DEATH DUE TO PHYSICAL AGENTS

1. DEATH DUE TO PHYSICAL AGENTS Beatrice Ioan, PhD, MD, MA

2. LOW TEMPERATURE • General injuries- systemic hypothermia Def.: decrease of the human body temperature below 35 degrees C- loss of body heat exceeds heat production. • Mechanisms to raise the body temperature → diversion of blood away from the skin and shivering • Below 32°C → shivering ceases- extra muscular activity will no longer generate heat. • People whose temperature falls to 28°C or less → are almost certain to die, even with treatment Predisposing conditions: • malnutrition states, fatigue, • prolonged immobility: myxoedema, rheumatoid arthritis, • barbiturate intoxication, • disabling head injury and cerebrovascular lesions, • alcoholism

3. I. General injuries- systemic hypothermia Two types of hypothermia • dry cold hypothermia • immersion hypothermia- more grave due to more rapid loss of heat in water than in air (three times faster) Humans are able to retain body heat balance in water at 22 degrees C. Under this level, loss of heat gradually occurs and below 16 degrees C, survival time decreases sharply

5. Autopsy appearances External examination: • widespread, bright red lividities- nondissociation of oxygen • rigor mortis occurs slowly and lasts longer • delayed putrefaction • reddish-pink discoloration of the skin- hands, elbows, knees and feet- red cell haemolysis (?) • blue spots; blisters - hands, knees, feet- frostbite

7. Autopsy appearances Internal examination - frothy sanguinous fluid in trachea and bronchi; • edema, congestion and hemorrhages in the lungs; • the stomach lining is studded with numerousbrown-black acute erosions- Vischnevski spots • congestion of liver and spleen • haemorrhagic pancreatitis and associated fat necrosis- increased viscosity of the blood due to low temperatures → sludging of blood in the small vessels → micro-infarcts. - bronchopneumonia- long term complication

9. Causes of death in hypothermia • the most frequent cause of death is heart failure- ventricullar fibrilation; - death may occur later, due to: * pulmonary infections (e.g. bronchopneumonia) * following the rapid increase of the body’s temperature, due to thrombo-embolism

10. Type of death Medico-legal- violent Juridical - accident - most frequent; • work accident – rare- frosen industry; • medical malpractice – rare- surgery; • suicide – rare, in persons with psychiatrical diseases and alcohol consumption; • crime – especially in children & elderly; - disimulation of a crime- bad idea!- cold preserves very well the signs of violence on the corpse

11. II. Local injuries- frostbite • Exposure to dry cold or immersion at temperatures below 0 degrees C Classification • first degree – redness and edema of the skin; the lesion heals promptly without permanent damage; persists after death • second degree – epidermis is affected and there is blister formation but the underlying tissues are not damaged; • third degree – necrosis of the skin and subcutaneous tissues; • fourth degree – total loss of tissue in the exposed area, including muscles and eventually bones.

12. High temperature General injuries * sunstroke * hyperthermia Local injuries * dry heat- burns * moist heat(hot water, steam or other hot liquids)- scalds

13. Sunstroke • Mechanism→ the body (mainly the head) is exposed to hot sun (mixed with the action of ultraviolet rays); • Consequences: * redness of the skin, *cerebral and pulmonary edema, * cardiac failure- death.

14. Autopsy appearances ! No specific findings • body’s temperature remains high after death and may rise further; • rigor mortis sets in early and disappears early; • marked lividity; • putrefaction is rapid; • generalized stasis; • petechial hemorrhages in skin and organs; • pulmonary edema. • Microscopic exam → degeneration of neurons in cerebral cortex, cerebellum and basal ganglia.

15. Burns First degree: • damage is limited to the outer layer of the skin; • the burned area is red due to congestion, swollen due to edema and painful; • on a dead body discoloration rapidly fades, so it may not be recognizable; • mild sunburns may be classified like first degree burns. Second degree: • blister formation; • upper layers of the skin are destroyed; • scarring sometimes follows.

16. Burns Third degree: • involves the entire thickness of the skin; • epidermis and dermis are damaged; • pain is absent → nerve endings in the skin are destroyed; • scarring is the rule. Fourth degree burns (charring): • complete destruction of skin and underlying tissues

18. Burns Survival following burns depends on: • severity and extend of the burn; • age of the victim • in children, burns over 20% body surface are dangerous for life; • in adults, burns over 40% are dangerous

19. Burns Wallace rule of nine • head = 9% • each upper limb = 9% • trunk = 36% • each lower limb = 18% • genital external organs = 1%

20. Autopsy appearances External examination • cherry-red coloration of postmortem lividity- carbon monoxide; • delayed decomposition; • skin may be red, blackened, blistered or charred • hairs are singed; • in the burned areas the veins of the body stand out giving a marbled appearance; • boxing posture (pugilistic/ fencing posture)- in charried bodies- coagulation of proteins - generalized flexion- in antemortem or postmortem burning;

21. Autopsy appearances • heat fractures- artifact fractures of the skull caused by heat * several lines radiating from a common center; * the edges- more irregular and ragged than those of a physical trauma; * do not generally involve the sutures of the skull; • splits of the abdominal wall- run parallel to the muscle fibres; • the anus may be dilated and sometimes the rectal wall protrudes through the opening- this could be mistaken for evidence of sexual perversion

22. Autopsy appearances Internal examination • the blood is thick and cherry-hemoconcentration and carboxihemoglobin • petechial hemorrhages in organs • cerebral congestion and cerebral edema or the brain may be shrunken when the heat is excessive • heat hematoma- soft, friable clot of light chocolate color (or cherry-red - CO-Hb)- rupture of vessels caused by heat (e.g. extradural hematoma produced by the heat); • superior air ways or esophagus- black particles of soot mixed with mucus, • trachea and bronchi may be filled with froth; if hot air is inhaled, the mucosa of the larynx and trachea may be necrosed and detached in shreds;

23. Causes of death in burns Rapid death (usualy at the place of the fire) • A flash fire or an explosion, instantaneous death; • Inhalation of superheated air- edema of the superior airways-suffocation. • CO intoxication • Shock determined by intense pain Early death (in the first days after the fire): • Dehydration and electrolyte disturbances from plasma loss from the burned surfaces. Delayed death (after several days, weeks): - Renal failure - Toxemia from substances absorbed from the burned area - Local or systemic infections of widespread burns

24. Injuries due to scalding Extension and severity of the scalds depend on: • the temperature of the liquid; • duration of contact (household hot water may produce severe burns at 2 – 3 seconds of exposure); • sensitivity of the skin; the mucous membranes of the mouth and throat are more resistant to hot liquids as skin; • certain areas of the body are more sensitive than others (the palmar surface is more resistant than the face, abdomen or genital organs); • clothes worsen the damage by prolonging contact with the hot liquid and reducing the cooling effect of evaporation

25. Classification of scalds I. Reddening of the skin (erythema) II. Blister formation (vesication) III. Destruction of the deeper tissues

26. Autopsy appearances • the general features of scalds are similar to those of burns; • charring cannot occur unless the liquid is molten metal; • erythema and blisters- a fluid level at the edge of the scald; • no burning of the clothes or singeing of the hair; • no soot deposits • the liquid may be found on the clothes.

28. Electrocution Definition: electrocution occurs when the body is incorporated into an electrical circuit, determining the passage of electricity through the tissues→biological damages. • The current enters at one point and then exits the body at an exit point, usually to the earth. - The gravity of the lesions depend on the organs which happen to be in the way of the current.

30. Autopsy appearance External examination • Electric mark - thermal burn from heating of the epidermis and dermis as the current passes- coagulation necrosis • the injury is more severe as the surface of contact is smaller • an areola of blanched skin at the periphery • may reproduce the shape of the object in contact • resistanceto putrefaction

31. Autopsy appearances • hard, dry, without bleeding;no inflamatory reaction in the surrounding tissues • entrance point- deposit of metallic particles • electric mark may be missing when the resistance is very low and the contact surface is big (e.g. electrocution in the bathroom) • it appears either at the place of entrance of the current or at the exit place, showing the trajectory of the current in the organism; • the exit electric mark is frequently split in the form of punctured or lacerated wounds- no metalisation • microscopic examination- vacuolation of epidermis and dermis; the gap of the epidermis may be detached and raised into a blister; the cells of the epidermis are elongated with the nucleus orientated and stretched

33. Autopsy appearances 2. Biochemical effects of the current • electric edema- hard and pale edema- accumulation of liquids due to electrolisis and increased permeability of cellular membranes; • wet necrosis- decomposition of the fat at the entrance place and accumulation of Na, K, Mg which combine with the water from the tissues at the exit place; • metalisation of the skin and, sometimes of the subcutaneous tissue- small metal particles from the electric conductor which combine with the ions from the tissues- metalic salts; Metalisation is visible only in microscopic examination or by chemical methods (e.g. Skalos reaction).

35. Autopsy appearance 3. Burns- lightning of the clothes. 4. Traumatic injuries- projection of the victim away-great voltage of the electric current; 5. Early rigor mortis Internal examination: - Pulmonary edema - Signs of asphyxia - Cerebral edema and perivascular hemorrhage

37. Lightning Huge electrical forces- milions of amperes and huge voltages Causes of death • Damages to CNS- paralysis of cardiac or respiratory centre; • functional arrest of circulation and brething is possible, due to vagal or medullary stimulation due to sudden fright or spasm of the vessels)- in this situation, there may be no external or internal marks

38. Autopsy appearances External examination: 1. Arborescent mark (lightning prints)- erithema of the skin,at the entrance place of the current; • it affects only the epidermis; • it may lasts for few hours or after death it may dissapear. 2. An intense edema appears at the point of current entry. 3.Rigor mortis comes and goes soon. 4.Burning or tearing the clothes, tearing the shoe soles. 5. Singeing the hairs. 6. Injuries – erythema→severe wounds, fractures. 7.Fusing and magnetisation of metalic objects of the victim.

40. Autopsy appearance Internal examination: • Congestion of internal organs. 2. Petechial hemorrhages in all the organs under the serous membrane (meninges, pleura, pericardium and peritoneum). 3. Laceration of internal organs, coronary thrombosis.