Contributor: Taylor Lynch, MD

Educational Pearls:

What is NMS?

Neuroleptic Malignant Syndrome
Caused by anti-dopamine medication or rapid withdrawal of pro-dopamenergic medications
Mechanism is poorly understood
Life threatening

What medications can cause it?

How does it present?

Slowly over 1-3 days (unlike serotonin syndrome which has a more acute onset)
Altered mental status, 82% of patients, typically agitated delirium with confusion
Peripheral muscle rigidity and decreased reflexes. AKA lead pipe rigidity. (As opposed to clonus and hyperreflexia in serotonin syndrome)
Hyperthermia (>38C seen in 87% of patients)
Can also have tachycardia, labile blood pressures, tachypnea, and tremor

How is it diagnosed?

Clinical diagnosis, focus on the timing of symptoms
No confirmatory lab test but can see possible elevated CK levels and WBC of 10-40k with a left shift

What else might be on the differential?

What is the treatment?

Start with ABC’s
Stop all anti-dopaminergic meds and restart pro-dopamine meds if recently stopped
Maintain urine output with IV fluids if needed to avoid rhabdomyolysis
Active or passive cooling if needed
Benzodiazapines, such as lorazepam 1-2 mg IV q 4hrs

What are active medical therapies?

Dispo?

References

Oruch, R., Pryme, I. F., Engelsen, B. A., & Lund, A. (2017). Neuroleptic malignant syndrome: an easily overlooked neurologic emergency. Neuropsychiatric disease and treatment, 13, 161–175. https://doi.org/10.2147/NDT.S118438
Tormoehlen, L. M., & Rusyniak, D. E. (2018). Neuroleptic malignant syndrome and serotonin syndrome. Handbook of clinical neurology, 157, 663–675. https://doi.org/10.1016/B978-0-444-64074-1.00039-2
Velamoor, V. R., Norman, R. M., Caroff, S. N., Mann, S. C., Sullivan, K. A., & Antelo, R. E. (1994). Progression of symptoms in neuroleptic malignant syndrome. The Journal of nervous and mental disease, 182(3), 168–173. https://doi.org/10.1097/00005053-199403000-00007
Ware, M. R., Feller, D. B., & Hall, K. L. (2018). Neuroleptic Malignant Syndrome: Diagnosis and Management. The primary care companion for CNS disorders, 20(1), 17r02185. https://doi.org/10.4088/PCC.17r02185

Summarized by Jeffrey Olson MS2 | Edited by Meg Joyce & Jorge Chalit, OMSIII

Podcast 914: Neuroleptic Malignant Syndrome (NMS)

Emergency Medical Minute