Cyanide Poisoning

Overview

Cyanide poisoning is a serious, potentially fatal emergency. Cyanide interferes with the way cells use oxygen, so even though oxygen may be present in the blood, the body's tissues cannot use it to produce energy. This rapidly affects organs that need a great deal of oxygen, especially the brain and heart.

The most common source of significant cyanide exposure is smoke from house and building fires, because many burning materials release cyanide gas. Cyanide is also found in some industrial chemicals, and rarely in certain plant materials. Because the condition can worsen within minutes, immediate emergency care is essential.

Symptoms

Symptoms depend on the amount and speed of exposure. With high exposure they come on quickly:

• Headache, dizziness, and confusion
• Rapid breathing followed by slow or difficult breathing
• Fast then slowing heart rate
• Nausea and vomiting
• Weakness, seizures, and loss of consciousness
• In severe cases, collapse, coma, and cardiac arrest

In someone exposed to fire smoke, signs such as soot around the mouth or nose, a hoarse voice, and altered consciousness raise concern for cyanide along with carbon monoxide. Any suspected exposure is an emergency.

Causes

Cyanide can enter the body by breathing it in, swallowing it, or, less often, through the skin. Sources include:

• Smoke inhalation in house, building, or industrial fires
• Certain industrial and laboratory chemicals and processes
• Some chemicals used in metal cleaning, plating, and manufacturing
• Rarely, ingestion of certain plant materials or seeds, or deliberate poisoning

Risk Factors

• Exposure to smoke from fires, especially in enclosed spaces
• Occupations using cyanide-containing chemicals, such as metalworking and certain manufacturing
• Firefighting and rescue work
• Industrial accidents and chemical spills

Diagnosis

Cyanide poisoning is often diagnosed based on the situation and symptoms, because treatment cannot wait for test results. Clinicians consider it strongly in anyone with smoke inhalation and altered consciousness. Supporting evaluation may include:

• Clinical assessment: History of exposure, breathing, heart rate, and level of consciousness.
• Blood tests: Lactate and blood gas measurements can suggest poisoning; specific cyanide levels are not available quickly.
• Monitoring: Of oxygen, heart rhythm, and other vital signs.

Treatment

Treatment is urgent and begins as soon as poisoning is suspected.

• Removal from exposure: Getting the person to fresh air and away from the source, with rescuer safety in mind.
• High-flow oxygen and support of breathing and circulation.
• Antidotes: Specific medicines such as hydroxocobalamin can bind cyanide and are given by emergency teams when poisoning is suspected.
• Supportive care: Intravenous fluids, treatment of seizures, and management of low blood pressure in the hospital.

Rapid treatment greatly improves the chance of survival and recovery.

Prevention

• Install and maintain smoke alarms and have a fire escape plan
• Never re-enter a burning building; let trained firefighters handle rescues
• Follow safety procedures and use protective equipment when working with cyanide-containing chemicals
• Store industrial chemicals securely and according to regulations
• Ensure good ventilation in workplaces that use these substances

When to See a Doctor

Call emergency services immediately if cyanide poisoning is suspected, such as in someone who has inhaled smoke from a fire and becomes confused, drowsy, or collapses, or after any known chemical exposure with symptoms. Do not delay, as the condition can become fatal within minutes. Move the person to fresh air if it is safe to do so, and provide CPR if they are not breathing and you are trained while help is on the way.

Related Topics

Frequently Asked Questions

References

1. Centers for Disease Control and Prevention (CDC). Facts About Cyanide.
2. MedlinePlus, U.S. National Library of Medicine. Cyanide poisoning.
3. Agency for Toxic Substances and Disease Registry (ATSDR). Cyanide.
4. American Association of Poison Control Centers.