Heatstroke is a medical condition occurring when body is subjected to overheating, which usually results from prolonged exposure to physical exertion in high temperatures. This serious form of heat injury occurs if the body temperature rises to 104 degrees F (40 degrees C) or higher.
Brain Stroke happens when the blood flow to part of the brain is obstructed which results in damage to the oxygen dependent cells of the brain. There are three main types of strokes:
Ischemic Stroke is the most common type of brain stroke constituting the majority (87%) of strokes worldwide/across India: need reference to support data. It occurs when a bloodclot lodges in a blood vessel connected to the brain, thereby, cutting the blood supply. There are two causes for Ischemic Strokes: cerebral thrombosis, a blood clot that develops at the narrowed part of the vessel; and cerebral embolism, a blood clot that come from a distant location, i.e., a blood vessel in the neck, arch of the aorta, or heart.
Hemorrhagic Stroke accounts for about 13% of stroke cases worldwide/across India: need reference to support data. It is a result of ruptured blood vessels and accumulation of blood in the surrounding region. Two types of weakened blood vessels usually cause Hemorrhagic Stroke: Aneurysms, an abnormal dialatation of a blood vessel which ruptures and bleeds into the brain; and Arteriovenous Malformation(AVM), a clump of abnormal blood vessels which can rupture causing bleeding into the brain.
Transient Ischemic Attack (TIA) is a temporary blockage of the blood supply to the brain. They are also known as “mini-strokes” and “warning strokes”. If they are not identified and treated in time they can herald a bigger and complete stroke.
Causes of Heatstroke
There are two kinds of Heatstrokes:
- Non-exertional or Classic Heatstroke: Prolonged exposure to a high ambient temperature which causes elevation of the core body temperature.
- Exertional Heatstroke: Caused by an increase in core body temperature due to vigorous physical activity in hot weather.
Any one working in hot and humid temperatures can develop heatstroke. However, people who are not accoustomed to high ambient temperatures and/or are suddenly exposed to the same, like travelers, are the most vulnerable.
Heatstroke can be prevented by understanding and reversing the common precipitating factors:
- Avoid wearing excess clothes which can prevent sweat evaporation and thus, cooling of the body
- Heat makes our body loose water quickly. Replenish with plenty of fluids to avoid dehydration.
- Extremes of age, like children and elderly, are more prone to heatstrokes
- Military training and participating in active sports, like football or long-distance running events, during hot weather
- Sudden unaccustomed exposure to high ambient temperatures like an early-summer heat wave or traveling to a hotter climate
- Medicine intakes – like beta blockers, diuretics, anti-depressants or anti-psychotics, amphetamines and cocaine
- Patients with chronic heart or lung diseases and previous epiodes of heatstroke
Causes of Brain Stroke
Brain Strokes are preventable in nearly 80% of the cases if the risk factors are identified and addressed in time. The risk factors are divided into:
Modifiable – those factors that can be controlled, and
Non-modifiable – those factors which depend on the genetic environmental factors, for which we can not do anything, and those which are implicated in stroke causation but whose significance is debatable among the medical fatrenity.
The risk factors of Brain Stroke are enumerated in the table:
|Modifiable Risk Factors||Non-Modifiable Risk Factors||Other Risks|
|High Blood Pressure||Age > 60 Years||Lower Socio-Economic Status|
|Diabetes Mellitus||Family History of Strokes||Alcohol Intake|
|Smoking||Gender (Male Sex)||Drug Abuse|
|High Cholesterol||Race||Sleep Habits|
|Obesity/Sedentary Lifestyle||Prior Stroke or TIAs|
|Diet (High Sodium Consumption)|
|Carotid Artery Disease|
|Other Heart Disease (like RHD)|
|Sickle Cell Disease|
Signs and Symptoms of Heatstroke and Brain Stroke
- A core body temperature of 104 degree F (40 degrees C) or higher, checked by a rectal thermometer
- New onset of confusion, agitation, slurred speech, irritability, delirium, seizures, and coma after exposure to a hot environment
- Sweating abnormalities: skin is hot and dry to the touch in Heatstroke due to hot temperature exposure and feels dry or slightly moist when sternous exersice is the etiology
- Skin may turn red as body temperature rises as the blood vessels in the skin dilate
- Breathing may become rapid and shallow
- Pulse rate increases as heat stress burden the heart to help cool the body
- Throbbing pulatile headaches
Symptoms of brain stroke can be identified very easily by family and friends by understanding two easy and powerful words – ‘FAST’ and ‘बचाव’ (BACHAAV).
|Face: Is one side drooping?||बचाव: बाजु का कमजोर होना|
|Arms: Raise both arms. Is one side weak?||बचाव: चहरे का टेडा होजाना|
|Speech: Is the person able to speak? Are words Jumbled or slurred?||बचाव: अवाज का लडखडना य थरथराना|
|Time: Act quickly and call emergency and reach the hospital within 4.5 hours of onset of symptoms.||बचाव: 4.5 घण्टे में हॉस्पिटल पहूँच जाना|
Apart from these, there are other symptoms of stroke – development of new onset symptoms suddenly within seconds to minutes like numbness or weakness of the leg, confusion or trouble in understanding, inability to see from one or both eyes, imbalance while walking, dizziness, loss of balance or coordination, sudden severe headache with vomiting and loss of consciousness.
What To Do During a Heatstroke or Brain Stroke
For suspected Heatstroke try to cool the overheated person at the first contact with available resources till the patient is transferred to a hospital, like taking off the excessive clothing, preventing heat from dissipating, bring the patient away from direct sunlight into a shaded area, try to bring down the core temperature by cooling — putting the person in a cold tub of water or a cool shower, spraying with a garden hose, sponging with cold water, placing ice packs or cold, wet towels on the person’s head, neck, armpits and groin till the hospital ambulance arrives.
In-Hospital treatment includes:
- A bath with cold or ice water has proved to be the most effective way of quickly lowering your core body temperature. The quicker the patient can receive cold water immersion, the lesser the risk of death and organ damage.
- Other ways to lower body temperature include using an evaporation method. Cool water is misted on the body while warm air is fanned over the patient, causing the water to evaporate and thereby cooling the skin.
- Another method is to cover the patient in a cooling blanket and apply ice packs to the groin, neck, back, and armpits to lower the core temperature.
- Treatments to lower body temperature can cause shivering which can further raise the body temperature. Hence, muscle relaxants such as a benzodiazepine can be given to prevent shivering.
When a brain stroke is identified, immediately go to a hospital’s emergency wing with 24 hours CT scan facility. CT scan is a readily available test which can tell within seconds about the type of brain stroke that the patient has suffered, whether it is an Ischemic Stroke (blood clot-related) or Hemorrhagic Stroke (blood vessel rupture).
If the stroke is due to the blockage of blood supply to the brain and patient reaches the hospital within 4.5 hours of onset of symptoms, which is called the Golden Period, a blood clot-busting drug (T-PA) can be given and the dying brain cells can be saved from irreversible damage and long-term disability. If there is an obstruction in the neck vessels or the main blood vessels of the brain, new techniques of treatment are available. For example, by Mechanical Thrombectomy wherein a blood clot can be retrieved by a neuro interventionist by entering the leg’s blood vessel using special devices and taking out the clot. This will open the blood vessel and restore the blood flow to the brain.
By these treatment modalities, a patient can recover completely after a stroke, provided the symptoms are identified quickly and the patient is brought within 4.5 hours to a hospital with comprehensive stroke care facilities.
The writer, Dr. Sahil Kohli, is a Consultant Neurology at Narayana Superspeciality Hospital, Gurugram