Under the scorching sun – Heat Stroke Q&A

Under the scorching sun – Heat Stroke Q&A

Different parts of the world are experiencing extremes of temperature. Especially in the Middle East and Asia this time of the year, heatstroke is one of the commonest presentations in the emergency department (ED). Both developed and developing countries suffer from it.

Heatstroke can range from being mild to severe, and it can lead to multi-organ damage and eventually death, especially in cases not treated in time.

Heatstroke can present in various ways and may mimic other illnesses. In the ED, just like anything else, history is an essential part of management.

What is heatstroke and how does it occur?

The body functions well at a set temperature. When a person is present in extremes of temperature, dehydrated, or performs physical exertion in high temperatures, the thermoregulatory mechanism does not work effectively, causing overheating and body temperature to reach up to 40 degrees celsius. This change in body temperature, if not treated rapidly, causes different organs to deteriorate, as the organs function at the optimal temperature and a change from the normal causes their dysfunction.

Heatstroke is divided into two types – Classical or non-exertional heatstroke is common in children and the elderly who spend time outdoors in the heat and exertional heatstroke is seen in workers and soldiers who perform activities outdoors for long periods of time.

What are some risk factors that may increase the chances of developing a heat stroke?

Heatstroke can occur in almost anyone, but certain factors increase the risk, such as:

  • People of extremes of age and those who work outdoors during the daytime (eg – construction workers). 
  • Dehydration and exposure to high temperature with inadequate ventilation.
  • Certain medications such as antipsychotics, antidepressants, and diuretics etc.

How do the patients present to the ED?

The presentation of heatstroke may mimic many illnesses and history is one of the most important factors in making a decision. Here is the various presentations that can be related to heatstroke:

  • High body temperature >40 degrees celsius
  • Changes in behaviour
  • Changes in perspiration – skin would be dry and warm to touch 
  • Seizures
  • Symptoms of dehydration
  • Nausea and vomiting
  • Flushing of skin
  • Tachypnea and tachycardia
  • Headache
  • Coma

How to evaluate the patient?

The evaluation starts with taking a history from the patient or someone accompanying them. History of heat exposure increases the suspicion. You should also see:

  • Vitals signs and temperature monitoring, rectal if possible.
  • Cardiac monitoring – the monitor will show sinus tachycardia
  • Complete blood count (CBC), Reflo, Urea and Electrolytes, Liver and Kidney function, Lactate 
  • Creatine phosphokinase (CPK) levels

Management in the ED

  • Start with ABC’s – patients may present in a coma and may require intubation
  • Remove any excessive materials of clothing
  • Cool the patient with a cooling blanket
  • Fluid resuscitation – cold IV Fluids
  • The target temperature is 38.5 degrees celsius

Cooling Techniques

  • Cold exposure – Several techniques can be used such as cold water splashes/spraying, placing a fan, immersion in an ice bath, or cold water packs 
  • Dantrolene – A drug that reduces heat production in the body, has shown no effect in improving outcomes in patients with heatstroke and hence is not indicated.
  • Medications may be used for symptomatic relief. However, the gold standard management is rapid cooling using any of the above-mentioned methods.
689.3 - Figure 3. Waterproof matress and Cooling Unit

What complications can occur if the patient is not treated rapidly?

  • Coma
  • Seizures 
  • Electrolyte imbalance
  • Bleeding
  • Multi-organ damage
  • Neurological dysfunction 
  • ECG changes
  • Hypotension 

What are some of the differential diagnoses of heatstroke?

  • Drug ingestion and overdose
  • Meningitis
  • Malaria
  • Serotonin syndrome

How can we prevent heat stroke?

  • Public education and occupational health initiatives to spread awareness amongst the public and workers to protect themselves, stay hydrated at all times, and set duty and break hours during peak daytime.
  • Availability of rapid cooling equipment in emergency departments

References and Further Reading

Cite this article as: Sumaiya Hafiz, UAE, "Under the scorching sun – Heat Stroke Q&A," in International Emergency Medicine Education Project, October 25, 2021, https://iem-student.org/2021/10/25/heat-stroke/, date accessed: December 5, 2023

Question Of The Day #49

question of the day
Which of the following is the most likely cause of this patient’s condition?

This patient presents to the Emergency Department with altered mental status.  This presenting symptom can be due to a large variety of etiologies, including hypoglycemia, sepsis, toxic ingestions, electrolyte abnormalities, stroke, and more.  The management and evaluation of a patient with altered mental status depends on the primary assessment of the patient (“ABCs”, or Airway, Breathing, Circulation) to identify any acute life-threatening conditions that need to be managed emergently, the history, and the physical examination.  One mnemonic that may help in remembering the many causes of altered mental status is “AEIOUTIPS”.  The table below outlines this mnemonic.


Hyperthermia (or hypothermia) can cause altered mental status.  This patient arrives with altered mental status, severe hyperthermia, tachycardia, tachypnea, and hypotension.  The history of the patient running outside for exercise should raise concern for hyperthermia related to excess heat production due to overexertion.  This should narrow the differential diagnoses to heat exhaustion (Choice B) and heat stroke (Choice C).  Both heat exhaustion and heat stroke are marked by hyperthermia with temperatures often over 40ᵒC. Additional symptoms include weakness, nausea, vomiting, myalgias, syncope, and headache.  The differentiating factor between heat exhaustion and heat stroke is altered mental status and sweating.  Patients with heat exhaustion lack altered mental status and should still be able to thermoregulate through sweating.  On the contrary, heat stroke patients are more severely ill as they have altered mental status and can no longer thermoregulate with sweating.  The treatment in both conditions should be early and aggressive cooling measures.  This includes full body immersion in an ice bath, removal of clothes, and cold IV fluids.  Internal cooling with gastric, bladder, pleural, or peritoneal lavage with cold fluids can be done on more sick patients.  Antipyretic medications, like NSAIDs and paracetamol, have no benefit in patients with severe hyperthermia.  Evaluation for rhabdomyolysis, kidney failure, liver failure, sepsis, or other organ dysfunction should also be a part of the evaluation of hyperthermic patients.

Sympathomimetic toxicity (Choice A) is possible, but less likely as the skin is dry and the history of exercise outdoors.  Sympathomimetic toxicity manifests as diaphoresis, tachycardia, hypertension, hyperthermia, and sometimes altered mental status.  Thyroid storm (Choice D) is another possibility.  This diagnosis can also present with similar vital signs, hyperthermia, and altered mental status.  Again, the history of outdoor exercise should point more towards heat exhaustion vs heat stroke.

The diagnosis of this patient is heat stroke (Choice C) as he has altered mental status and lacks wet skin.

Correct Answer: C


Cite this article as: Joseph Ciano, USA, "Question Of The Day #49," in International Emergency Medicine Education Project, August 6, 2021, https://iem-student.org/2021/08/06/question-of-the-day-49/, date accessed: December 5, 2023