Neuroleptic Malignant Syndrome
Central dopamine blockade, or abrupt loss of dopaminergic therapy, disables thermoregulation and motor control together, so rigid muscle generates heat faster than the body can shed it.
Definition
Neuroleptic malignant syndrome is a rare, potentially fatal reaction to dopamine-receptor blockade or to abrupt withdrawal of dopaminergic therapy. The classic picture is a tetrad of altered mental state, hyperthermia, extrapyramidal signs and autonomic instability, but presentation is heterogeneous and second-generation cases may lack some or all of these. It is a clinical diagnosis of exclusion, supported by a markedly raised creatine kinase, leucocytosis and deranged liver function tests.
First principles
The drug history and the clock diagnose it, not the examination
Neuroleptic malignant syndrome (NMS) follows dopamine blockade. It usually appears within the first two weeks of an antipsychotic being started or its dose changed, but it also occurs on a long-term stable dose. Days after a dopamine blocker points here; hours after a serotonergic change points to serotonin syndrome. Every antipsychotic can cause it, at any dose.
This page is exam revision material, not medical advice, and must not be used for patient care. Always check drug doses against the BNF and current guidance. Full disclaimer.