A dead body is having cadaveric lividity of bluish green color. The most likely cause of death is by poisoning due to: AIIMS 06; DNB 10; NEET 13
**Core Concept**
Cadaveric lividity, also known as post-mortem lividity or livor mortis, is the discoloration of the skin that occurs after death due to the pooling of blood in the dependent areas of the body. In a deceased individual, the bluish-green coloration of the skin suggests an alteration in the normal process of livor mortis.
**Why the Correct Answer is Right**
The bluish-green coloration of cadaveric lividity is indicative of a process called methemoglobinemia. Methemoglobinemia is a condition characterized by the presence of methemoglobin, a form of hemoglobin that cannot bind oxygen. This condition can be caused by various substances, including certain heavy metals, local anesthetics, and most notably, cyanides. Cyanides cause the formation of methemoglobin by inhibiting the enzyme cytochrome c oxidase in the mitochondrial electron transport chain, leading to the accumulation of methemoglobin. The methemoglobin has a different optical absorption spectrum, which gives the skin a bluish-green color.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because the bluish-green coloration of cadaveric lividity is not typically associated with carbon monoxide poisoning, which would produce a cherry-red color due to the formation of carboxyhemoglobin.
* **Option B:** This option is incorrect because the bluish-green coloration of cadaveric lividity is not typically associated with hydrogen sulfide poisoning, which would produce a yellowish-green color due to the formation of sulfhemoglobin.
* **Option C:** This option is incorrect because the bluish-green coloration of cadaveric lividity is not typically associated with anoxia or hypoxia, which would produce a pale or cyanotic coloration.
**Clinical Pearl / High-Yield Fact**
In cases of suspected cyanide poisoning, the bluish-green coloration of cadaveric lividity can be a critical clue for the forensic pathologist. This finding, combined with other clinical and toxicological evidence, can help establish the cause of death.
**Correct Answer: D. Cyanide poisoning.