Chlorine

Epidemiology

  • Incidence: chlorine is one of the most common and potent inhalational exposures

Etiology of Chlorine Inhalation

  • Chlorine Gas: yellow-green acrid gas, which is heavier than air
    • Movement of gas to lowest point with gravity (due to weight relative air) explains its use in trench warfare during WW-I
    • However, there have been cases reported where chlorine gas was transferred via specific environmental conditions (example: from a basement through a centralized heating system)
    • Exposure
      • Industrial and transport-associated gas leaks
      • Leaks from water purification systems (swimming pool, water supply, etc)
      • Homemade chemical bombs
      • Household bleach products (hypochlorite liquid bleach or chlorinated phosphate powdered bleach) mixed with acids (hydrochloric, phosphoric, hydrofluoric) result in the release of chlorine gas: mixing may be incidental on surfaces
  • Chloramine Gas
    • Exposure: household bleach products mixed with ammonia
    • Pulmonary reaction occurs due to in situ release of chlorine gas, hypochlorous acid, and ammonia
  • Nitrogen Trichloride
    • Exposure: swimming pool with inadvertent contact with nitrogen donor compounds, household bleach products mixed with ammonia
    • Pulmonary reaction occurs due to in situ release of chlorine gas, hypochlorous acid, and ammonia
  • Hydrochloric Acid Aerosol
    • Exposure: industry
  • Hypochlorite (Bleach) Aerosol
    • Exposure: clening in an enclosed space, such as a bathroom
  • Hypochlorous Acid Aerosol
    • Exposure: industry
  • Chlorine Dioxide
    • Exposure: pulp paper processing and bleaching
  • Chlorinated Silanes
    • Exposure: gases used in microelectronics
  • Titanium or Antimony Chlorides: reactive metal halides
    • Exposure: industry
  • Thionyl Chloride: breaks down into hydrogen chloride and sulfur dioxide
    • Exposure: industry

Physiology of Chlorine Inhalation

  • Direct Irritation of Mucous Membranes and Skin
    • Airway injury due to inhalation of chlorine (with hydrochloric acid and hypochlorous acid serving as intermediates for tissue reaction in lung)
  • Extent of Lung Injury: related to the total inhalational dose delivered to the lung
  • Effect of Water Solubility: while all chlorine exposures result in mucous membrane and upper airway irritation, effect on mucosa is related to water solubility
    • Lower Water solubility (chlorine gas, chlorine dioxide, chloramines, nitrogen trichloride) -> lower degree of mucous membrane and upper airway irritation, higher degree of penetration into lung
    • Higher Water Solubility (hydrochloric aid aerosol, hypochlorous acid aerosol) -> higher degree of mucous membrane and upper airway irritation, lower degree of penetration into lung

Clinical Manifestations of Gas/Aerosol Inhalation

Upper Airway Manifestations

  • Mucous Membrane Irritation: present in all cases, to some extent
  • Upper Airway Irritation: present in all cases, to some extent
    • Delayed onset of pulmonary symptoms without upper airway irritation is distinctly unusual
  • Laryngospasm (see Laryngospasm)

Pulmonary Manifestations

Reactive Airway Dysfunction Syndrome (see Reactive Airway Dysfunction Syndrome)

  • Epidemiology: cases have been reported with chlorine gas and chlorine-containing products
  • Clinical: increased airway reactivity following acute exposure to respiratory irritant
  • Treatment
    • Bronchodilators: may be useful

Bronchiolitis (see Bronchiolitis)

  • Epidemiology

Bronchiolitis Obliterans (see Bronchiolitis Obliterans)

  • Epidemiology

Acute Lung Injury-ARDS/Diffuse Alveolar Hemorrhage (DAH) (see Acute Lung Injury-ARDS and Diffuse Alveolar Hemorrhage)

  • Diagnosis
    • FOB: may be necessary to rule out airway injury
    • OLB: diffuse alveolar damage
  • Treatment
    • Nebulized Sodium Bicarbonate: while may be beneficial in acute treatment of chlorine inhalation, has not been studied in controlled trials
    • Corticosteroids: may be benficial in acute lung injury-ARDS, but are unproven

Asthma-Occupational (see Asthma-Occupational)

  • Epidemiology: reported with chloramine

Pulmonary Alveolar Proteinosis (PAP) (see Pulmonary Alveolar Proteinosis)

  • Epidemiology: xxx

Exacerbation of Asthma (see Asthma)

  • Epidemiology: there is evidence that patients with underlying airway reactivity may be more responsive to chlorine

Clinical Manifestations of Dermal Exposure

Dermatologic Manifestations


Clinical Manifestations of Ocular Exposure

Ophthalmologic Manifestations

  • Ocular Irritation

References

  • xxx