Which symptoms can occur with carbon monoxide poisoning depending on carboxyhemoglobin level?

Which symptoms can occur with carbon monoxide poisoning depending on carboxyhemoglobin level?

• A. Headache and fever only
• B. Headache, giddiness, confusion, seizures, and coma
• C. Seizures and coma only
• D. Headache, giddiness, confusion, seizures, and coma

Answer: (D)

Carbon monoxide poisoning causes a range of symptoms that matches how much carboxyhemoglobin is formed in the blood. CO binds strongly to hemoglobin, reducing oxygen delivery to tissues, and the brain is especially vulnerable to this hypoxia. Because of this, symptoms appear along a spectrum as COHb levels rise: headaches and dizziness are common early signs, while confusion tends to appear with higher levels, and seizures or coma can occur at the most severe levels. The best answer reflects this full spectrum—from mild to severe—capturing both the early symptoms and the more serious neurologic effects. Fever is not a typical feature of CO poisoning, and a description that only lists late signs would miss the earlier, common symptoms.

Carbon monoxide poisoning causes a range of symptoms that matches how much carboxyhemoglobin is formed in the blood. CO binds strongly to hemoglobin, reducing oxygen delivery to tissues, and the brain is especially vulnerable to this hypoxia. Because of this, symptoms appear along a spectrum as COHb levels rise: headaches and dizziness are common early signs, while confusion tends to appear with higher levels, and seizures or coma can occur at the most severe levels. The best answer reflects this full spectrum—from mild to severe—capturing both the early symptoms and the more serious neurologic effects. Fever is not a typical feature of CO poisoning, and a description that only lists late signs would miss the earlier, common symptoms.