What is the aetiology and management of hyperpyrexia (elevated body temperature) with temperatures exceeding 40 degrees Celsius, characterized by severe hyperthermia?

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From the Guidelines

Hyperpyrexia (temperature >40°C) is a medical emergency that requires immediate intervention with rapid cooling and treatment of the underlying cause to prevent complications and reduce mortality risk. The main causes of hyperpyrexia include severe infections (sepsis, meningitis, malaria), heat stroke (exertional or classic), neuroleptic malignant syndrome, malignant hyperthermia, thyroid storm, and drug reactions (serotonin syndrome, anticholinergic toxicity). Management begins with rapid cooling through external methods such as:

  • Ice packs to groin and axillae
  • Cool mist sprays with fans
  • Cooling blankets
  • Administration of 2000–3000 ml of chilled (4°C) 0.9% saline at i.v. as recommended by the European Malignant Hyperthermia Group 1 Antipyretics like paracetamol (1g every 6 hours, maximum 4g daily) or ibuprofen (400-600mg every 6-8 hours) should be administered, although their effectiveness in reducing temperature in hyperthermic patients is still a topic of debate 1. Intravenous fluids (normal saline or Ringer's lactate) are essential to correct dehydration. The underlying cause must be identified and treated specifically, such as:
  • Antibiotics for infections
  • Dantrolene (2.5mg/kg IV) for malignant hyperthermia
  • Bromocriptine (2.5-10mg three times daily) for neuroleptic malignant syndrome
  • Discontinuation of causative medications Continuous monitoring of vital signs, temperature, and neurological status is crucial, with ICU admission often necessary. Benzodiazepines may be needed for seizures, and organ support measures should be implemented as required. The mortality risk increases significantly with temperatures above 41°C, making rapid diagnosis and aggressive management essential for survival. It is also important to note that induced hypothermia should only be considered in the context of ongoing clinical trials, as its benefit in patients with ischemic stroke is not well established 1.

From the Research

Aetiology of Hyperpyrexia

  • Hyperpyrexia is a severely elevated core body temperature secondary to an elevated hypothalamic set thermo-regulatory threshold 2
  • It can be caused by various factors, including:
    • Intracranial hypotension, which can lead to hypothalamic dysfunction and compression 2
    • Sepsis, heat illness, neuroleptic malignant syndrome, malignant hyperthermia, serotonin syndrome, and thyroid storm 3
    • Drug-induced hyperpyrexia, which can occur due to overdoses of certain medications such as monoamine oxidase inhibitors, benzodiazepines, and beta-adrenergic receptor blocking agents 4

Management of Hyperpyrexia

  • Accurate nursing assessment is crucial in determining the appropriate cooling intervention for hyperpyrexic patients 5
  • Hyperpyrexia responds best to central cooling interventions such as antipyretic therapy, whereas hyperthermia responds best to physical cooling methods 5
  • Tepid sponging and ice cool packs are not recommended as they can induce shivering and vasoconstriction 5
  • In cases of intracranial hypotension, adjusting the ventriculoperitoneal (VP) shunt settings can help resolve hyperpyrexia 2
  • Nurses should focus on supporting patients with pyrexia by meeting their subjective needs, providing comfort, and avoiding complications 6

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Hyperpyrexia in the emergency department.

Emergency medicine (Fremantle, W.A.), 2001

Research

Drug-induced hyperpyrexia. A case report.

South African medical journal = Suid-Afrikaanse tydskrif vir geneeskunde, 1979

Research

Improving evidence-based care for patients with pyrexia.

Nursing standard (Royal College of Nursing (Great Britain) : 1987), 2011

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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