Lithium Toxicity and Monitoring

A 52-year-old man with bipolar disorder has been on lithium 900 mg daily for 3 years with good symptom control. He presents to the psychiatry clinic for routine monitoring. Which is the most common cause of lithium toxicity in chronic users on stable dosing?

A 52-year-old man with bipolar disorder has been on lithium 900 mg daily for 3 years with good mood stabilization. He presents to the emergency department with tremor, confusion, ataxia, and slurred speech for 6 hours. His wife reports he had acute gastroenteritis with vomiting and diarrhea for 2 days and continued taking lithium. Serum lithium level is 2.8 mEq/L (therapeutic range 0.6–1.2 mEq/L). Serum creatinine is 1.4 mg/dL (baseline 1.0 mg/dL). What is the most appropriate immediate next step in management?

A 48-year-old woman on lithium for bipolar I disorder is found to have a serum lithium level of 1.1 mEq/L (therapeutic range 0.6–1.2 mEq/L) but presents with coarse tremor, polyuria, and polydipsia. Which finding best distinguishes nephrogenic diabetes insipidus caused by lithium from polyuria due to acute lithium toxicity?

Which of the following is the earliest clinical sign of lithium toxicity?

A 52-year-old woman with bipolar disorder has been on lithium 900 mg daily for 3 years with good mood stabilization. She presents to the emergency department with severe nausea, vomiting, coarse tremor, confusion, and ataxia that started 6 hours ago. Her serum lithium level is 2.8 mEq/L (normal therapeutic range 0.6–1.2 mEq/L). On examination, she is disoriented to time and place, has hyperreflexia, and clonus is elicited. Her renal function is normal (creatinine 0.9 mg/dL), and she denies recent NSAIDs or diuretic use. What is the most appropriate immediate management?