Neisseria gonorrhoeae C Lactobacilli D Herpes simplex virus E Trichomonas vaginalis

E

A 24-year-old man presents with severe headache, fever and chills, fatigue, and pain in his joints. His wife states that he has "the flu." During the physical exam, his doctor discovers a rash on the patient's thighs and arms. The patient says he has had it for "a while." The rash consists of large red indurated lesions with bright red outer borders and pale centers. The patient believed it to be poison ivy or sumac, because last month he and his wife spent the July 4th weekend with his brother camping and hiking in the Catoctin Mountains of Northern Maryland. What microorganism is probably causing this illness? Answer Choices: A Staphylococcus aureus B Streptococcus pyogenes C Pseudomonas aeruginosa D Coccidioides immitis E Borrelia burgdorferi

E

A 29-year-old woman is brought to the emergency room by her roommate. The patient's illness began 48 hours earlier with vomiting and diarrhea. The patient reports no travel history. Otherwise, she is healthy, with the exception of vaginitis for 1 week before becoming ill. Examination reveals a fever of 38.9° C, hypotension, generalized erythematous rash with desquamation, conjunctivitis, and hyperemic vaginitis. Laboratory results indicate renal failure and thrombocytopenia. Liver enzymes are elevated, but she is not icteric. Blood cultures are negative. What is the most likely diagnosis? Answer Choices: A Neisseria meningitidis septicemia B Leptospirosis C Measles D Malaria E Toxic shock syndrome

E

A 3-month-old infant develops rapid breathing and staccato cough, but otherwise appears well and is afebrile. Physical examination detects fine rales over the lungs as well as red and thickened tympanic membrane. A chest X-ray shows bilateral patchy infiltrates. Laboratory studies indicate eosinophilia and elevated serum immunoglobulin concentrations. What is the likely causative organism? Answer Choices: A Haemophilus influenzae B Mycoplasma pneumoniae C Streptococcus pneumoniae D Mycobacterium tuberculosis E Chlamydia trachomatis

E

A 50-year-old man presented with diffuse pain, stiffness and swelling of his right knee. His symptoms were of 3 weeks duration. He was living near a wooded area, and had history of tick-bite 7 months earlier. He had developed a local skin lesion at the site of the tick-bite, followed by flu-like symptoms, and had recovered without any specific treatment. Radiography of the knee joint showed evidence of effusion. Arthrocentesis yielded inflammatory fluid. What test is recommended for confirming the diagnosis? Answer Choices: A Microscopy of the synovial fluid B Culture of the synovial fluid C PCR analysis of the synovial fluid D Blood culture E Testing for serum antibodi

E

A new test for HIV has been developed. The local community clinic was selected to compare the new test with the Gold standard testing procedure. They found that of the 200 patients tested, 120 were confirmed cases of HIV. The new test detected 120 cases of HIV among the 200 patients as well. Of these, 30 were found to be HIV negative by the gold standard. What is the specificity of the new test? Answer Choices: A 15% B 25% C 75% D 35% E 62.5%

E

What is associated with syphilis? Answer Choices: A Calymmatobacterium granulomatis B Chlamydia trachomatis C Hemophilus ducreyi D Scarcoptes scabiei E Treponema pallidum

E

What noninvasive pathogen is involved in acute diarrheal illness? Answer Choices: A Vibrio parahaemolyticus B Salmonella C Shigella D Yersinia enterocolitica E Vibrio cholerae

E

An unresponsive 20-year-old female college student is brought to the emergency room. Respiratory rate is 50/min and systolic blood pressure is 60mm Hg. She is intubated and transferred to the ICU. The patient's roommate reports that the patient had been feeling ill for about 2 days and had been experiencing diarrhea. The physical examination reveals lungs that are clear; she has an elevated body temperature of 39.8°C, and there is a desquamation of the skin around the fingernails and underlying toes. A malodorous tampon is removed. Culture and Gram stain is obtained from exudate material from the cervix. Blood is drawn for a CBC and for coagulation studies. The CBC is significant for an elevated white blood cell count with a pronounced left shift and a platelet count that is significantly decreased. Prothrombin time is abnormally high. The Gram stain is significant for Gram-positive cocci in clusters. The culture is positive for Gram-positive cocci that are beta-hemolytic on 5% sheep blood agar, catalase-positive, and coagulase-positive. Refer to the image. This patient is diagnosed as having menstrual toxic shock syndrome due to what infection? Answer Choices: A Streptococcus agalactiae B Clostridium perfringens C Bacillus cereus D Streptococcus intermedius group (millerii) E Streptococcus pyogenes F Staphylococcus aureus

F