Odontogenic Sinusitis

Odontogenic sinusitis is sinusitis, usually of the maxillary sinus, caused by infection or disease of the upper teeth, or by dental procedures. It is often unilateral and resistant to usual rhinosinusitis treatment.

It accounts for 10% to 40% of unilateral maxillary sinusitis, and is more frequent in those with periapical disease, periodontitis, implant or extraction complications, and root filling material in the sinus. Organisms are mixed, with anaerobes (Prevotella, Fusobacterium, Peptostreptococcus) and streptococci.

Pathophysiology.

The roots of the upper molars lie close to or in the maxillary sinus floor. Infection, oroantral communication or foreign material breaches the sinus floor, and polymicrobial infection causes sinus inflammation and ostial blockage.

Unilateral nasal blockage, foul smelling discharge, cacosmia, facial pain or pressure, and tooth pain or a recent dental procedure. Fever is uncommon.

Red flags.

• Orbital swelling, double vision or visual change.
• Facial swelling or trismus (spreading dental infection).
• Fever with severe headache.
• Oroantral fistula with persistent discharge.

Examination of the teeth and nasal endoscopy. CT of the sinuses (or cone beam CT) shows maxillary sinus opacification with a periapical lesion, bone defect, root canal filling material or implant penetration. Dental radiographs help. Panoramic imaging is limited. Send a swab for culture (aerobic and anaerobic) from the middle meatus.

Differential diagnosis.

• Chronic rhinosinusitis.
• Fungal ball.
• Sinonasal tumour.
• Dentoalveolar abscess without sinus disease.
• Oroantral fistula.
• Trigeminal neuralgia or other facial pain.

Treat both the tooth and the sinus: dental treatment (root canal, extraction, removal of the foreign body, closure of fistula) combined with antibiotics and, if disease persists, endoscopic sinus surgery to clear the maxillary sinus.

• Co-amoxiclav: 625 mg orally three times daily for 7 to 14 days; maximum 1.5 g amoxicillin daily (3 g with high dose regimens); monitor liver tests, diarrhoea and rash; give 625 mg twice daily when creatinine clearance is 10 to 30 mL/min; children 25 mg/kg amoxicillin twice daily.
• Clindamycin (penicillin allergy): 300 to 450 mg orally four times daily for 7 to 14 days; maximum 1.8 g daily; monitor for diarrhoea and Clostridioides difficile infection; no renal adjustment.
• Metronidazole (added when anaerobes are suspected and clindamycin is not used): 400 mg orally three times daily for 7 days; maximum 1.2 g daily; monitor neuropathy; reduce to 400 mg twice daily in severe hepatic impairment.
• Oxymetazoline 0.05% nasal spray: 2 sprays into each nostril every 12 hours for up to 3 days; maximum 3 days of use (rebound congestion); monitor blood pressure; avoid in uncontrolled hypertension.
• Mometasone nasal spray 50 micrograms for each spray: 2 sprays into each nostril once daily for 4 to 8 weeks; maximum 200 micrograms daily in each nostril.

Monitoring. Review at 2 weeks and after dental work; endoscopy at 6 weeks.

Referral and escalation. Dentist or oral and maxillofacial surgeon, and ENT.

Special groups. Diabetes and immunosuppression need early surgery.