DEFINITION Chronic sinusitis refers to inflammation the paranasal sinuses for a period of at least 12 weeks. The most important cause of chronic sinusitis is failure of acute infections to resolve. PATHOPHYSIOLOGY Acute infection destroys the normal ciliated epithelium, thus impairing drainage from the sinuses. There is pooling and stagnation of secretions in the sinuses which favours infections. Persistence of infection causes mucosal changes, such as loss of cilia, edema and polyp formation. We eventually have a vicious cycle. CLINICAL FEATURES Patients may complain of blocked nose, runny nose, headache and a reduced sense of smell (hyposmia). Foul-smelling discharge suggests anaerobic infection. Some people will also have nasal polyps. TREATMENT 1) We should always search for underlying aetiological factors which obstruct sinus drainage and ventilation. 2) A work-up for nasal allergy may be required. 3) Culture and se...