Neuroleptic malignant syndrome. Analysis of 9 cases

The malignant neuroleptic syndrome (MNS) is an idiosyncratic reaction to neuroleptic drugs. Although it was described in the sixties, it is still a poorly known condition. Controversy still exists about its conceptual frame, and its true incidence is still unknown. We have evaluated 9 cases of MNS seen in a 37 month period. There were 5 females, with a mean age of 50 years. Haloperidol, either single or in association, was the most commonly implicated drug. The estimated frequency of MNS in our population at risk was 1.5%. Eight patients had complications and 5 died from them (55%). We discuss the pathogenetic mechanisms, the conceptual characterization and the current diagnostic criteria. We evaluate the causes of the high mortality in our series. We think that a higher suspicion index of this condition would be desirable, and we recommend early treatment with vigorous supportive measures and drug therapy. We think that prospective studies are required to assess the true incidence of MNS.