- The Impact of Hyperthermia
- Normal Temperature of the Human Body
- Fever versus Hyperthermia
- Causes of Hyperthermia: What Can Increase Its Risk?
- Clinical Manifestations
- Diagnosing Hyperthermia
- Treatment Modalities for Hyperthermia
- Preventive Measures for Hyperthermia
- Hyperthermia as a Treatment for Cancer
The Impact of Hyperthermia
The highest temperature recorded on earth was 58 degrees Celsius, at a desert in Libya. This level of temperature would certainly evoke hyperthermia, which is overheating, or body temperature above the normal range.
In fact, heat is one of usual causes of climate-related mortalities around the world. A major heat wave during the 1980s took away 1,250 lives. Thus, this just shows the importance of this following discussion. [1,2]
Normal Temperature of the Human Body
- The normal body temperature of humans ranges from 36.5 to 37.5 degrees Celsius.
- However, during late afternoons, when the atmospheric temperature is at its peak, the normal body temperature can still reach to as high as 37.7 degrees Celsius. Temperatures recorded below and above these levels are considered to be the conditions hypothermia and hyperthermia, respectively. Consequently, any abnormality in body temperature can lead to experiencing medical problems. [3, 4, 5, 6, 7]
Fever versus Hyperthermia
- Both fever and hyperthermia are characterized by elevations in the body temperatures. What is the main difference between the two?
- In fever, the hypothalamus reprograms and controls the body’s thermostat, as response to the presence of infection. On the other hand, the reprogramming function of the hypothalamus is nonexistent during hyperthermia.
- As a result, the body cannot maintain its temperature properly, it rises extremely causing hyperthermia’s detrimental effect: organ damage and death.
Hyperthermia is a condition in which the body either produces more heat, such as in fever, or absorbs more heat, thru excessive sun exposure. It is described as having an elevated body temperature brought about by failure in thermoregulation. [9, 10]
Hyperthermia is defined as a temperature more than 37.5 – 38.3 °C (100 – 101 °F) – (Ref : Wikipedia)
Causes of Hyperthermia: What Can Increase Its Risk?
A number of factors can increase one’s chances of acquiring hyperthermia, this includes: [3, 4, 9, 11]
- Being out and exposed in direct heat for a long period of time
- In close distance to a heat-inducing equipment for an extensive amount of time
- Inability to rehydrate
- Inability to seek and relocate to an area with a greater amount of shade and a lesser degree of temperature level
- Included in the younger age group
- Increased poverty
- Engaging in outdoor daytime activities for a lengthy period of time
- Certain medical disorders including pheochromocytoma, thyrotoxicosis, status epilepticus and brain hemorrhage.
- Having heat exhaustion and heat strokes, which are comprised of too much metabolic heat production, excessive environmental heat, and nonfunctioning heat losing mechanism
- Intake of medications such as monoamine oxidase inhibitors (MAOIs), selective serotonin reuptake inhibitors (SSRIs) and tricyclic antidepressants
- Use of illicit drugs, like cocaine, amphetamine, lysergic acid diethylamide (LSD), Phencyclidine (PCP), and ecstasy, or MDMA.
- With the aim of increasing heat loss, blood vessels begin to dilate in the presence of an elevated body temperature. This mechanism produces a dried, hot skin, lacking sweat and the concomitant ability of skin cooling. Along with this, headaches, hypotension, dizziness, and nausea and vomiting may also be evident, if dehydration is present.[3, 11]
- Symptoms of heat exhaustion can ensue. These include body malaise, dizziness, nausea, vomiting, headaches, and muscle cramps. If neglected, this eventually leads to heat stroke, a potentially fatal condition. Manifestations of which consist of heat rash, heat cramps, nausea, disorientation, seizures and dizziness.
- This condition can initially be considered based on the complete and thorough medical history and physical examination elicited. A concomitant elevation of the body temperature in the presence of humid and hot surroundings would lead one to consider heat stroke.
- An increased body temperature after taking a medication for which hyperthermia is a known adverse reaction can result to a person having drug-induced hyperthermia.[3, 11]
- Furthermore, hyperthermia can also be a diagnosis of exclusion. If antipyretic medications lower the core temperature of the human body, even if it does not totally retain its normalcy, hyperthermia can then be ruled out.
- Additional blood tests and diagnostic examinations can then be performed to consider other sources, and causes of temperature elevation.[3, 9, 11]
Treatment Modalities for Hyperthermia
- Elimination of the underlying reason for temperature increase must be done. If hyperthermia is caused by extensive sun exposure, then transferring to a cool, shaded place, with enough water intake should be enough to alleviate symptoms.
- Drug-related hyperthermia, on the other hand, should be managed by prompt termination of drug administration. Antipyretic agents, Paracetamol, Ibuprofen and Aspirin, can also diminish hyperthermia.
- Cooling techniques can be further subdivided into passive and active methods. Passive cooling and temperature lowering may be achieved by staying at a well shaded, cool area, with all clothing immediately removed. Active means of cooling, on the other hand, pertains to sponge baths using cool water, utilizing a fan or airconditioning, and consumption of cool drinking water.
- These all would regain proper functioning of the human body’s cooling mechanisms, which are mainly thru evaporation and sweating. 
Image 2 : Immediate management for hyperthermic patient should include cold compress application, usage of a fan, fluid intake, and elevation of feet, for those with hypotension.
- A hyperthermic patient can also be immersed on a tub of cool water. This method can get rid of a huge quantity of body heat in a short amount of time. In achieving its goal, it vasoconstricts the skin and prohibits heat from breaking out of the body. It is said to be the most effective cooling method for hyperthermia. [12, 13]
Image 3 : Immersion of a hyperthermic patient on a tub of cool, even iced water.
- Hyperthermia can be a medical emergency when faced with symptoms such as unconsciousness and disorientation. This is usually observed in patients with body temperature exceeding 40 degrees Celsius. This requires management at a hospital, wherein lavage with an iced saline, intravenous hydration, and even hemodialysis, for severe intractable cases, may be done.
Preventive Measures for Hyperthermia
The following measures must be done to avoid great extents of temperature elevation:
- Avoid too much sun exposure. If not possible, try to stay at a shaded area, where it is cool and there is less heat and humidity
- Stay clear of activities that generate more heat
- Increase oral fluid intake
- Drink cool, non-alcoholic and noncaffeinated beverages
- May consume beverages with enough sodium content to restore electrolytes lost from the body (fruit juices and sports drinks).
- Wear clothes of light, cotton material.
- May take a shower during hot humid times
- If a shower is not possible at the moment, one can use a damp wash cloth to cool the skin.
- If symptoms do persist, a consult to the physician is of immediate need.
Hyperthermia as a Treatment for Cancer
- Thermotherapy, also called thermal therapy, is a treatment modality used for cases of carcinoma. Using hyperthermia as its basis, the method exposes the infected tissues of the body to a soaring degree of temperature, even reaching 113 degrees Fahrenheit. This consequently damages cancer cells and decreases tumor size, but is safe to normal ones. [14, 15, 16]
- This treatment approach can be done locally, regionally and for the whole body. Performed either thru the external, intraluminal, or interstitial techniques, local hyperthermia applies heat at a small area, such that of a tumor. Regional hyperthermia, meanwhile, may be made for the treatment of larger areas, such as that of a cavity, limb, or organ. Whole body hyperthermia, on the other hand, is used for metastases, and is performed utilizing thermal chambers and heating blankets. [15, 17]
- Recent studies dealing with this type of treatment focused on eliminating different types of carcinomas: sarcoma, mesothelioma, melanoma, and cancers of the brain, esophagus, lung, breast, liver, cervix, bladder, rectum, and appendix. [14, 18]
- Marx, J, et al. Rosen’s Emergency Medicine: Concepts and Clinical Practice. Mosby/Elsevier. p.2239.
- Karakitsos, d, et al. Hypothermia Therapy After Traumatic Brain Injury In Children. New England Journal of Medicine. 2008 September. 359(11):1179-80.
- Axelrod, Y, et al. Temperature Management in Acute Neurologic Disorders. Neurology Clinical. 2008 May. 26 (2): 585-603.
- Laupland, K, et al. Fever in the Critically Ill Medical Patient. Critical Care Medicine. 2009 July. 37 (7).
- Fausi, A, et al. Harrison’s Principles of Internal Medicine. 2008. 17th ed. Mc-Graw Professional. Pp.117-121.
- Britain Journal of Sports Medicine, 2005.
- Bouchama, A, et. al. Cooling and Hemodynamic Management in Heatstroke: Practical Recommendations. Critical Care. 2007. 11(3).
- Van der Zee, J, et al. Heating the Patient: A Promising Approach? Annals of Oncology. 2002; 13 (8): 1173-1184.
- Hilderbrandt, B, et al. The Cellular and Molecular Basis of Hyperthermia. Critical Reviews in Oncology/ Hematology. 2002; 43 (10):33-56.
- Wust, P, et al. Hyperthermia in Combined Treatment of Cancer. The Lancet Oncology. 2002; 3 (8): 487-97.
- Kapp, DS, et al. Principles of Hyperthermia. Cancer Medicine. 5th ed. Hamilton, Ontario: BC Decker, Inc, 2000.