Case report on lithium intoxication with normal lithium levels.

An 18-year old female was admitted to a psychiatric hospital with an initial episode of mania. Treated with routine dosages of lithium bicarbonate, her symptoms resolved after two weeks; she was discharged on a dosage of 250mg lithium bid. Five days after discharge she was taken to the emergency department of a general hospital with loss of appetite and disturbed consciousness. The general hospital physicians were unable to diagnose the problem so she was transferred back to the psychiatric hospital. At that time she had a lithium blood level of 0.57 mmol/L (i.e., at the lower end of the therapeutic range) but was, nevertheless, clearly experiencing lithium intoxication with anuria, trembling extremities, blurred speech, muscle rigidity and hyperactive tendon reflexes. Treated with intravenous mannitol, her acute symptoms resolved quickly. The case highlights the need to monitor clinical symptoms of intoxication in all patients taking lithium, regardless of their blood level, and to inform patients, family members, and general physicians about the symptoms and management of lithium intoxication.