Home HealthTopics Health Centers Reference Library Research
Join us on Facebook Join us on Facebook Share on Facebook


Fever after anesthesia is given



During minor throat surgery I developed a fever which my doctor thought could be infection setting in so I stayed there for two days. I always thought the anesthesia caused this. Could I be correct?


It is true that a mild fever is common in the first 24 hours after surgery. There is no evidence that fever is caused by anesthesia.

The most cautious approach to a postoperative fever is to keep the patient in hospital and look for serious causes like infection. Infectious causes of fever include pneumonia, urinary tract infection, infection of intravenous line sites, and surgical site infection. Other non-infectious causes of fever are pulmonary aspiration, pulmonary embolism, (blood clot), drug fever, and blood product reaction.

A condition called atelectasis, which is where parts of the lungs are "collapsed" (the small airways are closed and air cannot get in or out of that area of lung), has traditionally been thought to cause fever. Perhaps this is because atelectasis is common, and fever is common! But again there is no hard evidence that atelectasis causes fever.

When these other causes are ruled out fever is most likely to due to the release of various molecules, called cytokines, in response to tissue injury (surgery). The fever is self-limiting (goes away without treatment) and benign (harmless).

For more information:

Go to the Anesthesia health topic, where you can:

Response by:

Gareth S Kantor, MD Gareth S Kantor, MD
Assistant Professor of Anesthesiology
School of Medicine
Case Western Reserve University