Is the EEG helpful in diagnosing and monitoring lithium intoxication? A case report and review of the literature.

Lithium is potentially toxic to the central nervous system. Clinical lithium neurotoxicity may appear at any time during therapy and may go unrecognized. Failure to appreciate this fact leads to delays in diagnosis and treatment, placing the patient at risk of permanent neurological damage or death. In spite of a largely clinical diagnosis of lithium intoxication, the EEG provides an objective criterion of intoxication. We report a case of lithium intoxication with neurotoxic symptoms associated with marked EEG changes despite moderate lithium serum levels. In contrast to the interindividually varying EEG changes under uncomplicated lithium therapy, pathological EEG findings are the rule in the case of intoxication. Several reports evince a closer relationship between neurotoxic symptoms with EEG changes than with serum levels of lithium. This is of clinical interest with respect to intoxication under therapeutic lithium serum levels, since the EEG is the only examination indicating an intoxication. In patients with intoxication, the phenomenon of long-lasting EEG changes after discontinuation of lithium is discussed with respect to neuronal storing of lithium and persisting neurological disturbances.