Renal failure can have prerenal, renal, or postrenal causes. A patient with acute kidney injury is being assessed to determine where, physiologically, the cause is. If the cause is found to be prerenal, which condition most likely caused it?

Correct Answer: A

Rationale: By causing inadequate renal perfusion, heart failure can lead to prerenal failure. Glomerulonephritis and aminoglycoside toxicity are renal causes, and ureterolithiasis is a postrenal cause.

Correct Answer: C

Rationale: High ADH increases collecting duct permeability to water (C) via aquaporin-2, concentrating urine. They remain impermeable to water without ADH (A), proteins (B) are not filtered, and sodium/chloride (D) are regulated elsewhere, making C the effect of ADH.

Correct Answer: A

Rationale: Interlobar veins collect blood from arcuate veins and drain into the renal vein (A), a true venous pathway in kidney anatomy. False (B) would deny this standard flow, making A the correct statement.

Correct Answer: D

Rationale: The kidney's coverings are the renal capsule (A), adipose capsule (B), and renal fascia (C). Renal adventitia (D) is not a standard term for kidney layers, making D the incorrect option.

Correct Answer: A

Rationale: Metformin with dye can cause lactic acidosis, so discontinuing it is the priority.