🚨 Poisoning and Overdose

Poisoning and overdose involve exposure to a substance that causes toxicity, either accidental or intentional. Rapid identification of the substance and supportive care are crucial, as presentation can range from asymptomatic to life-threatening multi-organ failure.

Recognise poisoning by a history of substance ingestion, empty containers, or characteristic toxidromes (e.g., cholinergic, anticholinergic, opioid). Patients may present with altered mental status, respiratory depression, cardiovascular instability, or specific organ dysfunction. Always consider non-accidental ingestion in children.

Perform an ABCDE assessment, prioritising airway protection (especially with reduced GCS or vomiting) and breathing (assess respiratory rate, depth, oxygen saturation). Assess circulation for signs of shock or arrhythmias. Determine GCS and pupil size. Try to identify the substance, dose, and time of ingestion from the patient or collateral history.

Red flags include reduced GCS (especially <8), respiratory depression (bradypnoea, hypoxia), hypotension, arrhythmias, seizures, severe metabolic acidosis, or evidence of end-organ damage (e.g., liver failure, renal failure). Ingestions of highly toxic substances (e.g., paraquat, tricyclic antidepressants) are always high risk.

Bedside: ECG (for QT prolongation, arrhythmias), capillary blood glucose, urine drug screen (if relevant). Bloods: FBC, U&Es, LFTs, ABG, paracetamol level (always check), salicylate level, specific drug levels if available and indicated (e.g., digoxin, lithium). Imaging: Chest X-ray (for aspiration), abdominal X-ray (for radiopaque tablets).

Provide supportive care based on the ABCDE assessment. Maintain airway patency and support breathing with oxygen or ventilation if needed. Manage hypotension with intravenous fluids and vasopressors if necessary. Correct hypoglycaemia. Administer activated charcoal if indicated (within 1 hour of ingestion for suitable substances). Consider specific antidotes if available and appropriate (e.g., naloxone for opioids, flumazenil for benzodiazepines).

Escalate to a senior registrar or consultant immediately for any haemodynamic instability, respiratory compromise, reduced GCS, seizures, or ingestion of highly toxic substances. Discuss with the National Poisons Information Service (NPIS) for complex cases or unknown substances. Consider critical care referral for patients requiring advanced organ support.

Paracetamol overdose is common and requires urgent management with N-acetylcysteine. Always check a paracetamol level in any overdose. Activated charcoal is contraindicated in caustic ingestions or if the patient has a reduced GCS without airway protection. Toxidromes are key for identifying unknown substances.