Managing Poisened Patients Flashcards
Important parts of the history in a poisoned patient
- What did they take, how much and when?
2. Why did they take it
Cause of miosis (small pupils)
Opiates
Cause of mydriasis (large pupils)
Sympathomimmetics and anticholinergics (e.g. ecstasy, amphetamines)
Potential cause of jaundice in OD patient
paracetamol OD / alcholic liver disease
Things to look for on examination of someone who has OD
- pupil size, conjunctival haemorrhage, jaundice
- self harm, track marks
- extensive bruising from long lie (risk of rhabdomyolysis)
Rhabdomyolysis
- hypoxic skeletal muscle damage –> release of muscle cell contents: creatine kinase, myoglobin and K+
Effects/complications of rhabdomyolysis
- hyperkalaemia
- myoglobin precipitation in kidney –> renal failure
- coca-cola urine due to myoglobin
Investigations in OD patient
- urine toxicology, specific drug assays
- imaging
- 02 sats, temp, ECG/cardiac monitor
- Bloods: U&E, creatine kinase, creatinine, LFT’s, clotting
Diagnostic feature cluster for opiate OD
- coma
- miosis
- reduced respiratory rate
Diagnostic feature cluster for stimulant OD
- agitation and delirium
- mydriasis
- hyperthermia
- tachycardia and arrhythmias
Diagnostic feature cluster for salicylates
- n&v
- tinnitus and deafness
- sweating and hyperventilation
- metabolic acidosis
Diagnostic feature cluster for anticholinergics including TCA’s
coma, hypertonia, mydriasis, tachycardia
Managment methods of OD
- symptomatic and supportive measures
- Reducing absorption
- Enhancing elimination
- specific antidotes
Methods to reduce absorption of drug after OD
- gastric lavage
- single dose activated charcoal
- whole bowel irrigation
Gastric lavage
- rarely used
- pump stomach with water via NG tube to reduce absorption of drug
- has to be done within an hour
Single dose activated charcoal
- patient drinks charcoal solution
- drug gets caught in charcoal matrix in stomach - can then be carried through gut without being absorbed
- must be done within an hour of OD
NB: does not bind alcohol, glycols, acid/alkali, iron or lithium
Whole bowel irrigation
- isotonic solution pass through NG tube to flush out bowel or 2L/hour oraly
- used for body packers
Methods of enhancing elimination of drug (OD)
- multiple dose activated charcoal
- urine alkanisation
- extracorporeal elimiation
- chelating agents for heavy metal poisoning
Multiple dose activated charcoal
- enhances elimination by GI dialysis
- absorbed drug moves by diffusion down concentration gradient from capillaries to gut –> excreted with charcoal
- used for carbamazepine, quinine, theophylline and dapsone
Urine Alkalinisation
- give IV sodium bircarbonate to acheive urine pH of 7.5-8.5
- used in salicylate poisoining - changes the amount of salicylate that is ionised to that it can easily pass out of the kidney into the urine (not reabosrbed into tubules)
Extracorporeal elimination
- haemodialysis/haemofiltration
- used for poisoning complicated by renal failure
- elimination of ethanol, methanol, salicylates, ethylene glycol and lithium
Chelating Agent
- used for heavy metal poisoining
- sodium calcium edetate for lead poisoning (Ca replaced by Pb - Pb renally eliminated bound to the lattice)
Antidote to paracetamol poisoining
acetylcysteine - glutathione precursor for paracetamol poisoning
Antidote to opiate
Naloxone - opiate antagonist
Antidote to benzodiazepine
GABA antagonist
NB: can induce seizures if patient has taken anti-epileptic drug
