TMJ Septic Arthritis

Temporomandibular joint septic arthritis is infection of the joint space by bacteria, with a risk of rapid cartilage and bone destruction, ankylosis and spread to the skull base. It is rare but serious.

Infection arises by the blood (Staphylococcus aureus, streptococci, Neisseria gonorrhoeae), by spread from adjacent sites (otitis media, parotitis, odontogenic infection, mastoiditis), by injection or arthrocentesis, and after trauma or surgery. Risk factors include rheumatoid arthritis, diabetes, immunosuppression, intravenous drug use, previous joint disease and prostheses.

Pathophysiology. Bacteria enter the synovial space and trigger intense inflammation with neutrophil infiltration and release of proteolytic enzymes, leading to rapid cartilage breakdown.

Pus raises intra-articular pressure and causes effusion, with pain and displacement of the condyle, so the bite changes. In children, the growth centre can be damaged, leading to later deformity and ankylosis.

Acute pain in front of the ear, swelling and warmth over the joint, restricted opening or trismus, fever, and an altered bite with the jaw displaced away from the affected side (a posterior open bite on the affected side from the effusion). Pain on any movement is severe.

Neonates and infants present with irritability and refusal to feed. Look for features of a source: ear discharge, parotid swelling, dental infection, recent injection, or a sexually transmitted infection with skin lesions and tenosynovitis.

Sepsis, neck stiffness, headache, cranial nerve signs and extension to the skull base need emergency admission.

• Joint aspiration under sterile conditions: Gram stain, culture, cell count (usually over 50 000 white cells/mm3, with neutrophils), and crystals. Culture before antibiotics.
• Bloods: full blood count, C-reactive protein, ESR, and blood cultures. Urethral, cervical and pharyngeal swabs or nucleic acid tests for gonococcus and chlamydia when risk exists.
• MRI of the joint: effusion, synovial enhancement, bone marrow oedema and soft tissue abscess. CT for bone destruction and for the skull base.
• Panoramic radiograph is normal in early disease.
• HIV, glucose and immunological assessment as indicated.

Differential diagnosis.

• Inflammatory arthritis flare (rheumatoid, juvenile idiopathic arthritis)
• Crystal arthritis (gout, pseudogout)
• Haemarthrosis after trauma
• Otitis externa or media, mastoiditis and parotitis
• Osteomyelitis of the mandible or skull base
• Fracture of the condyle
• Tumour of the joint

• Urgent drainage: joint aspiration and lavage (arthrocentesis with 100 to 300 mL of sterile saline), repeated if needed, or arthroscopic or open drainage and debridement for failed or complicated cases. Early drainage reduces cartilage damage.
• Empirical intravenous antibiotics immediately after cultures:
  • Flucloxacillin 2 g intravenously every 6 hours, or cefazolin 2 g intravenously every 8 hours (reduce to 2 g every 12 hours at eGFR 10 to 30).
  • When methicillin resistant Staphylococcus aureus is likely or in severe penicillin allergy: vancomycin 15 to 20 mg/kg intravenously every 8 to 12 hours, adjusted to trough levels (15 to 20 mg/L in severe infection) and renal function.
  • Suspected gonococcal infection: ceftriaxone 1 g intravenously once daily, with azithromycin 1 g orally once (or doxycycline 100 mg twice daily for 7 days when chlamydia is covered), with partner treatment and testing for other infections.
  • Add metronidazole 500 mg intravenously every 8 hours for suspected odontogenic or anaerobic infection.
• Duration: intravenous therapy for 2 to 3 weeks, with a switch to oral therapy directed by cultures and the clinical response, for a total of 4 to 6 weeks. Longer when osteomyelitis is present.
• Analgesia: paracetamol 1 g every 6 hours (maximum 4 g daily) and ibuprofen 400 mg every 8 hours with food when renal function allows. Rest and a soft diet, with gentle physiotherapy once the infection is controlled to prevent ankylosis.
• Treat the source: ear, parotid and dental infection, and diabetes control.
• Late complications: ankylosis, condylar destruction, growth disturbance and chronic osteomyelitis, needing reconstruction.

Special groups. Children need weight based dosing and paediatric orthopaedic or maxillofacial care. Immunosuppressed patients need a broader empirical cover with infectious disease advice.

Monitoring. Daily temperature, pain, opening range and C-reactive protein. Repeat MRI or CT if there is no improvement within 48 to 72 hours. Monitor vancomycin levels and renal function. Review at 4 to 6 weeks for opening range and function.

Referral and escalation. Immediate referral to oral and maxillofacial surgery and infectious diseases. Emergency escalation for sepsis, intracranial spread or cranial nerve signs.