What is the physiology and management of fever?

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Last updated: June 17, 2025View editorial policy

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From the Guidelines

Fever management should focus on identifying and treating the underlying cause while providing symptomatic relief, with the most recent guidelines suggesting avoiding routine use of antipyretic medications for critically ill patients, unless they value comfort by reducing temperature 1. The physiology of fever involves the body's natural response to infection or inflammation, characterized by an elevation in core body temperature above the normal range of 36.5-37.5°C (97.7-99.5°F). Some key points to consider in the management of fever include:

  • Identifying and treating the underlying cause of the fever
  • Providing symptomatic relief with antipyretic medications, such as acetaminophen or ibuprofen, when necessary
  • Maintaining hydration with regular fluid intake
  • Using non-pharmacological measures, such as wearing light clothing and using tepid sponging or lukewarm baths
  • Monitoring for severe symptoms, such as altered mental status, difficulty breathing, severe headache, stiff neck, or rash, which may indicate serious conditions requiring specific treatment beyond antipyretics. According to the most recent guidelines, for critically ill patients with fever, antipyretic medications should only be used when the patient values comfort by reducing temperature, and not as a routine practice 1. It's also important to note that fever itself is not an illness, but a symptom, and the body's increased temperature actually helps fight infection by enhancing immune function and inhibiting pathogen replication. In terms of specific treatment, ibuprofen can be used for antipyretic purposes when the temperature is higher than 38.5 ℃, with a dose of 0.2 g per time, every 4–6 h in continuous fever, but no more than 4 times in 24 h 1. Overall, the management of fever should be individualized and based on the specific needs and circumstances of each patient, with a focus on providing symptomatic relief and treating the underlying cause of the fever.

From the Research

Physiology of Fever

  • Fever is a normal adaptive response to infection, characterized by a rise in body temperature above 38 degrees C [(2,3,4,5)].
  • The febrile response is a complex physiologic reaction involving a cytokine-mediated rise in body temperature, generation of acute-phase reactants, and activation of numerous endocrinologic and immunologic systems 4.
  • Fever can be caused by both infectious and noninfectious causes, and its development in critically ill patients is associated with an increased risk for death 2.

Management of Fever

  • The management of fever is controversial, and it is not clear whether most medical patients with moderate degrees of fever should be treated with antipyretic or direct cooling therapies 2.
  • Treatment of fever may improve patient comfort and reduce metabolic demand, but fever suppression is potentially harmful 2.
  • In children younger than 3 years, uncomplicated fever is harmless and should not be treated, but antipyretics such as acetaminophen may be used to relieve discomfort 3.
  • In older adults, fever is generally beneficial and seldom requires treatment, except in certain patients who may not tolerate the stress 5.

Assessment and Evaluation

  • Critical care nurses should be knowledgeable in assessing and treating fever in critically ill patients 6.
  • An evidence-based plan of care for the assessment, planning, intervention, and evaluation of the patient with fever is essential 6.
  • Repeated observation of the feverish patient is important to follow any evolution and to guide therapy [(3,6)].

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Fever in the critically ill medical patient.

Critical care medicine, 2009

Research

[Management of fever in children younger then 3 years].

Journal de pharmacie de Belgique, 2010

Research

Pathophysiology and management of fever.

The journal of supportive oncology, 2006

Research

Management of fever in older adults.

Journal of gerontological nursing, 2009

Research

Fever: applying research to bedside practice.

AACN advanced critical care, 2007

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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