Tuberculous Arthritis

Tuberculous arthritis is infection of a synovial joint by Mycobacterium tuberculosis, usually by haematogenous spread from a pulmonary or distant focus, with the hip and knee most often affected. It accounts for 1 to 3 percent of tuberculosis and is more common in HIV, diabetes and in children.

• Slow, indolent course (months to years) with delayed diagnosis.
• Frequently accompanied by adjacent osteomyelitis.

Chronic monoarticular pain, swelling, stiffness and limp, with night pain and limited movement; low grade fever, weight loss and night sweats in some.

• Cold abscess, sinus formation, muscle wasting, flexion deformity, and joint destruction later.
• Differential diagnosis: pyogenic arthritis, brucellar arthritis, rheumatoid arthritis, gout, pigmented villonodular synovitis, osteoarthritis, sarcoidosis, fungal arthritis, Charcot joint, non tuberculous mycobacterial infection, tumour.
• Complications: articular destruction and ankylosis, pathological dislocation, limb shortening, chronic sinus with secondary infection, spinal involvement, amyloidosis.

Obtain synovial fluid or tissue.

• Synovial fluid: inflammatory, lymphocytes, low glucose; Xpert MTB/RIF Ultra, acid fast stain and culture with drug susceptibility testing.
• Synovial biopsy (needle or arthroscopic) with histology (caseating granuloma) and culture, the most sensitive test.
• Plain radiograph (periarticular osteopenia, marginal erosions, preserved joint space early then narrowing); MRI for synovial thickening, effusion, abscess and bone involvement; chest radiograph and sputum Xpert.
• HIV test, CD4, ESR, CRP, glucose.

Prolonged antituberculous therapy with joint rest and surgery for destruction.

• Supportive: rest and splinting in the functional position, traction for painful joint, analgesia (paracetamol 1 g four times daily, ibuprofen 400 mg three times daily), nutrition, physiotherapy after pain settles, avoid weight bearing until improved.
• Pharmacological: 2 months of isoniazid, rifampicin, pyrazinamide and ethambutol followed by 10 months of isoniazid and rifampicin (12 months total); daily doses isoniazid 5 mg/kg (maximum 300 mg), rifampicin 10 mg/kg (maximum 600 mg), pyrazinamide 25 mg/kg, ethambutol 15 mg/kg; pyridoxine 25 to 50 mg daily. Children: isoniazid 10 mg/kg, rifampicin 15 mg/kg, pyrazinamide 35 mg/kg, ethambutol 20 mg/kg. HIV: antiretroviral therapy within 2 weeks if CD4 is under 50 and within 8 weeks otherwise, with dolutegravir 50 mg twice daily during rifampicin; cotrimoxazole 960 mg daily.
• Procedures: aspiration of abscess; synovectomy and debridement for persistent disease; arthrodesis, excision arthroplasty or total joint replacement (after 12 months of quiescent disease) for destroyed joints.
• Special groups: pregnancy, first line regimen with pyridoxine; children, weight band dosing and orthopaedic review; HIV, monitor for immune reconstitution inflammatory syndrome; liver disease, specialist modified regimen.
• Red flags: rapidly increasing pain, fever, sinus with pus, neurological deficit from adjacent spine, loss of joint movement, no response at 3 months.
• Follow-up: monthly review for function and inflammatory markers; radiograph or MRI at 3 and 12 months; long term follow-up for deformity.