What is the most common cause of fever in the first 48 hours after noncardiac surgery?

What is the most common cause of fever in the first 48 hours after noncardiac surgery?

• A. The normal inflammatory response to tissue injury
• B. Pneumonia
• C. Urinary tract infection
• D. Atelectasis

Answer: (A)

Early postoperative fever is most commonly the body's normal inflammatory response to tissue injury from surgery. Surgical trauma releases cytokines and other mediators that raise the hypothalamic set point, producing fever that is usually mild and self-limited within the first day or two after the operation. Because infections such as pneumonia or urinary tract infection typically require more time to develop, they are less likely explanations in this immediate 48-hour window. Atelectasis has been blamed in the past, but it is not a reliable cause of fever and is not the typical source in the early period. If fever persists beyond the initial inflammatory phase or is accompanied by signs like localized infection, leukocytosis, or hemodynamic instability, then infectious etiologies should be considered.

Early postoperative fever is most commonly the body's normal inflammatory response to tissue injury from surgery. Surgical trauma releases cytokines and other mediators that raise the hypothalamic set point, producing fever that is usually mild and self-limited within the first day or two after the operation. Because infections such as pneumonia or urinary tract infection typically require more time to develop, they are less likely explanations in this immediate 48-hour window. Atelectasis has been blamed in the past, but it is not a reliable cause of fever and is not the typical source in the early period. If fever persists beyond the initial inflammatory phase or is accompanied by signs like localized infection, leukocytosis, or hemodynamic instability, then infectious etiologies should be considered.