A body is found with lividity that is cherry-red on the dependent back but also on the non-dependent face and anterior trunk. The MOST appropriate interpretation is:
- A The body was found in the prone position; lividity is gravitational
- B The body was moved and the non-dependent cherry-red colour indicates secondary (paradoxical) lividity
- C Cold environment exposure causing cold haemoglobin to retain its oxygenated form
- D Carbon monoxide poisoning producing cherry-red carboxyhaemoglobin throughout the body, overriding the typical purple-blue of deoxy-haemoglobin, causing cherry-red colour regardless of position ✓
Explanation
Cherry-red lividity diffusely distributed over both dependent and non-dependent areas is pathognomonic of carbon monoxide poisoning. Carboxyhaemoglobin (COHb) maintains its bright cherry-red colour regardless of tissue oxygen extraction. Normal lividity is dependent (gravitational), purple-blue due to deoxyhaemoglobin. When lividity is cherry-red throughout, carbon monoxide poisoning should be the primary diagnosis, confirmed by COHb saturation on postmortem blood spectrophotometry or carbon monoxide in blood. Cold exposure can produce pink lividity (from cold-induced oxygen shift), but cherry-red diffuse lividity is classic CO poisoning.
Reference: The Essentials of Forensic Medicine and Toxicology (Narayan Reddy), 34th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.