Neuroleptic malignant syndrome

A serious, potentially life-threatening complication of treatment with antipsychotic drugs or abrupt withdrawal of dopamine agonists.

Characterised by a tetrad of altered mental status, muscle rigidity, autonomic instability, and hyperthermia.

A diagnosis of exclusion. Common differential diagnoses are sepsis and drug reactions.

NMS is a medical emergency. Treatment consists of immediate cessation of the offending medication and provision of supportive measures (hydration and cooling). Additional treatment may be considered if supportive interventions fail.

A delay of at least 2 weeks in restarting antipsychotic treatment after an NMS episode has fully resolved is advised.

Documenting this reaction in the medical records is important.

Neuroleptic malignant syndrome (NMS) is an uncommon, idiosyncratic, life-threatening complication of treatment with antipsychotic medications. NMS has also been associated with other psychotropic agents that block central dopamine pathways (e.g., metoclopramide). It is characterised by altered mental state, increased muscle tone or frank rigidity, alterations in the autonomic nervous system, hyperactivity, and hyperthermia.[1]Strawn JR, Keck PE Jr, Caroff SN. Neuroleptic malignant syndrome. Am J Psychiatry. 2007 Jun;164(6):870-6. http://www.ncbi.nlm.nih.gov/pubmed/17541044?tool=bestpractice.com [2]Buckley P, Adityanjee M, Sajatovic M. Neuroleptic malignant syndrome. In: Katirji B, Kaminski HJ, Preston DC, et al, eds. Neuromuscular disorders in clinical practice. Boston, MA: Butterworth-Heinemann; 2002:1264-1275.[3]Caroff SN, Mann SC. Neuroleptic malignant syndrome. Med Clin North Am. 1993 Jan;77(1):185-202. http://www.ncbi.nlm.nih.gov/pubmed/8093494?tool=bestpractice.com [4]Lazarus A, Mann SC, Caroff SN. The neuroleptic malignant syndrome and related conditions. Washington, DC: American Psychiatric Press; 1989. None of these signs are exclusive to this condition, and other important diagnoses (e.g., sepsis) should be excluded first.[5]Hasan S, Buckley P. Novel antipsychotics and the neuroleptic malignant syndrome: a review and critique. Am J Psychiatry. 1998 Aug;155(8):1113-6. http://www.ncbi.nlm.nih.gov/pubmed/9699705?tool=bestpractice.com [6]Levinson DF, Simpson GM. Neuroleptic-induced extrapyramidal symptoms with fever: heterogeneity of the 'neuroleptic malignant syndrome'. Arch Gen Psychiatry. 1986 Sep;43(9):839-48. http://www.ncbi.nlm.nih.gov/pubmed/2875701?tool=bestpractice.com