Elevated Body Temperature: Physiology and Associated Conditions

An overview of hyperthermia and the systemic response triggered by it.

Physiological Mechanisms of Temperature Regulation

Human body temperature is tightly regulated by the hypothalamus. Mechanisms to maintain thermal homeostasis include vasodilation, vasoconstriction, sweating, shivering, and behavioral adjustments. Disruptions to this balance can lead to a rise in core temperature.

Etiology of Hyperthermia

Numerous factors can induce hyperthermia. These can be broadly categorized as:

• Infectious: Bacterial, viral, fungal, or parasitic infections are common triggers. Pathogens release pyrogens that affect the hypothalamic set point.
• Non-Infectious: Conditions such as autoimmune diseases, malignancies, drug reactions (e.g., neuroleptic malignant syndrome, malignant hyperthermia), endocrine disorders (e.g., hyperthyroidism), and central nervous system lesions can also cause elevations in body temperature. Environmental factors such as heat stroke also fall under this category.

Associated Signs and Symptoms

Elevated body temperature is often accompanied by a range of other clinical manifestations, reflecting the systemic impact. Common signs and symptoms include:

• Chills and Rigors
• Sweating
• Headache
• Muscle aches (Myalgia)
• Fatigue and Weakness
• Loss of Appetite
• Increased Heart Rate (Tachycardia)
• Rapid Breathing (Tachypnea)
• Skin Flushing
• Confusion or Altered Mental Status (in severe cases)

Diagnostic Evaluation

Evaluation typically includes a detailed medical history and physical examination to identify potential causes. Diagnostic tests may include:

• Blood tests (e.g., complete blood count, blood cultures, inflammatory markers)
• Urine analysis
• Chest X-ray
• Lumbar puncture (if meningitis is suspected)
• Other specialized tests based on clinical suspicion

Management Approaches

Treatment focuses on addressing the underlying cause while providing supportive care to reduce the elevated temperature and manage associated symptoms. Strategies include:

• Antipyretic medications (e.g., acetaminophen, ibuprofen)
• Fluid rehydration
• Cooling measures (e.g., cooling blankets, tepid baths)
• Treatment of the underlying infection or condition

Potential Complications

Prolonged or uncontrolled high body temperature can lead to significant complications, including:

• Dehydration
• Electrolyte imbalances
• Seizures
• Organ damage
• Delirium