Hyperthermia
The content of the article:
- Causes
- Kinds
- Signs
- Diagnostics
- Treatment
- Prevention
- Consequences and complications
Hyperthermia (from Greek.
Hyperthermia - the accumulation of excess heat in the body with an increase in body temperature
The human body is homeothermal, that is, it is capable of maintaining a normal body temperature regardless of the temperature of the external environment.
A stable temperature regime is possible due to the independent production of energy and developed mechanisms for correcting the balance of heat production and heat transfer. The heat generated by the body is constantly released into the external environment, which prevents overheating of the body's structures. Normally, heat transfer is carried out through several mechanisms:
- heat radiation (convection) of the generated heat into the environment through the movements and movements of the air heated by the heat;
- heat conduction - direct transfer of heat to objects with which the body is in contact, in contact;
- evaporation of water from the surface of the skin and from the lungs during breathing.
Under extreme external conditions or violation of the mechanisms of heat production and (or) heat transfer, an increase in body temperature and overheating of its structures occur, which entails a change in the constancy of the body's internal media (homeostasis) and triggers pathological reactions.
Hyperthermia must be distinguished from fever. These states are similar in manifestations, but fundamentally differ in the mechanism of development, severity and provoked changes in the body. If hyperthermia is a pathological breakdown of thermoregulation mechanisms, then fever is a temporary, reversible shift of the set point of thermoregulatory homeostasis to a higher level under the influence of pyrogens (substances that increase temperature) while maintaining adequate homeothermal mechanisms of regulation.
Causes
Normally, when the temperature of the external environment decreases, the superficial vessels of the skin narrow and (in severe cases) arteriovenous anastomoses open. These adaptive mechanisms contribute to the concentration of blood circulation in the deeper layers of the body and to maintain the temperature of the internal organs at the proper level in conditions of hypothermia.
At high ambient temperatures, the opposite reaction occurs: superficial vessels dilate, blood flow in the shallow layers of the skin is activated, which promotes heat transfer using convection, sweat evaporation also increases and breathing becomes more frequent.
Hyperthermia - a violation of body thermoregulation due to various reasons
Under various pathological conditions, the mechanisms of thermoregulation break down, which leads to an increase in body temperature - hyperthermia, its overheating.
Internal (endogenous) causes of thermoregulation disorders:
- damage to the center of thermoregulation, located in the brain, as a result of tissue hemorrhage or thromboembolism of the supplying vessels (stroke), traumatic brain injury, organic lesions of the central nervous system;
- overdose of stimulating substances that activate metabolism;
- an excessive stimulating effect of the cortical centers on the thermoregulation center located in the hypothalamus (intense psychotraumatic effects, hysterical reactions, mental illness, etc.);
- extreme muscular work in conditions of difficult heat transfer (for example, the so-called "drying" in professional sports, when intensive training is carried out in thermal clothing);
- activation of metabolism in somatic pathologies (in diseases of the thyroid gland, adrenal glands, pituitary gland, etc.);
- pathological contractile thermogenesis (tonic tension of skeletal muscles, which is accompanied by an increase in heat production in the muscles, with tetanus, poisoning with certain substances);
- dissociation of oxidation and phosphorylation processes in mitochondria with the release of free heat under the influence of pyrogenic substances;
- vasospasm of the skin vessels or decreased sweating as a result of intoxication with anticholinergics, adrenomimetics.
Hyperthermia can be due to high ambient temperatures
External causes of hyperthermia:
- high ambient temperature combined with high air humidity;
- work in hot production shops;
- long stay in the sauna, bath;
- clothes made of fabrics that impede heat transfer (the air gap between clothes and the body is saturated with vapors, which makes it difficult to sweat);
- lack of adequate ventilation of the premises (especially with a large crowd of people, in hot weather).
Kinds
According to the provoking factor, there are:
- endogenous (internal) hyperthermia;
- exogenous (external) hyperthermia.
By the degree of increase in temperature digits:
- subfebrile - from 37 to 38 ºС;
- febrile - from 38 to 39 ºС;
- pyretic - from 39 to 40 ºС;
- hyperpyretic or excessive - over 40 ºС.
By severity:
- compensated;
- decompensated.
By external manifestations:
- pale (white) hyperthermia;
- red (pink) hyperthermia.
Separately, rapidly developing hyperthermia is distinguished, with rapid decompensation and an increase in body temperature figures to life-threatening (42-43 ºС) - heatstroke.
Heatstroke - rapidly developing hyperthermia
Heatstroke forms (by dominant manifestations):
- asphyxia (respiratory disorders prevail);
- hyperthermic (the main symptom is high body temperature numbers);
- cerebral (cerebral) (accompanied by neurological symptoms);
- gastroenterological (dyspeptic manifestations come to the fore).
Signs
Hyperthermia has the following manifestations:
- increased sweating;
- tachycardia;
- hyperemia of the skin, skin hot to the touch;
- significant increase in breathing rate;
- headache, possible dizziness, flickering of flies or darkening in the eyes;
- nausea;
- feeling of heat, sometimes hot flashes;
- unsteadiness of gait;
- short-term episodes of loss of consciousness;
- neurological symptoms in severe cases (hallucinations, seizures, confusion, stunning).
A characteristic feature of pale hyperthermia is the absence of skin hyperemia. The skin and visible mucous membranes are cold, pale, sometimes cyanotic, covered with a marble pattern. Prognostically, this type of hyperthermia is the most unfavorable, since under conditions of spasm of superficial vessels, there is a rapid overheating of internal vital organs.
Signs of hyperthermia - headache, dizziness, darkening of the eyes
Signs of heatstroke do not have characteristic features, the main distinguishing features are rapidly increasing symptoms, the severity of the general condition, the previous effect of external provoking factors.
Diagnostics
The diagnosis of hyperthermia is based on characteristic symptoms, an increase in body temperature to high numbers, resistance to antipyretic drugs and physical methods of cooling (rubbing, wrapping).
Treatment
The main method of treating hyperthermia is taking antipyretic drugs (non-steroidal anti-inflammatory drugs, anilides), if necessary, in combination with analgesics, antihistamines.
With hyperthermia, the use of antipyretic drugs is indicated
With pale hyperthermia, it is necessary to use antispasmodics, vasodilators to improve microcirculation and relieve symptoms of peripheral vasospasm.
Prevention
Prevention of endogenous hyperthermia consists in the timely and adequate treatment of the conditions that caused it. In order to prevent exogenous hyperthermia, it is necessary to follow the rules of work in hot workshops, reasonably approach sports, observe the hygiene of clothing (in hot weather, clothes should be lightweight, made of fabrics that allow air to pass through freely), etc. measures to prevent overheating of the body.
Consequences and complications
The complications of hyperthermia are life-threatening:
- paralysis of the center of thermoregulation;
- paralysis of the respiratory and vasomotor centers;
- acute renal failure;
- acute heart failure;
- acute progressive intoxication due to renal failure;
- convulsive syndrome;
- swelling of the brain;
- thermal overheating of neurons with damage to the main functional elements of the nervous system;
- coma, death.
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Olesya Smolnyakova Therapy, clinical pharmacology and pharmacotherapy About the author
Education: higher, 2004 (GOU VPO "Kursk State Medical University"), specialty "General Medicine", qualification "Doctor". 2008-2012 - Postgraduate student of the Department of Clinical Pharmacology, KSMU, Candidate of Medical Sciences (2013, specialty "Pharmacology, Clinical Pharmacology"). 2014-2015 - professional retraining, specialty "Management in education", FSBEI HPE "KSU".
The information is generalized and provided for informational purposes only. At the first sign of illness, see your doctor. Self-medication is hazardous to health!
