MD Renal and Urinary Systems 4

Question 1

A patient with polycystic kidney disease asks about the risk to their children. What is the inheritance pattern of autosomal dominant PKD?

Accepted Answer

Autosomal dominant, 50% risk to each child

Answer

ADPKD (PKD1/PKD2 mutations) follows autosomal dominant inheritance with 50% probability of transmission to each offspring.

Question 2

Which diuretic acts on the thick ascending limb of the loop of Henle and is most effective in patients with reduced GFR?

Accepted Answer

Furosemide

Answer

Furosemide (a loop diuretic) inhibits the Na-K-2Cl cotransporter in the thick ascending limb and remains effective even with low GFR, unlike thiazides.

Question 3

A patient presents with cola-colored urine, periorbital edema, hypertension, and hematuria 2 weeks after a strep throat infection. What is the most likely diagnosis?

Accepted Answer

Post-streptococcal glomerulonephritis

Answer

Post-streptococcal GN occurs 1-3 weeks after pharyngitis, presenting with nephritic syndrome and is the classic post-infectious GN in children.

Question 4

Aldosterone causes sodium retention primarily by upregulating which channel/transporter on the apical membrane of principal cells?

Accepted Answer

Epithelial sodium channel (ENaC)

Answer

Aldosterone increases transcription and membrane insertion of ENaC on principal cells of the collecting duct, promoting sodium reabsorption.

Question 5

A patient with renal cell carcinoma has polycythemia. What is the mechanism?

Accepted Answer

Tumor secretion of EPO leading to increased RBC production

Answer

RCC can autonomously secrete erythropoietin as a paraneoplastic syndrome, stimulating erythropoiesis and causing polycythemia.

MD - Doctor of Medicine Practice Test

MD - Doctor of Medicine Practice Test

MD Renal and Urinary Systems 4