Epidemiology

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

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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

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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

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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

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Clinical Manifestations of Dermal Exposure

Dermatologic Manifestations

• Contact Dermatitis-Irritant Type (see Contact Dermatitis, [[Contact Dermatitis]])

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Clinical Manifestations of Ocular Exposure

Ophthalmologic Manifestations

• Ocular Irritation

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References

• xxx