Heatwaves are commonly associated with dehydration, fatigue and heat exhaustion. However, emergency departments are increasingly encountering patients with far more serious complications linked to prolonged heat exposure. Individuals are arriving throughout the day and night with severe weakness, repeated vomiting, abdominal pain, loose motions, confusion and episodes of collapse. In some cases, what begins as heat stress progresses into a life-threatening medical emergency affecting multiple organs.

Many people do not immediately connect symptoms such as stomach pain, diarrhea, nausea or extreme weakness with heat exposure. As a result, they often delay seeking medical attention, assuming the problem is related to food poisoning, a stomach infection or general fatigue. By the time they reach the emergency department, significant physiological damage may already be underway.

Recognising heat-related illness early is often challenging because several symptoms overlap with other medical conditions. Patients may present with vomiting, dizziness and dehydration, while others arrive with altered behaviour, confusion or loss of consciousness. Understanding the clinical condition and identifying heat related illness at the right time is critical because management and outcomes can differ significantly.

Understanding Heat Exhaustion: Symptoms

Heat exhaustion is commonly associated with excessive sweating, weakness, fatigue, dizziness and dehydration. However, when exposure to extreme temperatures continues and the body's ability to regulate heat begins to fail, heat stroke can develop. Heat stroke is a medical emergency defined by a core body temperature exceeding 40 degrees Celsius along with central nervous system dysfunction.

Patients with heat stroke may present with:

  • Confusion or delirium
  • Seizures
  • Loss of consciousness
  • Hot skin and elevated body temperature
  • Rapid heart rate
  • Difficulty breathing

At this stage, the condition extends far beyond dehydration. The body's organs begin to experience direct thermal injury and a widespread inflammatory response.

Also Read: Heat Stroke Warning Signs You Should Never Ignore In Summer

Heat Exhaustion Complications: Treating Emergencies

Potential complications include:

  • Acute kidney injury
  • Liver dysfunction or liver failure
  • Acute respiratory distress syndrome
  • Severe electrolyte disturbances
  • Disseminated intravascular coagulation, a serious clotting disorder
  • Rhabdomyolysis, a condition involving rapid breakdown of muscle tissue

Rhabdomyolysis is one of the most important yet lesser known complications associated with severe heat illness. As muscle tissue breaks down, substances released into the bloodstream can overwhelm the kidneys and contribute to acute kidney injury. At the same time, the inflammatory response triggered by heat stroke can worsen organ damage. In severe cases, rhabdomyolysis may also lead to dangerous cardiac rhythm disturbances, compartment syndrome and life threatening coagulation abnormalities.

This is why the management of severe heat stroke extends well beyond administering intravenous fluids. Emergency teams often find themselves managing a complex multisystem illness requiring rapid cooling, intensive monitoring and organ support. Kidney function, liver function, clotting status, electrolyte levels and neurological status all require close assessment from the moment a patient arrives.

62-Year-Old Woman With Heat Stroke: A Case Study

One such patient was a 62-year-old woman who had spent two consecutive days shopping for her daughter's wedding during a period of extreme heat. Living alone, she continued her activities despite feeling increasingly unwell. She was eventually found unconscious and brought to the emergency department by a bystander. On arrival, her body temperature was 107 degrees Fahrenheit, and her skin was hot and dry. She was diagnosed with heat stroke complicated by multiple organ dysfunction and required intensive care management for nearly two weeks.

Cases such as these highlight how rapidly heat related illness can escalate when warning signs are overlooked. Once the body's cooling mechanisms fail, injury can occur across multiple organs simultaneously, affecting the brain, kidneys, liver, muscles, lungs and circulatory system.

The Impact On Healthcare Systems

The impact is also being felt at a healthcare system level. Studies estimate that extreme heat contributes to more than 10 lakh excess emergency department visits annually in India, representing approximately 6 per cent of baseline emergency visits during peak summer months. Beyond patients presenting directly with heat related illnesses, extreme temperatures can worsen outcomes in people with underlying medical conditions and place additional pressure on already stretched emergency services.

Also Read: Heatwaves Are Ruining Sleep Even In Air Conditioned Rooms: Doctors Explain Why

Who Is At Risk?

Certain groups face a higher risk of severe complications:

  • Older adults
  • Young children
  • Outdoor workers
  • People with heart disease, kidney disease or diabetes
  • Individuals living alone
  • Those taking medications that affect fluid balance or temperature regulation

One of the important clinical observations during heatwaves is that not all patients present with classic symptoms of heat stroke. Many arrive complaining primarily of abdominal pain, repeated vomiting, loose motions, nausea, dizziness or profound weakness. These symptoms may appear mild initially but can represent the early stages of a serious heat related illness.

Symptoms such as persistent weakness, repeated vomiting, abdominal pain, loose motions, dizziness, unusual fatigue, confusion or behavioural changes during periods of extreme heat should be assessed promptly, particularly when they follow prolonged exposure to high temperatures. Early recognition and timely medical intervention remain critical in preventing heat-related illness from progressing to organ failure and other life-threatening complications.

(By Dr Md Nadeem, Head - Emergency Medicine, Fortis Hospital Gurugram)



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