Pulmonary chemical agents: Difference between revisions

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==Background==
==Background==
*Ammonia, methyl isocyanate, methyl bromide, hydrochloric acid and chlorine, phosgene
*Include [[ammonia toxicity|ammonia]], [[methyl isocyanate]], [[methyl bromide]], [[hydrochloric acid]] and [[chlorine gas]], [[phosgene]]
*Common toxic industrial chemicals, transported widely across country
*Common toxic industrial chemicals, transported widely across country
*Can affect central or peripheral airways
*Can affect central or peripheral airways
**burning and irritation to epithelial lining causing airway edema or pulmonary edema, hypoxia, and hypotension
**burning and irritation to epithelial lining causing airway edema or [[pulmonary edema]], [[hypoxia]], and [[hypotension]]


''Chlorine''
===Pathophysiology===
*Smells of a swimming pool or bleach
*Most common exposure is secondary to mixing household cleaners
*Irritation of conjunctivae, nose, pharynx, larynx, trachea, and bronchi
*Individuals with gas exposure may not need decon, if skin symptoms absent
*Rare ocular injury as tears protect mucous membranes from direct damage
 
''Phosgene''
*Smell of freshly cut hay or grass
*Not to be confused with phosgene oxide (vesicant)
*Denser than air, settles in low-lying places – trenches/basements
*Rapid olfactory fatigue can occur leading to prolonged exposure
*Exposure may be secondary to fire at textile factory/house, metalwork, or burning Freon
*Symptoms dependent on concentration
**Low: mild cough, chest tightness, shortness of breath
**Moderate: Lacrimation
**High: Non-cardiogenic pulmonary edema within 2 to 6 hours after exposure with death within 24-48 hours
*Symptoms may take 2-24 hours to develop
 
=== Pathophysiology ===
*Choking agents combine with water in respiratory tract to form acids
*Choking agents combine with water in respiratory tract to form acids
*Both chlorine and phosgene react with water in respiratory tract to form hydrochloric acid
*Both chlorine and phosgene react with water in respiratory tract to form hydrochloric acid
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**Anhydrous, ammonia, Hydrogen chloride, Sulfur dioxide, Formaldehyde
**Anhydrous, ammonia, Hydrogen chloride, Sulfur dioxide, Formaldehyde
**Rapidly react with water causing damage to upper airway to vocal cords
**Rapidly react with water causing damage to upper airway to vocal cords
**Direct tissue damage causing edema/airway obstruction and laryngospasm
**Direct tissue damage causing bronchiolar/alveolar edema/airway obstruction and laryngospasm
**Nasopharyngeal and tracheal [[chemical burns]], upper airway obstruction
**Laryngospasm (can occur immediately upon exposure)
**[[Respiratory distress]]/failure, [[hypoxia]]
**[[Cough]]
**[[Chest pain]]
**[[Arrhythmias]] (hydrochloric acid)
*Moderately water-soluble
*Moderately water-soluble
**Damage to moderate-sized airways (bronchioles)
**Damage to moderate-sized airways (bronchioles)
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**Inhaled deeply into alveoli
**Inhaled deeply into alveoli
**Lack of irritation of mucous membranes can cause them to go undetected
**Lack of irritation of mucous membranes can cause them to go undetected
**[[Respiratory distress]], tachypnea, [[cough]], [[pulmonary edema]]


==Differential Diagnosis==
==Differential Diagnosis==
{{Chemical weapon DDX}}


==Workup==
==Evaluation==


==Management==
==Management==
*Liquid phosgene can cause off-gassing with release of toxin from clothes post-exposure
*'''Decontaminate''' patient!
**Liquid phosgene can cause off-gassing with release of toxin from clothes post-exposure
*Do not allow patient to be active as it worsens condition
*Do not allow patient to be active as it worsens condition
*Diuretics and corticosteroids not shown to be effective
*Inhaled [[bronchodilators|beta agonists]] for bronchoconstriction
*Inhaled beta agonists for bronchoconstriction
*Diuretics and corticosteroids ''not'' shown to be effective


==Disposition==
==Disposition==
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==External Links==
==External Links==


==Sources==
==References==
<references/>
<references/>
[[Category:Toxicology]]
[[Category:Pulmonary]]

Latest revision as of 14:34, 13 October 2019

Background

Pathophysiology

  • Choking agents combine with water in respiratory tract to form acids
  • Both chlorine and phosgene react with water in respiratory tract to form hydrochloric acid

Clinical Features

Symptoms dependent on the water solubility of the chemical

  • Highly water-soluble
    • Anhydrous, ammonia, Hydrogen chloride, Sulfur dioxide, Formaldehyde
    • Rapidly react with water causing damage to upper airway to vocal cords
    • Direct tissue damage causing bronchiolar/alveolar edema/airway obstruction and laryngospasm
    • Nasopharyngeal and tracheal chemical burns, upper airway obstruction
    • Laryngospasm (can occur immediately upon exposure)
    • Respiratory distress/failure, hypoxia
    • Cough
    • Chest pain
    • Arrhythmias (hydrochloric acid)
  • Moderately water-soluble
    • Damage to moderate-sized airways (bronchioles)
    • Bronchospasm and wheezing
  • Poorly water-soluble

Differential Diagnosis

Chemical weapons

Evaluation

Management

  • Decontaminate patient!
    • Liquid phosgene can cause off-gassing with release of toxin from clothes post-exposure
  • Do not allow patient to be active as it worsens condition
  • Inhaled beta agonists for bronchoconstriction
  • Diuretics and corticosteroids not shown to be effective

Disposition

See Also

External Links

References