Poisoning Flashcards
Which are the 2 most groups most likely to present with poisoning?
- accidental/ deliberate
- more common in males/ females
Young children (1-5yo)
More common in Males.
Accidental.
Adolescents
Equal rates in Males and Females.
Deliberate self-harm
4 top poisons causing death in UK
- Paracetamol
- TCAs
- Opiates (heroin, methadone)
- Carbon monoxide (smoke from housefires)
State whether the following are depressants or stimulants:
- BZDs
- opioids
- cocaine
- MDMA
- theophylline
- BZDs: depressant
- opioids: depressant
- cocaine: stimulant
- MDMA: stimulant
- theophylline: stimulant
Which poison should be tested for in everyone who presents with overdose?
Why?
Paracetamol
Cos most common overdose method + won’t show early signs
Features of BZD overdose
- CNS depression (ataxia, nystagmus, dysarthria)
- Respi depression
- Hypothermia
- Rhabdomyolysis
ECG features in BZD overdose
- Heart block (1st/2nd degree)
2. QT prolongation
Treatment for BZD overdose
- Flumazenil
2. Activated charcoal, MDAC
Late clinical features of paracetamol overdose (including metabolic disturbances)
- RUQ liver pain
- Jaundice, encephalopathy
- Coagulopathy
- Raised creatinine
Metabolic disturbances
- Hyperglycaemia
- Metabolic acidosis
Which investigations are best for predicting prognosis after a paracetamol overdose.
What levels of this indicate poor prognosis
PT and INR
POOR PROGNOSIS
- PT or INR rising after day 3
- PT >180s at any time
What investigative features (including ABG) indicate that someone requires a liver transplant after paracetamol overdose
- Metabolic acidosis
- Raised lactate
- Encephalopathy (3 or 4 ie worsened confusion, coma)
- Creatinine >300umol/L
Treatment for paracetamol overdose
- Activated charcoal
- N-acetylcysteine
- Haemodialysis (if v high paracetamol concentration >700mg/L)
How long/ what method should N-acetylcysteine be given for?
IV for 21h
How does N-acetylcysteine work
Can be converted by body into glutathione so that it can then detoxify NAPQI (toxic metabolite of paracetamol)
Common complication of N-acetylcysteine.
How is this managed?
Anaphylactoid reaction
-urticaria, wheeze, hypotension
Give antihistamine + reduce dose of N-acetylcysteine
What level of paracetamol ingestion requires treatment with N-acetylcysteine
> 150mg/kg
How long after paracetamol overdose can blood tests be done to determine whether or not to treat
4h after overdose
Overdose with what drug should be considered in a pt with metabolic acidosis + respiratory alkalosis
Aspirin
Symptoms of mild/ moderate aspirin overdose
- Tinnitus
- Sweating, vomiting, dizziness
- Hyperventilation
Symptoms of severe aspirin overdose
- Agitation, delirium, coma, fits
- Arrhythmias
- Pulmonary/ cerebral oedema
- Heart/ renal failure
Metabolic complications of severe aspirin overdose
- Metabolic acidosis
- Respiratory alkalosis
- Hypoglycaemia
- Hypokalemia
Treatment for aspirin overdose
- Charcoal, MDAC
2. Sodium bicarbonate (prevents CNS penetration, enhances elimination by alkalinising urine)
Symptoms of opioid overdose
- Pin point pupils
- CNS, respiratory depression
- Hypotension, tachycardia
- Hallucinations
- Rhabdomyolysis
- Non-cardiac pulmonary oedema
Metabolic complications of opioid overdose
- Respiratory acidosis
2. Metabolic acidosis
Treatment for opioid overdose
Nalozone (opioid receptor antagonist)
Half life of naloxone
40-60min
Complications of naloxone
ACUTE WITHDRAWAL SYNDROME
- arthralgia
- tremor, irritability, palpitations
- DnV, cramps
- rhinorrhoea
Symptoms of TCA overdose due to anticholinergic effects
- Pupil dilation
- Dry eyes
- Urinary retention
- Tachycardia
- Agitation, delirium
- Fits, coma
- Hypertonia, hyper-reflexia
Symptoms of TCA overdose due to sodium channel blocking effects
- Heart block
- Heart arrhythmias
- Prolonged QT/ wide QRS
What signs on ECG indicate poor prognosis in TCA overdose
QRS >120ms (3 small sq) = urgent action required
QRS >160ms (4 small sq) = high risk of arrhythmia
Treatment for TCA overdose
- Charcoal, MDAC
- Sodium bicarbonate (treat arrythmia, correct acidosis)
- BZD for fits
Early features of iron overdose
- NnV, abdo pain
- Bloody diarrhoea
- Massive GI fluid loss
Late features of iron overdose
- Black offensive stools
- Reduced GCS, coma, fits
- Shock
- Liver/ renal failure
- Gastric strictures
Features of severe iron poisoining (list by ABCDE)
C: shock, hypotension
D: reduced GCS/ fits; hypergycaemia
E: metabolic acidosis/ rectal bleed/ vomiting blood
Treatment for iron overdose
- Desferrioxamine (binds to iron)
2. Gastric lavage if large OD (charcoal won’t work)
When is Desferrioxamine used
For severe iron OD
- iron conc >3mg/L +
- features of severe poisoning
2 antidotes for alcohol poisoning
- Methanol
2. Ethylene glycol
