Neuroleptic malignant syndrome.

Few conditions have attracted such widespread attention among both neurologists and psychiatrists in recent years as the neuroleptic malignant syndrome. First described in 1960 by French clinicians in a study of haloperidoll and subsequently named the "syndrome malin des neuro-leptiques",2 this nomenclature suffered in translation to the neuroleptic malignant syndrome; this term has endured, in the face of continued debate.3-6 Neuroleptic malignant syndrome is an uncommon but potentially fatal idiosyncratic reaction characterised by the development of altered consciousness, hyperthermia, autonomic dysfunction, and muscular rigidity on exposure to neuroleptic (and probably other psychotropic) medications. Yet, despite its notoriety and a now replete medical literature,357 the pathobiology of neuroleptic malignant syndrome remains disappointingly enigmatic. The over-representation of single or brief series of case studies and the application of variable diagnostic criteria for neuroleptic malignant syndrome have hampered rigorous scientific enquiry into the nature of this condition. The lack of universally accepted diagnostic criteria is, perhaps, the most serious drawback to understanding.89 The core features of neuroleptic malignant syndrome, as enumerated, are common to established sets of diagnostic criteria.9 Yet the relative weight of each component, in the face of an apparent spectrum of clinical severity, remains unclear. For instance, some researchers have advocated that a pyrexia in excess of 38°C or 39°C is necessary for the diagnosis of neuroleptic malignant syndrome .7 10 Because raised temperature in such cases often occurs with dehydration or concomitant sepsis, the relevance of this sign is confounded and the potential for diagnostic error is heightened. Moreover, there has been a general over-reliance on the estimation of creatine kinase (CK) as a potential diagnostic marker for neuro-leptic malignant syndrome."1-"3 Prominent increases have been found in upwards of 70% of patients taking neuro-leptics who become pyrexial due to infection,'2 and some 30% of medically ill patients (not receiving neuroleptics) show a similar, albeit less exaggerated, rise in CK. 13 Given such poor specificity, claims for the use of CK values as a marker for the diagnosis and course of neuro-leptic malignant syndrome appear injudicious." The newly available diagnostic and statistical manual of mental disorders-fourth edition (DSM-IV) has now incorporated research criteria for neuroleptic malignant syndrome ,'4 placing prominence on signs of increase in temperature and muscle rigidity; these must be accompanied by two or more of: diaphoresis, dysphagia, tremor, incontinence, altered consciousness, tachycardia, blood pressure changes, leucocytosis, and raised CK concentrations. It will be important to compare the …