A 34-year-old woman with bipolar I disorder has been stable on lithium 900 mg daily for 3 years. She presents with tremor, confusion, and ataxia. Temperature is 37.1°C, blood pressure is 104/68 mmHg, and heart rate is 96/min. Laboratory studies show a serum lithium level of 2.8 mEq/L (normal: 0.6–1.2) and serum creatinine of 0.9 mg/dL, indicating normal renal function. She reports recent gastroenteritis with significant diarrhea, for which she was prescribed a thiazide diuretic five days ago. Which of the following best explains the elevated lithium level?
- A)Thiazide diuretics decrease glomerular filtration and lithium renal clearanceGABARITO
- B)Lithium protein binding is decreased due to hypoalbuminemia
- C)Lithium metabolism via hepatic glucuronidation is inhibited
- D)Diarrhea increases lithium absorption in the small intestine
- E)Gastroenteritis directly inhibits the Na-K-ATPase pump
Explicação
Thiazide diuretics promote sodium excretion and volume depletion, reducing glomerular filtration rate and lithium renal clearance. Since lithium is not metabolized and depends entirely on renal elimination, reduced filtration leads to toxicity. Ver explicação completa e trilha adaptativa →