Sinusitis and fever of unknown origin.

Fever without a diagnosis continues to perplex the modern clinician. The differential diagnosis of fever is one of the most extensive in all of medicine. More than 200 conditions affecting all body organs and systems have been identified as causes of fever. Patients in the ICU are often intubated because of limited mental status and may have limited airway protective mechanisms. These patients cannot communicate their symptoms, leaving the clinician without an essential part of the history of the disease for which they are evaluating the patient. The search for the source of a fever in these patients can be extremely difficult and frustrating for the clinician. Like the police captain in the movie ‘‘Casablanca,’’ the clinician must round up the usual suspects, one of which is sinusitis. The diagnosis of acute bacterial rhinosinusitis continues to generate controversy in critically ill patients. Some of the controversy stems from the lack of a definition of this disease, the lack of a uniform diagnostic test, disagreement about which surgical or medical intervention should be instituted, and uncertainty about the origins of the disease. This article reviews sinusitis as a cause of fever in the critically ill patient.