Neuroleptic malignant syndrome

Question 1

Definition

Answer 1

Uncommon, idiosyncratic, life threatening complication of treatment with antipsychotic medications.
Characterised by AMS, muscle rigidity, altered ANS, hyperthermia

Question 2

Is it a reproducible dose dependant relationship

Answer 2

Not dose dependant. Predisposing brain abnormalities (PD, Wilsons), show sensitivity.
Speculation the risk is genetic

Question 3

Key diagnostic features

Answer 3

Presence of risk factors
Altered mental status: confusion, delirium, stupor
Muscle rigidity
Autonomic dysfunction: Tachycardia, labile hypertension, diaphoresis, tachypnoea, urinary incontinence
Hyperthermia
Psychiatric history

Question 4

Strong risk factors

Answer 4

Exposure to antipsychotic medications
Abrupt withdrawal of dopaminergic agents
Structural brain abnormality

Question 5

Weak risk factors

Answer 5

Older age
Pre-existing agitation
Akathsia
Male sex
Iron deficiency
Catatonia
Dehydration

Question 6

Investigations

Answer 6

FBC- elevate
Serum CK _
Metabolic panel- N
Brain CT/MRI- may show structural abnormality
Urine, blood, LP, toxicology screen, CXR->rule out differential, generally normal

Question 7

Important differentials

Answer 7

Sepsis
Drugs
Catatonia
Serotonin toxicity
Mania
Malignant hyperthermia
Heat stroke
Metabolic
Infarction
NPH
Brain tumors

Question 8

Differentiating from Serotonin toxicity

Answer 8

SS will have twitching, shivering, restless vs global rigidity
SS will be flushed, sweaty vs pale
SS will have vomiting, diarrhea vs no GI symptoms

Question 9

Management

Answer 9

1. ABC
2. Withdrawal of antipsychotics/dopamine antagonists must be stopped
3. Dopamine agonists must be restored->bromocriptine
4. Fluids
5. Physical cooling methods for hyperthermia
6. If dysphagia- may require a NGT
7. For agitation Lorazepam 1-4mg
8. Sedation and intubation may be required (diazepam, midazolam)

Question 10

What to do is patients psychiatric symptoms compel resumption of antipsychotic meds

Answer 10

Delay of at least two weeks following resolution of NMS episode advised.

Question 11

Follow up recommendations

Answer 11

Will need CK level monitoring

Tests repeated daily until symptoms and laboratory abnormalities resolve