A 56-year-old woman with bipolar disorder on lithium presents with coarse tremor, ataxia, and confusion after 3 days of vomiting and diarrhea. Vital signs show BP 108/72, HR 102, RR 18, temp 37.8°C, SpO2 98%. Serum lithium level is 2.1 mEq/L (therapeutic: 0.6-1.2). She denies recent NSAIDs or ACE inhibitors. Urinalysis reveals low specific gravity. Which mechanism most likely precipitated her toxicity?

  1. A)Use of mesna
  2. B)Volume depletion reducing renal clearanceGABARITO
  3. C)Use of methylene blue
  4. D)Concurrent naloxone administration
  5. E)High dietary sodium intake

Explicação

Lithium is cleared by the kidney and is reabsorbed similarly to sodium in the proximal tubule. Volume depletion increases proximal sodium and lithium reabsorption, reducing lithium clearance and precipitating toxicity. Ver explicação completa e trilha adaptativa →

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