Heat stroke makes man's organs feel like they've been boiled? It's not the high body temperature that kills cells directly!

Hot, hot, hot

Hot, hot

The most widespread high temperature weather this year has arrived!

The local maximum temperature may exceed 40℃

"Shanghai has reached 40 degrees"

"The temperature in Hangzhou is approaching 40 degrees"

“Hunan people are going crazy”

"Zhejiang occupies six of the top ten high temperature rankings in the country"

…

Hot weather in various places

In recent days, it has dominated the hot searches on Weibo.

"Man suffers from heat stroke, multiple organs damaged, like being 'cooked'"

This Weibo trending search

Let heat stroke, a disease that is familiar yet unfamiliar to everyone

"Swipe the screen" again

What is heat stroke? Why do we get it? How can we prevent and treat it?

In fact, a previous research result published in Science

The fatal mechanism of heat stroke was revealed

Man suffers from heat stroke after continuous outdoor work

Multiple organs damaged as if they were "cooked"

Since the beginning of summer this year, high temperatures have broken records one after another. The high temperatures in various places have caused many people to suffer from heat stroke.

According to the "Big Reference" column of the People's Livelihood Channel of Henan Radio and Television Station, recently, a man in Zhengzhou, Henan, suddenly vomited and fell unconscious due to heatstroke. When he was sent to the hospital for emergency treatment, the doctor monitored that his core temperature had reached 42.3 degrees. All the organs in his body were like they had been "boiled" in water, and he suffered liver and kidney damage.

The report video showed that one doctor was fanning the patient, while another was spraying diluted alcohol on the patient. Everyone used various methods to cool down the patient.

According to Liu Xiaogang, director of the ICU at the High-tech Campus of Zhengzhou Central Hospital affiliated to Zhengzhou University, who treated the patient, Mr. Zhang fainted on the side of the road after working continuously for two hours outdoors in a temperature of nearly 40 degrees Celsius.

"In addition to fanning and spraying diluted alcohol, we also used a hypothermia therapy device to cool the patient down, laid and covered the patient with an ice blanket, and put an ice cap on his head, all in an effort to lower his body temperature to a safe range as quickly as possible," said Liu Xiaogang.

After rapidly cooling down, considering that Mr. Zhang had been exposed to high temperatures and had impaired consciousness and multiple organ damage, the doctor diagnosed him with heat stroke.

Heat stroke is also known as severe heat stroke. "After Mr. Zhang was admitted to the hospital, we found that he had liver dysfunction, anuria, renal dysfunction, shock and other symptoms. Once the core temperature of the human body rises, blood will flow with the heart to supply the organs of the whole body. All organs will be like being 'boiled' in water, and will show symptoms of multiple organ dysfunction. According to statistics, the mortality rate of severe patients is about 50%." Liu Xiaogang introduced.

High body temperature does not directly "kill" cells

Instead, it activates the programmed cell death pathway

Heat stroke is a fatal emergency with a high mortality rate. So why do people get heat stroke and what is its lethal mechanism?

In May this year, Professor Lu Ben's team from the Third Xiangya Hospital of Central South University published a research paper online in Science, revealing the important lethal mechanism of heat stroke.

As the global climate continues to warm, the number of deaths caused by heat stroke is increasing year by year. However, the mechanism of how high body temperature causes organ damage and death has not been well understood in the past.

The current treatment for heat stroke patients is generally to cool the patient down first. If the patient has organ failure after cooling down, the patient will be immediately given corresponding organ function protection treatment. Although the equipment and technology for treating the kidney, liver and other organs are very advanced, the cure rate of heat stroke is still low.

In other words, it is generally believed that heat stroke causes death because high body temperature directly "kills" cells, leading to the patient's death.

Professor Lu Ben’s team found that high body temperature does not directly “kill” cells and cause physical damage to the cells, but instead activates the cells’ programmed death pathway.

This discovery came from an experiment.

"When we used high ambient temperature (39°C) and high humidity (60%) to prepare a heat stroke mouse model, we found that high body temperature can induce phosphorylation of RIPK3 and MLKL in organ tissues such as the liver, lungs and intestines, as well as the cleavage of apoptosis-related proteins such as caspase-8; knocking out the RIPK3 gene can prevent high body temperature-induced inflammatory response, DIC, multiple organ damage and death." said Lu Ben.

In other words, heat stroke causes death due to key genes.

The team then used RIPK3 kinase-inactivated mice, MLKL knockout mice, and MLKL-Caspase-8 double gene knockout mice to confirm that the lethal effect induced by high body temperature mainly depends on programmed cell necrosis mediated by RIPK3 kinase and its phosphorylated substrate MLKL, and to a small extent depends on programmed cell death mediated by caspase-8.

"This suggests that even if doctors can quickly cool down patients with high body temperatures, they still cannot stop the course of heat stroke. The discovery of this lethal mechanism will provide a new approach to the treatment of heat stroke."

Lu Ben said that the previous view was that heat stroke is a physical injury process, and high fever produces cytotoxic effects. When the body temperature continues to rise to a certain threshold, it will directly cause irreversible damage to cells, and then cause symptoms such as inflammation and thrombosis, and then multiple organ failure. Although active cooling treatment and organ support treatment are taken clinically, the mortality rate of heat stroke remains high due to the lack of specific effective treatment drugs and methods.

Take good precautions against heatstroke and stay cool, lie down more often and avoid sun exposure

Statistics from the Central Meteorological Observatory show that since June this year, my country has experienced two large-scale high-temperature weather processes. The last one was from June 13 to 26, and the first regional high-temperature weather process this year occurred in central and southern North China, Huanghuai, Jianghuai, Jianghan and other places, covering an area of ​​3.636 million square kilometers. The high-temperature weather process that began on July 6 will affect a wider range and last longer.

At 18:00 on July 10, the Central Meteorological Observatory continued to issue a yellow high temperature warning. Image source: Central Meteorological Observatory

At 18:00 on July 10, the Central Meteorological Observatory continued to issue a yellow high temperature warning. It is expected that during the daytime on July 11, the temperature in Turpan, Xinjiang, the southern plains of Shaanxi, central and northern Zhejiang, central Fujian, the southeastern Sichuan Basin, and western and northern Chongqing may reach above 40°C.

"Shanghai has reached 40 degrees", "The temperature in Hangzhou is approaching 40 degrees", "Hunan people are going to melt due to the heat", "Zhejiang occupies six seats in the top ten of the national high temperature list"... The high temperature weather in various places has "dominated" the hot searches on Weibo in recent days.

The high temperatures in various places have "dominated" the hot searches on Weibo in recent days.

The temperature is rising. How can we effectively prevent heatstroke and cool down to avoid heat stroke or heat stroke?

Yuan Fangfang, the first author of the paper and a postdoctoral fellow at Central South University, said that heatstroke can be divided into mild and severe cases according to the severity of the disease. Mild heatstroke is characterized by normal or slightly elevated body temperature, and patients will experience heavy sweating, thirst, dizziness, tinnitus, blurred vision, visual and auditory hallucinations, chest tightness, nausea, general fatigue, slow movements, etc. Some patients will experience symptoms of circulatory failure such as pale complexion and weak pulse.

Severe heatstroke is manifested by a core body temperature exceeding 40°C, hot and dry skin, and neurological dysfunction such as convulsions and coma; or cold and clammy skin, pale complexion, and low blood pressure after excessive sweating; it can affect multiple organs such as the liver, kidneys, intestines, lungs, coagulation, and striated muscle, and may even lead to death.

Yuan Fangfang said that people should try to avoid working or high-intensity exercise and training in hot climates; maintain good eating habits and adequate sleep, otherwise the body's heat tolerance will decrease and heat stroke will occur easily; if you have symptoms such as colds and diarrhea, you should try to avoid high-intensity work or training, as the incidence of heat stroke will increase; if you experience severe physical exhaustion, chest tightness, shortness of breath, dizziness, or confusion during work or training, you should stop working or training in time; if you experience dizziness, diarrhea, hematuria, and other discomforts after work, be alert to the occurrence of heat stroke and seek medical attention in time.

Doctors also remind people to seek medical attention immediately if they experience dizziness, nausea, or a body temperature close to 40 degrees Celsius. They should get more rest, drink more water, and replenish water and salt in time when working outdoors or in high-temperature environments.

China Science Daily reporter Wang Haohao compiled reports from the Central Meteorological Observatory, Henan Radio and Television Station's People's Livelihood Channel's "Big Reference" column, and other sources.

Editor | Zhao Lu

Typesetting | Guo Gang