Postmortem Lividity Color in Phosphorus Poisoning
The likely color of postmortem lividity in this case of phosphorus poisoning is dark brown (Option D).
Clinical Context and Diagnosis
The autopsy findings are pathognomonic for yellow/white phosphorus poisoning 1:
- Garlicky odor of gastric contents is a classic finding in phosphorus ingestion
- Luminous appearance (phosphorescence) of gastric contents occurs due to the chemiluminescent properties of white phosphorus when exposed to air
- The occupational setting (rodenticide factory) provides strong circumstantial evidence, as phosphorus compounds are used in rodenticides
Postmortem Lividity Characteristics
Expected Finding in Phosphorus Poisoning
Dark brown lividity is the characteristic finding in phosphorus poisoning 1. This occurs due to:
- Formation of methemoglobin and other altered hemoglobin derivatives
- Oxidative damage to red blood cells from phosphorus toxicity
- The resulting dark brown discoloration differs markedly from the typical red-purple lividity seen in most deaths
Differential Diagnosis of Lividity Colors
The color of postmortem lividity can provide crucial diagnostic information about the cause of death 1:
- Cherry-red or pink lividity: Carbon monoxide poisoning, cyanide poisoning, or hypothermia 2, 1
- Bluish-green lividity: Not a typical finding in poisoning cases; more related to decomposition changes 3
- Black lividity: Not a recognized pattern in toxicological deaths
- Dark brown lividity: Phosphorus poisoning, methemoglobinemia-inducing agents 1
Important Caveats
Timing Considerations
Lividity assessment must account for postmortem interval 4:
- Lividity typically appears within 2 hours of death, sometimes as early as 20 minutes 1
- Becomes confluent and more apparent after 4-6 hours 1
- Becomes "fixed" (non-blanchable) after 8-12 hours 1
Potential Confounders
Be aware that postmortem changes can be misinterpreted 3:
- Bluish discoloration from normal lividity is commonly mistaken for traumatic bruising in 27.8% of misinterpretation cases 3
- However, the dark brown color in phosphorus poisoning is distinct from typical red-purple lividity 1
- The combination of characteristic gastric findings (garlicky odor, luminescence) with dark brown lividity makes the diagnosis highly specific
Body Position and Distribution
The distribution pattern of lividity can confirm or refute body movement after death 1:
- Lividity appears in dependent (gravity-dependent) areas
- Contact pallor occurs where direct pressure prevents blood pooling
- Fixed lividity that doesn't match body position indicates the body was moved post-mortem