Salicylate overdose
A key concept for the exam is to understand that salicylate overdose leads to a mixed respiratory alkalosis and metabolic acidosis. Early stimulation of the respiratory centre leads to a respiratory alkalosis whilst later the direct acid effects of salicylates (combined with acute renal failure) may lead to an acidosis. In children metabolic acidosis tends to predominate
Features
Treatment
Indications for haemodialysis in salicylate overdose
*salicylates cause the uncoupling of oxidative phosphorylation leading to decreased adenosine triphosphate production, increased oxygen consumption and increased carbon dioxide and heat production
Features
- hyperventilation (centrally stimulates respiration)
- tinnitus
- lethargy
- sweating, pyrexia*
- nausea/vomiting
- hyperglycaemia and hypoglycaemia
- seizures
- coma
Treatment
- general (ABC, charcoal)
- urinary alkalinization with intravenous sodium bicarbonate - enhances elimination of aspirin in the urine
- haemodialysis
Indications for haemodialysis in salicylate overdose
- serum concentration > 700mg/L
- metabolic acidosis resistant to treatment
- acute renal failure
- pulmonary oedema
- seizures
- coma
*salicylates cause the uncoupling of oxidative phosphorylation leading to decreased adenosine triphosphate production, increased oxygen consumption and increased carbon dioxide and heat production