All of the following are causes of postrenal failure EXCEPT

Correct Answer: D

Rationale: Urethral prolapse doesn't typically cause postrenal failure rare obstruction (e.g., females), unlike bladder tumor (outflow block), phimosis (urethral), and neurogenic bladder (emptying failure). Minimal obstructive impact distinguishes it, key to postrenal etiology, unlike clear blockages.

Correct Answer: A

Rationale: Cercarial dermatitis results from non-human schistosomes penetrating skin, not S. mansoni/haematobium (human parasites) or Trichomonas (STD). This distinguishes parasitic dermatitis, critical for epidemiology, contrasting with human-specific species.

Correct Answer: B

Rationale: Renal cell carcinoma (RCC) invades veins early, has clear cells, causes hematuria, and affects adults not children (Wilms'). This corrects RCC epidemiology, vital for diagnosis, contrasting with pediatric tumors.

Correct Answer: D

Rationale: Medullary hyperosmolarity arises from Na+ and urea (countercurrent), not glucose or K+ alone. This defines concentration gradient, critical for urine concentration, contrasting with single solutes.

Correct Answer: C

Rationale: Chronic renal failure (CRF) features hypertension, proteinuria progression, osteodystrophy, and hyperkalemia not hypokalemia (dyslipidemia true). This corrects electrolyte error, critical for CRF management, contrasting with hypokalemic states.