UWorld 4/26
E. Right mainstem bronchus obstruction (26%) This patient's decreased breath sounds, hemithorax opacification on the right, and deviation of the trachea toward the opacified side are suggestive of a collapsed lung due to bronchial obstruction. Complete collapse of a lung usually occurs following obstruction of a mainstem bronchus (eg, central lung tumors in chronic smokers). As the air trapped in the lung gradually gets absorbed into the blood, there is loss of lung volume due to alveolar collapse (ie, atelectasis), which causes the trachea to deviate toward the affected side. Other mediastinal structures (eg, heart, esophagus, great vessels) may also shift in the same direction. The loss of radiolucent air, combined with shifting of organs into the hemithorax, appears as a completely opacified hemithorax on chest x-ray. (Choice A) Fluid in the alveolar spaces can occur with pulmonary edema. This typically manifests as bilateral fluffy-appearing infiltrates, not unilateral lung opacification. (Choice B) Interstitial lung disease, such as pulmonary fibrosis, would cause reticular markings in both lungs on chest x-ray rather than complete opacification. (Choice C) Intrapleural air accumulation (pneumothorax) would show increased lucency on the affected side, whereas a large pleural effusion can cause complete hemithorax opacification. Tension pneumothorax or a large pleural effusion will cause tracheal deviation away from the affected lung because the excess air or fluid pushes against the mediastinal structures. (Choice D) Pulmonary embolism is a form of pulmonary vascular disease that usually presents with a normal chest x-ray. Characteristic findings such as Westermark sign (area of lucency due to reduced perfusion) or Hampton's hump (wedge-shaped opacity adjacent to the pleura) occur less frequently.
A 65-year-old man with a long history of smoking comes to the emergency department with shortness of breath and a chronic mild cough. His symptoms progressed gradually over the last week and today have become suddenly worse. The patient has hypertension that is controlled with hydrochlorothiazide. On examination, his temperature is 36.7 C (98 F), blood pressure is 135/85 mm Hg, pulse is 94/min, and respirations are 24/min. Pulse oximetry shows 86% on room air. He has decreased breath sounds over the right chest. His chest x-ray is shown in the image below. Which of the following is the most likely cause of this patient's radiographic findings? A. Fluid in the alveolar spaces (%) B. Interstitial lung disease (%) C. Pleural space disease (%) D. Pulmonary vascular disease (%) E. Right mainstem bronchus obstruction (%)
A 52-year-old man comes to the office due to easy bruisibility and muscle weakness. Medical history is unremarkable, but the patient has smoked a pack of cigarettes daily for 30 years. Blood pressure is 160/110 mm Hg, and pulse is 80/min. BMI is 29 kg/m2. Physical examination shows facial plethora, slight centripetal distribution of body fat, diffuse skin pigmentation, and bilateral peripheral edema. Fasting blood glucose is 160 mg/dL and creatinine is 1.2 mg/dL. Chest x-ray reveals a lung mass. Which of the following is the most likely cause of this patient's elevated blood pressure? A. Activation of renal mineralocorticoid receptors (%) B. Elevated plasma catecholamine level (%) C. Impaired glomerular filtration of sodium and water (%) D. Marked urinary loss of albumin (%) E. Renal resistance to antidiuretic hormone (%)
A. Activation of renal mineralocorticoid receptors (%) This patient has Cushing syndrome (CS) presenting with hypertension, facial plethora, easy bruising, centripetal obesity (ie, trunk, abdomen), and hyperglycemia. In light of the associated hyperpigmentation (due to the cosecretion of ACTH and melanocyte-stimulating hormone) and lung mass, this is likely due to an ACTH-secreting small cell lung cancer. Paraneoplastic CS often develops rapidly, and the characteristic facial features may not be present at the time of diagnosis. High levels of cortisol, as seen in patients with CS, frequently cause hypertension due to a combination of the following: Increased peripheral vascular sensitivity to adrenergic stimuli Increased hepatic production of renin substrate (angiotensinogen) Activation of renal tubular mineralocorticoid receptors Activation of renal mineralocorticoid receptors usually occurs in patients with severe hypercortisolism, which is often due to ectopic ACTH secretion. This receptor activation induces sodium reabsorption and potassium wasting in the renal collecting tubules.
A 32-year-old man is evaluated in the emergency department due to fever, night sweats, and chills over the last several days. The patient has been using intravenous drugs recently as he is "stressed out." He has otherwise been in good health with no medical problems. Temperature is 38.3 C (101 F), blood pressure is 120/80 mm Hg, and pulse is 105/min and regular. Further evaluation reveals aortic valve endocarditis with an intracardiac abscess and small fistula formation between the aortic root and right ventricle. Doppler ultrasound interrogation of the fistula will most likely reveal which of the following blood flow patterns? A. Flow from the aortic root to the right ventricle continuously (%) B. Flow from the aortic root to the right ventricle only in diastole (%) C. Flow from the aortic root to the right ventricle only in systole (%) D. Flow from the right ventricle to the aortic root continuously (%) E. Flow from the right ventricle to the aortic root only in diastole (%) F. Flow from the right ventricle to the aortic root only in systole (%)
A. Flow from the aortic root to the right ventricle continuously (%) This patient with aortic valve endocarditis has developed an intracardiac fistula between the aortic root and right ventricle. Aortocavitary fistulas are an uncommon complication of bacterial endocarditis caused by extension of the infection from the valve to the adjacent myocardium. Echocardiography with Doppler analysis can be used to detect and quantify shunts in patients with intracardiac fistulas. During the normal cardiac cycle, central aortic pressure (eg, 120/80 mm Hg) is higher than right ventricular pressure (eg, 25/5 mm Hg) during systole and diastole. Consequently, in patients with aortocavitary fistula, Doppler interrogation will most likely demonstrate continuous blood flow from the higher-pressure aortic root to the lower-pressure right ventricle (left-to-right cardiac shunt) (Choices B and C). This can lead to a continuous murmur heard on cardiac auscultation.
A 25-year-old woman comes to the office to follow up type 1 diabetes mellitus. She takes long- and short- acting insulin with good glycemic control and has no diabetes-related complications. She also has a history of hypothyroidism for which she takes levothyroxine. The patient has been covered under her parent's medical insurance for the last several years, but she recently started working full time for a company that provides a broad variety of employee insurance choices. She requests advice in choosing a health insurance plan. The patient has no disability and says that her main priority is low monthly payments. Which of the following insurance options would be most appropriate for this patient? A. Health maintenance organization (%) B. Medicaid (%) C. Medicare (%) D. Point-of-service plan (%) E. Preferred provider organization (%)
A. Health maintenance organization (%)
38-year-old man comes to the office with reports of dyspnea on exertion and decreased exercise tolerance. His medical history is unremarkable, and he has no history of childhood asthma or cough. He has never smoked and has no known occupational exposures. The patient has gained almost 100 lb over the past 4 years since leaving the military due to a sedentary lifestyle. He currently weighs 135 kg (297.6 lb) and has a BMI of 41 kg/m2. His respiratory rate is 22/min and pulse oximetry is 93% on room air at rest. Physical examination is notable for central obesity. Lungs are clear on auscultation bilaterally. Which of the following changes (forced expiratory volume in 1 second [FEV1], forced vital capacity [FVC], expiratory reserve volume [ERV], residual volume [RV], and total lung capacity [TLC]) are most likely to be seen on pulmonary function testing in this patient? FEV1 FVC ERV RV TLC A. ↓ ↓ ↓ Normal ↓ (%) B. ↓ ↓ Normal ↑ ↑ (%) C. ↓ Normal Normal ↑ ↑ (%) D. ↑ ↑ ↓ Normal Normal (%) E. ↑ Normal ↑ ↑ ↑ (%)
A. ↓ ↓ ↓ Normal ↓ (%) The most common indicator of obesity-related disease is a reduction in expiratory reserve volume (ERV), which is the maximum volume of air that can be expired after a normal tidal expiration. Obesity has minimal effect on residual volume (RV), but functional residual capacity, which is the sum of RV and ERV, is reduced due to the marked reduction in ERV. Obesity can also cause reductions of forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), and total lung capacity (TLC), depending on the severity of obesity and body fat distribution (abdominal obesity causes greater impairment). However, these reductions are generally modest, especially relative to decrements in ERV.
A boy is admitted to the neonatal intensive care unit shortly after being born to a 28-year-old woman who had poor prenatal care. His temperature is 37.2 C (99 F), blood pressure is 70/30 mm Hg, pulse is 128/min, and respirations are 40/min. Pulse oximetry shows 85% on room air. Physical examination is significant for orbital hypertelorism, a submucous cleft palate, and bifid uvula. An echocardiogram reveals right ventricular hypertrophy, pulmonary stenosis with ventricular septal defect, and overriding aorta. The patient's diagnosis is eventually confirmed by fluorescence in situ hybridization. These findings are most consistent with which of the following mechanisms? A. Abnormal ciliary motility (%) B. Chromosome microdeletion (%) C. Defect in fibrillin synthesis (%) D. Genomic imprinting (%) E. Mutation of tumor suppressor gene (%) F. Nucleotide repeat expansion (%)
B. Chromosome microdeletion (%) Chromosome 22q11.2 microdeletion involves deletion of genes residing in adjacent loci. This results in variable phenotypes including DiGeorge syndrome (cardiac anomalies, hypoplastic/absent thymus, hypocalcemia) and velocardiofacial syndrome (cleft palate, cardiac anomalies, dysmorphic facies); the latter is exemplified in this patient. Defective neural crest migration into derivatives of the third and fourth pharyngeal pouches results in maldevelopment of the thymus and parathyroid as well as subsequent T-cell deficiency and hypocalcemia. Cardiac defects include interrupted aortic arch and tetralogy of Fallot (described in this patient). Dysmorphic facial features include orbital hypertelorism, short palpebral fissures and short philtrum, cleft palate, and bifid uvula. In fluorescence in situ hybridization (the gold standard test), genes of interest are hybridized with fluorescently labeled DNA probe. Lack of fluorescent signal is indicative of a microdeletion
A 5-year-old girl is brought to the office for evaluation of a persistent cough. The patient has had a productive cough daily for the past month. History includes recurrent episodes of otitis media despite bilateral ear tube placement, numerous lower respiratory tract infections, and occasional ulcerative skin lesions. Laboratory evaluation shows normal levels of total B and T cells and serum immunoglobulin. Genetic testing reveals a mutation in the TAP1 gene, which encodes a protein involved in the transport of cytosolic molecules into the endoplasmic reticulum. Which of the following processes is most likely to be impaired by this mutation? A. B cell differentiation into plasma cells (%) B. Cytotoxic T cell activation by MHC class I molecules (%) C. Destruction of phagocytized organisms (%) D. MHC class II molecule expression on B cells (%) E. Migration and extravasation of neutrophils (%)
B. Cytotoxic T cell activation by MHC class I molecules (%) Transporter associated with antigen processing (TAP) proteins are transmembrane proteins necessary for the presentation of cytosolic antigens on major histocompatibility complex (MHC) molecules. When cellular proteins (or pathogen-derived proteins) are degraded by proteasomes, some of the resulting peptide fragments are transported into the endoplasmic reticulum by TAP proteins and loaded onto MHC class I molecules. The MHC class I-peptide complexes then translocate to the cell surface where they can activate cytotoxic T cells through interaction with T cell receptors and CD8 coreceptors
A 6-year-old girl with cerebral palsy undergoes selective dorsal rhizotomy surgery. The patient was born prematurely with a very low birth weight and had experienced periventricular cerebral white matter injury. During the procedure, dorsal rootlets of lumbosacral spinal nerves are selectively severed, as shown in the image below: Which of the following is the most likely effect of this intervention in this patient's lower extremities? A. Decreased muscle mass (%) B. Decreased muscle tone (%) C. Increased tendon reflexes (%) D. Muscle fasciculations (%) E. Muscle paralysis (%)
B. Decreased muscle tone (%) This patient has cerebral palsy, a heterogeneous condition characterized by permanent, nonprogressive motor dysfunction caused by damage to the developing brain. Certain subtypes result in significant spasticity (eg, hypertonia, hyperreflexia). Spastic cerebral palsy may be caused by periventricular white matter necrosis (as in this patient), which leads to a loss of descending inhibitory control from the upper motor neurons. Specifically, lack of CNS inhibition leads to a hyperactive stretch reflex. The stretch reflex is a monosynaptic reflex mediated at the level of the spinal cord through the following pathway: Muscle lengthening is sensed by muscle spindles Afferent signal of stretch is conveyed to the spinal cord via the dorsal nerve fibers Efferent signals are conveyed via the ventral root of the spinal cord Extrafusal fibers are stimulated, causing muscle contraction The stretch reflex is responsible for deep tendon reflexes (eg, patellar, achilles) and the maintenance of muscle tone by constant muscular activity occuring even at rest, so a hyperactive stretch reflex leads to increased muscle tone (ie, spasticity). A selective dorsal rhizotomy procedure destroys the afferent (sensory) arm of the reflex arc, decreasing muscle tone without sacrificing motor innervation of the muscles
A 27-year-old woman, gravida 1 para 0, at 37 weeks gestation comes to the emergency department after spontaneous rupture of membranes with leakage of blood mixed with fluid. Emergency cesarean delivery is performed due to severe fetal bradycardia. On delivery, the neonate is apneic and hypotonic. Resuscitation with endotracheal intubation and assisted ventilation is performed, which improves bradycardia. Apgar scores are <5 at 5 and 10 minutes. Umbilical cord blood analysis shows high anion gap metabolic acidosis. Controlled hypothermia to maintain body temperature at 33-35 C (91.4-95 F) is begun. This therapy is most likely to provide benefit via which of the following mechanisms? A. Decreased activation of the coagulation cascade (%) B. Decreased reactive oxygen species-mediated neuronal injury (%) C. Increased conversion of bilirubin to less toxic water-soluble isomers (%) D. Increased hepatic clearance of lactic acid (%)
B. Decreased reactive oxygen species-mediated neuronal injury (%) This early-term infant has sustained hypoxic-ischemic injury during delivery and is at risk of worsening neonatal encephalopathy (eg, decreased consciousness, impaired respiration, seizures). Hypoxia can lead to neuronal injury through multiple injury cascades, many of which lead to the formation of reactive oxygen species (ROS). ROS can mediate cellular damage of DNA, cell membranes, proteins, and enzymes, leading to widespread neuronal death. Therapeutic hypothermia (maintenance of temperature at 33-35 C [91.4-95 F]) leads to improved neurologic outcomes in a variety of hypoxia-induced injuries (eg, after cardiac arrest, seizures). The formation of ROS after ischemic injury is temperature dependent, so it can be decreased by therapeutic hypothermia. In addition, therapeutic hypothermia decreases cerebral blood flow, oxygen consumption, and glucose metabolism, thereby decreasing the formation of ROS due to both cellular metabolism and reperfusion. Therapeutic hypothermia has other beneficial effects, including lowering intracranial pressure, reducing excitatory neurotransmitters, and decreasing activation of inflammatory and apoptotic pathways (eg, blocks tumor necrosis factor and caspase pathways).
A 28-year-old woman, gravida 2 para 1, comes to the emergency department for evaluation of vaginal bleeding. The patient has had bright red spotting for the past 24 hours but no contractions or leakage of fluid. She is at 31 weeks gestation by last menstrual period and has not had prenatal care this pregnancy. Her first pregnancy ended in an uncomplicated spontaneous vaginal delivery at term. Vital signs and fetal heart rate tracing are normal. Physical examination shows a nontender uterus consistent in size with 31 weeks gestation. A pelvic ultrasound reveals a complete placenta previa. The findings are discussed with the patient, and she states that she would still like to have a vaginal delivery. The physician says, "Unfortunately, the only safe option for delivery is a cesarean delivery." The physician's statement is an example of which of the following ethical principles? A. Assisted decision-making (%) B. Directive counseling (%) C. Informed refusal (%) D. Shared decision-making (%) E. Substituted judgment (%)
B. Directive counseling (%) Most medical decisions are made via shared decision-making, in which the patient's preferences and personal values are considered when discussing ≥2 medically reasonable treatment options (Choice D). However, when there is only 1 medically reasonable treatment option that has clearly superior evidence-based support, it is ethically appropriate for the physician to provide directive counseling, in which only a single treatment option is recommended to a patient. This patient has a complete placenta previa, a condition in which the entire placenta covers the cervix, which is associated with a high risk of maternal (eg, hemorrhage) and fetal (eg, intrauterine demise) morbidity and mortality with vaginal delivery. Due to these risks, the only safe option for delivery, as stated to this patient, is cesarean delivery. Although this patient prefers a vaginal delivery, it is inappropriate for the physician to discuss this choice as a safe and reasonable option. It is the physician's ethical responsibility to advise against it and provide directive counseling by explaining why a cesarean delivery is medically necessary.
A 19-year-old man comes to the office due to frequent episodes of disorientation, palpitations, tremulousness, and excessive sweating over the past 3 months. He says the symptoms resolve quickly after drinking some juice or a carbonated beverage. The patient was diagnosed with type 1 diabetes mellitus at age 12 and takes short- and long-acting insulin. He has had no dose changes in the past 2 years or diabetic complications and follows up with an ophthalmologist frequently. The patient is a college student and reports some stress due to an upcoming midterm examination. He does not use tobacco, alcohol, or illicit drugs. Vital signs and physical examination are within normal limits. Laboratory results show a hemoglobin A1c of 6.8% and no proteinuria. Which of the following factors most likely precipitated this patient's current symptoms? A. Fructose-rich drink consumption (%) B. Intense exercise (%) C. Mental stress (%) D. Respiratory infection (%) E. Sleep deprivation (%) F. Weight gain (%)
B. Intense exercise (%) This patient has frequent symptomatic hypoglycemia—disorientation, sweating, and palpitations, which are relieved by intake of glucose—despite no changes to his chronic insulin regimen. Hypoglycemia is often induced in patients with type 1 diabetes by inadvertent overdose of insulin or decreased carbohydrate intake (eg, skipped meal), but can also be triggered by intensive physical activity/exercise. Glucose uptake by skeletal muscle cells is mediated by glucose transporter type 4 (GLUT4). GLUT4 is translocated to cell membranes and transverse tubules (deep invaginations in the cell membrane) in response to insulin. GLUT4 translocation also occurs during muscle contraction by an insulin-independent mechanism, which is mediated by several cellular factors, including AMP-activated kinase, nitric oxide, and calcium-calmodulin-activated protein kinase. In normal individuals, overt hypoglycemia does not occur with exercise because a drop in blood glucose suppresses insulin release from the beta cells, and counterregulatory hormones (eg, glucagon) increase endogenous glucose production via glycogenolysis and gluconeogenesis. However, patients taking exogenous insulin are vulnerable to exercise-induced hypoglycemia because insulin will continue to be released from the injection site despite falling glucose levels (Choices C, D, and E) Infection, pain, sleep deprivation, and severe mental/emotional distress tend to cause hyper- rather than hypoglycemia due to increased production of counterregulatory hormones (eg, catecholamines, cortisol). These hormones raise glucose by increasing glycogenolysis and gluconeogenesis and decreasing pancreatic insulin secretion (in patients with residual islet cell function)
A 58-year-old man comes to the office due to worsening right upper extremity weakness over the past 4 weeks. The patient frequently travels for work and has had difficulty carrying heavy bags and getting luggage into or out of the overhead bins. He also has had neck and shoulder pain for the past several months, which he attributes to stress. The patient reports no trauma, and medical history is significant for hypertension. Physical examination shows weakness of shoulder abduction and loss of the biceps reflex on the right side. Pinprick sensation is decreased over the right lateral arm and forearm. Which of the following pathologic processes is most likely underlying this patient's current symptoms? A. Axonal loss in the corticospinal tracts (%) B. Cystic expansion of the central canal (%) C. Degenerative changes in the vertebral joints (%) D. Microinjury and tear of the rotator cuff tendons (%) E. Rupture of the long head of the biceps tendon (%)
C. Degenerative changes in the vertebral joints (%) Educational objective:Cervical radiculopathy typically results in neck and/or arm pain associated with neurologic deficits that follow a dermatomal/myotomal pattern. Osteophytes that form due to degenerative changes in the vertebral joints can progressively narrow the neural foramina leading to nerve root compression
A 62-year-old man comes to the emergency department due to severe colicky upper abdominal pain, nausea, and vomiting. He reports several episodes of similar abdominal discomfort in the past. The patient does not use tobacco, alcohol, or illicit drugs. He immigrated to the United States from East Asia several years ago. Physical examination shows right upper quadrant abdominal tenderness. An imaging study shows several gallstones in the common bile duct and gallbladder. The stones are removed from the duct endoscopically, and a cholecystectomy is also performed. The gallstones are dark brown, soft, and composed primarily of calcium bilirubinate with variable amounts of cholesterol. Which of the following enzymes most likely played an important role in the pathogenesis of this patient's condition? A. 7-alpha-hydroxylase (%) B. Aromatase (%) C. Beta-glucuronidase (%) D. Desmolase (%) E. HMG-CoA reductase (%)
C. Beta-glucuronidase (%) Gallstones can be categorized as cholesterol, pigment, or mixed stones. Cholesterol stones are formed when the ability of bile salts to solubilize cholesterol is overwhelmed by high concentrations of cholesterol in bile. Cholesterol stones are yellow to pale gray and hard. By contrast, pigment gallstones are composed of calcium salts of unconjugated bilirubin, are comparatively soft, and are dark brown to black. Brown pigment stones typically arise secondary to bacterial (eg, Escherichia coli) or helminthic (eg, Ascaris lumbricoides, Clonorchis sinensis) infection of the biliary tract, which results in the release of beta-glucuronidase by injured hepatocytes and bacteria. This enzyme hydrolyzes bilirubin glucuronides and increases the amount of unconjugated bilirubin. The liver fluke C sinensis is a common cause of pigmented stones in East Asian countries and can have a prolonged quiescent phase before inducing symptoms
A 42-year-old woman comes to the emergency department for evaluation of chest pain. She was moving furniture in her summer house 2 days ago when she experienced sharp pain in the left side of the sternum that quickly subsided. Since then, the patient has had episodic pain with deep inspiration or trunk movement. She has no fever or cough. The patient has a history of hypertension. Her father died of myocardial infarction at age 67. She does not use tobacco or illicit drugs. Blood pressure is 146/85 mm Hg in the right arm and 142/80 mm Hg in the left arm, pulse is 86/min, and respirations are 12/min. She has localized tenderness to palpation at the left sternal border. Lungs are clear to auscultation, and cardiac examination reveals normal heart sounds without gallops or murmurs. The abdomen is soft and nontender. There is no peripheral edema. Which of the following is the most likely cause of this patient's symptoms? A. Acute pericarditis (%) B. Aortic dissection (%) C. Costochondritis (%) D. Esophageal spasm (%) E. Gastroesophageal reflux disease (%) F. Panic disorder (%) G. Pneumonia (%) H. Pulmonary arterial hypertension (%) I. Pulmonary embolism (%) J. Unstable angina (%)
C. Costochondritis (%) This patient's chest pain is most likely due to costosternal syndrome (also known as costochondritis or anterior chest wall syndrome) involving the regional chest wall. It usually occurs after repetitive activity and involves the upper costal cartilage at the costochondral or costosternal junctions. The pain is typically reproduced with palpation and worsened with movement or changes in position (eg, horizontal arm flexion). Patients typically do not have palpable warmth, swelling, or erythema
A 6-year-old boy is brought to the emergency department by his parents with a 2-day history of fever and headaches. The parents report that he vomited once this afternoon. All of his vaccinations are up-to-date and he has no significant past medical history. His temperature is 38.7 C (102 F). Examination shows mild pharyngeal erythema in addition to neck stiffness. Cerebrospinal fluid analysis reveals the following: Glucose 65 mg/dL Protein 85 mg/dL Leukocytes 300/mm3 Differential Neutrophils 15% Lymphocytes 85% Red blood cells none Which of the following infectious agents is most likely to have caused this patient's illness? A. Coronavirus (%) B. Cryptococcus neoformans (%) C. Enterovirus (%) D. Mumps virus (%) E. Neisseria meningitidis (%) F. Streptococcus agalactiae (%) G. Streptococcus pneumoniae (%)
C. Enterovirus (%) This child has clinical evidence of meningitis (fever, headache, vomiting, stiff neck). Analysis of the cerebrospinal fluid (CSF) shows normal glucose, marginally elevated protein, and pleocytosis with a lymphocytic predominance. This pattern suggests aseptic meningitis, which is usually viral in etiology. Enteroviruses (eg, coxsackievirus, echovirus, poliovirus) are responsible for >90% of cases. Clinical symptoms are similar to meningitis caused by bacterial or fungal pathogens. However, aseptic meningitis is generally less severe, and focal neurologic signs, seizures, and alterations in mental status are absent. The presence of any of these should prompt consideration of other conditions, including bacterial meningitis, encephalitis, and intracranial hemorrhage. A negative Gram stain and sterile culture will further support the diagnosis of aseptic meningitis
A 43-year-old man comes to the office with a several-month history of fatigue, rash, flushing, and abdominal cramps. His rash is worse with rubbing or scratching, and he has diffuse itching after hot showers. The patient is frequently dizzy and light-headed after prolonged standing and had an episode of syncope while working in the hot sun. He used to be healthy and physically active but has had to reduce his normal activity. The patient does not use tobacco, alcohol, or illicit drugs. Vital signs are normal. Skin examination shows a maculopapular rash. Skin biopsy shows large clusters of mast cells that are positive for KIT (CD 117). Which of the following additional findings are most likely present in this patient? A. Bacterial colonization of the stomach (3%) B. Gastric atrophy (%) C. Gastric hypersecretion (%) D. Gastric hypomotility (%) E. Pancreatic endocrine tumor (%) F. Pernicious anemia (%)
C. Gastric hypersecretion (%) Gastric acid secretion by parietal cells in the fundus and body of the stomach is stimulated by: Histamine binds H2 receptors and increases intracellular cyclic AMP (cAMP) concentration. Acetylcholine binds M3 muscarinic receptors and leads to an increase in intracellular calcium. Gastrin binds to the cholecystokinin B receptor and increases the intracellular calcium concentration. It also stimulates histamine synthesis and release by enterochromaffin-like cells in the stomach. Intracellular calcium and cAMP activate protein kinases and lead to increased transport of H+ by H+/K+ ATPase into the gastric lumen. In systemic mastocytosis, clonal mast cell proliferation occurs in the bone marrow, skin, and other organs. Mast cell proliferation often is associated with mutations in the KIT receptor tyrosine kinase. These cells are characterized by prominent expression of mast cell tryptase. Excessive histamine release from degranulation of mast cells mediates many of the symptoms of the disease, such as syncope, flushing, hypotension, pruritus, and urticaria. In addition, histamine induces gastric acid secretion, which can lead to gastric ulceration. The excess acid also inactivates pancreatic and intestinal enzymes, causing diarrhea. Other gastrointestinal symptoms include nausea, vomiting, and abdominal cramps.
A 30-year-old man comes to the emergency department with a 4-day history of progressively worsening abdominal pain and bloody diarrhea. He was started on mesalamine therapy 6 months ago after being diagnosed with ulcerative colitis but has been noncompliant with treatment. His temperature is 38.8 C (102 F), blood pressure is 100/70 mm Hg, and pulse is 130/min. The patient is lethargic and has dry mucous membranes. There is marked abdominal distension and tenderness without rebound or guarding. Rectal examination shows guaiac-positive, maroon-colored, liquid stool. Which of the following is the best next step in this patient's workup? A. Abdominal ultrasonography (%) B. Barium enema (%) C. Colonoscopy (%) D. Plain abdominal x-ray (%) E. Small-bowel contrast study (%)
D. Plain abdominal x-ray (%) This patient with abdominal pain/distension, bloody diarrhea, fever, and signs of shock (eg, hypotension, tachycardia) in the setting of untreated ulcerative colitis likely has toxic megacolon. This is a common life-threatening complication of inflammatory bowel disease and is seen more frequently in ulcerative colitis than in Crohn disease. Toxic megacolon can also be associated with Clostridium difficile infection and other forms of infectious colitis. Severe, occasionally transmural inflammation causes release of inflammatory mediators, bacterial products, and increased nitric oxide, which contribute to colonic smooth muscle paralysis. Rapid colonic distension ensues, thinning the intestinal wall and making it prone to perforation. Plain abdominal x-ray is the preferred diagnostic imaging study as it may show colonic dilation (as seen above) with multiple air-fluid levels (not seen in this image). Free air may also be visualized in the setting of intestinal rupture, which presents with generalized peritonitis (eg, abdominal rebound tenderness/guarding).
A 36-year-old man comes to the office after he was found to have an abnormal lipid panel during employee wellness testing at his company. He has no prior medical problems and takes no medications. The patient is a software technician and has a sedentary lifestyle. He eats mostly fast foods, rarely exercises, and drinks 2-3 cans of beer daily. His BMI is 31 kg/m2. Physical examination is unremarkable. Results of laboratory studies performed in the office are as follows: Total cholesterol 290 mg/dL High-density lipoprotein 45 mg/dL Low-density lipoprotein 110 mg/dL Triglycerides 675 mg/dL Lifestyle modification with a balanced diet, regular exercise, and reduced alcohol intake is advised. He is also started on fenofibrate therapy. This medication is most likely to help the patient by which of the following mechanisms? A. Blocking intestinal cholesterol absorption (%) B. Decreasing hepatic cholesterol synthesis (%) C. Increasing fecal loss of cholesterol derivatives (%) D. Inhibiting LDL receptor degradation (%) E. Reducing hepatic VLDL production (%)
E. Reducing hepatic VLDL production (%) This patient has a moderately elevated (>500 mg/dL) triglyceride level, which is associated with an increased risk of cardiovascular disease. Lifestyle modifications (increased aerobic exercise, decreased alcohol and total caloric intake) can decrease triglycerides, but moderate (or worse) hypertriglyceridemia usually requires pharmacologic therapy. Lipoprotein lipase (LPL) hydrolyzes triglycerides in chylomicrons and VLDL to release free fatty acids, which can be used for energy or converted back to triglycerides for storage in adipose tissue. It also facilitates the transfer of triglycerides from these lipoproteins to HDL. Fibrates (eg, gemfibrozil, fenofibrate) activate peroxisome proliferator-activated receptor alpha (PPAR-α), which leads to decreased hepatic VLDL production and increased LPL activity. They are able to decrease triglyceride levels by 25%-50% and increase HDL by 5%-20%. Fish oil supplements containing high concentrations of omega-3 fatty acids also decrease VLDL production, and inhibit synthesis of apolipoprotein B as well. These supplements lower triglycerides and can be used as an alternate treatment for patients with moderate hypertriglyceridemia.
A 52-year-old woman comes to the office due to fatigue for the last 2 weeks. The patient was previously healthy, but over the past 3 months, she has had significant weight loss without changing her diet. She also reports increased sweating, hand tremor, and decreased sleep. Examination shows diffuse, nontender enlargement of the thyroid gland. The eyeballs are protuberant. The remainder of the examination is notable for 1+ pitting edema in the ankles. Which of the following parameters is most likely to be decreased in this patient? A. Cardiac contractility (%) B. Myocardial oxygen consumption (%) C. Pulmonary artery pressure (%) D. Pulse pressure (%) E. Systemic vascular resistance (%) F. Systolic blood pressure (%)
E. Systemic vascular resistance (%) Educational objective:Hyperthyroidism causes characteristic cardiovascular changes. Increased metabolic demand in the tissues and a direct vasodilatory effect of thyroid hormone lead to reduced systemic vascular resistance (and decreased diastolic blood pressure). A direct sympathetic-like effect of thyroid hormone on the myocardium leads to increased heart rate, contractility, and cardiac output. Increased stroke volume increases pulse pressure and systolic blood pressure.
A 32-year-old woman comes to the office due to postprandial abdominal pain and nausea. The patient has no diarrhea, constipation, bloody stools, or vomiting. Medical history is significant for rheumatoid arthritis. The abdomen is mildly tender to palpation at the epigastrium but without distension or hepatosplenomegaly. Laboratory studies reveal anemia. A small gastric ulcer is seen during upper endoscopy, and biopsies are negative for Helicobacter pylori. Biopsies of the duodenum reveal numerous intraepithelial lymphocytes, villous atrophy, and crypt hyperplasia. Based on these biopsy findings, this patient is at increased risk for developing which of the following conditions later in life? A. Angiodysplasia of the small bowel (%) B. Colon adenocarcinoma (%) C. Portal vein thrombosis (%) D. Pyloric stenosis (%) E. T-cell lymphoma (%)
E. T-cell lymphoma (%) This patient's presentation (abdominal pain, anemia) and biopsy findings are suggestive of celiac disease, an immune-mediated disorder triggered by gluten, a protein found in wheat, barley, and rye. Diarrhea is also common in celiac disease but may be absent. Gliadin, a breakdown product of gluten, is primarily responsible for causing chronic inflammatory changes of the small bowel. Classic histologic findings, which are most prominent in the proximal small bowel (eg, duodenum, proximal jejunum), include intraepithelial lymphocytosis, villous atrophy, and crypt hyperplasia. Chronic lymphocytic recruitment and proliferation within the small-bowel mucosa predisposes to monoclonal T-cell expansion, putting these patients at risk for enteropathy-associated T-cell lymphoma. This small-bowel cancer is usually very aggressive and has a poor prognosis despite chemotherapy
A 44-year-old man with a history of heavy alcohol consumption comes to the emergency department with a nosebleed after getting into a fight while intoxicated. Continuous local pressure is applied and his bleeding resolves within 30 minutes. A detailed physical examination is performed after the bleeding subsides and shows distended paraumbilical veins, ascites, and a flapping hand tremor on wrist extension. Which of the following laboratory findings would be most indicative of a poor prognosis for this patient? A. High aspartate aminotransferase (19%) B. High fibrinogen levels (3%) C. High gamma glutamyl transferase (14%) D. Prolonged bleeding time (5%) E. Prolonged prothrombin time (56%)
Laboratory findings in cirrhosis reflect both hepatocellular/biliary injury and loss of hepatic function. Hepatocyte injury causes a release of intracellular enzymes and an increase in serum transaminases; biliary injury is reflected by increases in alkaline phosphatase and gamma-glutamyl transpeptidase (GGT). Although these laboratory studies are indicative of ongoing hepatobiliary injury, they do not provide information on the liver's functional reserve, a key determinant of prognosis in patients with cirrhosis. Serum albumin levels and prothrombin time (PT) are better indicators of the liver's biosynthetic function, and its ability to transport and metabolize organic anions is reflected by the serum bilirubin level. Hypoalbuminemia, elevated bilirubin levels, and prolonged PT are signs of inadequate liver function (eg, liver failure) and indicate a poor prognosis in cirrhotic patients. For this reason, they are included in multiple scoring systems used to assess the severity of liver failure and need for transplantation (Choice D) The bleeding time is a measure of platelet function (not liver synthetic function) and is often prolonged in severe alcohol-related liver disease, although with a fair degree of variance. Thrombocytopenia develops with chronic alcohol use due to both direct toxic effects of alcohol on the bone marrow as well as splenic sequestration of platelets.
A 65-year-old man comes to the office due to progressive weight loss, jaundice, and anorexia over the last 3 months. His urine has been dark and his stools have been pale. The patient has no prior medical conditions and takes no medications. He has smoked a pack of cigarettes a day for 40 years. He drinks 2 cups of coffee every day and 1 or 2 glasses of wine on most nights. He used illicit drugs for 2 years when he was in his teens but has used none since. The patient has a sedentary lifestyle and frequently consumes red and processed meats. Vital signs are within normal limits. BMI is 28 kg/m2. Physical examination shows scleral icterus. The chest is clear to auscultation and percussion. Abdominal examination shows an enlarged but nontender gallbladder. There is no ascites. Which of the following is the strongest factor predisposing to this patient's current condition? A. Alcohol use (%) B. Cigarette smoking (%) C. Coffee consumption (%) D. Low-fiber diet (%) E. Processed meat consumption (%) F. Viral hepatitis (%)
Pancreatic adenocarcinoma should be considered in any patient with painless obstructive jaundice (elevated bilirubin, dark urine, pale stools) and weight loss. Courvoisier sign (painless palpable gallbladder in a jaundiced patient) can also raise suspicion, although this can be seen in a number of conditions (eg, cholangiocarcinoma, hepatic duct obstruction). Symptoms of pancreatic malignancy vary with location; tumors at the pancreatic head typically produce obstructive symptoms due to compression of the common bile duct (CBD), whereas those in the body and tail do not obstruct the CBD and often produce midepigastric pain due to invasion of the splanchnic plexus. Smoking is the most important environmental risk factor for pancreatic cancer and doubles the risk.
(Choice A) Assisted decision-making occurs when
a family member or other caregiver helps the patient in making a medical decision (but does not make the decision for the patient). Common scenarios include when patients have intellectual disability or a potentially reversible impairment in decision-making capacity (eg, fluctuating mental illness [schizophrenia]).
(Choice E) Substituted judgment occurs when
a surrogate decision-maker makes a health care decision for an incapacitated patient based on the surrogate's knowledge of the patient's wishes and values
Reflux occurs in most pregnant women and is common in all trimesters. The major underlying cause is
elevated estrogen and progesterone levels, which relax the smooth muscle of the LES leading to decreased LEStone and reduced sensitivity to contractile stimuli (eg, high-protein meal). Later in pregnancy, reflux can also occur when the gravid uterus compresses the stomach and results in an altered LES angle or increased gastric pressure.
Uricosuric agents (eg, _____) are second-line drugs for chronic management of gout. These drugs increase renal excretion of uric acid and are therefore contraindicated in patients with a history of renal stones.
probenecid
(Choice C) Informed refusal refers to
the patient's refusal of a recommended medical treatment following an informed consent discussion (including full disclosure of the risks of refusing treatment). This would occur in this case if, after discussion of the need for cesarean delivery, the patient refuses the procedure.