Mood Stabilizers — Lithium

A 34-year-old woman with bipolar I disorder has been stable on lithium 900 mg daily for 2 years. She presents to the emergency department with confusion, coarse tremor, hyperreflexia, and rigidity. Serum lithium level is 2.8 mEq/L (therapeutic range 0.6–1.2 mEq/L). Serum creatinine is 1.8 mg/dL (baseline 0.9 mg/dL), and serum sodium is 128 mEq/L. What is the most appropriate immediate management?

A 28-year-old man with bipolar I disorder started on lithium 600 mg daily 1 week ago is brought to the clinic by his wife with complaints of polyuria (8–10 L/day), polydipsia, and nocturia ×5. Serum lithium level is 0.8 mEq/L (therapeutic). Serum sodium is 145 mEq/L, osmolality is 310 mOsm/kg, and urine osmolality is 200 mOsm/kg despite high serum osmolality. What is the most likely diagnosis and the best management?

A 28-year-old man with bipolar II disorder presents with a depressive episode. He has a history of poor tolerability to lithium (tremor, polyuria). Which is the drug of choice for mood stabilization in this patient?

A 38-year-old woman with bipolar disorder has been on lithium 900 mg daily for 6 months with good mood stabilization. She now presents with polyuria, polydipsia, and nocturia. Which investigation is most appropriate to confirm the suspected diagnosis of lithium-induced nephrogenic diabetes insipidus?

A 42-year-old man on lithium 750 mg daily for bipolar I disorder presents with tremor, confusion, ataxia, and coarse tremor. He had vomiting and diarrhea 2 days ago. Which investigation is most appropriate as the first step to evaluate suspected lithium toxicity?