MD Internal Medicine 4

Question 1

A 48-year-old man presents with fatigue, bronze skin discoloration, elevated liver enzymes, and diabetes. Serum ferritin is 2,800 ng/mL and transferrin saturation is 72%. What is the most likely diagnosis?

Accepted Answer

Hereditary hemochromatosis

Answer

Hereditary hemochromatosis (HFE gene mutation) presents with iron overload causing liver disease, diabetes, skin bronzing, and cardiomyopathy; transferrin saturation >45% is a key screening marker.

Question 2

A 25-year-old woman with asthma presents with worsening shortness of breath. Peak flow is 45% of predicted. She has already used her rescue inhaler three times. What is the most appropriate next treatment step?

Accepted Answer

Administer IV magnesium sulfate as add-on therapy

Answer

In severe acute asthma exacerbations not responding to bronchodilators and steroids, IV magnesium sulfate causes bronchial smooth muscle relaxation and reduces hospital admission rates.

Question 3

A 62-year-old man presents with polyuria, polydipsia, and a serum sodium of 154 mEq/L. Urine osmolality is 80 mOsm/kg after water deprivation; it rises to 600 mOsm/kg after desmopressin administration. What is the diagnosis?

Accepted Answer

Central diabetes insipidus

Answer

Central diabetes insipidus is confirmed when urine concentrates appropriately after exogenous desmopressin (ADH), indicating the kidney can respond but lacks sufficient endogenous ADH.

Question 4

Which of the following best describes the mechanism of warfarin's anticoagulant effect?

Accepted Answer

Inhibition of vitamin K epoxide reductase, reducing synthesis of factors II, VII, IX, X

Answer

Warfarin inhibits vitamin K epoxide reductase, preventing recycling of vitamin K, which is required for gamma-carboxylation of clotting factors II, VII, IX, and X.

Question 5

A 55-year-old woman with a BMI of 38 undergoes evaluation for nonalcoholic fatty liver disease. Liver biopsy shows steatohepatitis with bridging fibrosis. Which intervention has the strongest evidence for improving histologic outcomes?

Accepted Answer

Significant weight loss (>10% body weight)

Answer

Sustained weight loss of ≥10% body weight is the most effective intervention for NASH, leading to histologic improvement including regression of fibrosis.

MD - Doctor of Medicine Practice Test

MD - Doctor of Medicine Practice Test

MD Internal Medicine 4