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?
Typical antipsychotics
Haloperidol, chlorpromazine, prochlorperazine, fluphenazine, trifluoperazine
Atypical antipsychotics
Less risk
Risperidone, clozapine, quetiapine, olanzapine, aripiprazole, ziprasidone
Anti-emetic agents with anti dopamine activity
Metoclopramide, promethazine, haloperidol
Not ondansetron
Abrupt withdrawal of levodopa
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?
Sepsis
CNS infections
Heat stroke
Agitated delirium
Status eptilepticus
Drug induced extrapyramidal symptoms
Serotonin syndrome
Malignant hyperthermia
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?
Controversial treatments
Bromocriptine, dopamine agonist
Dantrolene, classically used for malignant hyperthermia
Amantadine, increases dopamine release
Use as a last resort
Dispo?
Mortality is around 10% if not recognized and treated
Most patients recover in 2-14 days
Must wait 2 weeks before restarting any medications
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