Which of the following is a choking (pulmonary) agent?

Which of the following is a choking (pulmonary) agent?

• A. Phosgene.
• B. Sarin.
• C. Cyanide.
• D. Chlorine.

Answer: (D)

Choking (pulmonary) agents cause injury primarily to the lungs, especially the airways and alveolar membranes, leading to edema and impaired gas exchange. When chlorine gas is inhaled, it reacts with water in the respiratory tract to form hydrochloric and hypochlorous acids. These acids burn and inflame the airway lining and the delicate capillaries, triggering inflammation and fluid leakage into the alveoli. The result is swelling of the lungs and disrupted oxygen transfer, which can develop hours after exposure. That lung-directed injury is the defining feature of a choking/pulmonary agent, distinguishing it from agents that act mainly on nerves or blood. Phosgene would produce a similar lung injury, while sarin is a nerve agent and cyanide a blood agent, each with a different mechanism and clinical pattern.

Choking (pulmonary) agents cause injury primarily to the lungs, especially the airways and alveolar membranes, leading to edema and impaired gas exchange. When chlorine gas is inhaled, it reacts with water in the respiratory tract to form hydrochloric and hypochlorous acids. These acids burn and inflame the airway lining and the delicate capillaries, triggering inflammation and fluid leakage into the alveoli. The result is swelling of the lungs and disrupted oxygen transfer, which can develop hours after exposure. That lung-directed injury is the defining feature of a choking/pulmonary agent, distinguishing it from agents that act mainly on nerves or blood. Phosgene would produce a similar lung injury, while sarin is a nerve agent and cyanide a blood agent, each with a different mechanism and clinical pattern.