From the Guidelines
Fever in the first 7 days after surgery is most likely caused by wound infections, atelectasis, urinary tract infections, deep vein thrombosis, pulmonary embolism, pneumonia, medication reactions, anastomotic leaks, or C. difficile colitis, with the specific cause often related to the timing and clinical presentation of the fever. The timing of the fever can provide clues to the underlying cause, with atelectasis and non-infectious causes being more common in the first 24-48 hours, and wound infections typically appearing 3-5 days post-op 1. Urinary tract infections often develop 2-4 days after surgery, especially in catheterized patients, while deep vein thrombosis and pulmonary embolism can cause fever throughout the first week, accompanied by leg pain or respiratory symptoms 1. Pneumonia typically develops 3-5 days post-op, particularly in patients with prolonged immobility or intubation, and medication reactions can occur at any time 1. Less common causes of fever in the post-operative period include anastomotic leaks after bowel surgery, presenting 5-7 days post-op with abdominal pain and peritoneal signs, and C. difficile colitis in patients receiving antibiotics, causing diarrhea and fever 3-7 days after surgery. Some key points to consider when evaluating post-operative fever include:
- Atelectasis is a common cause of fever in the first 24-48 hours after surgery
- Wound infections are rare in the first few days after operation, except for group A streptococcal infections and clostridial infections
- Urinary tract infections are common post-operatively, especially in catheterized patients
- Deep vein thrombosis and pulmonary embolism can cause fever throughout the first week
- Pneumonia typically develops 3-5 days post-op, particularly in patients with prolonged immobility or intubation
- Medication reactions can occur at any time
- Evaluation should include a thorough physical examination, laboratory tests, and imaging studies based on suspected causes, with treatment directed at the underlying etiology 1. It is essential to approach the evaluation of post-operative fever in a systematic and thorough manner, considering the timing, clinical presentation, and potential causes of the fever, and to direct treatment at the underlying etiology to optimize patient outcomes and minimize morbidity and mortality.
From the Research
Causes of Post-Operative Fever
The causes of post-operative fever can be divided into infectious and non-infectious categories.
- Infectious causes include:
- Ventilator-associated pneumonia
- Catheter-associated urinary infection
- Catheter-related bloodstream infection
- Bacteremia
- Surgical site infection
- Intra-abdominal infection
- Ventriculitis
- Necrotizing soft tissue infection 2
- Non-infectious causes can include a normal inflammatory response to surgery 3
Evaluation of Post-Operative Fever
The evaluation of post-operative fever is crucial to determine its cause.
- A brief bedside evaluation has the highest yield for determining the fever etiology 4
- Extensive evaluations with cultures and chest imaging have little to no benefit in patients admitted for elective surgery 4
- The role of the healthcare provider in managing surgical patients requires being able to accurately assess and evaluate the cause of post-operative fever and take action accordingly 3
Timing and Duration of Post-Operative Fever
The timing and duration of post-operative fever can provide clues to its cause.
- New or continuing fever more than three days after surgery should raise a strong suspicion of persistent illness or a new complication 5
- Early post-operative fever is a common event and rarely caused by an infection 4
- Post-procedure fevers vary in the timing of their occurrence, duration, and severity 6