Ammonia toxicity


Routes of Exposure

  • Inhalation of ammonia may cause nasopharyngeal and tracheal burns, bronchiolar and alveolar edema, and airway destruction resulting in respiratory distress or failure.
  • Skin/Eye Contact - the extent of injury produced by exposure to ammonia depends on the duration of the exposure and the concentration of the gas or liquid. Contact with concentrated ammonia solutions, such as some industrial cleaners (25%), may cause serious corrosive injury, including skin burns, permanent eye damage, or blindness. The full extent of damage to the eyes may not be clear until up to 1 week after the injury is sustained. Contact with liquefied ammonia can cause frostbite injury.
  • Ingestion - ingestion of ammonium hydroxide, while uncommon, results in corrosive damage to the mouth, throat, and stomach. Ingestion of ammonia does not normally result in systemic poisoning.

Clinical Features

  • Respiratory
    • The extent of injury produced by exposure to ammonia depends on the duration of the exposure, the concentration of the gas, and the depth of inhalation
    • Even fairly low airborne concentrations (50 ppm) of ammonia produce rapid onset of eye, nose, and throat irritation; coughing; and narrowing of the bronchi.
    • More severe clinical signs include immediate narrowing of the throat and swelling, causing upper airway obstruction and accumulation of fluid in the lungs. This may result in low blood oxygen levels and an altered mental status. Mucosal burns to the tracheobronchial tree can also occur. Immediate onset of laryngospasm with respiratory arrest can occur.
  • Dermal
    • Dilute aqueous solutions (less than 5%) rarely cause serious burns but can be moderately irritating. **Exposure to concentrated vapor or solution can cause pain, inflammation, blisters, necrosis and deep penetrating burns, especially on moist skin areas.
    • Skin contact with compressed, liquid ammonia (which is stored at -28 °F) causes frostbite injury, and may also result in severe burns with deep ulcerations.
  • Ocular
    • Ammonia has a greater tendency to penetrate and damage the eyes than does any other alkali. Even low concentrations of ammonia vapor (100 ppm) produce rapid onset of eye irritation.
    • Contact with high concentrations of the gas or with concentrated ammonium hydroxide may cause swelling and sloughing of the surface cells of the eye, which may result in temporary or permanent blindness.
  • Gastrointestinal
    • Nausea, vomiting, and abdominal pain are common symptoms following ingestion of ammonia. Ingestion of household ammonia (5-10%) has resulted in severe esophageal burns. Esophageal pain with swallowing, drooling and refusal of food suggest a more significant injury. Substernal chest pain, abdominal pain and rigidity suggest profound injury and potential perforation of the esophagus and/ or stomach.

Differential Diagnosis




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