CURRENT Essentials of Critical Care.pdf

234 Current Essentials of Critical Care■■■LithiumEssentials of Diagnosis• May be acute, chronic, or acute plus chronic lithium toxicity• CNS symptoms include tremor, weakness, hyperreflexia, musclerigidity, slurred speech, tinnitus, seizures, confusion, coma;GI symptoms more common with acute toxicity, including nauseaand vomiting• May have prolonged QT interval, ST and T wave abnormalities,myocarditis, cardiovascular collapse (rare)• Nephrogenic diabetes insipidus in 20–70%• Thyrotoxicosis, hyperthermia, hyperparathyroidism, hypercalcemia• Risk factors for toxicity in patients previously stable on lithiumtherapy include ACE inhibitors, NSAIDs, loop diuretics, thiazides,volume depletion, decreased sodium intake, renal insufficiency• Serum lithium level 1.5 mEq/L is toxicDifferential Diagnosis• Stroke, meningitis, tardive dyskinesia, other CNS disorders• Neuroleptic malignant syndrome• Sedative-hypnotic or ethanol withdrawal• Psychotropic or stimulant overdoseTreatment• Gastric lavage, with whole bowel irrigation for significant ingestions• Maintenance of fluid and electrolyte balance• Hemodialysis effective; should be considered early in ingestionof sustained-release preparations, chronic ingestions with toxicity,with impaired renal function, if neurologic findings, or ifserum lithium 4.0 mEq/L■ PearlAs lithium is not metabolized and is eliminated entirely via the kidney,any patient with abnormal renal function should be considereda hemodialysis candidate if there are signs of toxicity.ReferenceTimmer RT, Sands JM: Lithium intoxication. J Am Soc Nephrol 1999;10:666.[PMID: 10073618]