Poisoning and overdose Flashcards
Paracetamol overdose symptoms
No symptoms
Nausea and vomiting
Loin pain
Haematuria and proteinuria
Jaundice
Abdominal pain
Coma
Severe metabolic acidosis
<4h since paracetamol ingestion
Activated charcoal given while paracetamol still in GI tract
Prevents it being absorbed by small bowel
4-15h since paracetamol ingestion
Take level, treat according to nomogram
If above line, NAC required
16h since paracetamol ingestion
Start N Acetyl cysteine straight away
NAC should be started regardless of nomogram if
- If a patient presents after 16 hours
- there is uncertainty about timing
- or has a staggered overdose
then NAC should be started regardless of the nomogram
NAC can also be administered immediately if there is an increased risk of toxicity. This occurs in the following:
Patient on long-term enzyme inducers
Regular alcohol excess
Pre-existing liver disease
Glutathione-deplete states: eating disorders, malnutrition and HIV
Aspirin overdose clinical features
hyperventilation, tinnitus, deafness, vasodilatation, and sweating. Coma
respiratory alkalosis and a metabolic acidosis.
Management aspirin overdose
Activated charcoal if ingestion <1 hours ago
IV fluid, sodium bicarbonate and potassium chloride
urinary alkalinization with intravenous sodium bicarbonate - enhances elimination of aspirin in the urine
Haemodialysis
Digoxin poisoning clinical features
Yellow green colour disturbance Visual haloes Dizziness Nausea and vomiting Palpitations ( due to arrhythmias) Bradycardia typically without hypotension Confusion Hyperkalemia reverse tick ST depression with first degree heart block
Management digoxin poisoning
Immediate digoxin level IV fluids Correct electrolyte abnormalities Continuous cardiac monitoring Give digibind if : Level > 15ng/ml after 6 hours of last dose Level >10ng/ml within 6 hours of last dose Symptomatic
Benzodiazepine poisoning clinical features
drowsiness, ataxia, dysarthria, nystagmus, and occasionally respiratory depression, and coma
Benzodiazepine poisoning management
Charcoal, activated can be given within 1 hour of ingestion
benzodiazepine antagonist flumazenil [unlicensed indication] can be hazardous, particularly in mixed overdoses involving tricyclic antidepressants or in benzodiazepine-dependent patients.Should be used with caution as it may precipitate seizures.
Antidepressant poisoning clinical features
CNS effects : Delirium/confusion/agitation, sedation, seizures, coma, hyperreflexia, extensor plantar responses,
CVS effects: Sinus tachycardia, hypertension, hypotension (due to alpha2-adrenoreceptor blockade), broad complex tachycardia (can develop bradycardia pre-arrest)hypothermia
Anticholinergic effects: Can occur at time or presentation or be delayed and prolonged. Agitation, restlessness, delirium, mydriasis (big pupil), dry mouth , warm skin, tachycardia, ileus, urinary retention, respiratory failure
Dilated pupils and urinary retention also occur.
Metabolic acidosis may complicate severe poisoning; delirium with confusion, agitation, and visual and auditory hallucinations are common during recovery
Antidepressant poisoning Management points:
Intravenous lorazepam or intravenous diazepam for convulsions
Activated charcoal given within 1 hour of the overdose reduces absorption of the drug
The use of anti-arrhythmic drugs is best avoided, but intravenous infusion of sodium bicarbonate can arrest arrhythmias or prevent them in those with an extended QRS duration
Iron overdose clinical presentation
abdominal pain, nausea, vomiting, diarrhea, and haematemesis within 30 minutes to 6 hours of ingestion.rectal bleeding
Shock ,metabolic acidosis, Hepatotoxicity and coagulopathy
Iron overdose treatment
desferrioxamine mesilate chelates iron.
Lithium poisoning
Restlessness
Vomiting, diarrhoea
ataxia, weakness, dysarthria, muscle twitching, and tremor
Convulsions, coma, renal failure, electrolyte imbalance, dehydration, and hypotension
Lithium poisoning management
Conc > 2 mmol/litre may need treatment with haemodialysis if neurological symptoms or renal failure are present
In acute overdosage may only need to take measures to increase urine output (e.g. by increasing fluid intake but avoiding diuretics). Otherwise, treatment is supportive (electrolyte balance, renal function, and control of convulsions)
Stimulant-drug poisoning
wakefulness, excessive activity, paranoia, mydriasis, hallucinations, and hypertension followed by exhaustion, convulsions, hyperthermia, and coma
Early stages can be controlled by diazepam or lorazepam
Theophylline poisoning
vomiting,agitation, restlessness, dilated pupils, sinus tachycardia, and hyperglycaemia
haematemesis, convulsions, and supraventricular and ventricular arrhythmias,hypokalaemia
Theophylline poisoning management
Activated charcoal
Ondansetron may be effective for severe vomiting
Potassium chloride for hypokalaemia
Lorazepam/diazepam for seizures
Short-acting beta-blocker can be administered IV to reverse severe tachycardia, hypokalaemia, and hyperglycaemia.
Organophosphorus insecticides poisoning features
They inhibit cholinesterase activity, thereby prolonging and intensifying the effects of acetylcholine.
SLUD Salivation, lacrimation, urination, diarrhoea
small pupils ,muscle weakness and fasciculation
Convulsions, coma, pulmonary oedema with copious bronchial secretions
small pupils
Organophosphorus insecticides poisoning management
clear airway, wash skin, frequent removal of bronchial secretions, and adequate ventilation and oxygenation; gastric lavage may be considered provided that the airway is protected.
Atropine sulfate will reverse the muscarinic effects of acetylcholine
Pralidoxime chloride, a cholinesterase reactivator if severe as adjunct
Cyanide poisoning symptoms
N&V if small doses, rapid LOC, apnoea, seizures, cardiac arrest
