Clinical features

The smell of bitter almonds is characteristic but is not always present. Cyanosis is absent and the skin may be brick red in colour.

The effects of acute poisoning may include:

• hypoxia, hypotension, tachycardia
• headache, vomiting, weakness
• chest tightness, dyspnoea, hyperventilation, pulmonary oedema
• confusion, vertigo, ataxia, convulsions, coma, paralysis
• cardiac arrhythmias
• metabolic acidosis

Chronic poisoning may present with:

• ataxia, optic atrophy, nerve deafness, peripheral neuropathy, dermatitis

Toxic amblyopia may result from the cyanide component of tobacco smoke.

At points of skin contact, there is irritation, redness and pain, and, sometimes, burns. The chemicals are absorbed through the skin causing a picture similar to that seen from direct inhalation or ingestion.