DELIRIUM AND PERSISTENT DYSKINESIA INDUCED BY A LITHIUM-NEUROLEPTIC INTERACTION

We report the case of a bipolar patient developing severe delirium and extrapyramidal signs shortly after initiation of a lithium-neurolepti c combination therapy. Clinical presentation, EEG changes and lithium plasma levels showed a close correlation. The delirium was reversible when all drugs were stopped; however, dyskinesia was found to be persi stent after a period of 6 months. This rare syndrome is difficult to d ifferentiate from lithium intoxication and neuroleptic malignant syndr ome. Given the additional use of valproate and biperiden in this patie nt, valproate encephalopathy and anticholinergic delirium are further differential diagnoses. To avoid this serious pharmacodynamic drug int eraction, patients should be closely monitored when lithium-neurolepti c comedication is started.