Criteria used by clinicians to differentiate sinusitis from viral upper respiratory tract infection

Acute sinusitis and upper respiratory tract infections (URIs) share many common symptoms and signs. Objective criteria have been identified that are valid for distinguishing between these two clinical problems. The objective of this study was to determine how often clinicians use these validated criteria and how often they rely on clinical cues that are less valuable for differentiating sinusitis from URI.

We performed a retrospective review of 734 patients with a diagnosis of acute sinusitis (n = 367) or URI (n = 367) at a family practice residency training site over a 3-year period. Charts were reviewed to ascertain patient demographics, past history, current symptoms, physical findings, and treatment prescribed.

Patients with sinusitis were likely to be older, female, smokers, have a history of allergic rhinitis, and have longer symptom durations. Complaints of sinus pressure or discolored nasal discharge and the finding of sinus tenderness were strongly associated with the diagnosis of sinusitis. In multivariate analysis, eight factors were independently associated with the diagnosis of sinusitis. Four clinical cues alone (sinus tenderness, sinus pressure, postnasal drainage, and discolored nasal discharge) were highly associated with the diagnosis of sinusitis and explained 60% of the variation in the diagnosis between sinusitis and URI.

Physicians tend to rely on four factors to differentiate sinusitis from URIs. Only one of these has been shown to be a reliable predictor of acute sinusitis. This use of unreliable criteria may lead to misdiagnoses and inappropriate prescriptions for antibiotics.