The nurse is caring for a patient in acute kidney injury. Which of the following complications would most clearly warrant the administration of polystyrene sulfonate (Kayexalate)?

Correct Answer: C

Rationale: Hyperkalemia, a common complication of acute kidney injury, is life-threatening if immediate action is not taken to reverse it. The administration of polystyrene sulfonate reduces serum potassium levels.

Correct Answer: D

Rationale: Antidiuretic hormone (ADH) is produced in the hypothalamus (D), specifically in supraoptic and paraventricular nuclei, then stored in the posterior pituitary. Juxtaglomerular cells (A) produce renin, anterior pituitary (B) releases ACTH, and adrenal cortex (C) makes aldosterone, making D correct.

Correct Answer: A

Rationale: The macula densa, part of the distal convoluted tubule, contacts juxtaglomerular cells at the afferent arteriole, forming the JGA to regulate renin (A). This anatomical feature is true, not false (B), making A correct.

Correct Answer: D

Rationale: Na⁺ reabsorption in the PCT uses active transport (D) via Na+/K+ ATPase and Na+/H+ exchangers, not phagocytosis (A), endocytosis (B), or diffusion (C), making D the primary mechanism.

Correct Answer: A

Rationale: Seafood allergy increases risk of severe reaction to urography dye, requiring urgent attention.