Acute cyanide Intoxication: A rare case of survival

A 30-year-old male jewellery factory worker accidentally ingested silver potassium cyanide and was brought to the emergency department in a state of shock and profound metabolic acidosis. This patient was managed hypothetically with use of injection thiopentone sodium intravenously until the antidote was received. Cyanide is a highly cytotoxic poison and it rapidly reacts with the trivalent iron of cytochrome oxidase thus paralysing the aerobic respiration. The result is severe lactic acidosis, profound shock, and its fatal outcome. The patient dies of cardio-respiratory arrest secondary to dysfunction of the medullary centres. It is rapidly absorbed, symptoms begin few seconds after exposure and death usually occurs in <30 min. The average lethal dose for potassium cyanide is about 250 mg. We used repeated doses of thiopentone sodium till the antidote kit was finally in our hands, hypothesising that it contains thiol group similar to the antidote thiosulphate. Moreover, it is an anticonvulsant. We were successful in our attempts and the patient survived though the specific antidotes could be administered after about an hour.