Below are some of the common presentations for heat stroke [7].

• High body temperature: The main sign of heatstroke is body temperature at 104 F (40° C) or higher.
• Altered mental state or behaviour: Some patients of heatstroke may present seizures, delirium, confusion, agitation, slurred speech, irritability, and coma with a heat stroke episode.
• Alteration in sweating: In heatstroke induced by hot weather, the skin will feel hot and dry to the touch. However, in heatstroke brought on by strenuous exercise, the skin may feel moist.
• Other common symptoms are: Headache, increased heart rate, rapid breathing, flushed skin and vomiting or nausea. 

• Unconsciousness

  Watch for signs of rapidly progressing heatstroke, such as seizure, unconsciousness for longer than a few seconds, and moderate to severe difficulty breathing. Apply ice packs over as much of the body as you can. [northshore.org]

  His wife shared the same bed with him and was found unconscious. The wife's axillary temperature was 40 degrees C (104 degrees C) when she was admitted to the hospital. She fully recovered after medical treatment. [ncbi.nlm.nih.gov]

  Unconsciousness. What should I do? Firstly, you'll need to reduce their temperature as quickly as possible as babies and small children can fall unconsciousness easily. Read More First aid advice for parents Then call an ambulance. [mirror.co.uk]

  Heat stroke is the more severe form of heat illness that can lead to unconsciousness or death. Here are the symptoms to look for that set it apart. [rd.com]

• Fever

  A 14-month-old female with familial dysautonomia was referred to the pediatric department with high fever (41.6 degrees C), watery diarrhea, and vomiting. A few hours later, signs of encephalopathy appeared. [ncbi.nlm.nih.gov]

  Can have a mild fever 100 - 102° F (37.8 - 39° C) for a short time. Most of the time, there is no fever. Most of these symptoms are caused by dehydration from sweating. A person can progress from heat exhaustion to heatstroke. [seattlechildrens.org]

  People have a high fever, symptoms of brain malfunction, and a history of being exposed to high heat and humidity. [msdmanuals.com]

  Any illness that causes weakness, fever, vomiting, or diarrhea. Treatment A heat stroke is a medical emergency. Heat exhaustion may respond to self-care measures. If not, medical care is needed. [healthy.net]

• Fatigue

  Associated clinical manifestations such as extreme fatigue; hot dry skin or heavy perspiration; nausea; vomiting; diarrhea; disorientation to person, place, or time; dizziness; uncoordinated movements; and reddened face are frequently observed. [ncbi.nlm.nih.gov]

  Fatigue. Weakness. Listlessness. Muscle cramps. Feeling lightheaded or faint. With hot conditions, do you sweat a lot and have a headache and nausea? Self-Care / First Aid First Aid for a Heat Stroke Call 9-1-1! [healthy.net]

  When heat exhaustion occurs, the victim may have the following signs and symptoms: l Dizziness l fatigue l Nausea l Vomiting l Rapid heart beat l Profuse sweating l Thirsty l Muscle cramping Heatstroke If victim of heat exhaustion does not take timely [hkfsd.gov.hk]

  Symptoms may include: Thirst Less-frequent urination Dry skin Fatigue Light-headedness Dizziness Confusion Dry mouth and mucous membranes Increased heart rate and breathing In children, additional symptoms may include: Dry mouth and tongue No tears when [hopkinsmedicine.org]

  Symptoms of Heat Exhaustion: CDC According to the Centers for Disease Control and Prevention, the symptoms of heat exhaustion include heavy sweating, extreme weakness or fatigue, dizziness and confusion, nausea, clammy or moist skin, pale or flushed complexion [nbcdfw.com]

• High Fever

  A 14-month-old female with familial dysautonomia was referred to the pediatric department with high fever (41.6 degrees C), watery diarrhea, and vomiting. A few hours later, signs of encephalopathy appeared. [ncbi.nlm.nih.gov]

  If someone has a high fever or has been exposed to heat for a long time, then their body can become dangerously overheated. Someone can also get heatstroke after using drugs such as ecstasy. [sja.org.uk]

  Symptoms and a history of exposure to high heat and humidity The diagnosis of heatstroke is usually evident. People have a high fever, symptoms of brain malfunction, and a history of being exposed to high heat and humidity. [msdmanuals.com]

  Symptoms include hot, flushed skin with high fever over 105° F (40.5° C). A rectal temperature is more accurate than an oral temperature in these cases. 50% of children with heatstroke do not sweat. Heatstroke can cause confusion, coma or shock. [seattlechildrens.org]

• Malaise

  Heat exhaustion is characterized by nonspecific symptoms such as malaise, headache, and nausea. Treatment involves monitoring the patient in a cool, shady environment and ensuring adequate hydration. [aafp.org]

• Tachypnea

  Tachycardia, even when the patient is supine, and tachypnea are common. Sweating may be present or absent. Temperature is > 40 ° C. [merckmanuals.com]

  Tachycardia, even when the patient is supine, and tachypnea are common. Sweating may be present or absent. Temperature is > 40° C. [msdmanuals.com]

  Tachycardia, tachypnea, and normotension are common in heatstroke. Temperature also should be measured in the initial survey. [aafp.org]

• Vomiting

  This may be a challenge if the person begins to suffer from nausea and vomiting. Small sips of water, a mouthful at a time, might be tolerated even if some vomiting persists. [medicinenet.com]

  Heatstroke can cause nausea and vomiting. [oregonlive.com]

  If the child is vomiting, turn onto his or her side to prevent choking. Think Prevention! Teach kids to always drink plenty of liquids before and during any activity in hot, sunny weather — even if they aren't thirsty. [kidshealth.org]

  Heat stroke is a life-threatening condition which is characterised by nausea, vomiting, confusion, disorientation and coma. Aggressive treatment in the form of intravenous fluids along with other symptomatic management can be life saving. [ncbi.nlm.nih.gov]

• Nausea

  Dehydration occurs with water loss from excessive sweating, which causes muscle cramps, weakness, and nausea and vomiting. [medicinenet.com]

  vomiting Heatstroke can cause nausea and vomiting. [oregonlive.com]

  Heat stroke is a life-threatening condition which is characterised by nausea, vomiting, confusion, disorientation and coma. Aggressive treatment in the form of intravenous fluids along with other symptomatic management can be life saving. [ncbi.nlm.nih.gov]

  There are a number of warning signs for heat exhaustion and they vary from person to person, but the chief symptoms to look out for include: Heavy sweating, muscle cramps, paleness, tiredness, weakness, dizziness, headache, nausea, vomiting, fainting, [hindustantimes.com]

• Hypotension

  In addition, pulmonary edema, coma, hypotension, and hyperpyrexia occurred. HBOT was used successfully to combat these syndromes and to rescue the patient from heat stroke death. [ncbi.nlm.nih.gov]

  Vasoconstrictors used to treat hypotension may reduce cutaneous blood flow and decrease heat loss. When vasoconstrictors are used in an ICU, a pulmonary artery catheter may be used to monitor filling pressures. [merckmanuals.com]

• Tachycardia

  Fever has been related to polymorphic ventricular tachycardia particularly in children; nevertheless, prevalence is higher within males in their fourth to fifth decade. [ncbi.nlm.nih.gov]

  Tachycardia, tachypnea, and normotension are common in heatstroke. Temperature also should be measured in the initial survey. [aafp.org]

  Tachycardia, even when the patient is supine, and tachypnea are common. Sweating may be present or absent. Temperature is > 40 ° C. [merckmanuals.com]

  Tachycardia, even when the patient is supine, and tachypnea are common. Sweating may be present or absent. Temperature is > 40° C. [msdmanuals.com]

• Orthostatic Hypotension

  As dehydration increases from the loss of body water, lightheadedness may occur and fainting ( syncope ) may occur, especially if the affected individual stands up quickly (due to orthostatic hypotension ).The person also may have a low-grade fever. [medicinenet.com]

• Bounding Pulse

  A full bounding pulse 6. [sja.org.uk]

• Flushing

  His renal output was minimal until he was cooled and given a large fluid flush. His initial echocardiogram showed a "stunned" myocardium with an ejection fraction of 35%. [ncbi.nlm.nih.gov]

  S.Hot08.2-31a.mb.8-08-01 The Oregonian/OregonLive/File photo No 4: The skin turns red, hot or moist Signs of heatstroke can include flushed skin as the body temperature rises. [oregonlive.com]

  […] increased sweating cool, clammy skin body temperature rises, but to less than 105°F (40.5°C) Of heatstroke: severe headache weakness, dizziness confusion fast breathing and heartbeat loss of consciousness (passing out) seizures little or no sweating flushed [kidshealth.org]

  Hot flushed and dry skin 4. A fast deterioration in the level of response 5. A full bounding pulse 6. [sja.org.uk]

  Signs and symptoms of heatstroke are: l Hot and flushed skin l Body temperature may be over 40.6 o C (105 o F) l Altered level of consciousness When heatstroke is suspected, l Move the patient to a cool place l If level of consciousness is altered, place [hkfsd.gov.hk]

• Hot, Dry Skin

  Associated clinical manifestations such as extreme fatigue; hot dry skin or heavy perspiration; nausea; vomiting; diarrhea; disorientation to person, place, or time; dizziness; uncoordinated movements; and reddened face are frequently observed. [ncbi.nlm.nih.gov]

  The signs of heat stroke include: High body temperature ( often as high as 40 degrees C) Red, hot, dry skin Deteriorating conscious level Rapid pulse, gradually weakening Vomiting Collapse and seizures Coma – death First aid management Move the casualty [nfti.edu.au]

  severe headache weakness, dizziness confusion fast breathing and heartbeat loss of consciousness (passing out) seizures little or no sweating flushed, hot, dry skin body temperature rises to 105°F (40.5°C) or higher What to Do If your child has symptoms [kidshealth.org]

  Symptoms of Heat Stroke: CDC According to the Centers for Disease Control and Prevention, the symptoms of heat stroke include hot, dry skin or profuse sweating; hallucinations, chills, throbbing headache, high body temperature, confusion/dizziness and [nbcdfw.com]

  Someone who once looked bright pink and sweaty becomes pale with hot dry skin. With no way of cooling down, core body temperature can soar above 40C (it is normally 37C). [bbc.com]

• Increased Sweating

  Signs and Symptoms Of heat exhaustion: increased thirst weakness and extreme tiredness fainting muscle cramps nausea and vomiting irritability headache increased sweating cool, clammy skin body temperature rises, but to less than 105°F (40.5°C) Of heatstroke [kidshealth.org]

  Heatstroke Introduction When our body is exposed to a hot environment, our thermo-regulatory mechanism will automatically step up the cooling process by increasing sweating and breathing rate. [hkfsd.gov.hk]

  Acclimatization to hot environments usually occurs over 7-10 days and enables individuals to reduce the threshold at which sweating begins, increase sweat production, and increase the capacity of the sweat glands to reabsorb sweat sodium, thereby increasing [emedicine.com]

• Decreased Sweating

  One would expect to sweat a lot if out in the sun, but if there is decreased sweating it’s another sign of dehydration so limit any strenuous activity. [nbcnews.com]

  Conditions that interfere with heat loss, including certain skin disorders and drugs that decrease sweating, increase the risk. Heatstroke can temporarily or permanently damage vital organs, such as the heart, lungs, kidneys, liver, and brain. [msdmanuals.com]

• Petechiae

  Autopsy findings included diffuse petechiae and hemorrhages of serosal membranes (n = 7/7) and lung congestion (n = 3/7). [ncbi.nlm.nih.gov]

• Oliguria

  View/Print Table TABLE 2 Signs and Symptoms of Heat Exhaustion and Heatstroke Core Temperature* Signs Symptoms Heat Exhaustion 37°C to 40°C (98.6°F to 104°F) Anxiety Confusion Cutaneous flushing Hypotension Oliguria Pyrexia Tachycardia Vomiting Anorexia [aafp.org]

• Confusion

  You should also call 999 if the person feels hot and dry, has a temperature of 40C or above, has rapid shortness of breath, is confused, has a seizure, loses consciousness, is unresponsive. [metro.co.uk]

  Heat stroke is a life-threatening condition which is characterised by nausea, vomiting, confusion, disorientation and coma. Aggressive treatment in the form of intravenous fluids along with other symptomatic management can be life saving. [ncbi.nlm.nih.gov]

  Check for signs of heat exhaustion The signs of heat exhaustion include: headache dizziness and confusion loss of appetite and feeling sick excessive sweating and pale, clammy skin cramps in the arms, legs and stomach fast breathing or pulse temperature [nhs.uk]

  Symptoms of Heat Stroke: CDC According to the Centers for Disease Control and Prevention, the symptoms of heat stroke include hot, dry skin or profuse sweating; hallucinations, chills, throbbing headache, high body temperature, confusion/dizziness and [nbcdfw.com]

• Dizziness

  There are a number of warning signs for heat exhaustion and they vary from person to person, but the chief symptoms to look out for include: Heavy sweating, muscle cramps, paleness, tiredness, weakness, dizziness, headache, nausea, vomiting, fainting, [hindustantimes.com]

  Associated clinical manifestations such as extreme fatigue; hot dry skin or heavy perspiration; nausea; vomiting; diarrhea; disorientation to person, place, or time; dizziness; uncoordinated movements; and reddened face are frequently observed. [ncbi.nlm.nih.gov]

  Symptoms of Heat Stroke: CDC According to the Centers for Disease Control and Prevention, the symptoms of heat stroke include hot, dry skin or profuse sweating; hallucinations, chills, throbbing headache, high body temperature, confusion/dizziness and [nbcdfw.com]

  At first signs of heat illness – dizziness, nausea, headaches, muscle cramps – move to a cooler place, rest a few minutes, then slowly drink a cool beverage. Seek medical attention immediately if conditions do not improve. [wakehealth.edu]

  Recognizing Heat Exhaustion Warning signs of heat exhaustion include the following: Heavy sweating Paleness Muscle cramps Tiredness Weakness Dizziness Headache Nausea or vomiting Fainting The skin may be cool and moist. [msdh.ms.gov]

• Headache

  Signs and Symptoms Of heat exhaustion: increased thirst weakness and extreme tiredness fainting muscle cramps nausea and vomiting irritability headache increased sweating cool, clammy skin body temperature rises, but to less than 105°F (40.5°C) Of heatstroke [kidshealth.org]

  There are a number of warning signs for heat exhaustion and they vary from person to person, but the chief symptoms to look out for include: Heavy sweating, muscle cramps, paleness, tiredness, weakness, dizziness, headache, nausea, vomiting, fainting, [hindustantimes.com]

  At first signs of heat illness – dizziness, nausea, headaches, muscle cramps – move to a cooler place, rest a few minutes, then slowly drink a cool beverage. Seek medical attention immediately if conditions do not improve. [wakehealth.edu]

  Recognizing Heat Exhaustion Warning signs of heat exhaustion include the following: Heavy sweating Paleness Muscle cramps Tiredness Weakness Dizziness Headache Nausea or vomiting Fainting The skin may be cool and moist. [msdh.ms.gov]

  Fainting may be the first sign of heat stroke, other symptoms include: throbbing headache, feeling and being sick, dizziness, muscle cramps, intense thirst, darker wee than normal, rapid heartbeat, confusion, seizures, unconsciousness. [metro.co.uk]

• Seizure

  Heat stroke is a condition caused by an excessive increase in body temperature in a relatively short period of time, and is clinically characterized by central nervous system dysfunction, including delirium, seizures, coma, and severe hyperthermia. [ncbi.nlm.nih.gov]

  An injectable benzodiazepine (eg, lorazepam, diazepam ) may be used aggressively to prevent agitation and to treat seizures (which increase heat production). [merckmanuals.com]

  An injectable benzodiazepine (eg, lorazepam, diazepam) may be used aggressively to prevent agitation and to treat seizures (which increase heat production). [msdmanuals.com]

  Convulsion ( seizure ). Signs of moderate to severe difficulty breathing. A rectal temperature over 104°F (40°C) after exposure to a hot environment. Confusion, severe restlessness, or anxiety. Fast heart rate. [northshore.org]

• Irritability

  Hot weather August 2016 The Oregonian/OregonLive/File No. 1: It can alter your mental state Heatstroke can cause confusion, agitation, slurred speech, irritability, delirium and seizures, according to the Mayo Clinic in Minnesota. [oregonlive.com]

  Signs and Symptoms Of heat exhaustion: increased thirst weakness and extreme tiredness fainting muscle cramps nausea and vomiting irritability headache increased sweating cool, clammy skin body temperature rises, but to less than 105°F (40.5°C) Of heatstroke [kidshealth.org]

  […] rapid, strong pulse and dizziness Heat exhaustion - an illness that can precede heatstroke; symptoms include heavy sweating, rapid breathing and a fast, weak pulse Heat cramps - muscle pains or spasms that happen during heavy exercise Heat rash - skin irritation [web.archive.org]

  Heat rash - skin irritation from excessive sweating. It is more common in young children. You can lower your risk of heat illness by drinking fluids to prevent dehydration, replacing lost salt and minerals, and limiting your time in the heat. [nlm.nih.gov]

  […] following symptoms: A temperature of 103 degrees Fahrenheit (39.4 degrees Celsius) or higher — but no sweating Hot, red, dry skin Rapid pulse Restlessness Confusion Choose shady areas when out with small children Dizziness Headache (which may make him irritable [mirror.co.uk]

A heatstroke case is apparent to the trained naked eye but laboratory tests can aid in confirmation of the diagnosis [8]. This will also rule out other likely causes of symptoms presented. The tests to aid in diagnosis include:

• Blood test: To examine blood sodium or potassium and confirm if there has been damage to the central nervous system. 
• Urine test: Urine with dark coloration confirms heat related ailment and this test also helps in confirming kidney function. 
• Muscle function test: This will help in checking for rhabdomyolosis.
• X-rays and other imaging tests: Further confirmation of damage in the internal organs. 

Heat stroke is a medical emergency and continues to be one of the major causes of death in sports. The main treatment is a quick reduction of the core body temperature [9]. This is because the primary determinant of outcome is how long hyperthermia lasts. Unless the condition is a mild one, all patients who are diagnosed with any of the two types of heat stroke must be on admission for 48 hours to forestall occurrence of complications.

As soon as heat stroke is suspected, cooling needs to begin instantly and should be sustained throughout the duration of the patient’s resuscitation. If the heat stroke is suspected outside a hospital, cooling must be initiated on the spot before the individual is taken to the hospital.

Benzodiazepine and other muscle relaxants are used to stop shivers if treatments for lowering of body temperature kicks in [10]. Shivering increases the body temperature, countering the treatment being given.

When quick and effective treatment is produced, a lot of people will recover with very little problems if any but many develop increased sensitivity to hot weather afterwards. As complications come into play however, there is a rapid decline in prognosis [6].

Vital organs like the brain, liver and kidneys may be permanently damaged and this often leads to long term effects on the health of the individual. Organ damage is as a result of swelling and this is why prognosis in such patients ranges from fair to poor.

People become susceptible to heatstroke with consumption of certain substances that are known to inhibit cooling and bring about dehydration [2]. These include alcohol, caffeine, stimulants and medications. Age-related physiological changes can also predispose to so-called "classic" heat stroke.

Exertional heat stroke can happen in young people without health problems or medications, most often in athletes and military recruits.

Heat waves claim more lives every year in the US than other weather-related problems combined. This equates to 334 deaths each year approximately, more than hurricanes, tornadoes, floods and earthquakes combined [3]. 

Internationally, heatstroke is uncommon especially in subtropical climates. In places like Japan, heat strokes are seen occasionally and it is also seen in Mecca where people from cold environments gather on pilgrimage. 

Although there is big disparity in ambient temperatures, humans and other mammals can maintain a constant temperature by simply balancing heat gain and heat loss. When heat gain becomes higher than heat loss, the body temperature rises and this sees the onset of a major heat sickness [4].

With excessive heat comes protein denaturation. It also brings about the destabilization of lipoproteins and phospholipids and liquefies the lipid membranes. All of these lead to cardiovascular collapse, multiorgan failure and death.

There is no temperature threshold at which cardiovascular collapse must occur. This is because it varies among individuals due to certain factors like existence of a disease, drugs etc. Patients with observed temperature of as high as 46°C can survive the ordeal while those with much lower temperatures die. Temperatures that exceed 41.1°C however, require quick and aggressive therapy as most of the time it is leads to catastrophe [5].

Heat affects the body on a cellular level by interfering with cellular process along with denaturing of proteins as well as cellular membranes. When this happens, an array of inflammatory cytokines, interleukins and heat shock proteins are produced. The body becomes overwhelmed when the heat shock proteins produced go on to die as a result of the stress.

Some of the steps that can be taken to prevent occurrence of heatstroke are:

• Wearing of lightweight clothing or loose clothing in hot weather
• Protection against prolonged, direct exposure to sunlight
• Intake of copious amount of fluids
• Adhering to right dosage or serving for certain substances
• Avoiding prolonged stay in parked cars
• Being mindful of strenuous activities during hot weather
• Acclimatisation to hot weather before embarking on stressful activities

Heat stroke is the most severe form of heat injury. It is regarded a medical emergency. This is because heat stroke can damage vital organs including the brain [1]. Heat stroke affects older adults more but it also affects healthy young individuals and children.

Heat stroke is the end point of other heat-related illnesses such as heat cramps, heat exhaustion and fainting (syncope). However, it can still arise even if there is no previous sign of heat injury.

Heatstroke is a condition that arises as a result of the body overheating. It often arises from prolonged exposure to high temperatures or strenuous activities in such high temperatures. Heatstroke is the most serious form of heat injury and kicks in when the temperature of rises beyond 40° C or higher.

Most of the time heatstroke requires emergency treatments. When left untreated, heatstroke can not only damage the brain but the heart, kidneys and muscle. As treatment is delayed, damage worsens and this increases risk of death and other serious complications may also arise.

1. Heat illness among high school athletes --- United States, 2005-2009. MMWR Morb Mortal Wkly Rep. Aug 20 2010;59(32):1009-13.
2. Mazerolle SM, Pinkus DE, Casa DJ, et al. Evidence-based medicine and the recognition and treatment of exertional heat stroke, part II: a perspective from the clinical athletic trainer. J Athl Train. Sep-Oct 2011;46(5):533-42
3. Mazerolle SM, Ganio MS, Casa DJ, Vingren J, Klau J. Is oral temperature an accurate measurement of deep body temperature? A systematic review. J Athl Train. Sep-Oct 2011;46(5):566-73.
4. Heled Y, Rav-Acha M, Shani Y, Epstein Y, Moran DS. The "golden hour" for heatstroke treatment. Mil Med. Mar 2004;169(3):184-6.
5. Akhtar MJ, al-Nozha M, al-Harthi S, Nouh MS. Electrocardiographic abnormalities in patients with heat stroke. Chest. Aug 1993;104(2):411-4.
6. Lipman GS, Eifling KP, Ellis MA, Gaudio FG, Otten EM, Grissom CK. Wilderness Medical Society practice guidelines for the prevention and treatment of heat-related illness. Wilderness Environ Med. Dec 2013;24(4):351-61
7. McGugan EA. Hyperpyrexia in the emergency department. Emergency Medicine Australasia 2001 13 (1): 116–20.
8. McDermott, Brendon P. Casa DJ. Ganio MS. Lopez RM. Yeargin SW. Armstrong LE. Maresh CM. Acute Whole-Body Cooling for Exercise-Induced Hyperthermia: A Systematic Review. Journal of Athletic Training 2009 44 (1): 84–93.
9. Khosla R, Guntupalli KK. Heat-related illnesses. Crit Care Clin 1999; 15:251.
10. Bouchama A, Knochel JP. Heat stroke. N Engl J Med 2002; 346:1978.