Techniques for evaluating fever in the ICU. A stepwise approach for detecting infectious and noninfectious causes.

The initial work-up of a critically ill patient with fever begins with a hunt for an infectious cause. A positive urine culture, or the presence of dysuria or suprapubic tenderness, suggests urinary tract infection. Diagnosing pneumonia in ventilated patients is particularly difficult; CT may be helpful when chest films are hard to interpret. Blood cultures can rule out septicemia. Other common causes of fever in the ICU include abdominal abscesses and catheter-related infections; atelectasis has not been shown to cause fever. If the initial work-up fails to establish a cause of postoperative fever, and the fever resolves within 4 days, no further work-up is required.