Diagnosis of chronic sinusitis is based on medical history, radiological studies, endoscopy, a physical exam and laboratory tests. Chronic sinus disease should be considered if there is persistent unexplained nasal congestion or post nasal drip. A prior history of a short lived response to antibiotics with a subsequent recurrence of symptoms also suggests chronic sinusitis. It is possible that you may present with a relatively normal physical exam. However you are more likely to have evidence of nasal congestion, turbinate swelling, nasal crusting (dried mucus) and/or post nasal drip present.
A nasopharyngolaryngoscopic examination greatly helps assess whether there is a thickened mucous discharge draining from the sinus openings or blockage of the osteomeatal complex.
Sinus Imaging for Chronic Sinusitis
As with acute sinus disease, CT scans help assess chronic sinus disease. They can also track response to antibiotic therapy. CT scans also provide a roadmap for surgery. Special video assisted CT scans may be helpful in increasing the precision of surgical procedures. CT scans are usually performed without radiocontrast material (dye). However if complications around the eye, brain, or facial bones are suspected, a dye study may be helpful.
Magnetic Resonance Imaging (MRI) is not as useful as a CT of the sinuses, but it may be of particular benefit in some unusual cases of chronic sinusitis. Specifically an MRI may be important for assessing fungal sinusitis. Both viral and bacterial infections in the sinuses produce a certain signal intensity shown by MRI. In contrast, fungal infections have a low signal or no signal at all. This difference can help identify fungal sinus disease. Unlike CTs, MRIs are unable to clearly identify bone. Therefore MRI does not provide accurate landmarks for surgery or for assessing bony changes.