Heatstroke

The Heat stroke is a cover of a systemic inflammatory response hyperthermia that causes multiple organ dysfunction and often death. Symptoms include temperatures> 40 ° C and an altered mental state; Sweating may be absent or be present. The diagnosis is made clinically. The treatment consists of rapid external cooling, intravenous fluid replacement therapy and, as required, supportive measures in organ dysfunction.

For heat stroke occurs when the compensatory mechanisms that resolve heat, do not work and the core body temperature significantly increased. Inflammatory cytokines are activated, and it can develop a multiple Organdversagen. Endotoxins from the gastrointestinal flora may also play a role. Organ dysfunction may be in the CNS, skeletal muscle (rhabdomyolysis), liver, kidneys, lungs (acute respiratory distress syndrome, ARDS) and occur in the heart. The coagulation cascade is activated and sometimes causes disseminated intravascular coagulation. Hyperkalemia and hypoglycemia may occur.

The Heat stroke is a cover of a systemic inflammatory response hyperthermia that causes multiple organ dysfunction and often death. Symptoms include temperatures> 40 ° C and an altered mental state; Sweating may be absent or be present. The diagnosis is made clinically. The treatment consists of rapid external cooling, intravenous fluid replacement therapy and, as required, supportive measures in organ dysfunction. For heat stroke occurs when the compensatory mechanisms that resolve heat, do not work and the core body temperature significantly increased. Inflammatory cytokines are activated, and it can develop a multiple Organdversagen. Endotoxins from the gastrointestinal flora may also play a role. Organ dysfunction may be in the CNS, skeletal muscle (rhabdomyolysis), liver, kidneys, lungs (acute respiratory distress syndrome, ARDS) and occur in the heart. The coagulation cascade is activated and sometimes causes disseminated intravascular coagulation. Hyperkalemia and hypoglycemia may occur. Heat stroke is sometimes split into two variants, although the benefits of this classification is controversial (some differences between classic and exercise heatstroke): Classical load The classic heat stroke requires an exposure of 2-3 days to develop. He comes in the summer before when heat waves, usually in older people with sedentary life without air conditioning and often with limited access to drinks. The load-dependent heat stroke occurs abrupt and affects healthy active people (eg. As athletes, military recruits, factory workers). It is the second leading cause of death in young athletes. An intensive effort in a hot environment causes a sudden massive heat load that can not regulate the body. Rhabdomyolysis is common, acute renal failure and coagulopathy are somewhat more likely and more severe. A heat exhaustion can pass into a heat stroke, when the heat disease progresses and is characterized by impairment of mental status and neurological function. Some differences between classic and exercise heatstroke feature Classic heatstroke stress Heat stroke onset 2-3 days hours Usually, patients affected older, predominantly sedentary people healthy, active people (eg. As athletes, military recruits, factory workers). Risk Factors No air conditioning in summer heat waves intense effort, especially without acclimatization skin Usually hot and dry, but sometimes moist from sweat often damp with sweat Heat stroke can after taking certain drugs and medications occur (eg. As cocaine, phencyclidine [PCP ], amphetamine, monoamine oxidase inhibitors), which cause a hypermetabolic state. Usually an overdose is necessary, however, effort and environmental conditions can be added. Malignant hyperthermia (malignant hyperthermia) can be triggered by some anesthetics in genetically predisposed patients. Neuroleptic malignant syndrome (Neuroleptic malignant syndrome) may develop in patients taking antipsychotics. These diseases are life-threatening. Symptoms and signs A CNS dysfunction, rangierend of confusion to delirium, convulsions and coma is the main symptom. Ataxia may be an early manifestation. Tachycardia, even in patients in the supine position, and tachypnea are common. Sweating may be present or absent. The temperature is> 40 ° C Diagnosis Clinical evaluation, including measurements of core temperature laboratory tests on organ dysfunction Diagnosis is obvious usually after a history of physical exercise and excessive heat. Heat stroke is detected by the presence of the following criteria: CNS dysfunction temperature> 40 ° C If the diagnosis of heat stroke is not clear, should be able to cause other disorders CNS disorders and hyperthermia, are considered. These disorders include: Acute infections (. Eg sepsis, malaria, meningitis, toxic shock syndrome) Pharmacotherapy Neuroleptic malignant syndrome Serotonin syndrome status epilepticus (interictal) stroke hyperthyroid crisis are for laboratory testing, a complete blood count, prothrombin time (PT), partial thromboplastin time ( PTT), electrolytes, urea, creatinine, calcium, creatine phosphokinase (CPK) and liver function, so that the organ function can be evaluated. A bladder catheter is positioned to receive urine, the excretion is controlled investigated with a test strip for occult blood. Tests for the detection of myoglobin are not necessary. Myoglobinuria is likely if the urine sample does not contain red blood cells, but it is a positive reaction for blood there, and if the creatine phosphokinase (CPK) is increased in serum. An examination of the urine for drugs and medications can be helpful. A constant monitoring of core body temperature, usually by measuring the rectum, esophagus or bladder is desirable. Prognosis The mortality and morbidity are significant, but they vary clearly with age, underlying diseases, the maximum temperature and, most importantly, the duration of hyperthermia and promptness of cooling. Without prompt and effective treatment, the mortality reached almost 80%. In about 20% of survivors residual brain damage remain, regardless of treatment. In some patients, renal failure persists. The body temperature can be unstable for weeks. Aggressive treatment cooling Aggressive and supportive treatment. Classic heat stroke and heat exhaustion due to physical exertion are treated similarly. The importance of rapid detection and effective, aggressive cooling can not be stressed enough. Cooling techniques The main cooling techniques immersion in cold water evaporative cooling are diving in cold water leads to the lowest morbidity and mortality and is the drug of choice when available. Large cooling tanks are often used in outdoor activities such as football and long distance races. In remote areas, patients can plunge into a cool pond or river. Dipping may be used in an emergency ward if the appropriate equipment is available and the patient is stable enough (z. B. no need for intubation bsteht, no seizures are present). The rate of heat loss during the cooling can be reduced by vasoconstriction and shivering; Jitter can be reduced by a benzodiazepine (z. B. Diazepam Lorazepam i.v. 5 mg or 2 to 4 mg with additional doses as needed) or chlorpromazine 25 to 50 mg i.v. is given. Evaporative cooling can also be effective, but works best when the environment is dry and the patient has adequate peripheral circulation (requires adequate cardiac output). When humidity is high or low vibration immersion should be done in cold water. Evaporative cooling can be by spraying of warm water over the patient during this befächert be achieved. Evaporative cooling is more effective when it is performed with warm instead of cold water. Hot water maximizes the skin-air vapor pressure gradient and minimizes vasoconstriction and shivering. In some specially developed body cooling devices, patients are laid naked on a network via a dewatering table, is sprayed from above and below while finely atomized water at 15 ° C over the body. Fans are used to 45 to 48 ° C heated air around the body to circulate. With this technique, most patients can be cooled with heat stroke minutes at <60th Moreover, ice or chemical cold packs to the neck, armpits and groin or hairless areas of the skin (ie, palms, soles, Wangen) that are densely populated with subcutaneous vessels are attached, to enhance the cooling, but are not the only cooling methods angemessen.Andere measures resuscitation should follow during the cooling is carried out. Intubation and ventilation (sometimes with paralysis) may be needed to prevent aspiration in patients with impaired consciousness, which often develop vomiting and seizures. Supplementary O2 is given because heat stroke increased metabolic demand. The patient is admitted to an intensive care unit, and intravenous hydration with 0.9% saline solution is introduced, as in the heat exhaustion (heat exhaustion: treatment). Theoretically, 1-2 l of a 0.9% strength can at 4 ° cooled i.v. help saline during cooling, as it says in the guidelines for hypothermia after cardiac arrest to lower the core temperature. Fluid deficits range from minimal (eg., 1 to 2 L) to severe dehydration. Infusions should be given as boluses, by monitoring the blood pressure, urine output and central venous pressure, the reactions are observed and recognized the need for additional boluses. Excessive amounts of infusions, particularly if patients develop heatstroke-induced acute kidney injury can lead to acute pulmonary edema. Organ dysfunction and rhabdomyolysis be treated (s. On the respective sides in the MSD Manual). An injectable benzodiazepine (z. B. lorazepam or diazepam) may be used aggressively to prevent physical agitation and to treat convulsions (which increases the heat generation). Platelets and fresh frozen plasma may be required in severe disseminated intravascular coagulation. If myoglobinuria is present, can adequate hydration to maintain a urinary excretion of ? 0.5 ml / kg / h and i.v. NaHCO3, help to alkalize the urine to prevent or minimize nephrotoxicity. Intravenous calcium salts may be used to treat a hyperkalemic Kardiotoxität. Vasoconstrictors for the treatment of hypotension can reduce the dermal blood circulation and reduce the heat loss. If vasoconstrictors are used in intensive care, pulmonary artery catheter can be used to monitor filling pressures. Catecholamines (epinephrine, norepinephrine and dopamine) can increase heat production. Hemodialysis is necessary eventually. Fever depressants (eg. As paracetamol) are worthless and can contribute to kidney damage. Dantrolene is used to treat anesthesia-induced malignant hyperthermia, but in severe hyperthermia other causes no advantage could be demonstrated. Activated protein C shows promising results in animal studies, but has not been tested in humans. Important points heatstroke differs from heat exhaustion due to the failure of mechanisms that distribute body heat, by the presence of CNS dysfunction and temperature> 40 ° C. If the diagnosis of heat stroke in febrile patients with impaired consciousness is not obvious, pull a variety other diseases such as infections, poisoning, thyroid storm, strokes, seizures (interictal), neuroleptic malignant syndrome and serotonin syndrome into consideration. Rapid detection and effective, aggressive cooling are extremely important. Apply if possible immersion in cold water on. Evaporative cooling can also be effective, but requires a dry environment and adequate peripheral circulation; use lukewarm (not cold) water and fanning. Monitor patients closely (including its liquid state) and provide for an aggressive supportive care.

Health Life Media Team

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