Neuroleptic Malignant Syndrome (NMS)

Exam Cram

• Neuroleptic Malignant Syndrome (NMS) is a medical emergency caused by acute low levels of dopamine

• Presentation: fevers, rigidity; recent dopamine antagonist or cessation of dopamine agonist

• Differentiating feature with serotonin syndrome:  wood pipe rigidity vs clonus & hyper-reflexivity

• Management: IVF, bromocriptine, dantrolene

Outline

Assessment

History

• Recent cessation of dopamine agonist or starting of dopamine antagonist

• < 4d

• Myalgaia, fatigue, vomiting, catatonia

Examination

• Wood-pipe muscle rigidity

• High temperature c.40 degrees

• Muscle spasms, extrapyramidal signs, tremor

Investigations

• High CK

• Leukocytosis

• Urinanalysis: blood & protein

Diagnosis

Diagnostic criteria: clinical

Differentials: serotonin syndrome- hyper-reflexivity & clonus

Management

1. IVF, cooling, withdraw causative agent

2. HDU for IV benzodiazepines

3. Consider bromocriptine (scare evidence) or dantrolene

Med Reg Notes

Causes

1. Drug (dopamine antagonists)

   1. Metoclopramide

   2. Phenoxthiazines

Prognosis

Can occur within hours of drug therapy and last up to a week

Complications

• Rhabdomyolysis

• Acute Kidney Injury (AKI) 

• Acute Hepatitis 

• Haemodynamic instability

• DIC

• Death c.10%

Resources and References

Links

1. Body systems: Nervous

2. Specialty: psychiatry, Neurology

Page written in 2024.