UEU-co logo

Ovid: Oxford Handbook of Acute Medicine

Editors: Ramrakha, Punit S.; Moore, Kevin P. Title: Oxford Handbook of Acute Medicine, 2nd Edition Copyright ©1997,2004 Oxford University Press (Copyright 1997, 2004 by Punit S Ramrakha and Kevin P Moore) > Table of Contents > Chapter 9 – Endocrine emergencies > Neurolepetic malignant syndrome Neurolepetic malignant syndrome The neurolpetic malignant syndrome results from an imbalance of dopaminergic neurotransmitters following neuroleptic drug use. The incidence is ~0.5% in patients taking neuroleptic drugs. This syndrome is clinically distinct from malignant hyperthermia (P604); it is not an allergic reaction. The mean age of onset is 40 years. The mortality is ~10%. Drugs associated with the neuroleptic malignant syndrome

  • Haloperidol
  • Phenothiazines
  • Loxapine
  • Thioxanthenes
  • Dopamine-depleting drugs
    • metoclopramide
    • tetrabenazine
    • withdrawal of levadopa or amantadine

Clinical features

  • Muscular rigidity incl. dysphagia, dysarthria early (96%)
  • Extra-pyramidal signs (pseudo-parkinsonism), tremor (90%)
  • Catatonia: muteness (95%)
  • Altered consciousness ± coma
  • Increased serum CPK/AST (97%)
  • Pyrexia (rarely >40°C) follows onset of rigidity.

The syndrome can occur within hours of initiating drug therapy, but typically takes ~1 week. It can also occur following a dosage increase of a well-established drug. Complications

  • Rhabdomyolysis (P392)
  • Renal (15%) and hepatic failure
  • Fitting is rare
  • Cardiovascular collapse
  • DIC
  • Respiratory failure.

Differential diagnosis

  • Malignant hyperthermia (P604)
  • Heat stroke (P842)
  • Other causes of catatonia
  • Thyrotoxic crisis (P590)
  • Phaeochromocytoma (P598)
  • Drug-induced hyperthermia (caused by cocaine, LSD, phencyclidine, amphetamine, tricyclics, and aspirin).


  • Withdrawal of causative agent
  • Dantrolene (1–2mg/kg every 6 hours up to a maximum 300mg/day)
  • Paralysis and ventilation (curare, pancuronium)
  • Bromocriptine, amantadine, levodopa (increase dopaminergic tone and reduce rigidity, thermogenesis, and extra-pyramidal symptoms).

Leave a Reply

Time limit is exhausted. Please reload the CAPTCHA.


apply_now Pepperstone Group Limited