Objectives: This study evaluated different symptoms, signs, and blood tests in the diagnostic process of patients with a clinical diagnosis of acute sinusitis.
Methods: A total of 201 primary care patients in southern Norway aged 15 years or older with a clinical diagnosis of acute sinusitis were evaluated. Computed tomography (CT) was used as a reference standard to divide the patients into two groups: one with and one without confirmed sinusitis. Fluid level or total opacification of any sinus on CT were used as hallmarks of confirmed sinusitis. Blood tests that included erythrocyte sedimentation rate (ESR), C-reactive protein, and white blood count were taken. The patients were evaluated in a standardized way for the medical history and the clinical investigation.
Results: A total of 127 (63%) patients had fluid level or total opacification in one or more sinus regions. "Double sickening," purulent rhinorrhoea, purulent secretion in cavum nasi, and ESR > 10 had the highest likelihood ratios and were independently associated with acute sinusitis.
Conclusions: This study confirms the uncertainty of the clinical diagnosis of acute sinusitis in primary care, based on the clinical evaluation alone. Only four symptoms and signs had a high likelihood ratio and were independently associated with acute sinusitis. A combination of at least three of these four symptoms and signs gave a specificity of .81 and a sensitivity of .66.