MD Medical Doctor General 2 — Questions and Answers
Question 1: A 55-year-old male presents with sudden-onset tearing chest pain radiating to the back. BP is 180/100 mmHg in the right arm and 150/90 mmHg in the left arm. What is the most likely diagnosis?
- Acute MI
- Aortic dissection (Correct answer)
- Pulmonary embolism
- Esophageal rupture
Correct answer: Aortic dissection
Aortic dissection classically presents with tearing chest pain radiating to the back and a blood pressure differential between arms due to involvement of subclavian artery origins.
Question 2: Which electrolyte abnormality is most commonly associated with prolonged QT interval and increased risk of torsades de pointes?
- Hypernatremia
- Hyperkalemia
- Hypomagnesemia (Correct answer)
- Hyperchloremia
Correct answer: Hypomagnesemia
Hypomagnesemia prolongs the QT interval and is the most common electrolyte cause of torsades de pointes, often treated with IV magnesium sulfate.
Question 3: A 30-year-old woman with SLE presents with a butterfly rash, joint pain, and a new serositis. Her anti-dsDNA titers are rising. Which complement levels would you expect?
- Elevated C3 and C4
- Normal C3 and C4
- Low C3 and C4 (Correct answer)
- Low C3, normal C4
Correct answer: Low C3 and C4
Active SLE consumes complement via immune complex deposition, leading to low C3 and C4 levels that correlate with disease activity.
Question 4: Which mechanism best explains why metformin is the preferred first-line agent for type 2 diabetes in most patients?
- Increases insulin secretion from beta cells
- Decreases hepatic glucose production and improves insulin sensitivity (Correct answer)
- Blocks glucose absorption in the intestine
- Enhances renal glucose excretion
Correct answer: Decreases hepatic glucose production and improves insulin sensitivity
Metformin primarily reduces hepatic gluconeogenesis and improves peripheral insulin sensitivity without causing hypoglycemia or weight gain.
Question 5: A patient with chronic kidney disease has a GFR of 20 mL/min. Which acid-base disorder is most expected?
- Respiratory alkalosis
- Metabolic alkalosis
- High anion gap metabolic acidosis (Correct answer)
- Hyperchloremic normal anion gap acidosis
Correct answer: High anion gap metabolic acidosis
Chronic kidney disease causes accumulation of unmeasured anions (sulfate, phosphate, organic acids) leading to high anion gap metabolic acidosis.
Question 6: A 68-year-old man is found to have a PSA of 12 ng/mL. Biopsy reveals Gleason score 7 (3+4) prostate cancer confined to the prostate. What is the most appropriate initial treatment approach?
- Active surveillance only
- Radical prostatectomy or radiation therapy (Correct answer)
- Immediate androgen deprivation therapy alone
- Watchful waiting with no intervention
Correct answer: Radical prostatectomy or radiation therapy
Gleason 7 (grade group 2) intermediate-risk localized prostate cancer is treated with curative intent via radical prostatectomy or radiation therapy.
Question 7: Which finding on lumbar puncture is most characteristic of bacterial meningitis compared to viral meningitis?
- Lymphocytic pleocytosis with normal glucose
- Elevated protein with neutrophilic pleocytosis and low glucose (Correct answer)
- Clear CSF with mildly elevated protein
- Xanthochromia with RBCs
Correct answer: Elevated protein with neutrophilic pleocytosis and low glucose
Bacterial meningitis classically shows neutrophilic pleocytosis, markedly elevated protein, and low glucose due to bacterial consumption and disrupted transport.
MD Medical Doctor General 2
A 55-year-old male presents with sudden-onset tearing chest pain radiating to the back.
BP is 180/100 mmHg in the right arm and 150/90 mmHg in the left arm.
What is the most likely diagnosis?