Thermal Injuries MCQs

Once the body temperature has fallen below about 85°F (30°C), the ability of the hypothalamus to regulate temperature is lost. For each 10°F decrease in body temperature, the rate of chemical heat production in each cell is depressed almost twofold. This is the reason for diminished temperature regulation. Sleepiness followed by coma, depresses the activity of the CNS heat control mechanisms and prevents shivering. Our internal body temperature is regulated by a part of our brain called the hypothalamus. The hypothalamus checks our current temperature and compares it with the normal temperature of about 37°C. If our temperature is too low, the hypothalamus makes sure that the body generates and maintains heat. Reference: Guyton and Hall, Textbook of Medical Physiology, 13th Edition, Page No. 921

Elevated levels of carbon monoxide in the circulating blood and carbon particles in the air passages and lungs are reliable indicators suggesting that the victim was alive while the fire was in progress. Option (A) & (B): The exposed skin surface may be reddened in both ante-mortem and post-mortem burns, the classical distinction of a 'red flare' or 'vital reaction' being unsafe as an index of infliction before death. Option (D): Blisters can form post-mortem, but are pale yellow unless on scorched skin. Reference: Knight's Forensic Pathology, 4th Edition, Page No. 319, 320

The hold-on effect is seen in electrical injuries . When, as most often happens, the entry point is in the hand, the stronger flexor muscles of the arm go into spasm and cause a hold-on effect. This means that any object being held in the hand is involuntarily clenched and, as it is likely to be the faulty electrical appliance or a wire, the object cannot be released and the current thus continues to flow. This adds to the time element and progressively worsens the risk of both cutaneous burns and the risk of cardiac or respiratory arrest. Reference: Knight's Forensic Pathology 4th edition, Page No. 326-328

The degrees of thermal damage were investigated by Moritz and Henriques, who found that the lowest temperature that would cause damage was 44°C, though it required no fewer than 5 hours before a burn appeared. Only 3 seconds was needed, however, if the object was at 60°C. Reference: Knight's Forensic Pathology, 4th Edition, Page Number-311.

Singeing of eyebrows & facial hair is not a proof of inhalational burns; singeing can occur only by dry flme, not by inhalation INHALATIONAL BURNS It include: Hypoxia → Flame utilizes the available oxygen Hoarseness of voice and stridor → Hot air injures the laryngeal mucosa Soot deposition in air passage → Due to flying ashes Yellow sputum → Oxides of N2 converts the sputum into yellow After a more severe exposure, signs may range from mild respiratory distress (e.g., tachypnoea, accessory muscle use) to more severe signs of wheezes and rales, yellow frothy sputum, and yellow staining of the mucous membranes. Reference: https://emedicine.medscape.com/article/771194-clinical; Textbook of Forensic Medicine & Toxicology, Anil Aggrawal, Page No. 322

'Hide and die' syndrome: In some hypothermic deaths, bodies are found in some strange places -under a bed or bench, on a shelf or behind a wardrobe, or alternatively may pull down household articles into a heap on top, which may give the impression of their attempt to 'hide' (protective 'burrow-like' or 'cave-like' situation). This may also lead to the assumption of a homicide or robbery . It is due to mental confusion from hypothermia and may be related to hibernation reflex. An apparent self-protective behaviour, known as "terminal burrowing", or "hide-and-die syndrome", occurs in the final stages of hypothermia. Those affected will enter small, enclosed spaces, such as underneath beds or behind wardrobes. It is often associated with paradoxical undressing. Reference: Review of Forensic Medicine and Toxicology, 5th Edition, Gautam Biswas, Page No. 285

Hypothermia occurs when the body's core temperature drops below 35°C. Mild hypothermia - Core temperature 32 to 35°C (90 to 95°F) Moderate hypothermia - Core temperature 28 to 32°C (82 to 90°F) Severe hypothermia - Core temperature below 28°C (82°F) Hypothermia is caused by prolonged exposures to very cold temperatures. When exposed to cold temperatures, your body begins to lose heat faster than it's produced. Lengthy exposures will eventually use up your body's stored energy, which leads to lower body temperature. Reference: Harrison's Principles of Internal Medicine, 19th Edition, Page No. 478e-1

The given scenario is suggestive of heatstroke and a core temperature >40.5°C helps establish the diagnosis. As body core temperature rises, excessive cutaneous vasodilation can lead to a fall in arterial pressure and therefore to a decrease in brain perfusion . This leads to a total loss of thermoregulatory function. As core temperature approaches 41°C, sweating stops, confusion and, ultimately, loss of consciousness occurs. Patients who become acutely hyperthermic often display signs of neurological dysfunction. The neurological injury may manifest in several ways, including cognitive dysfunction, agitation, seizures, unsteadiness, or disturbance of consciousness from lethargy to coma. Reference: Harrison's Principles of Internal Medicine, 20th Edition, Page No. 3345