Difference between poison, toxin and venom
Poison - substance that causes disturbance
Toxin - biological poison
Venom - toxin injected via bite or sting
Categories of toxic actions & give example of each
Selective: specific pathways e.g. Rattex - disturbs Vit K pathways
Non-selective: Inoculation irritation and denaturing e.g. acid/alkali
Immediate: organophosphates
Delayed: iron - 3 phases (early, quiescent, life-threatening)
ABC of Poisoning Mx
Airway, Breathing, Circulation & cardiac,
Diagnosis & decontamination,
Enhance drug clearance,
Further symptom Mx & frequent re-evaluation,
Give Antidote,
Help
Skin decontamination
PPE
Remove clothing
wash with soap & water
Eye decontamination
Irrigation with water or saline for 15 to 30 minutes
Gastric emesis & lavage
Both induce vomiting
Emesis (usually for children)
- gag reflex
- natural ipecac syrup
Lavage (adults)
- Large bore catheter flush
Gastric emesis/lavage contraindications
- Impaired consciousness
- Risk of seizures
- Hydrocarbons
- Corrosive substances
Activated charcoal
Charcoal in syrup form given orally or via NGT
Activated charcoal adverse effects
- vomiting
- constipation/diarrhoea
- intestinal obstruction
Activated charcoal indications
Salicylates
Paracetamol
Digoxin
TCAs
Activated charcoal contra-indications
- Oral antidote
- Hydrocarbons
- Corrosive substances
- Due for endoscopy
- Cyanide; lithium
- Iron salts
Whole bowel irrigation indications
- Drug packers
- Iron poisoning
Whole bowel irrigation contra-indications
- Bowel obstruction
- Ileus
- Compromised airway
3 methods to enhance drug clearance
Urinary alkalinisation
- IV Na Bicarb to maintain urine pH
Haemodialysis
- For renal impairment or deteriorating clinically after intervention
Charcoal haemoperfusion
- Binds charcoal to toxin to clear it
- Also renal impairment or deteriorating pts
* more expensive
6 Vital conditions to treat in all poisoning cases
- hypoventilation
- hypoglycaemia
- hypo/hyperthermia
- seizures
- cardiac compromise
- liver/kidney failure
Hypertension Tx
Benzodiazepines
Sodium nitropusside
Hypotension Tx
Fluids
Vasopressors
Arrhythmic Mx
Brady - B2 agonists e.g. atropine
Tachy - stimulants e.g. benzos
Stable V-tach - lidocaine/lignocaine
Digoxin antidote
Digoxin immune fab
Paracetamol antidote
Acetylcysteine
Iron antidote
Deferoxamine
Benzodiazepine antidote
Flumazenil
Opioid antidote
Naloxone
