Neuroleptic malignant syndrome (NMS) is a potentially life-threatening complication of treatment with antipsychotic drugs, or abrupt withdrawal of dopamine agonists.
Characterized 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 is advised following full resolution of an NMS episode.
Documenting this reaction in the medical records is important.
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) and with abrupt cessation of dopamine agonists. It is characterized by altered mental state, increased muscle tone or frank rigidity, dysregulated autonomic nervous system, hyperactivity, and hyperthermia. None of these signs are exclusive to this condition, and other important diagnoses (e.g., sepsis) should be excluded first.
This topic covers the diagnosis and management of neuroleptic malignant syndrome in adults.
History and exam
Key diagnostic factors
- history of exposure to antipsychotic medications
- history of abrupt withdrawal of dopaminergic drugs
- history of structural brain abnormality
- altered mental status
- muscle rigidity
- autonomic dysfunction
- psychiatric history
Other diagnostic factors
- history of iron deficiency
- history of Wilson disease
- exposure to antipsychotic medications
- structural brain abnormality
- abrupt withdrawal of dopaminergic drugs
- older age
- preexisting agitation
- male sex
- iron deficiency
- preexisting dehydration
- exposure to dopamine antagonists and other antipsychotics
1st investigations to order
- serum creatine kinase
- basic metabolic panel
- brain CT scan
- brain MRI
- myoglobin levels and urinalysis
- urine culture
- blood culture
- lumbar puncture
- toxicology screen
- chest x-ray
Investigations to consider
- serum iron
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