All physiological activities of the body are based on metabolism, and normal body temperature is the most suitable temperature for metabolism. Too high or too low body temperature will affect the normal operation of human metabolism, which will lead to physiological dysfunction and even death in severe cases. Hyperthermia is the "fever" we often hear, and hypothermia is rare. Let's take a look.
0 1
What is normal body temperature?
The human body temperature is controlled by the thermoregulatory center located in the front of the hypothalamus, which can balance the extra heat generated by the metabolic activities of muscles and liver with the heat emitted by the skin and lungs, so the human body can maintain a fairly stable body temperature under normal circumstances.
Normal body temperature varies slightly according to the test site. Commonly used body temperatures include:
(1) Oral temperature: the normal range is 36.3℃-37.2℃;
(2) Rectal temperature: the normal value is about 0.3℃-0.5℃ higher than the oral temperature;
(3) Axillary temperature: convenient and hygienic, and it is the most commonly used measurement method at present. The normal range is 36. 1℃-37℃, which is about 0.2℃-0.4℃ lower than the oral temperature.
02
What is hypothermia?
Hypothermia refers to the core temperature < 35℃. According to the core temperature, hypothermia is divided into the following categories:
The clinical manifestations of hypothermia grading core body temperature are mild 32℃-35℃, confusion, tachycardia and chills increase, moderate 28℃-32℃ lethargy, bradycardia, arrhythmia, disappearance of pupillary reflex and chills decrease, and severe coma, hypotension, arrhythmia, pulmonary edema and rigidity.
03
Possible causes of hypothermia
1. Environmental exposure
The human body uses the autonomous mechanism to regulate heat dissipation and heat production to adapt to the surrounding environment and maintain this temperature as much as possible, but the physiological ability of the human body to adapt to the cold environment is limited. For the outside world is too cold, beyond the body's defense ability, there will be hypothermia.
2. Physical illness
Many physical diseases can cause hypothermia, as shown in the following table:
The main reasons are the increase of heat energy damage of dermatoses, burns, psoriasis and exfoliative dermatitis, the decrease of heat energy production of endocrine diseases, pituitary hypofunction, adrenalin hypofunction, hypothyroidism, insufficient hypoglycemia intake, malnutrition, peripheral spinal cord injury, diabetes, central cerebrovascular accident, subarachnoid hemorrhage, Parkinson's disease, hypothalamic dysfunction and other septicemia, cancer, trauma, vascular insufficiency, uremia and so on.
3. medicine
Some drugs can directly or indirectly cause hypothermia by destroying thermoregulation mechanism, reducing cold cognitive ability or through fuzzy judgment.
Mainly includes:
(1) Damage mechanism to body temperature: sedatives and hypnotics (diazepam, etc. ), anti-anxiety drugs, antidepressants, antipsychotics (olanzapine, risperidone, etc. ), opioids (pethidine, etc. );
(2) Compensation ability of injury to low temperature environment: oral hypoglycemic agents, β-blockers, α -adrenergic agonists and general anesthetics.
Some antipyretic drugs, such as ibuprofen, are antipyretic, analgesic and anti-inflammatory drugs, which have obvious anti-inflammatory, cooling and analgesic effects and are commonly used antipyretic drugs. Some data show that the use of this product will cause hypothermia, which is related.
4. Others
Some substances that can induce vasodilation, including some poisons and excessive drinking.
References:
[1] Zimmerman et al., Unexpected hypothermia. Intensive care clinic1999; 15:235.
[2] Yang Baofeng et al. Pharmacology (9th Edition). People's Medical Publishing House, 20 18: 170.
[3] Donati M et al., "Ibuprofen-related hypothermia in children: analysis of Italian spontaneous reporting database". European Journal of Clinical Pharmacy. 2065 438+06 Oct； 72( 10): 1239- 1243.
Biem J, Koehncke N N, Classen D, Dosman J, et al. Out of the cold: management of hypothermia and frostbite [J].CMAJ. 2003; 168(3):305.