Cyanide Toxicity

Death can occur in minutes

Diagnostic features

symptom onset: inhaled < ingested < plant-derived ingestion

(cyanide levels not usually readily available)

Mechanism

Sources

Decontamination

Treatment

Cobalt EDTA (Aust.)

Eli-Lily Kit (U.S.) - Amyl nitrite, Sodium nitrite, Sodium thiosulphate

Nitrite

(contraindicated in combined carbon monoxide poisoning - use thiosulphate with HBO)

Sodium thiosulphate

Hydroxycobalamin/Vitamin B12 (Europe)

 

Adverse reactions  - Cyanide treatments

Drug Mechanism ADR
Cobalt EDTA Chelates to cyanide to form cobalt-cyanide Tachycardia/Hypotension
Arrhythmias
Anaphylaxis
Vomiting
Seizures
Amyl nitirite

Sodium nitrite

Combines with Hb to form metHb
MetHb binds with CN to form CyanometHb
Hypotension
Methaemoglobinaemia
Low reading SpO2 (due to metHb)
Sodium thiosulphate Provides sulphur group to liver rhodanase to convert cyanometHb to thiocyanate
Thiocyanate is excreted in urine
 
Hydroxycobalamin binds to form cyanocobalamin which is excreted by kidney