All practice questions

An academic medical center's endocrinology and genetics board is reviewing complex cases presenting with differences in sex development and severe electrolyte abnormalities. Based on the integrated clinical and laboratory profiles provided, match each patient's presentation to the most accurate underlying primary enzymatic deficiency.

A 62-year-old man presents to the clinic with a 1-month history of progressive proximal muscle weakness, primarily affecting his thighs and hips. He reports significant difficulty climbing stairs and rising from a seated position, but notes that his strength temporarily improves after a few minutes of continuous walking. He has a 45-pack-year smoking history. Physical examination reveals decreased deep tendon reflexes in the lower extremities and proximal muscle weakness that transiently improves following repetitive muscle contraction. A basic metabolic panel, including serum calcium, is within normal limits. A chest radiograph demonstrates a $4.5$-cm, centrally located left lung mass with associated hilar adenopathy. Which of the following best describes the underlying pathogenesis of this patient's neurologic symptoms and the most appropriate next step in his care?

A physician evaluates an ambulatory patient who recently developed a progressively worsening rash on both lower extremities. The patient also reports significant new-onset fatigue and bilateral pain in the metacarpophalangeal and knee joints over the past $14$ days. Medical history is significant for a diagnosis of chronic hepatitis C virus (HCV) infection confirmed several years ago, though the patient has not undergone any targeted antiviral treatment. On physical examination, the physician notes multiple non-blanching, raised, red-purple lesions distributed over the shins and calves. Joint examination shows mild, symmetric swelling without warmth. Laboratory analysis demonstrates the following:

Serum aspartate aminotransferase: $85$ U/L
Serum alanine aminotransferase: $92$ U/L
Rheumatoid factor: Positive
Complement C3: Normal
Complement C4: Markedly decreased
Urinalysis: $2+$ protein, $15$-$20$ red blood cells/hpf, occasional dysmorphic red blood cells

Which of the following immunopathologic mechanisms is most likely responsible for this patient's current clinical presentation?

A 34-year-old man is brought to the emergency department after a high-speed motor vehicle collision. He complains of severe shortness of breath and right-sided chest pain. He is fully immobilized on a backboard with a cervical collar in place. Vital signs include a blood pressure of 115/75 mm Hg, pulse of 112/min, and respiratory rate of 28/min. Physical examination reveals decreased breath sounds over the right hemithorax. The trachea is midline, and there is no jugular venous distention. Because the patient cannot sit upright due to strict spine precautions, a supine portable anteroposterior chest radiograph is obtained. The image demonstrates a markedly radiolucent and abnormally deepened right costophrenic angle extending toward the hypochondrium. The apical visceral pleural line is not clearly visible. Which of the following is the most likely diagnosis based on this specific radiographic finding?

Evaluate the following multiphasic cross-sectional imaging descriptions of incidentally discovered solid liver lesions. Match each specific contrast-enhancement kinetic pattern observed on computed tomography (CT) or magnetic resonance imaging (MRI) with its most likely corresponding hepatic diagnosis.

A hospital ward team is evaluating a 74-year-old female who was admitted three days ago for an acute exacerbation of chronic systolic heart failure. Since admission, she has received continuous intravenous bumetanide. Over the past 24 hours, her urine output has significantly decreased, and routine morning laboratory studies reveal an acute rise in her serum creatinine from a baseline of $1.1 \text{ mg/dL}$.

The following laboratory values are obtained:

Due to the confounding effect of ongoing loop diuretic therapy, the standard fractional excretion of sodium (FENa) may be misleading. The attending physician asks for the calculation of the most appropriate alternative diagnostic index to differentiate between prerenal azotemia and intrinsic acute tubular necrosis in this specific clinical context.

What is the value of this alternative index (expressed as a percentage)?

Match each pediatric patient's clinical presentation with the underlying primary immunologic defect.

A 42-year-old woman comes to the ambulatory care clinic with a 4-month history of worsening joint pain and stiffness in her hands. The stiffness is most severe upon awakening and typically lasts for 2 to 3 hours before gradually improving. She has noted increasing difficulty with tasks that require fine dexterity, such as typing and opening jars. Vital signs are within normal limits. On physical examination, there is bilateral, symmetrical, boggy swelling and tenderness over the metacarpophalangeal (MCP) and proximal interphalangeal (PIP) joints of both hands. The distal interphalangeal (DIP) joints are notably spared. There is mild atrophy of the dorsal interosseous muscles. If this patient's underlying condition continues to progress without intervention, which of the following physical examination findings is most likely to develop over time?

A 45-year-old woman is brought to the emergency department by her husband due to progressive confusion, tinnitus, and multiple episodes of vomiting over the past 24 hours. She has a history of major depressive disorder and chronic osteoarthritis, for which she takes several over-the-counter medications. Her temperature is 38.1°C (100.6°F), blood pressure is 112/70 mm Hg, pulse is 118/min, and respiratory rate is 28/min. She appears agitated and diaphoretic.

Laboratory studies show:

Arterial blood gas on room air:

Based on these laboratory results, which of the following is the most accurate interpretation of this patient's acid-base status?

A 36-year-old woman presents to the clinic complaining of progressive muscle weakness and fatigue over the past several weeks. She also reports a gritty sensation in her eyes and needing to drink water frequently to swallow dry foods. Vital signs are within normal limits. Physical examination reveals dry oral mucosa and bilaterally enlarged parotid glands. Laboratory studies are obtained:

Which of the following best describes the primary pathophysiologic mechanism responsible for this patient's laboratory findings?

Match each clinical and pathologic description of a hematologic malignancy with its defining molecular or cytogenetic mechanism.

Match each patient's clinical presentation with the most appropriate targeted laboratory evaluation panel to establish the diagnosis.

A 58-year-old man with a 15-year history of type 2 diabetes mellitus and peripheral neuropathy presents to his primary care physician for evaluation of a malodorous wound on the bottom of his right foot. He first noticed the ulcer three weeks ago and reports that the drainage has increased over the past several days. He denies fever, chills, or night sweats. Current medications include metformin, empagliflozin, and atorvastatin. Vital signs show a temperature of 37.1°C (98.8°F), blood pressure of 134/82 mmHg, heart rate of 78/min, and respiratory rate of 14/min. Physical examination reveals a 2.5 cm by 2.0 cm deep ulceration underlying the first metatarsal head. There is surrounding erythema, induration, and purulent discharge. A sterile metal probe introduced into the ulcer easily palpates hard, gritty tissue at the base. Dorsalis pedis and posterior tibial pulses are slightly diminished bilaterally, and monofilament testing reveals loss of protective sensation in bilateral feet. Laboratory studies reveal a leukocyte count of 11,800/mm³ and an erythrocyte sedimentation rate of 88 mm/h. Which of the following is the most appropriate initial imaging study for this patient?

A 24-year-old nulligravid woman comes to the emergency department due to sudden-onset, severe, right-sided pelvic pain that began 4 hours ago. The pain is colicky, radiates to her right flank, and is associated with multiple episodes of nausea and vomiting. Her last menstrual period was 3 weeks ago. She has no history of sexually transmitted infections or prior abdominal surgeries. Her temperature is 37.1°C (98.8°F), blood pressure is 122/76 mm Hg, and pulse is 108/min. Physical examination reveals exquisite tenderness to palpation in the right lower quadrant with voluntary guarding, but no rebound tenderness. Pelvic examination demonstrates a palpable, tender right adnexal mass; there is no cervical motion tenderness. A urine pregnancy test is negative. Complete blood count shows a leukocyte count of 11,500/mm³. A transvaginal ultrasound is performed. The right ovary measures 6.5 x 5.0 x 4.5 cm and exhibits central stromal edema with multiple small, peripherally displaced follicles. Color Doppler evaluation of the right ovary demonstrates absent venous flow but reveals preserved arterial waveforms. The left ovary and uterus appear unremarkable. A small amount of free fluid is noted in the posterior cul-de-sac. What is the most appropriate next step in the management of this patient based on the sonographic findings?

A 45-year-old man presents to the clinic with a 3-week history of profound fatigue, intermittent low-grade fevers, and diffuse joint pains. He also reports the recent appearance of a rash on both of his legs. He has no significant past medical history and takes no daily medications. He works as a plumber and is in a monogamous relationship with his wife. Vital signs are within normal limits except for a temperature of 37.9°C (100.2°F). Physical examination reveals a nonblanching, violaceous, maculopapular rash over the bilateral lower extremities, consistent with palpable purpura. Mild hepatomegaly is noted on abdominal palpation. Laboratory studies reveal:

Aspartate aminotransferase (AST): 85 U/L
Alanine aminotransferase (ALT): 92 U/L
Rheumatoid factor: Positive
Complement C3: Normal
Complement C4: Markedly decreased

Which of the following historical elements is most critical to query during this patient's medical history evaluation to determine the primary underlying etiology of his current condition?

During the evaluation of patients presenting to the emergency department with acute abdominal pain, specific physical examination findings are critical for establishing a differential diagnosis. Match each described physical examination maneuver or finding with the clinical condition it most strongly indicates.

A $58$-year-old man with a history of decompensated alcoholic cirrhosis presents to the emergency department with diffuse abdominal pain and a low-grade fever over the past $24$ hours. Vital signs are temperature $37.9^\circ C$ ($100.2^\circ F$), blood pressure $105/65$ mmHg, heart rate $98$/min, and respiratory rate $18$/min. Physical examination reveals scleral icterus and a distended, diffusely tender abdomen with a positive fluid wave. To evaluate for spontaneous bacterial peritonitis, a diagnostic paracentesis is performed. The procedure is complicated by a traumatic tap, yielding noticeably bloody fluid. The ascitic fluid laboratory analysis reveals the following:

Ascitic fluid red blood cell (RBC) count: $62,500/\mu L$
Ascitic fluid white blood cell (WBC) count: $1,250/\mu L$
Ascitic fluid differential: $50\%$ neutrophils, $30\%$ lymphocytes, $20\%$ macrophages

Based on these results, what is the corrected ascitic fluid absolute neutrophil count (in cells/$\mu L$) that should be used to evaluate the patient for spontaneous bacterial peritonitis?

A 44-year-old female is evaluated in the ambulatory care clinic due to progressive weight gain, easy bruising, and profound proximal muscle weakness over the past eight months. Physical examination is notable for facial plethora, prominent supraclavicular fat pads, and broad purplish abdominal striae. Her blood pressure is 158/96 mmHg. She has no history of exogenous glucocorticoid use. The physician suspects endogenous hypercortisolism.

Arrange the following diagnostic laboratory tests and procedures in the most appropriate sequential order to establish the diagnosis and identify the precise etiology.

Emergency medical services bring a 23-year-old male to the emergency department after his roommate found him diaphoretic, lethargic, and disoriented. The patient has a history of type 1 diabetes mellitus and recently increased his running mileage. Capillary blood glucose on arrival is 34 mg/dL. The physician promptly administers an intramuscular injection of a counter-regulatory peptide hormone, resulting in a rapid improvement of the patient's mental status and a steady rise in blood glucose over the next 15 minutes. Arrange the following intracellular and enzymatic steps in the correct chronological sequence detailing the hepatic mechanism by which this treatment reversed the patient's hypoglycemia.

Match each of the following comprehensive hepatic laboratory profiles with the most likely clinical diagnosis. Assume all patients are adults and the reference ranges are as follows: AST 8-40 U/L, ALT 7-56 U/L, ALP 44-147 U/L, Total Bilirubin 0.1-1.2 mg/dL, Direct Bilirubin <0.3 mg/dL.