Toxicology Flashcards
How can the effects of an ingested agent be reduced?
Minimise absorption - Charcoal Reduce gut transit time - Bowel irrigation Enhance elimination Administer antidote Antagonise effects
For which toxins is charcoal not recommended?
Electrolytes
Heavy metals
Alkaline/acid ingestion
Hydrocarbons
How is elimination enhanced in salicylate poisoning?
Alkalinise urine
What is the antidote for opioid poisoning?
Naloxone
What is the antagonist used in organophosphate poisoning?
Atropine
What is the normal dose of paracetamol?
15 mg/kg
What is the toxic dose of paracetamol?
Anything above 8 g considered possibly lethal
What is the antidote in paracetamol toxicity?
N-acetyl-cysteine
- Precursor for glutathione > increases levels in liver
- Binds with toxic breakdown products of paracetamol
How does paracetamol toxicity manifest itself?
Toxic metabolite builds up and can’t be mopped up by glutathione > hepatic toxicity
How long do you continue N-acetyl-cysteine treatment for in paracetamol toxicity?
Until ALT peaks
What is the narcotic toxidrome?
CNS depression
Miosis
Slow respiration
Hypotension
What is the cholinergic toxidrome of insecticide poisoning?
Blocks acetylcholinesterase > SLUDGE syndrome
What is the SLUDGE syndrome?
S = salivation L = lacrimation (tears) U = urination D = diarrhoea G = GI distress E = emesis
What is the anticholinergic toxidrome, caused by tricyclic antidepressants, for example?
Blurry vision Mydriasis Tachycardia Dry mouth Confusion Agitation Delirium Seizures Urinary retention
What is the sympathomimetic toxidrome, caused by ecstasy, for example?
Tachycardia
Hypertension
CNS excitation
Seizures
What is the extrapyramidal toxidrome?
Rigidity
Tremor
Dystonia
Oculogyric crisis = prolonged involuntary upward deviation of eyes
What is the serotonergic toxidrome, caused by tramadol and SSRIs, for example?
Tachycardia Hypertension CNS excitation Seizures Clonus
What do you do if you can’t see the bite site for a snake or spider bite?
Do urine test > looking for venom - use venom detection kit
Measure clotting factors
- Activated with snake bites
- Happens very quickly
What is the immediate treatment for snake bites?
Compression and immobilisation to limit systemic effects
Why is compression and immobilisation not recommended for spider bites?
Can cause concentrated local effect
What is the management for a snake bite?
Confirm venom present
Administer 1 ampule of brown, and 1 ampule of tiger antivenom from antivenom kit, even with confirmed tiger snake bite
If not working after 4 hours > administer another ampule of antivenom
What is the mechanism of action for snake venom?
Neurotoxic
Myotoxic
Coagulopathic
What is the mechanism of action for blue ringed octopus venom?
Tetrodotoxin
Muscle paralysis
What is the treatment for blue ringed octopus venom?
Respiratory support
No antidote
What is the mechanism of action for box jellyfish venom?
Multi-component venom
Cardiotoxic
What is the treatment for box jellyfish venom?
Vinegar as first aid
Antivenom
What is the mechanism of action for stonefish venom?
Neurotoxic
Myotoxic
Cardiotoxic
What is the treatment for stonefish venom?
Antivenom
What is the mechanism of action for funnel web spider venom?
Stimulation of nerves
What is the treatment for funnel web spider venom?
Antivenom
What is the mechanism of action for red back spider venom?
Cholinergic effect
