Cyanide Poisoning

Cyanide is rapidly absorbed by inhalation, skin absorption, ingestion

In gaseous form, hydrogen cyanide is an important component of fire smoke

Cyanide-generating glycosides also found in the pits of apricots and other related plants

Cyanide is generated by breakdown of nitroprusside; poisoning can result from rapid high-dose infusions

Also formed by metabolism of acetonitrile, found in some over-the-counter fingernail glue removers

Onset of toxicity is nearly instantaneous after inhalation

However, it may be delayed for minutes to hours after ingestion of cyanide salts or cyanogenic plants or chemicals

Effects include

• Headache

• Dizziness

• Nausea

• Abdominal pain

• Anxiety

• Confusion

• Syncope

• Shock

• Seizures

• Coma

• Death

"Bitter almond" odor may be detected on the victim's breath or in vomitus, although this is not a reliable finding

The venous oxygen saturation may be elevated (> 90%) in severe poisonings because tissues have failed to take up arterial oxygen

Obtain blood cyanide levels (not usually readily available)

Remove the victim from exposure, taking care to avoid exposure to rescuers

Activated charcoal

• Administer 60–100 g mixed in aqueous slurry orally or via gastric tube

• Do not use for comatose or convulsing patients unless they are endotracheally intubated

At the scene, induce emesis if charcoal is not immediately available

Stop or slow the nitroprusside infusion rate for suspected cyanide toxicity

In the United States, there are prepackaged cyanide antidotes (eTable 38–1)