thermal deaths - burns

Thermal Deaths:

Thermal Deaths Dr. madhao Raje 15.12.2010

Mechanism of Thermal injury:

Mechanism of Thermal injury Local & Generalized Cold injury. Local cold injury - Direct & Indirect – Direct effect on fatty tissue & on myelinated nerves. Indirect effect on vessels. Clinical picture : (i) Blanching due to vascular spasm (ii) Erythema & edema due to vascular permeability. Numbness/ paralysis. (iii) blister formation – may involve skin,vessles,muscles, nerves etc. (iv) Frozen stiff/hard surface. Frost bite (2.5 C), Immersion foot, trench foot (5- 8 C). (“F I T”)

Generalized cold injury:

Generalized cold injury Stage I - Cold, shivering , Stage II – below 32 C, shivering stops, depressed, lethargic, drowsy, sleepy, dull responses, mobility impaired, stiff muscles, cannot talk, cannot walk, gets prostrated, Stage III – below 27 C, Coma ensues. Fatal after 24 hours. Death due to “Anoxia”. Circulatory failure.

Factors affecting cold injury :

Factors affecting cold injury 1) Intensity of cold, 2) Duration of exposure, 3) Wet kin worsens effect of cold, 4) Age & sex, Youth & female tolerate cold better,

P M Findings of death due to cold:

P M Findings of death due to cold External – red patches, blisters, pale mucosa, generalized edema, Rigor mortis develops slowing & lasts longer, P M Lividity _ Blue & red colored, Internal – Not specific, Fat necrosis of Pancreas, ice crystals in vessels, Medico legal Imp: Accidents, effect of alcohol, etc.

Effect of Heat :

Effect of Heat Environmental effect: (i) Heat cramps (ii)Hyperpyrexia, (iii) Heat prostration. Heat cramps: Seen among workers, due to high temperature, due to profuse sweating, dehydration takes place, Sudden onset, painful muscle cramps, paroxysmal, Headache, vomiting, dizziness, etc. IV Saline gives great relief.

Hyperpyrexia:

Hyperpyrexia Causal factors: Exposure to direct heat, humidity, heavy exertion, lack of acclimatization, old age, fever/pre-existing infection, alcoholism, sedatives, tight clothing, etc. Clinical picture: Sudden onset, Prodromal symptoms: headache, dizziness, weakness, fainting, staggering gait, mental confusion, muscle cramps, restlessness, etc. High grade fever, more than 105 -106 c, no sweating, dehydration, pulse & breathing rapid, Low BP, convulsions, Fatal period – 5 min to 3 days,

Hyperpyrexia :

Hyperpyrexia Lab. Inv.: TLC raised, Urine – RBC, Abumin + te . PM findings: Not specific, Organs congested.

Heat prostration :

Heat prostration Causal factors: Unsuitable clothing, exposure to high temperature, heavy exertion, etc. Clinical picture: Sudden onset, sudden prostration/extreme exhaustion, or fall, No fever, Peripheral circulatory collapse.

Burns:

Burns Caused by dry heat, on external or internal surface, 44 c for 4 to 6 hrs. or 65 c for only 2 sec can produce burn. Types of burn: Flame burn: blackening of skin, singeing of hairs, vesication may be absent. Kerosene or Petrol burn: Sooty blacking of skin, odour of kerosene/petrol. Explosion burn: extensive blacking & tattooing of skin,

Burns:

Burns Burns due to Ultra violet rays, X rays, radium produce Erythema, or clinical picture like dermatitis Burns due to Corrosive substances, cause Ulcerated patches without blisters, hairs not singed, red line of demarcation is absent. Electrical burns.

Degree of Burns:

Degree of Burns Dupuyetran’s classification – 6 types of burns, Wilson’s classification – 3 types, Epidermal, Dermo -epidermal & deep burns. Epidermal Burns – Superficial, blisters, painful, heal without scar. Dermoepidermal Burns – Whole thickness of skin involved, depressed areas of burns, surrounded by reddish margin with small blisters, necrotic tissue seen blackish, painful, heal with scar or contractures.

Degree of Burns:

Degree of Burns Deep Burns – muscles or bones are involved, painless due to burned nerve endings, Effect of burns depend on – degree of heat, duration of exposure, & extent of burns. Rule of 9 – to measure extent of burn.

Cause of death :

Cause of death 1) Neurogenic shock, 2) Shock due to fluid loss, dehydration. Within 48 hours. 3) Toxemia – within 3 – 4 days, 4) ARF – 3 to 4 days, 5) Edema of glottis, respiratory infection, etc. 6) Pyaemia within 7 to 14 days.

P M Findings:

P M Findings External : Examine cloths, belongings,etc. Examine skin – decide degree of burn, measure extent of burn by applying rule of 9. Zones of Hyperaemia . Pugilistic attitude – Boxing attitude – Heat rupture – usually over extensor surface, look like LW, but no bleeding, vessels & nerve can be seen intact over floor of the wound, Flash burns – due to explosion,

Internal findings :

Internal findings Skull # - (i) Due to raised intracranial pressure due to heat. (ii) Due to Drying of skull, rapid drying causes outer table of skull to #. # line crosses across the suture line. It is commonly radiating # lines from a common center. Laryngeal edema, Lungs – cut section of bronchus, lung to be seen. Blisters – serous fluid, raised enzyme levels,

Ante mortem & post mortem burns :

Ante mortem & post mortem burns Lines of redness – Blisters – Vital reaction – Enzymes -