Poisoning Flashcards
What is the management for poisoning
- Identify the agent (ask patient, parents, look for clinical signs)
- Determine toxicity of agent - use ToxBase, report dose, symptoms, time since ingestino
- Within 1 hour of ingestion → consider reduction of absorption using activated charcoal
- Investigations
- Management as according to agent ingested
If low-toxicity + asymptomatic → reassure and discharge ± health visitor for risk assessment and health promotion advice for safe storage
What investigations should be done for poisoning
ECG (drug has cardiovascular toxicity)
Urine toxicology screen
FBC
Renal screen, U&Es
LFTs
Glucose
Blood gas
Specific blood concentrations (ALWAYS paracetamol, salicylates)
INR
What are the indications for activated charcoal
Within 1 hour of ingestion → 50g every 4 hours with water
Indicated in:
- Paracetamol
- Carbamazepine
- Dapsone
- theophylline
- Quinine
- Phenobarbital
When is activated charcoal contra-indicated
Alcohol
Metal salts (lithium, iron)
petroleum
Corrosives
Clofenotane
Malathion
Paracetamol poisoning: mechanism, symptoms, management
Gastric irritation, saturation of liver metabolism → toxic metabolite NAPQI
Early: abdo pain + vomiting
Late: liver failure (12-24h)
Measure plasma paracetamol
IV N-Acetylcysteine
Carbon monoxide poisoning: mechanism, symptoms, management
Binds to Hb → tissue hypoxia
Early: headache, nausea
Late: confusion, drowsiness, coma
High flow oxygen (hasten CO dissociation)
Button battery poisoning: mechanism, symptoms, management
Electrical circuit production from caustic hydroxide → corrosion of gut wall
Abdo pain, gut perforation and stricture formation
CXR/AXR: identify position
In the oesophagus, fails to pass, symptoms present → Endoscopic removal
Salicylates poisoning: mechanism, symptoms, management
Direct stimulation of the resp. centre
Uncouples oxidative phosphorylation → metabolic acidosis + hypoglycaemia
Early: vomiting, tinnitus
Late: resp. alkalosis → met. acidosis
Measure plasma salicylate concentration 2-4h after ingestion
Alkalinisation of urine (increased salicylate excretion)
Haemodialysis
Tricyclic antidepressant poisoning: mechanism, symptoms, management
Anti-cholinergic, interferes with cardiac conduction pathways
Early: tachycardia, drowsiness, dry mouth
Later: arrhythmias, seizures
Arrhythmia →. Sodium bicarbonate
Support breathing
Ethylene glycol poisoning: mechanism, symptoms, management
Produces toxic metabolites that interferes with intracellular energy production
Early: intoxication
Later: tachycardia, metabolic acidosis → renal failure
Fomepizole
Haemodialysis
Alcohol poisoning: mechanism, symptoms, management
Inhibitory effect on glycolysis in the liver + brain neurotransmission
Hypoglycaemia, coma, respiratory failure
Monitor blood glucose, correct if necessary
Support ventilation
Iron poisoning: mechanism, symptoms, management
Local corrosion to gut mucosa + disruption of oxidative phosphorylation in the mitochondria → free radicals, lipid peroxidation, metabolic acidosis
Initial: vomiting, diarrhoea, haematemesis, melaena, acute gastric ulceration
→ latent period of improvement
6-12h later: drowsiness, coma, shock, liver failure + hypoglycaemia, convulsions
Long term: gut strictures
Serum iron level 4 hours after ingestion
IV deferoxamine (iron chelation)
Hydrocarbons e.g. paraffin, kerosene poisoning: mechanism, symptoms, management
Facilitates aspiration → lung toxicity
Direct inhibitory effect on neurotransmission in the brain
Supportive treatment
Organophosphorus poisoning: mechanism, symptoms, management
Inhibition of acetylcholinesterase → ACh accumulation in the nervous system
Salivation, lacrimation, urination, diarrhoea, vomiting, muscle weakness, cramps and paralysis, bradycardia and hypotension
Seizures and coma
Atropin
Supportive care
Pralidoxime (reactivates acetylcholinesterase)
Management for digoxin poisoning
Digifab
