Written by: Maren Leibowitz, MD (NUEM ‘23) Edited by: Nick Wleklinski, MD (NUEM ‘22)
Expert Commentary by: Zachary Schmitz, MD (NUEM '21)
Expert Commentary
This is an awesome, focused review of neuroleptic malignant syndrome (NMS). NMS is hard to diagnose because it's rare. There is no gold standard with respect to its definition, and it requires a medication history (which we typically don't do very well in the emergency department). A tricky cause of NMS is the removal of a dopamine agonist. For this reason, carbidopa/levodopa should never be discontinued during hospital admission - or ED boarding. [1]
Supportive care is more important than antidotal therapy during NMS management. The most acute cause of death from NMS is hyperthermia, which is induced both by D2 receptor antagonism leading to rigidity and impaired thermoregulation from the striatum and hypothalamus. Any life-threatening hyperthermia should be treated immediately with an ice bath.[2] Rigidity will lead to rhabdomyolysis with subsequent hyperkalemia and myoglobin-induced renal failure. Therefore, fluid resuscitation and maintenance are important. Profound immobility can precipitate DVT, so anticoagulation may be necessary.
In terms of pharmacotherapy, benzodiazepines are universally used. Dantrolene inhibits calcium-mediated muscle contraction to reduce muscle rigidity. However, it doesn't address the underlying central D2 antagonism, and its efficacy has only been shown in case reports. Bromocriptine acts more centrally as a dopamine agonist but should be used cautiously in patients with psychiatric diseases as it may exacerbate psychosis. Overall, benzodiazepine use and supportive care should get you through most cases of NMS, though additional therapies may be necessary in severe cases.
References
1. Institute for Safe Medication Practices. Delayed Administration and Contraindicated Drugs Place Hospitalized Parkinson’s Disease Patients at Risk. 12 March 2015. Accessed February 11, 2022.
2. Juurlink JN. Antipsychotics. In: Nelson LS, Howland M, Lewin NA, Smith SW, Goldfrank LR, Hoffman RS. eds. Goldfrank's Toxicologic Emergencies, 11e. Page 1037-1039. McGraw Hill; 2019. Accessed February 11, 2022.
Zachary Schmitz, MD
Toxicology Fellow
Ronald O. Perelman Department of Emergency Medicine
NYU Langone Health
How To Cite This Post:
[Peer-Reviewed, Web Publication] Leibowitz, M. Wleklinski, N. (2022, May 9). Neuroleptic Malignant Syndrome. [NUEM Blog. Expert Commentary by Schmitz, Z]. Retrieved from http://www.nuemblog.com/blog/neuroleptic-malignant-syndrome.
