In some parts of Spain, there have already been five heat waves so far this summer. The clear impact of climate change on the intensity of hot summers is evident in the activity at emergency rooms. Cristóbal Rodríguez-Leal, MD, physician in the Emergency Medicine Service, Hospital Universitario del Henares, Coslada, Spain, warned that prolonged heat waves are changing the profile of patients arriving at emergency departments and calls for adapting the healthcare system to a climate reality that “is no longer what it was 20 years ago.”

The increasingly frequent and intense heat waves no longer result solely in an increase in heatstroke or dehydration cases. “They are also quietly changing the profile of patients arriving at emergency departments, with a rise in exacerbations of chronic diseases, especially among the elderly and other vulnerable groups,” he explained to El Médico Interactivo, part of the Medscape Professional network.

“We’re seeing heat-related emergencies that were exceptional 20 years ago, such as classic heatstroke or exercise-induced heatstroke. But that’s just the tip of the iceberg,” he added.

In the internist’s view, the real problem isn’t just the most striking cases that make headlines but the cumulative effect of the heat on the most vulnerable people. “What really strains the system are the complications of chronic diseases because these are the patients who are hospitalized and who may die,” he emphasized.

Rodríguez-Leal explained that tropical nights, the inability to adequately cool many homes, and sustained heat stress are causing an increase in conditions that were not traditionally associated with summer.

“We’re seeing a host of exacerbations of chronic diseases similar to what we observe in winter with respiratory infections,” he noted. Among these, he cited the increase in cases of heart failure, thromboembolic disease exacerbated by dehydration, and other cardiovascular complications. When heat waves are prolonged and last for several consecutive days, we begin to see decompensated chronic conditions in older and vulnerable individuals — conditions that were not previously as common during the summer.

Although heatstroke, heat exhaustion, sunburn, and dehydration are also on the rise among workers exposed to the sun and young people, the specialist insists that these cases represent only part of the problem.

That also places a burden on emergency departments, without a doubt, but it’s not what puts the most strain on the system.

Three Particularly Vulnerable Groups

Rodríguez-Leal identifies three groups of patients who are particularly sensitive to high temperatures. The first are people with cardiovascular diseases, especially those suffering from heart failure. These patients take diuretics and other medications that lower blood pressure. The need for these medications is not the same in summer as in winter because sweating also causes fluid loss.

However, he acknowledges that these dynamic adjustments to medication based on the weather are not routinely made, which contributes to dehydration, kidney failure, and heat-exacerbated adverse effects.

The second group consists of people with cognitive impairment. “They won’t ask for water on their own,” he warned. Often, families feel they’ve done everything possible, but the patient may refuse to drink or simply not realize the need to drink, which can lead to severe dehydration.

The third group consists of patients with severe mental disorders treated with certain psychotropic medications. Some antipsychotics reduce the ability to sweat and dissipate heat, so these individuals have a harder time cooling down and are at greater risk in extreme temperatures.

A System Designed for a Climate That No Longer Exists

For Rodríguez-Leal, climate change also requires rethinking of healthcare organization. “European healthcare services were designed for a climate that no longer exists,” he argued. He noted that summer traditionally meant a decline in healthcare activity, a circumstance that justified reducing resources during the vacation period.

“When I was training 18 years ago, August in Madrid was much quieter than it is now,” he recalled. “And I’m not talking about half a century ago, but less than two decades.”

For this reason, he believes it is necessary to develop specific heat-related plans, just as there are special measures in place for the winter flu. Perhaps in the summer, there should also be planning to mitigate these effects, with adequate human and material resources.

In addition, he called for updating clinical protocols for the treatment of heatstroke and for promoting greater coordination between emergency departments, primary care, and specialties such as cardiology to temporarily adjust the medication of the most vulnerable patients.

Infectious Diseases and Transmission Vectors

The specialist points out that the climate crisis is also altering the geographic distribution and seasonality of various infectious diseases. Diseases we once considered tropical are no longer limited to tropical regions because climatic conditions now allow them to spread in our latitudes.

He cited as examples the spread of the West Nile virus, as well as the emergence of locally acquired cases of dengue and chikungunya in various parts of southern Europe. Emergency departments serve as a sentinel for identifying and detecting these diseases because what isn’t considered isn’t diagnosed.

This story was translated from El Médico Interactivo on Univadis.