Lithium treatment of a patient with Addison's disease and affective psychosis

A female patient born in 1941, who suffers from affective psychosis and Addison's disease, first received lithium carbonate in 1983 during a severe, therapy-resistent depression. With lithium treatment she showed a considerable improvement. In the following months, with a daily dosage of 24.4 mmol, the blood lithium levels were between 0.8 and 0.9 mmol/l. One year later she suffered a severe lithium intoxication after a virus infection. Shortly afterwards, she had a manic and then a depressive phase. She was now put on a regimen of with 12.2 mmol lithium carbonate per day, which produced blood levels between 0.3 and 0.4 mmol/l. In the following years, values of about 0.9 mmol/l were observed several times, therapy and clinical condition remaining unchanged. These spontaneous fluctuations of the blood lithium level, a hitherto unreported phenomenon are discussed as a possible cause of the lithium intoxication. The consequences for clinical practice are outlined.