At autopsy, the cyanide poisoning case will show the following features, except:
**Core Concept**
Cyanide poisoning is a rapid-onset form of acute toxicity caused by the inhibition of cellular respiration, leading to tissue hypoxia and ultimately, cellular death. This occurs due to the binding of cyanide to the ferric ion of cytochrome c oxidase in the mitochondrial electron transport chain, preventing the transfer of electrons and thereby halting oxidative phosphorylation.
**Why the Correct Answer is Right**
The hallmark features of cyanide poisoning include a distinctive "bitter almond" odor, often detected on the breath or clothing of the victim. This is due to the volatile cyanohydrin compounds produced as a byproduct of cyanide metabolism. Additionally, victims often exhibit symptoms such as headache, dizziness, nausea, and rapid onset of coma, followed by respiratory and cardiac arrest. The presence of a cherry-red discoloration of the skin and mucous membranes, despite the absence of oxygen, is another characteristic finding.
**Why Each Wrong Option is Incorrect**
**Option A:** The presence of a "bitter almond" odor is a characteristic feature of cyanide poisoning, making this option incorrect.
**Option B:** The cherry-red discoloration of the skin and mucous membranes, despite the absence of oxygen, is a classic finding in cyanide poisoning, so this option is also incorrect.
**Option D:** The rapid onset of coma and respiratory arrest in cyanide poisoning is a well-documented clinical feature, making this option incorrect as well.
**Clinical Pearl / High-Yield Fact**
In cases of suspected cyanide poisoning, prompt administration of cyanide antidotes such as hydroxocobalamin or sodium nitrite is crucial to prevent further tissue damage. This is a critical concept to remember in emergency medicine and toxicology.
**Correct Answer: A.**