Cyanides- toxicology. Characteristics. Medical activities
Written by Anam Hussain
General characteristics for Cyanide:
- Is a tissue poison
- Exists in several forms- liquid, gas, or salt
- Low boiling point and evaporates quickly for several minutes
- Most effective in gas form when enclose in a small space
- Strong musty smell of almonds
- Has strong affinity for metals
- As a gas: dissipates rapidly (hydrogen cyanide)
- As a liquid: ranges from blue-colourless stable hydrocyanic acid
- As a solid: it is a white granular powder
Pathophysiology:
- Target: mitochondria of the cells
- Mitochondria composed of enzyme called cytochrome oxidase which participates in oxidative phosphorylation
- Cytochrome oxidase composed of Fe3+ ions which cyanide has strong affinity to
- Cyanide binds to Fe3+, interferes with oxidative phosphorylation
- Aerobic metabolism and energy production blocked
- This cause hypoxia and eventually cell death
- No aerobic respiration causes shift to anaerobic respiration leading to build up of lactic acid
- Presentation depends on dose and routes of exposure:
- When inhaled: death within 6-8mins
- When ingested: delayed onset of 15-30 mins with additional symptoms of sore throat and diarrhoea
- Skin contact: onset delayed from 15-30mins with additional signs of erythema and pain at site of contact