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Choking/Lung/Pulmonary Agents (Irritant/Corrosive - Inhalation Toxidrome)

Choking/lung/pulmonary agents are chemicals that cause severe irritation or swelling of the respiratory tract (lining of the nose, throat, and lungs). Chemicals such as ammonia, chlorine, and phosgene cause eye, nose, and throat irritation, cough, wheezes, and dypsnea, also known as Irritant Gas Syndrome.

Concise toxidrome definition: Immediate effects to the respiratory/pulmonary tract presenting as nasal and oral secretions, coughing, wheezing, and/or respiratory distress that may progress to rapid systemic toxicity.

Rationale or reasoning for toxidrome decisions: A secondary pulmonary syndrome is not needed because the inhalation exposure and the pulmonary tract have a likelihood of similar exposure. Spectrum of injury presentation suggests a combination of upper and lower pulmonary into one toxidrome is appropriate for use by first responders. Initial assessment will focus on general respiratory complaints which will not differentiate between upper and lower pulmonary injury. The initial treatment will be similar.

Issues or concerns about this toxidrome: Lower pulmonary agents will in their ideal presentation be noted by the absence of upper pulmonary and mucus membrane signs and symptoms. Odor may be used for specific agent recognition. Hydrofluoric Acid (HF) specific antidote (calcium), there may be systemic effects after absorption (cardiac).

Inhalation Irritant/Corrosive examples of industrial chemicals and potential chemical warfare/terrorism agents: Chemical Warfare Agents (CWA, e.g., Phosgene), Toxic Industrials Chemicals/Toxic Industrial Materials (TICs/TIMs, e.g., chlorine, ammonia, and riot control agents).

The clinically relevant routes of exposure and types of sources: Mouth, nose, and mucosal membranes.

The organ systems generally affected: Upper pulmonary- upper respiratory tract to include airway and bronchi; Lower pulmonary- air space and alveoli.

The initial signs and symptoms: Respiratory distress, increased respiratory rate (shallow and/or rapid), shortness of breath, plus or minus secretions (e.g., drooling, mucus), coughing, use of accessory muscles for breathing (tri-pod position). Upper pulmonary- effects are immediate - wheezing, stridor, nasal and oral secretions (drooling, mucus), excessive eye tearing/lacrimation. Lower pulmonary- effects are progressive - absent breath sounds, rhonchi, rales.

A progression of signs and symptoms includes: Bronchial spasm, respiratory failure (e.g. cyanotic, apnea). Irritant symptoms are immediate signs and symptoms which typically are upper pulmonary, with classic pulmonary disease are delayed. However, they can all lead to respiratory failure if left untreated (affects oxygenation and ventilation).

The underlying pathology, biological processes, or modes of action include: Upper respiratory- bronchospasm, highly soluble agents. Lower respiratory- air space disease.

Common treatment protocol, specific antidotes and key supportive measures: Oxygen, bronchodilators, corticosteroid, mechanical ventilation, suction, (Sodium Bicarbonate).

Report to the Toxic Chemical Syndrome Definitions and Nomenclature Workshop (PDF - 2.01 MB) (DHS, NLM, May, 2012)

Information from Other Resources

Resource Comparison Table of Resource Comparison
Information from CDC, WISER, and CAMEO
Emergency Response Safety and Health Database (CDC/NIOSH) arrow WISER (NIH/NLM) arrow CAMEO (EPA, NOAA) arrow Medical Management Guidelines for Acute Chemical Exposures (CDC/ATSDR) arrow Chemical Emergencies (CDC) arrow

Additional Resources:

ChemIDplus - Chemical dictionary, structures, and links to many Internet resources (NIH/NLM)
Ammonia, Bromine, Chlorine, Hydrogen Chloride, Methyl Bromide, Methyl Isocyanate, Osmium Tetroxide, Diphosgene, Phosgene, Phosphine, Phosphorus Sulfuryl Fluoride

Hazardous Substances Data Bank - Comprehensive, peer-reviewed toxicology data (NIH/NLM)
Ammonia, Bromine, Chlorine, Hydrogen Chloride, Methyl Bromide, Methyl Isocyanate, Osmium Tetroxide, Diphosgene, Phosgene, Phosphine, Phosphorus, Elemental, Sulfuryl Fluoride

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