Synopsis
Recognise dopamine-related hyperthermic rigidity, stop the precipitant, prevent renal and cardiorespiratory injury, and distinguish neuroleptic malignant syndrome from serotonin toxicity, catatonia, infection and seizures.
- Neuroleptic malignant syndrome is an idiosyncratic reaction to dopamine-receptor blockade or abrupt withdrawal of dopaminergic treatment, producing altered mental state, generalised rigidity, hyperthermia and autonomic instability.
- High-potency antipsychotics, rapid dose escalation, parenteral or depot administration, agitation, dehydration and previous NMS increase risk, but any dopamine antagonist can be implicated.
- Symptoms usually evolve over one to three days rather than within hours: anxiety or confusion and rigidity may precede the peak fever and laboratory injury.
Key red flags
Temperature rise with dysrhythmia, hypoxia, acidosis, oliguria, coagulopathy or reduced consciousness requires immediate intensive-care escalation.
Investigation priorities
Identify dopamine blockade, depot exposure, interaction or dopaminergic withdrawal.
Management branches
Hyperthermia, rigidity and mental-state change follows dopamine blockade or withdrawal.
- Stop the suspected culprit and non-essential psychoactive medicines, restore omitted dopaminergic therapy only through specialist advice and contact critical care and poisons information.
- Use ABCDE assessment, active external cooling, intravenous fluids, cardiac monitoring and rapid treatment of hypoxia, hyperkalaemia, seizure and aspiration.
Key medicines
LorazepamUse small titrated intravenous or oral doses from the current BNF with airway and respiratory monitoring, especially when agitation or catatonic features are prominent.
BromocriptineSpecialists may use an enteral dopamine-agonist regimen titrated over several days from toxicology guidance; there is no routine unsupervised ward dose.