Yes! Even though we often think of temperatures of 100.4°F (38° C) or greater as fever, older people often fail to mount an appropriate febrile response despite having a serious infection. ¹

Infectious Diseases Society of America (IDSA) guideline on evaluation of fever in older adult residents of long-term care facilities has defined fever in this population as:²

• Single oral temperature >100° F (>37.8° C) OR
• Repeated oral temperatures >99° F (>37.2° C) OR
• Rectal temperatures >99.5° F (>37.5° C) OR
• Increase in temperature of >2° F (>1.1° C) over the baseline temperature

Even at these lower than traditional thresholds for defining fever, remember that many infected elderly patients may still lack fever. In a study involving bacteremic patients, nearly 40% of those 80 years of age or older did not have fever (defined as maximum temperature over 24 hrs 100° F [37.8°C] or greater).³  

So our patient meets the criteria for fever as suggested by IDSA guidelines and, particularly in light of her recent poor intake and falls, may need evaluation for a systemic source of infection.

Bonus Pearl: Did you know that blunted febrile response of the aged to infections may be related to the inability of cytokines (eg, IL-1) to reach the central nervous system?¹

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References 

1. Norman DC. Fever in the elderly. Clin Infect Dis 2000;31:148-51. https://academic.oup.com/cid/article/31/1/148/318030
2. High KP, Bradley SF, Gravenstein S, et al. Clinical practice guidelines for the evaluation of fever and infection in older adult residents of long-term care facilities: 2008 update by the Infectious Disease Society of America. Clin Infect Dis 2009;48:149-71. http://www.idsociety.org/uploadedFiles/IDSA/Guidelines-Patient_Care/PDF_Library/Fever%20and%20Long%20Term%20Care.pdf
3. Manian FA. Fever, abnormal white blood cell count, neutrophilia, and elevated serum C-reactive protein in adult hospitalized patients with bacteremia. South Med J 2012;105;474-78. http://europepmc.org/abstract/med/22948327

Disclosures: The listed questions and answers are solely the responsibility of the author and do not necessarily represent the official views of Mercy Hospital-St. Louis or its affiliate healthcare centers, Mass General Hospital, Harvard Medical School or its affiliated institutions. Although every effort has been made to provide accurate information, the author is far from being perfect. The reader is urged to verify the content of the material with other sources as deemed appropriate and exercise clinical judgment in the interpretation and application of the information provided herein. No responsibility for an adverse outcome or guarantees for a favorable clinical result is assumed by the author. Thank you!