Neuroleptic Malignant Syndrome
OVERVIEW
life-threatening extrapyramidal complication of using neuroleptic drugs
PATHOPHYSIOLOGY
- ? -> 2 theories
- neuroleptic-induced alteration of central neuroregulatory mechanisms -> impaired heat dissipation
- abnormal reaction of predisposed skeletal muscle (like MH)
CLINICAL FEATURES
- develops over 24-72 hrs
- hyperthermia
- rigidity
- rhabdomyolysis
- RESP – decreased chest wall compliance, tachypnoea, pulmonary infection
- NEURO – dyskinesia, dysarthria, parkinsonianism, agitation, stupour, coma, GTC seizures, chorea, babinski, chorea, trismus
- RENAL – renal faliure
- CVS – tachycardia, high BP, autonomic dysfunction
- HAEM – high WCC
- HEPATIC – increased LFT’s
RISK FACTORS
- phenothiazines (chlorpromazine, promethazine)
- butyrophenones (droperidol, haloperidol)
- thioxanthenes (chlorprothixene)
- benzamides (sulpiride)
- clozapine
- respiradone
- abrupt ceasing of neuroleptic or PD drugs
- alcoholics
- exhaustion
- dehydration
- malnutrition
Important differences between serotonin syndrome and neuroleptic malignant syndrome:
(1) NMS is a idiosyncratic reaction after prolonged exposure to neuroleptics or after withdrawal of a dopamine receptor agonist.
(2) NMS usually develops over days or weeks
(3) NMS usually accompanied by hyperthermia, severe muscle rigidity and rhabdomyolysis (not mydriasis, diarrhoea, hyperreflexia, myoclonus)
(4) NMS frequently associated with multi-organ failure
MANAGEMENT
Goals
(1) early recognition
(2) withdrawal of precipitents
(3) supportive care
Resuscitation
- airway assessment and securing if not patent (jaw trismus)
- hyperventilation
- liberal fluid resuscitation
- cool
- cardiovascular support (may require cautious beta-blockade)
- paralyse -> rigidity will respond to NDNMBS
Electrolytes and Acid-base
- hypermetabolic syndrome
- may require bicarbonate therapy if there is documented severe acidosis that is unresponsive to specific treatment
Specific Therapy
- bromocriptine
- amantidine
- dantrolene
Underlying cause
- stop agents
References and Links
CCC Toxicology Series
General
Approach to acute poisoning, ECGs in Tox, Evidenced-based Tox, Toxicology literature summaries, Does anti-venom work?
Toxins / Overdose
Amphetamines, Barbituates, Benzylpiperazine, Beta Blockers, Calcium Channel Blocker, Carbamazepine, Carbon Monoxide, Ciguatera, Citrate, Clenbuterol, Cocaine, Corrosive ingestion, Cyanide, Digoxin, Ethanol, Ethylene Glycol, Iron, Isoniazid, Lithium, Local anaesthetic, Methanol, Monoamine oxidase inhibitor (MAOI), Mushrooms (non-hallucinogenic), Opioids, Organophosphate, Paracetamol, Paraquat, Plants, Polonium, Salicylate, Scombroid, Sodium channel blockers, Sodium valproate, Theophylline, Toxic alcohols, Tricyclic antidepressants (TCA)
Envenomation
Marine, Snakebite, Spider, Tick paralysis
Syndromes
Alcohol withdrawal, Anticholinergic syndrome, Cholinergic syndrome, Drug withdrawals in ICU, Hyperthermia associated toxidromes, Malignant hyperthermia (MH), Neuroleptic malignant syndrome (NMS), Opioid withdrawal, Propofol Infusion Syndrome (PrIS) Sedative toxidrome, Serotonin syndrome, Sympatholytic toxidrome, Sympathomimetic toxidrome
Decontamination
Activated Charcoal, Gastric lavage, GI Decontamination
Enhanced Elimination
Enhanced elimination, Hyperbaric therapy for CO
Antidotes
Antidote summary, Digibind, Glucagon, Flumazenil, HIET – High dose euglycaemic therapy, Intralipid, Methylene Blue, N-Acetylcysteine (NAC), Naloxone
Miscellaneous
Cocaine chest pain, Digoxin and stone heart theory, Hyperbaric oxygen, Hypoxaemia in tox, Liver failure in tox, Liver transplant for paracetamol, Methaemoglobinaemia, Urine drug screen
Critical Care
Compendium
Chris is an Intensivist and ECMO specialist at The Alfred ICU, where he is Deputy Director (Education). He is a Clinical Adjunct Associate Professor at Monash University, the Lead for the Clinician Educator Incubator programme, and a CICM First Part Examiner.
He is an internationally recognised Clinician Educator with a passion for helping clinicians learn and for improving the clinical performance of individuals and collectives. He was one of the founders of the FOAM movement (Free Open-Access Medical education) has been recognised for his contributions to education with awards from ANZICS, ANZAHPE, and ACEM.
His one great achievement is being the father of three amazing children.
On Bluesky, he is @precordialthump.bsky.social and on the site that Elon has screwed up, he is @precordialthump.
| INTENSIVE | RAGE | Resuscitology | SMACC
