Which size renal stones have a 90% chance of passing?

Correct Answer: B

Rationale: <5 mm stones have ~90% spontaneous passage small enough for ureteral transit (e.g., distal stones). <3 mm passes easily near 100%. <7 mm drops to ~50% size matters. <8 mm rarely passes obstructs. 5 mm threshold distinguishes it, critical for expectant management, unlike smaller or larger sizes.

Correct Answer: D

Rationale: Both are true: High-dose furosemide lacks ARF benefit only aids overload (e.g., no GFR improvement). Dopamine (1-5 µg/kg/min, not mg) is renal-dose, used post-volume correction in oliguria unproven efficacy, but fits scenario. Dual accuracy distinguishes it, key to evidence-based ARF care, unlike single or negated options.

Correct Answer: A

Rationale: Calcium oxalate is the commonest ureteric stone ~70-80% (e.g., hypercalciuria), metabolic driver. Triple phosphate (struvite) ties to infection less frequent. Urate (~10%) and cysteine (rare, genetic) minority. Oxalate's prevalence distinguishes it, critical for stone epidemiology, unlike infection or metabolic rarities.

Correct Answer: A

Rationale: MMR vaccine is contraindicated in transplant patients live attenuated, risks viremia in immunosuppression. Nystatin (candida), pneumococcal, and hepatitis B vaccines safe, recommended. Prophylaxis for dental procedures aligns standard. Live vaccine ban distinguishes it, critical for transplant safety, unlike protective measures.

Correct Answer: D

Rationale: Irregular menses isn't a UTI risk unrelated to urinary tract (e.g., hormonal, not mechanical). Intercourse introduces bacteria proven. Uterine prolapse impairs emptying stasis. Diaphragm/spermicide alter flora E. coli growth. Lack of association distinguishes menses, key to risk factors, unlike mechanical/microbial triggers.