Sinusitis: What Is It? Diagnosis & Management

The term "sinusitis" has now been officially replaced by "rhinosinusitis" in the Otolaryngology literature. Rhinosinusitis is divided into two main categories: acute (sinus infection lasting less than four weeks) and chronic (sinus infection lasting greater than twelve weeks). Sub-acute rhinosinusitis refers to a sinus infection lasting between four and twelve weeks.

Rhinosinusitis usually begins after obstruction of the sinus drainage pathways secondary to a viral URTI, or some other cause, resulting in stagnation of secretions within the sinus. Bacteria from the nasal cavity invade the mucus filled sinuses if the obstruction does not resolve within a few days. If the infection does not resolve within a few weeks, the mucus membrane will undergo polypoid change causing further obstruction. The flora will gradually change from one of acute sinusitis (S. pneumo, H.influenzae and Moraxella) to one of chronic sinusitis (anaerobes, gram negative enterococci). Once the infection has lasted greater than four weeks, it becomes increasingly difficult to treat because of increasingly resistant bacteria as well as a significant reduction of ciliary activity within the obstructed drainage pathways.

It is therefore imperative to treat an established acute rhinosinusitis aggressively to avoid the development of chronic sinusitis.

Symptoms of rhinosinusitis include facial congestion/fullness, nasal obstruction, nasal discharge / purulence / discoloured PND, hyposmia, purulence, facial pain and pressure. Other symptoms include headache, fatigue, halitosis, dental pain, cough and ear pain.

CT scanning remains the modality of choice and should be obtained in the coronal plane ONLY if medical therapy has failed. It's purpose is NOT to detect acute sinusitis but to reveal underlying chronic pathology. Plain films are the least accurate imaging technique with high false positive and false negative rates.

Treatment for acute rhinosinusitis should include non-medical management i.e. saline irrigation, steaming, increased water intake/hydration. Medical management should include topical or systemic decongestants, antimicrobial and topical nasal steroids. Mometasone (Nasonex) is currently the only nasal steroid indicated for the treatment of acute sinusitis. It reduces the number of basophils and eosinophils in the mucosa and inhibits the late-phase reaction after exposure to allergens. Antimicrobial therapy for acute sinusitis should include amoxicillin-clavulanate or macrolide antibiotics. For chronic rhinosinusitis systemic decongestants, topical nasal steroids and occasionally systemic steroids are used. Antimicrobial therapy should include amoxicillin-clavulanate, clindamycin, cefuroxime and or quinolones. Endoscopically guided culture directed treatment is far superior to empiric therapy for choosing the appropriate antibiotic. Patients with recalcitrant chronic sinusitis non-responsive to medical management should be referred to a sinus centre.