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Explained: Toxin overload, how heat kills?

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.

Written by Pritha Chatterjee | New Delhi | Updated: May 29, 2015 8:34 am
heat wave, heat wave in india, heat-stroke, heat-stroke death, heat wave india, heat wave news, heat wave deaths, Indian express Experts also say a heat-stroke death can be identified only after examination, and after other causes have been ruled out.

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.

[PHOTOS: Heat Wave Melts Roads, Death Toll Over 1,500]

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.

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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.

heatProlonged 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.”

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  1. R
    R
    May 29, 2015 at 7:50 am
    Just like scientist genetically modify plants genes to yield better products or to make them pest resistant ,if our scientists take project to genetically modify human genes to make all the human physiological systems to function at 45*C,instead of the present 37*C,deaths due to heat stroke can be averted .I do not know if it is possible.
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    1. Rudolph Furtado
      Jun 1, 2015 at 7:53 am
      Sadly its mostly the poorest of the poor in society that become victims of "HEAT STROKE".Just staying indoors and consuming liquids can avoid a "HEAT STROKE". Its the "LABOUR CL" , the "HOMELESS" and a few people with chronic diseases that become victims of "HEAT STROKE".
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      1. N
        Nishant
        May 29, 2015 at 7:44 am
        Air temperature alone is a misleading measure of heat. It is just a mere air tempperature taken in shade. Other factors that increase the heat index is the radiant heat which comes directly from the sun and infra red coming out of ground and surrounding rocks or buildings. Heat index takes into account only humidity, which is usually important in costal cities. There is no heat index which takes into consideration air velocity, which is 'loo factor'. Hot wind can trump all other reasons for raising the body temperature by its sheer conduction power, overpowering the bodys cooling mechanism and raising the core temperature quickly by vascular areas important for losing heat (head, neck, hands etc). Drinking enough water is not sufficient in extreme heat...one must escape the radiant heat, seek shelter from hot winds in a shade, and if feeling sick take a water bath or wet ones clothing and head. Drinking cold fluids such as nimbu pani- with sugar and salt- can quickly correct dehydration. If u find someone disoriented or fallen in the high sun, one can not go wrong in lifting that individual into a shaded area and throwing cold water onto the head and armpits to help lower the temperature, and take to the doctor.
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        1. N
          Nishant
          May 29, 2015 at 8:28 am
          There are ways to survive high heat 1. Stay indoors when the sun goes up 2. Shade your windows by curtains and apply newspaper to gl windows the old way...aluminum foil could be even better 3. Wear white or light colored clothes only 4. Stay hydrated 5. Keep windows and doors closed to protect from loo during the afternoon ensuring that the residentialructure will not overheat as a result. 6.pool the resources such as ACs and water coolers. ac works best in small rooms, but water cooler needs bigger rooms or a roomy place. Water coolers may fail in extreme heat...but the leftover water may be chilled. One may bring it in to soak towels for cooling the body.7. Underground water is always cool...and could serve well. 8. Consider colouring ones roof white using white cement slurry and acrylic modifier to enhance adhesion to bricks. It should last more than a decade when nothing else survives in an abrasive climate for more than a season or two.
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          1. P
            prem sobti
            Jun 1, 2015 at 8:12 am
            Indians are accustomed to hot climate. Usual degree of heat does not bother young and rural agricultural laborers who have both the physical adaptation and mental knowhow what to do when it gets too hot. However, when the temperatures hover close to 50, and one is caught outdoors in sun or hot winds, the survival would depend upon techniques adapted by people who survive in the desert conditions. A similar situation arises when people traveling in non AC buses or trains. These can become death traps in no time for those who come unprepared. So, what is special about the desert dwellers. They do everything that i described earlier, but they dress specifically for that environment, and we can learn from them. 1. Cover up almost entirely, but only with a white colored cotton cloth...cotton has characteristics unlike any other modern fabric to keep the skin cool by promoting evaporation next to the only 2. Cover up very loosely 3. Covering the head with a large scarf. Imagine as if one is going to dress like a middle eastern man, or a pathani loose kurta pyjama with a head gear. The loose cotton dress creates a micro environment which is shaded, offering protection from hot winds, and into which one can sweat; and thus optimizing the ability of ones sweating to cool the body. A good lesson to be learnt at the governmental and societal level is to change timings for offices and construction/labour activities very early in the day. Offices and schools should close down on very hot days as per the weather forecast, and compensate for days lost on weekends. Law should enforce suspension of labour like activities on very hot days, with a guaranteed minimum wage, and mandate provision of ample cold water for the laborers during hot and humid weather conditions.
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