[Reversible choreoathetosis associated with lithium intoxication].

Several reports have been published in the literature of choreoathetosis associated with lithium intoxication, but little is known about choreoathetosis without concurrent antipsychotic treatment. We report a 65-year-old woman with lithium intoxication whose choreoathetosis completely recovered without sequela following decrease of her serum lithium level. She had been treated elsewhere for bipolar II disorder and also for hypertension, chronic hepatitis type C and diabetes mellitus. As she became hypomanic, lithium carbonate at 600 mg/day was commenced, which was increased to 1200 mg/day due to unfavorable therapeutic response. She began to manifest disorientation and abnormal involuntary movement and was therefore referred to our Department of Psychiatry. Her clinical symptoms at admission included consciousness disturbance with marked bilateral symmetrical slow-wave activity in her EEG and choreoathetosis was observed in her face and upper and lower extremities. Cerebellar symptoms were minimal with only mild ataxic gait and finger-to-nose test did not show dysmetria or intention tremor. Her serum lithium level was 3.52 mEq/L, which was clearly in the toxic range. She demonstrated no metabolic abnormalities including hyperglycemia, and was diagnosed with lithium intoxication and treated with water loading and mannitol for forced diuresis. On the 14th day after admission her consciousness disturbance and choreoathetosis resolved, but EEG abnormalities still persisted. On the 23rd day after admission, she was discharged with clinical remission and normal EEG background activity. Although she developed mild renal dysfunction, hemodialysis was not indicated. Hypersensitivity of dopamine receptor in the nigrostriatal pathways may contribute to choreoathetosis in association with the patient's vulnerability. Choreoathetosis can be a sign of lithium intoxication and prompt treatment is required following careful differential diagnosis.