Residual catatonic state following neuroleptic malignant syndrome

Neuroleptic malignant syndrome (NMS) is usually a self-limited disorder, with most cases resolving within 2 weeks after antipsychotic drug discontinuation. However, the course of NMS may not always be short-lived. In this report, the authors describe five patients who developed a residual catatonic state that persisted after acute hyperthermic symptoms of NMS had subsided and compare them with 27 similar cases in the literature. Two of our patients recovered gradually with supportive treatment. Three patients were treated with electroconvulsive therapy (ECT). Of these, two showed a positive response, although one died later of intercurrent pneumonia. A third patient did not respond to ECT, but recovered gradually thereafter. Although dopamine agonists or benzodiazepines have been advocated for the treatment of residual symptoms in previous case reports, ECT was the treatment most often associated with a rapid response and no mortality, even in patients refractory to pharmacotherapy. In conclusion, catatonic and parkinsonian symptoms of NMS may persist as a residual state lasting for weeks to months after more fulminant acute symptoms abate. These residual symptoms may be more likely to develop in patients with pre-existing structural brain disorders. Although patients may improve gradually with supportive care or pharmacotherapy, ECT can often be highly effective in treating the residual catatonic state that follows NMS.