Introduction
Poisons are chemical or physical agents that produce adverse responses in biological systems.
Poisoning on the other hand is the ingestion by, or exposure of a patient to excessive doses of a medicine or other substances that may cause harm.
Aspirin toxic doses are associated with increased sensitivity of the respiratory center, incomplete oxidative phosphorylation and increased rate of metabolism
Clinical features of aspirin poisoning
Initial manifestations
(The initial manifestations of aspirin poisoning occur 3-6 hours after an overdose greater than 150mg/kg)
- Vomiting
- Sweating
- Tachycardia
- Hyperventilation
- Tinnitus
- Fever
- Lethargy
- Confusion
- Respiratory alkalosis
- Impaired renal function
- Increased anion gap
- Metabolic acidosis may result
Severe poisoning:
- Coma
- Respiratory depression.
- Seizures
- Cardiovascular collapse
- Cerebral and pulmonary oedema
Investigations
- FBC, ESR
- Electrolytes, Urea and Creatinine
- Random Blood Glucose
- Liver function tests including prothrombin time
- Blood aspirin levels
Treatment for aspirin poisoning
Treatment objectives
The treatment objectives of aspirin poisoning are:
- To prevent or reduce damage to organs
- To restore normal metabolic functions
Non-drug treatment
- Gastric lavage and whole bowel irrigation
Drug treatment
- Activated charcoal can be used up to 12 – 24 hours after ingestion (see
Paracetamol poisoning) - Intravenous infusion of sodium chloride 0.9% (preferably with glucose)
- Correct dehydration and ensure good urine output (saline diuresis)
- Supplemental oxygen
- Supplemental glucose
- Intravenous vitamin K 10 mg daily for coagulopathy
- Intravenous NaHCO, to alkalinize urine
- Correct other electrolyte derangements
- Haemodialysis for severe salicylate poisoning
Indications for haemodialysis.
- Severe clinical toxicity
- Aspirin (acetylsalicylic acid) levels > 7 mmol/L (100 mg/dL) a rapidly rising plasma salicylate level even if not up to 7 mmol/L is an indication forbdialysis
- Failure of other treatment modalities
- Renal failure
- Heart failure
- Seizures
- Severe acidosis