These prescriptions are continued until the patient is well and then half again as long. They can be administered for 6,12,18 or more weeks. The long-term toxicity and risk of low dose antibiotics is less than even the shortest of general anesthetics. Complications include periorbital infection and brain abscess. Frontal and sphenoid sinusitis also require prompt aggressive treatment and early referral because of their propensity to cause meningitis and brain abscess.
Diagnosis is a clinical one.
Sinus CT without contrast is used to determine operative strategy. The diagnosis of sinusitis is made from the clinical history. The CT is a road map for the endoscopic surgery. If your Utilization Review Committee requires an abnormal CT, order the CT when the patient is ill. If they do not require an abnormal CT, order the sinus CT when the patient is well for this will show the baseline disease.