Poisoning

Related Subjects: |Drug Toxicity - clinical assessment |Metabolic acidosis |Aspirin/Salicylates toxicity |Ethylene glycol toxicity |Ethanol toxicity |Methanol toxicity |Ricin toxicity |Carbon Tetrachloride Toxicity |Renal Tubular Acidosis |Lactic acidosis |Iron Toxicity |Tricyclic Antidepressant Toxicity |Opiate Toxicity |Carbon monoxide Toxicity |Benzodiazepine Toxicity |Paracetamol (Acetaminophen) toxicity |Amphetamine toxicity |Beta Blocker toxicity |Calcium channel blockers toxicity |Cannabis toxicity |Cyanide toxicity |Digoxin Toxicity |Lithium Toxicity |NSAIDS Toxicity |Ecstasy toxicity |Paraquat toxicity |Quinine toxicity |SSRI Toxicity |Theophylline Toxicity |Organophosphate (OP) Toxicity |Toxin elimination by dialysis |Drug Toxicity with Specific Antidotes |Toxicological Emergencies |Poisonings

☣️ Poisoning is a frequent cause of emergency admission in both adults and children. It may result from accidental ingestion, therapeutic error, or deliberate self-harm. Always consider specialist support: 👉 National Poisons Information Service (NPIS) 👉 TOXBASE (login required for clinicians).

🧠 About

• Poisoning can mimic many acute medical emergencies - always maintain a high index of suspicion.
• Patients may under-report or conceal ingested substances, especially in suicide attempts.
• Accidental poisoning is common in children under 5 (household products, medications, plants).
• In adults, self-harm overdoses (paracetamol, antidepressants, opioids) predominate.

📦 Sources & History

• Seek a detailed drug history: substance name, dose, formulation, route, time of ingestion, and co-ingestants (alcohol, recreational drugs).
• Note whether tablets were vomited soon after ingestion - does not rule out toxicity.
• Gather collateral evidence: medication packets, witnesses, ambulance crew, suicide note, or electronic records.
• In children: enquire about storage of medicines, cleaning agents, or exposure to grandparents’ medications.

🔎 Clinical Clues – Bedside Features

🧪 Investigations

• Bloods: FBC, U&E, glucose, calcium, LFTs, clotting (INR/PT), CK if seizures.
• ABG: look for high anion gap acidosis (salicylates, methanol, ethylene glycol).
• Calculate osmolar gap if suspected toxic alcohol ingestion.
• ECG: arrhythmias, QRS/QT prolongation (TCAs, arsenic, digoxin).
• Urinalysis: haematuria, crystals (ethylene glycol).
• Toxicology levels: paracetamol (at 4 hrs+), digoxin, lithium, theophylline, salicylate, iron.
• Consider imaging if aspiration or foreign body ingestion suspected.

🛠️ Management – General Principles

• 📌 ABCDE first: A – secure airway, B – support breathing, C – IV access + fluids, D – decontamination if indicated, E – enhance elimination, F – focused antidote therapy, G – get NPIS/TOXBASE advice.
• Supportive care is the cornerstone – many toxins clear within 12–24 hrs.
• Consider early ITU input if GCS < 9, hypoventilation, or refractory shock.

💊 Specific Treatments

• Activated charcoal: within 1 hr of ingestion (50 g adult; 1 g/kg child). 🚫 Not effective for metals (iron, lithium), alcohols, corrosives.
• Multi-dose charcoal: for carbamazepine, dapsone, theophylline, quinine, phenobarbital.
• Whole bowel irrigation: iron, lithium, body packers (opioids, cocaine).
• Antidotes:
  • Paracetamol → N-acetylcysteine (NAC)
  • Opiates → Naloxone
  • Benzodiazepines → Flumazenil (⚠️ use with caution – risk of seizures)
  • Digoxin → Digibind
  • Iron → Desferrioxamine
  • Organophosphates → Atropine + Pralidoxime
  • Methanol/Ethylene glycol → Fomepizole or ethanol, dialysis if severe
  • Cyanide → Hydroxocobalamin or sodium thiosulfate
  • Beta-blocker toxicity → Atropine, glucagon, IV fluids
  • TCAs → IV sodium bicarbonate for QRS widening/arrhythmias
• Enhanced elimination: haemodialysis for lithium, salicylates, methanol, ethylene glycol, valproate.

👶 Paediatric Considerations

• Common causes: paracetamol, iron tablets, household cleaning agents, berries/plants.
• Children absorb drugs rapidly and are at higher risk of severe toxicity.
• Never induce vomiting (risk of aspiration and caustic injury).
• Check weight-based doses for charcoal and antidotes.
• Admit if significant ingestion, abnormal obs, or unsafe home environment.

🧠 Psychiatric & Safeguarding

• All adults with intentional overdose require a mental health risk assessment.
• Children with accidental ingestion: assess home safety and consider safeguarding referral.
• Red flags for self-harm risk: previous attempts, psychiatric illness, male >50, isolation, intent to die.

💡 Key Clinical Pearls: - Always check paracetamol level, even if not admitted in the history. - Treat the patient, not just the drug – supportive care saves lives. - Early involvement of NPIS/TOXBASE is strongly recommended.

📚 References

• BNF – Poisoning, Emergency Treatment
• TOXBASE