Thermal Injuries

Burn or burn injuries • Burning or burn injuries are caused due to contact with dry heat. Thus, burning may occur due to contact with hot metal or any other hot solid or it may be caused due to contact with flame.

• 1. Death may occur within a few Causesdue of death in case of or burn injury hours to primary neurogenic shock. • 2. Secondary or hypovolumic shock may cause death within the first 2 days. After this period, death may occur due to any of the following reasons • 3. Renal failure.

• 4. Systemic absorption and action of the toxins from the ulcerated burn injuries. • 5. Infection and sepsis. Apart from all these direct effects of burn injuries, death of a person may occur for reasons, bearing with the circumstance of burning. These are –

6. Due to inhalation of asphyxiant gases like CO and CO2, during conflagration.

• 7. Due to mechanical asphyxiation e.g., traumatic asphyxia in case of collapse of a house resulting from out-break of fire in a house. • 8. Due to sustaining fatal mechanical injuries due to collapse of wall or house.

Factors which influence the outcome or prognosis of burn injuries

• 1. The extent of the surface area of the body involved - This is the single important criterion which influence the outcome (prognosis) maximum. Involvement of more than 30% of the body surface may be dangerous. But more than 50% involvement of body surface is expected to be fatal.

• 2. Age – Infants, very young children and old subjects are more likely to succumb to extensive burn injuries. Elderly children and young adults can withstand burn injury better. Subjects above 40 years of age are likely to succumb with over 40% surface burn injury.

• 3. Sex – Males withstand burn injury better than females. • 4. General physical condition and health – persons with good physical condition and without any systemic disease, stand burn injuries better than those with ill health and disease.

• 5. Degree of heat applied – High degree of heat causes deeper burn injuries. • 6. Time of contact – Application of dry heat for a prolonged period will cause deep injuries. In addition to that , prolonged contact may lead to neurogenic shock and death.

• 7. Depth of the burn injury – Depth of the burn injury makes the healing difficult and leads to complications. But so far fatality is concerned, area of involvement of the body surface is more important. A deep wound over a small area of the body is less dangerous than a superficial injury spread over an extensive area of the body surface.

• Postmortem findings in case of death occurs immediately or within some hours after sustaining burn injuries-

External findings • 1. The dead body may still bear burnt remains of dress, particularly the portions which were tightly in contact with the body and which during the process of burning got pressed on the skin.

• 2. Smell of kerosene or any such fuel which might have been used to set fire on the body may be detectable. • 3. The scalp hair and other body hair and other body hair may be singed. • 4. There may be blackening of extensive area of the body.

• 5. Due to coagulation of the muscle protein resulting in contraction of the muscle fibers, in which flexor muscles take upper hand, the whole body may assume a flexion attitude. The flexion attitude of the body is popularly termed as pugilistic or boxer’s or fencer’s attitude which is nearly similar to an attitude taken by a boxer to defend himself during boxing or fist-fighting.

• Singeing, blackening and pugilistic attitude do not indicate anything in speccific about the nature of burning. These are the results of exposure of the body to fire, soot and heat, either from before death or occurring after death. Hence, as in a case of antemortem burning, they will also be present in a case of postmortem burning.

• 6. Presence of blisters containing serum, rich in protein and chloride, surrounded by red (hyperaemic) line, and presence of ruptured blisters with evidence of seroanguinous discharge from the reddish raw floor are constant findings in a case of death due to burn injuries, death occurring within a few hours.

• 7. The postmortem staining is bright red in colour due to formation and presence of carboxyhaemoglobin which forms due to inhalation of CO. This can be taken as an antemortem feature of burning death.

• There is an argument that, in postmortem burning, absorption of CO through the skin and some absorption of the CO by the haemoglobin of red cells which has great affinity for the gas may also cause postmortem carboxyhaemoglobin formation.

• Heat rupture may be present at places which may occur due to severe contraction of the coagulated muscle fibers but occur mostly during movement of the body when the coagulated and contracted muscles tear easily.

• These heat ruptures may be confused with ante-mortem lacerations, or they may even be confused with incised wounds. But, if carefully examined, then there is no scope of confusion of a heat rupture with any other antemortem injury.

• There is no hemorrhage from a heat rupture. There is no marginal abrasion and swelling. Instead, there may be marginal blister formation with zone of red line surrounding the rupture, if the process of burning at that part started before the moment of death. The floor of a heat rupture will show intact vessels and nerves running across the floor.

• 9. Charring of the tissue may occur due to sustained burning, which is common with deep burns. Charring may involve even bone. Charring does not say anything specific of whether the burning was antemortem or postmortem and extensive charring may obliterate the ante-mortem features of burning.

• 10. There may be discharge of blood mixed fluid through the nose. This is due to excessive secretion in the lung due to inhalation of smoke and rupture of capillaries, as a result of contraction of muscles.

Internal findings • 1. The nasal and the mouth cavities may show presence of carbon soot. Soot may also be present, mixed with mucus, adhered on the wall of the lumen of the bronchioles.

• 2.The mucus membrane of the respiratory tract is congested. The lungs are congested and may also be edematous.

• 3.The blood in the vessels is fluid, bright red and thick. Muscles and the organs are congested and bright red in color.

4. The skull bone may show heat fracture. Heat haematoma in the form of firm, • friable, cherry red or chocolate red clot of blood present in the extradural level, which on sectioning has honeycomb appearance due to vaporisation of liquid part of blood, due to direct effect of heat. This haemorrhage appears to be due to heat rupture of vessels at the extradural level.

Medico-legal aspects of death due to burn injuries1.whether the burn injuries were ante-mortem in nature? If the burn injuries were ante-mortem in nature then, the findings which should be present are-

(1). Red hyperaemic patches, antemortem blisters which have red marginal linings and which contain serum, rich in protein and chloride and in case of rupture blisters, the floor will appear reddish slippery due to sero-sanguinous discharge.

• (2). There may be bright red or cherry red postmortem staining. • (3). In some cases there will be charring with marginal red lining.

• (4). In cases where death occurs after some days, there will be presence of ulcers which may have tags of epidermis of the ruptured blisters on the margins.

• (5). Internally, the most important findings of antemortem burning are, presence of soot in the larynx, trachea and bronchus and bright red coloration of blood, organs and the tissues.

• 2. Whether the antemortem burn injuries were sufficient to cause death. Burn of more than 30% body surface may cause death and when the burning involves more than 50% of the surface area, death is likely to occur. The factors which influence the prognosis or the outcome of burn injuries may be given due consideration.