clinical features

Last reviewed 03/2023

Dose and patient age are the most important factors. Over the age of 12 years, there is a characteristic sequence of respiratory alkalosis caused by an initial direct stimulation of the respiratory centre followed by metabolic acidosis. In children, metabolic acidosis develops more rapidly, but below the age of 4 years, preceding respiratory alkalosis is rare.

The patient may be restless, confused, febrile, sweating, and hyperventilating, and may complain of nausea, vomiting, epigastric discomfort, tinnitus and deafness. In severe toxicity, there may be coma, fits, cardiac arrest and ARDS.

Complicated metabolic effects occur including:

  • hypokalaemia and hyper- or hypo-natraemia
  • respiratory alkalosis followed by metabolic acidosis - except children
  • dehydration and hyperpyrexia
  • hyper- or hypo-glycaemia
  • hypoprothrombinaemia
  • pulmonary oedema