What are the causes of hyperthermia?

From the Guidelines

Hyperthermia is primarily caused by factors such as exposure to high environmental temperatures, strenuous physical activity, certain medications, medical conditions, dehydration, and inappropriate clothing. The causes of hyperthermia can be multifaceted, involving both external and internal factors that disrupt the body's ability to regulate its temperature. According to 1, in the context of acute ischemic stroke, hyperthermia can be secondary to the cause of stroke, such as infective endocarditis, or may represent a complication like pneumonia, urinary tract infection (UTI), or sepsis.

Key factors that contribute to hyperthermia include:

• Exposure to high environmental temperatures, especially when combined with high humidity
• Strenuous physical activity in hot conditions
• Certain medications like stimulants, antipsychotics, and anticholinergics
• Medical conditions such as thyroid disorders, infections, and neurological conditions affecting temperature regulation
• Dehydration, which impairs sweating
• Wearing inappropriate clothing that traps heat
• Drug-induced hyperthermia from medications like MDMA (ecstasy), cocaine, amphetamines, and during neuroleptic malignant syndrome or serotonin syndrome, as noted in 1
• Malignant hyperthermia, a rare genetic condition triggered by certain anesthetics

It's crucial to identify and address the underlying cause of hyperthermia to prevent further complications, especially in vulnerable populations like those with acute ischemic stroke, where hyperthermia is associated with poor neurological outcomes 1. Prevention strategies include staying hydrated, avoiding excessive heat exposure, wearing appropriate clothing, and being aware of medication side effects that might affect temperature regulation. In cases of heat stroke, where core body temperature exceeds 104°F (40°C), immediate medical attention with rapid cooling measures is necessary.

From the Research

Causes of Hyperthermia

The causes of hyperthermia can be diverse and include various factors. Some of the key causes are:

• Drug-induced hyperthermia, which can be caused by medications such as anticholinergic drugs, CNS stimulants, and salicylates 2, 3
• Neuroleptic malignant syndrome, serotonin syndrome, anticholinergic poisoning, sympathomimetic poisoning, and malignant hyperthermia, which are all types of drug-induced hyperthermia syndromes 4, 3
• Elevated body temperature due to non-infective and infective aetiologies, which can cause neurological and cognitive consequences 5
• Cellular mechanisms of neuronal damage from hyperthermia, including necrotic neuronal death and delayed death with apoptotic characteristics 6

Drug-Induced Hyperthermia

Drug-induced hyperthermia can be caused by a variety of medications, including:

• Anticholinergic drugs, such as tricyclic antidepressants, antipsychotics, and antihistamines 2
• CNS stimulants, such as phencyclidine, cocaine, and amphetamines 2
• Salicylates, which can cause hyperthermia when taken in combination with other medications 2
• Other medications, such as neuroleptics and serotonin reuptake inhibitors, which can cause hyperthermia as a side effect 4, 3

Non-Drug Related Causes

Non-drug related causes of hyperthermia can include:

• Elevated body temperature due to environmental factors, such as heat stroke or exposure to high temperatures 5
• Infections, such as sepsis, which can cause fever and hyperthermia 5
• Other medical conditions, such as thyroid disorders or adrenal insufficiency, which can cause hyperthermia as a symptom 5