Postoperative fever is defined as a temperature >100°F (38°C) on 2 consecutive postoperative days, or >102.2°F (39°C) on any 1 postoperative day. It is a common problem encountered by both surgeons and medical consultants. The reported incidence varies, but can be expected in about 13-14%.  Most cases are self-limiting, requiring only observation. However, it is crucial to recognize a small subset of patients who require further investigation and treatment for a more serious underlying cause. Causes of postoperative fever presenting up to and including 4 weeks postoperatively are discussed here.
The differential diagnosis is strongly influenced by the time of onset of the fever. The most common cause of fever within the first 48 hours is a pyretic response to surgery, which is self-limiting. Diagnostic testing is usually unrevealing in this period unless associated symptoms and signs suggest an underlying cause.   After 48 hours, the incidence of infectious etiologies increases and a CBC, chest radiograph, urinalysis with culture, blood cultures, and wound cultures are required as first tests in all patients. Further radiological or laboratory testing is directed toward the suspected etiology.
Program Director Internal Medicine
University of Florida-Health Science Center
Internal Medicine Residency Program
JH declares that he has no competing interests.
Associate Professor of Medicine
Florida State University
College of Medicine
IA declares that she has no competing interests.
Honorary Senior Lecturer
Chelsfield Park Hospital
ASER declares that he has no competing interests.
Section of Infectious Diseases
Department of Medicine
University of Manitoba
Infection Prevention and Control Unit Health Sciences Centre
JME declares that he has no competing interests.
Professor of Medicine
Department of Microbiology and Immunology
Albert Einstein College of Medicine
SGB declares that he has no competing interests.
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