Canine Space Infection

Canine space infection (infraorbital space) is an infection of the potential space between the levator anguli oris and levator labii superioris muscles, usually from an infected maxillary canine (and sometimes first premolar) whose root is short of the levator anguli oris attachment. Venous connections through the angular vein to the cavernous sinus make it dangerous.

• Mixed oral flora is responsible.
• Risk factors: untreated caries, periapical infection of the canine, diabetes, HIV.

Firm, tender swelling lateral to the nose, obliterating the nasolabial fold, with swelling of the upper lip and lower eyelid, pain, fever and facial erythema.

• Eyelid oedema may close the eye; the tooth is tender and may be non vital.
• Differential diagnosis: periorbital cellulitis, sinusitis, buccal space infection, facial erysipelas, lacrimal sac infection, angioedema, allergic reaction, tumour, nasal furuncle.
• Complications: cavernous sinus thrombosis, orbital cellulitis, brain abscess, meningitis, abscess pointing into the mouth or skin, sepsis.

Clinical with dental and eye assessment.

• Dental radiograph or orthopantomogram; CT with contrast if orbital signs or severe swelling.
• Full blood count, CRP, glucose, blood cultures if febrile; HIV test.
• Examine eye movements, vision and pupils.

Antibiotics with drainage and treatment of the tooth.

• Supportive: analgesia (paracetamol 1 g, ibuprofen 400 mg), hydration, warm compress, head elevation, no squeezing of the face.
• Pharmacological: amoxicillin 500 mg three times daily with metronidazole 400 mg three times daily for 5 to 7 days (or amoxicillin clavulanate 625 mg three times daily; clindamycin 300 mg four times daily if allergic); children, amoxicillin 25 mg/kg/day in three doses with metronidazole 7.5 mg/kg three times daily. Moderate or severe or with eyelid swelling: benzylpenicillin 1.2 to 2.4 g IV every 6 hours with metronidazole 500 mg IV every 8 hours, or ceftriaxone 2 g IV daily with metronidazole. Cavernous sinus thrombosis: ceftriaxone 2 g IV every 12 hours with vancomycin and metronidazole for 3 to 4 weeks with anticoagulation under specialist guidance.
• Procedures: intraoral incision and drainage above the canine tooth through the canine fossa; extraction or endodontic treatment of the canine.
• Special groups: pregnancy, penicillin and metronidazole after the first trimester; children, weight based doses and early admission; diabetes and HIV, IV therapy.
• Red flags: eyelid swelling, proptosis, painful eye movement, headache, drowsiness, rapid spread, nasal tip swelling.
• Follow-up: review at 24 hours; dental treatment after drainage; eye review for any orbital signs.