Sodium Azide Poisoning

TOXIC SYNDROME DESCRIPTION

The purpose of this document is to help health care workers and public health officials to recognize an unknown or suspected exposure to sodium azide. Sodium azide is a rapidly acting, potentially lethal chemical that exists as an odorless, white crystalline solid. It is used in automobile airbags to produce inflation of the airbag upon impact; after deployment, sodium azide is converted to nitrogen gas. Sodium azide is converted rapidly into hydrazoic acid vapor upon contact with water or an acid. Like sodium azide, hydrozoic acid is highly explosive. Similar to cyanide, sodium azide and hydrozoic acid also interfere with cellular respiration and aerobic metabolism, preventing the cells from using oxygen. The central nervous system and the cardiovascular system are most sensitive to acute sodium azide poisoning.

The amount and route of the exposure to sodium azide and the premorbid condition of the exposed person will contribute to the time of onset, duration, and the severity of illness.

Signs and symptoms of exposure

Following is a list of signs and symptoms that may be encountered in a person exposed to sodium azide. Signs and symptoms are not listed in order of importance, presentation or specificity. Also, partial presentations (an absence of some of the following signs/symptoms) do not necessarily imply less severe disease.

Central nervous system signs and symptoms

• Agitation
• Coma
• Convulsions
• Dizziness
• Headache
• Loss of consciousness (sudden collapse)

Respiratory signs and symptoms

• Bradypnea (decreased respiratory rate)
• Chest pain
• Dyspnea (shortness of breath)
• Hyperpnea (increased respiratory rate/depth)

Cardiovascular signs and symptoms

• Bradycardia (decreased heart rate)— late
• Flushing
• Hypertension (high blood pressure)— early
• Hypotension (low blood pressure)— late
• Tachycardia (increased heart rate)— early

Gastrointestinal signs and symptoms

• Abdominal pain
• Nausea
• Vomiting

Other signs

• Similar color of retinal arteries and veins
• Skin and eye irritation

Laboratory findings suggestive of sodium azide poisoning

• Metabolic acidosis
• Elevated anion gap
• Increased plasma lactate concentration

Differential diagnosis – poisoning with

• Carbon monoxide
• Cyanide
• Ethylene glycol
• Fluoroacetate
• Hydrogen sulfide
• Methanol
• Phosphine

Note: The actual clinical manifestations of an exposure to sodium azide may be more variable than the syndrome described in this document.