What percentage of kidney stones have microscopic haematuria?

Correct Answer: D

Rationale: ~90% of kidney stones cause microscopic hematuria abrasion of urothelium (e.g., oxalate stones), near-universal. 100% overstates rare exceptions exist. 20-70% underestimate too low. 90% (adjusted to D) distinguishes it, critical for diagnostic expectation, unlike absolute or lower estimates.

Correct Answer: D

Rationale: Antibiotics for strep don't prevent post-strep GN immune-mediated (e.g., anti-strep antibodies), not active infection, incorrect. Childhood predominance true. 7-14 days post-throat/skin accurate latency. Non-preventable nature distinguishes the error, key to GN's pathogenesis, unlike timing or demographic truths.

Correct Answer: D

Rationale: Pigment gallstones are radiopaque (~50%) calcium bilirubinate, visible on X-ray, unlike urate (radiolucent), cholesterol (bile, rare), or struvite (renal, not bile). Gallbladder context fits common site. Radiopacity distinguishes it, key to imaging detection, unlike ureteral or mislocated stones.

Correct Answer: C

Rationale: Azithromycin 1 g + ofloxacin 400 mg once treats urethritis (e.g., Chlamydia/gonorrhea) in young males with dysuria 5-10 WBC fits STD, most appropriate. Ciprofloxacin 2 weeks is pyelonephritis overkill. TMP-SMX 3 days is female UTI short. Cephalexin 7 days lacks STD coverage mismatch. STD regimen distinguishes it, key to age/context, unlike UTI-focused options.

Correct Answer: D

Rationale: Chronic glomerulonephritis features hyalinized glomeruli, granular subcapsular surface, shrunken kidneys, and prior disease history not normal calyces, enlargement, or no history. Hyalinization marks end-stage scarring, critical for diagnosis, contrasting with acute features like normal surfaces or enlarged kidneys typical of early inflammation.