Acute Bacterial Sinusitis

Acute bacterial sinusitis is bacterial infection of the paranasal sinuses lasting less than 4 weeks, usually following a viral upper respiratory infection or allergic rhinitis. The usual organisms are Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis.

• Only a minority of acute sinusitis is bacterial; most episodes are viral and settle within 10 days.
• Dental root infection is a cause of maxillary sinusitis, and nosocomial sinusitis follows nasal intubation.
• Smoking, allergy, nasal polyps, septal deviation, immunodeficiency and diabetes are risk factors.

Bacterial infection is suggested by symptoms lasting 10 days or more without improvement, severe onset (fever of 39 degrees Celsius or more with purulent discharge and facial pain for 3 to 4 consecutive days), or worsening after initial improvement.

• Purulent nasal discharge, nasal obstruction, facial pain or pressure worse on bending, reduced smell, cough, toothache, and fever.
• Examination may show tenderness over the maxillary or frontal sinus and pus in the middle meatus.
• Differential diagnosis: viral rhinosinusitis, allergic rhinitis, dental abscess, migraine, cluster headache, trigeminal neuralgia, temporal arteritis, nasal foreign body in children, fungal sinusitis, tumour.
• Complications: orbital cellulitis and subperiosteal abscess, cavernous sinus thrombosis, meningitis, brain abscess, frontal bone osteomyelitis (Pott puffy tumour), chronic sinusitis.

Diagnosis is clinical and imaging is not needed for uncomplicated disease.

• CT of the sinuses and orbits for suspected complications, recurrent disease, or failure of two courses of treatment.
• Endoscopic culture of the middle meatus in treatment failure or immunosuppression.
• Blood glucose and HIV test in recurrent or severe infection.

Most patients improve with symptom treatment; antibiotics are given when symptoms last 10 days or more, onset is severe, the illness worsens after initial improvement, or disease is complicated.

• Supportive: saline nasal irrigation, steam inhalation, adequate fluids, rest, sleeping with the head raised, avoid smoking.
• Pharmacological: paracetamol 1 g every 6 hours or ibuprofen 400 mg every 8 hours; mometasone nasal spray 200 micrograms twice daily or fluticasone 2 sprays per nostril daily for up to 3 weeks; oxymetazoline 0.05 percent for no more than 3 days. Antibiotics: amoxicillin 500 mg three times daily (or 1 g twice daily) for 5 to 7 days, children 45 mg/kg/day in two divided doses (80 to 90 mg/kg/day in high resistance settings); amoxicillin clavulanate 625 mg three times daily if there is no response in 72 hours; doxycycline 100 mg twice daily in penicillin allergy (adults only). Severe or complicated disease: ceftriaxone 2 g IV daily with metronidazole 500 mg IV every 8 hours.
• Procedures: antral washout or endoscopic drainage for failure of medical therapy or complications; drainage of subperiosteal or intracranial collections.
• Special groups: pregnancy, amoxicillin and saline irrigation, avoid doxycycline and decongestant tablets; children, weight based dosing and early review for periorbital swelling; diabetes and HIV, lower threshold for antibiotics and admission.
• Red flags: periorbital swelling, proptosis, double vision, reduced vision, severe headache, neck stiffness, altered consciousness, forehead swelling.
• Follow-up: review in 48 to 72 hours if no improvement; refer to ENT if more than 4 episodes in a year or symptoms beyond 12 weeks.