Topic: Toxicology
Question: How do you differentiate the extent of a burn? What is the difference between antemortem and post Mortem burns?
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Burns can be differentiated based on their depth and severity:
1. First-degree burns: Affect the epidermis only. Cause redness and pain. Heal within 3-5 days without scarring.
2. Second-degree burns: Extend into the dermis. Cause blistering and severe pain. Require medical attention. Heal within 2-3 weeks with potential for mild scarring.
3. Third-degree burns: Extend into underlying fat and tissues. Cause white/blackened skin and numbness. Require hospitalization and skin grafting. Heal over months with significant scarring.
4. Fourth-degree burns: Damage muscles and bones. Rare but very serious with high mortality. Require long hospitalization, multiple surgeries and physiotherapy.
The extent of a burn depends on the body surface area involved, rather than just the depth. The “rule of nines” is used to calculate approximate burn area in adults:
– Head and neck: 9%
– Chest: 9%
– Abdomen: 9%
– Upper back: 9%
– Lower back and buttocks: 9%
– Each arm: 9%
– Groin: 1%
– Each leg: 18% (front – 9%, back – 9%)
Antemortem vs postmortem burns:
Antemortem (before death):
– Vital reaction present: swelling, redness, blistering.
– Pattern relates to heat/fire source. Irregular borders.
– May see soot in airway/lungs, other signs of smoke inhalation.
– Underlying organs/tissues damaged.
Postmortem (after death):
– No vital reaction. Pale color, no blistering/swelling.
– Sharp demarcated borders. Oval/elliptical pattern.
– No signs of smoke inhalation (no breathing).
– Underlying tissues less damaged (no circulation).
– Requires very high temp/long time to cause full thickness burn after death.
Postmortem burns require much higher temperatures and longer exposure to cause the same depth of tissue damage seen in antemortem burns. They lack signs of vital reaction and a clear source/pattern relating to the heat or fire. Differentiating the timing of burns (antemortem vs postmortem) is important in forensic/suspicious death investigations.
