Neuroleptic Malignant Syndrome

Question 1

What is the mortality of Neuroleptic malignant syndrome/

Answer 1

10%

Question 2

What drugs can cause NMS?

Which most commonly cause it?

Answer 2

• Typical antipsychotics - Phenothiazines - Examples - promethiazine(phenergan), chlorpromazine (hiccups,schizophrenia) prochlorperazine (stemetil, buccastem).
• Butyrophenones (haloperidol)
• Atypical antipsychotics - clozapine, olanzapine, risperidone, quetiapine.
• Dopaminergic drugs - Levodopa.
• Anti-dopamingeric drugs - metoclopramide.

Question 3

What is the cause of NMS?

Answer 3

NMS is caused by a sudden, marked reduction in dopamine activity, either from withdrawal of dopaminergic agents or from blockade of dopamine receptors.

E.g. Increase in dose of antipsychotics or Metoclopramide could block dopamine receptors.

Decrease in Levodopa would cause a decrease.

Question 4

What are some features of NMS?

Answer 4

• More common in young male patients
• Onset usually in first 10 days of treatment or after increasing dose
• Pyrexia - >38C
• Rigidity
• Tachycardia
• Diaphoresis “sweat shock”
• Confusion

Question 5

What recreational drugs can cause similar symptoms to NMS?

Answer 5

Cocaine and Amphetamines

Question 6

What features distinguish serotonin syndrome from NMS?

Answer 6

Serotonin syndrome (SS) = too much serotonin.

Identical features

• Hypertension, tachycardia, tachypnoea & hyperthermia. Hypersalivation.

Distinct features

• NMS = Hyporeflexia, normal pupils.
  
  • Severe rigidity = NMS
  • Increased CK & WBC
• Serotonin syndrome = Hyperreflexia, Dilated pupils
  
  • Myoclonus = SS.
  • GI symptoms

Question 7

What is the management for NMS?

Answer 7

1. Stop antipsychotic
2. IV fluid to prevent renal failure
3. Dantrolene.
4. Bromocriptine, dopamine agonist, may also be used.