As deaths attributed to heat soar countrywide, experts point to two facts: one, excessive heat retention in the body can lead to fatal conditions at high temperatures and, two, after a certain temperature, things get difficult to manage, and need ICU care.
Experts also say a heat-stroke death can be identified only after examination, and after other causes have been ruled out.
“Symptoms usually seen in this weather are those of heat fatigue or heat exhaustion. Excessive heat increases metabolic activity, leading to a drop in blood pressure and increased sweating. The resulting dehydration and electrolyte imbalance can be corrected by giving cold fluids and electrolytes,” said Dr Anoop Mishra, chairperson, Fortis Centre for Diabetes and Allied Specialties.
Clinically, a heat stroke occurs only after body temperature crosses 104 degrees F, when excessive metabolism leads to a sharp fall in blood pressure and oxygen levels, a condition called hypoxia.
“Increase in metabolism primarily puts pressure on the heart in a very short time. It causes expansion of vessels, a major drop in blood pressure, and hypoxia. Metabolism goes haywire, creating a toxin overload which affects multiple organs,” Dr Mishra said. At that stage, things are “extremely difficult” to manage outside ICU care, he said.
Prolonged exposure to even moderate heat, and poor nutrition and hydration levels in these circumstances, too can lead to hypoxia, experts say. Those with pre-existing metabolic disorders like diabetes, the obese or the elderly, are more vulnerable.
“Hypoxia affects kidneys, liver and blood. Fluid retention may lead to renal failure; it also affects the heart and brain and, eventually, multiorgan failure. Muscles start to break down, a condition called rhabdomyolosis. This releases additional toxins which leads to electrolyte imbalances,” said Dr Sanjiv Sinha, head of AIIMS’s medicine department.
Hypoxia also causes blood components to disintegrate, which can lead to either clotting or coagulation, or excessive bleeding.
Humidity, as in coastal areas, aggravates symptoms, Dr Sinha said.
Autopsies usually show non-specific but characteristic findings. Dr Chittaranjan Behera, assistant professor of forensic medicine at AIIMS, said, “These indications can also happen in other conditions. Testing of tissues and organs can give additional findings on electrolyte levels, biochemical tests can give levels of urea or creatinine, which are indicative of metabolic findings. But all of these are also indicative of other conditions. We also have to rule out other causes like heart attacks. The viscera report has to be negative to rule out poisoning. These, coupled with general characteristic findings, are used to identify a heat-stroke death.”