Electrical Injuries: Causes, Effects, and Post-Mortem Findings

Dr. Shiuli from KGMU specializes in Forensic Medicine & Toxicology, focusing on the impact of electrical injuries such as ventricular fibrillation, thermal injuries, and post-mortem findings like external marks and histological changes. Detailed insights on path of current, causes of death, flash burns, and exit marks are provided with accompanying images.

• Electrical injuries
• Forensic Medicine
• Toxicology
• KGMU

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1. Dr. Shiuli, Forensic Medicine & Toxicology, KGMU. ELECTRICAL INJURIES, ATMOSPHERIC LIGHTENING, HEAT & COLD DISORDERS

2. Injuries produced by electricity Depends on: Nature of current In India, the domestic supply is 220-240 volts AC at 50 Hz Amperage vs voltage Amount of current A = V/R Dr. Shiuli, Forensic Medicine & Toxicology, KGMU.

3. Path of current Duration of current Q = I2 X R X t Dr. Shiuli, Forensic Medicine & Toxicology, KGMU.

4. Cause of death Low voltage (household) current Ventricular fibrillation High voltage (industrial) current paralysis of respiratory center Electro thermal injury Dr. Shiuli, Forensic Medicine & Toxicology, KGMU.

5. Post Mortem findings External Electric entry mark Joule burn produced in low voltage currents Appearance: Crater, 1-3 cm in diameter with a ridge around circumference Charring Metallization a. - - - Dr. Shiuli, Forensic Medicine & Toxicology, KGMU.

6. Histology: - Micro blisters - Electric channels cells separated in the form of sharp slits - Palisading and streaming of nuclei - Collagen stains blue in ordinary H&E stain Dr. Shiuli, Forensic Medicine & Toxicology, KGMU.

7. Flash/spark burn Produced in high voltage currents, when sparking occurs between conductor and victim b. Crocodile skin high temperatures causes keratin of skin to melt over multiple areas Arc eye superficial and painful keratitis Electric splits Point of entry shows laceration c. Dr. Shiuli, Forensic Medicine & Toxicology, KGMU.

8. Exit mark - Where the body was earthed - More damage than entry Internal Congestion of all organs Petechial hemorrhages along the line of passage of current Brain irregular tears and fissures Zenker s degeneration Bone pearls Dr. Shiuli, Forensic Medicine & Toxicology, KGMU.

9. Lightening Atmospheric discharge of electricity Dr. Shiuli, Forensic Medicine & Toxicology, KGMU.

10. Electrical discharge is between a negatively charged cloud and a positively charged object on earth - negative lightening 5% of lightening flashes are from positively charged clouds - positive lightening Temperature about 50,000*C Amperage 12,000 to 200,000 amperes Voltage equivalent to 1 million volts DC Dr. Shiuli, Forensic Medicine & Toxicology, KGMU.

11. Mechanism of lightening injuries Electrical injury Direct strike Splash injuries Contact injury Ground current Mechanical effects Burns Dr. Shiuli, Forensic Medicine & Toxicology, KGMU.

12. Post Mortem appearance Clothes Torn, burnt, may be stripped off Melting belt knuckles and zippers External Endogenous burns due to heat generated within the body. Tip toe sign small, circular, full thickness burns involving the sides of the soles of the feet and the tips of toes. Dr. Shiuli, Forensic Medicine & Toxicology, KGMU.

13. Arborescent burns irregular, superficial, thin, tortuous markings on skin resembling the pattern of a fern or tree - Seen in 20% to 33% cases - Not associated with burning - No pathological changes - Disappear in 1-2 days in survivors Exogenous burns Dr. Shiuli, Forensic Medicine & Toxicology, KGMU.

14. Mechanical lesions Internal Brain congestion, edema, hemorrhages Lungs congested, patchy hemorrhages Muscles necrosis Spinal cord damage Eyes & Ears cataracts, corneal edema, tympanic membrane perforation Dr. Shiuli, Forensic Medicine & Toxicology, KGMU.

15. Deaths due to cold and heat Dr. Shiuli, Forensic Medicine & Toxicology, KGMU.

16. Heat disorders Predisposing factors Hot and humid conditions Clothing Drugs Diseases Obesity Alcohol Dr. Shiuli, Forensic Medicine & Toxicology, KGMU.

17. 1. Heat edema Mild form Dependant soft tissue swelling - - Peripheral vasodilatation Pooling of interstitial fluid Dr. Shiuli, Forensic Medicine & Toxicology, KGMU.

18. 2. Heat rash (prickly heat) rash on anterior surface of elbows, posterior surface of knees, sternum , clavicle, waist - Prolonged sweating with no evaporation Periductal edema d/t NaCl Inflammation of sweat gland Rash Dr. Shiuli, Forensic Medicine & Toxicology, KGMU.

19. 3. Heat cramps (miners cramps) Common in manual laborers, miners, athletes, tennis players, runners Drinking large quantities of water only after sweating lowers the effective salt concentration Sudden onset, flushed face, dizziness, headache, vomiting, paroxysmal cramps in muscles of hands, calves, feet, thighs and abdomen. Dr. Shiuli, Forensic Medicine & Toxicology, KGMU.

20. 4. Heat syncope (heat collapse) Intense peripheral vasodilatation leading to peripheral pooling and hypotension Sudden change most imp. Prolonged standing factors Precipitating Fainting & giddiness Blurring of vision Epigastric distress Nausea Symptoms Dr. Shiuli, Forensic Medicine & Toxicology, KGMU.

21. 5. Heat exhaustion Severe dehydration after a huge amount of sweat loss Most commonly encountered clinically Both water and salt depleted circulatory deficiency Thermoregulation is maintained Symptoms- fever, nausea, fatigue, muscle aches If left untreated may progress to heat stroke Dr. Shiuli, Forensic Medicine & Toxicology, KGMU.

22. 6. Heat stroke (heat hyperpyrexia) Complete breakdown of thermoregulatory mechanism, complete loss of sweating and temperature >41*C sudden onset with sudden collapse and loss of consciousness Cramps, dizziness, excessive thirst, headache, weakness, nausea & vomiting, staggering gait Skin dry and flushed, cessation of all sweating Temp>42*C, BP , tachycardia Dr. Shiuli, Forensic Medicine & Toxicology, KGMU.

23. Cerebellar dysfunction, clouding of senses convulsions Delirium Speech difficulties Coma Dr. Shiuli, Forensic Medicine & Toxicology, KGMU.

24. Cold injuries Hypothermia core temp falls below 35*C First stage - Core tem 35-32*C Second stage - Core temp 32-26*C - Temp regulation lost below 30*C - Patient depressed, lethargic, drowsy - Muscles stiff, red patches on skin, edema of face Dr. Shiuli, Forensic Medicine & Toxicology, KGMU.

25. Third stage - Core temp < 26*C - Death ensues if this temp maintained for 24 hrs Cause of death failure of vital centers d/t anoxia Cessation of heart function d/t atrial and ventricular fibrillation Dr. Shiuli, Forensic Medicine & Toxicology, KGMU.

26. Local effects o Frost bite - Characterized by freezing of tissues - Temp below 0*C - Bluish black discoloration of fingers, toes or nose, ears & face - Microscopically, damage of endothelial cells, leakage of serum into tissues. Dr. Shiuli, Forensic Medicine & Toxicology, KGMU.

27. o Trench foot (immersion foot) - Caused by prolonged exposure - Affected part becomes numb, blue/red and may swell - Advanced conditions blisters or open sores Dr. Shiuli, Forensic Medicine & Toxicology, KGMU.

28. o Chillbains (pernio) - Redness and inflammation of skin - Acral ulcers - Due to constriction of capillary beds in skin Dr. Shiuli, Forensic Medicine & Toxicology, KGMU.