Why can elderly individuals be septic without presenting with fever (pyrexia)?

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Last updated: May 9, 2025View editorial policy

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From the Guidelines

Elderly individuals can be septic without having a fever due to age-related changes in their immune system and thermoregulatory responses. As people age, their immune system becomes less efficient (immunosenescence), resulting in a diminished inflammatory response to infections 1. The body's ability to mount a fever, which is a protective mechanism against infection, becomes impaired. Additionally, older adults often have a lower baseline body temperature, so even when they do develop a fever, it might not reach the traditional threshold of 38°C (100.4°F).

Some key points to consider in the diagnosis of sepsis in elderly patients include:

  • Chronic conditions common in the elderly, such as diabetes or kidney disease, can further suppress fever responses
  • Medications frequently prescribed to older adults, including non-steroidal anti-inflammatory drugs, steroids, and certain psychiatric medications, can mask fever symptoms
  • The clinical manifestations of diseases and infections are often subtle, atypical, or nonexistent in the very old, making diagnosis more challenging 1
  • Healthcare providers should maintain a high index of suspicion for sepsis in elderly patients who present with subtle changes in mental status, increased respiratory rate, decreased blood pressure, or other non-specific symptoms, even without fever

It is essential to note that the diagnosis of infections in residents of long-term care facilities is often difficult due to the unique characteristics of this population, including age-related immunologic changes, chronic cognitive and/or physical impairments, and diseases that alter host resistance 1. The guidelines and standards of practice used for diagnosis of infections in patients in acute-care facilities may not be applicable nor appropriate for residents in long-term care facilities. Healthcare providers should prioritize a thorough assessment and careful observation of elderly patients with suspected sepsis, rather than relying solely on the presence of fever.

From the Research

Sepsis in the Elderly

  • Sepsis is a potentially fatal response to infection that can affect patients of all ages, including the elderly 2.
  • The elderly are more susceptible to sepsis due to various risk factors, including age, chronic medical conditions, and the presence of invasive devices 2, 3.
  • Sepsis in older adults can present atypically, making diagnosis and management more challenging 2.

Atypical Presentation of Sepsis

  • Older adults with sepsis may not always exhibit typical symptoms, such as fever 3.
  • Instead, they may present with non-specific symptoms, such as altered mental status or functional decline 3.
  • This atypical presentation can lead to delayed diagnosis and treatment, which can worsen outcomes 3.

Diagnosis and Management

  • Early recognition and treatment of sepsis are crucial to reducing morbidity and mortality 4, 5.
  • Diagnosis of sepsis involves identifying the source of infection, as well as the presence of organ dysfunction 4, 5.
  • Management of sepsis includes antimicrobial therapy, fluid resuscitation, and supportive care 4, 5.
  • In older adults, management of sepsis must take into account unique considerations, such as antimicrobial selection and dosing, delirium management, and goals of care discussions 3.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

The older adult experiencing sepsis.

Critical care nursing quarterly, 2015

Research

Sepsis in Older Adults.

Infectious disease clinics of North America, 2017

Research

Sepsis: Current Definition, Pathophysiology, Diagnosis, and Management.

Nutrition in clinical practice : official publication of the American Society for Parenteral and Enteral Nutrition, 2017

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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