Neuroleptic malignant syndrome & Serotonin syndrome Flashcards
What is Neuroleptic malignant syndrome?
Idiosyncratic reaction to neuroleptics (Antipsychotics) thought to be due to central D2 receptor blockage or dopamine depletion in the hypothalamus/nigrostriatal pathways
What are the features of Neuroleptic malignant syndrome?
Fever - Elevated temperature set point/impaired thermal homeostasis due to dopamine effects
Severe generalised muscular hypertonicity - May be due to dopamine or due to changes in skeletal muscle Ca2+ metabolism
Akinetic mutism - p’s don’t move or speak
Autonomic disturbance eg tachycardia, pallor, tremor, incontinence, fluctuating BP, Diaphoresis (Excessive sweating)
When is Neuroleptic malignant syndrome likely to occur?
Initiation or increased dosage of neuroleptic, but can happen at any time of patient taking neuroleptics
Usually over 1-3 days
Always within 4 weeks
Symptoms can persist up to 10 days post discontinuation
What are the signs of Neuroleptic malignant syndrome?
Temperature above 38 Lead pipe muscular rigidity Likely to have altered mental state eg confusion Autonomic instability Dyspnoea due to muscle rigidity
What are some of the differentials for Neuroleptic malignant syndrome?
Serotonin syndrome
Malignant hyperpyrexia
Simple dystonic reaction to neuroleptics
Recreational drug toxicity eg cocaine
What investigations can be done in a patient with suspected Neuroleptic malignant syndrome?
FBC - Show leukocytosis (High WBCs) U+Es - May show renal failure or acidosis Hypocalcaemia Creatinine kinase LFTs Urinary drug screen CT head to exclude other diagnoses
What is the management of Neuroleptic malignant syndrome?
If severe, airway/breathing need to be protected
IV benzodiazepines may be needed for agitated patients eg Diazepam
Stop causative drug
IV fluids for rehydration
Cooling devices/antipyretics for hyperthermia eg paracetamol
What are the complications of Neuroleptic malignant syndrome?
Death MI Rhabdomyolysis AKI Seizures Respiratory failure DIC Aspiration pneumonia Deterioration in mental illness due to medications being stopped
What is the triad of symptoms for Serotonin syndrome?
Autonomic hyperactivity
Neuromuscular abnormality
Mental status changes
What are the symptoms of mild Serotonin syndrome?
Diarrhoea
Tremor
Akathisia (Restlessness)
What are the symptoms of more severe Serotonin syndrome?
Agitation
Hypervigilance
Pressured speech
Acute delirium - Most severe cases
What would be present on examination in a patient with Serotonin syndrome?
HTN, ↑HR, ↑Sweating, Hyperthermia, Hyperactive bowel sounds, Tremor, Clonus, Hypertonicity/Hyper-reflexia, Anxiety, Agitation, Confusion, Coma
What criteria can be used to differentiate between Serotonin toxicity and not toxic levels?
Hunter serotonin toxicity criteria
What are the differentials for Serotonin syndrome?
Malignant hyperthermia - would have patchy cyanotic skin + hyporeflexia
Anticholinergic poisoning - would have normal reflexes
NMS - Slower onset, bradykinesia + lead pipe rigidity
Hyperthyroidism - TFTs
What is the management of Serotonin syndrome?
Remove causing drug
IV fluids
Benzodiazepines if agitated
Mild cases - should resolve within 24 hours, supportive measures only
Moderate cases - CV/Thermal disturbances corrected. May use 5HT antagonists eg cyproheptadine
