tuberculous arthropathy

Tuberculous arthropathy is a type of musculoskeletal manifestation of tuberculosis (TB) and a common cause of infectious arthritis in developing countries. Any pathological joint lesion where the exact diagnosis is equivocal should be considered tubercular in origin unless proven otherwise.

Please, refer to the main article on tuberculosis for a general and broad discussion of this condition.

Epidemiology

Although rare in western countries, tuberculous arthropathy is still a common problem in developing countries. The tubercular arthropathy is never a primary lesion, it is always a sequela of pulmonary or lymph node tuberculosis. It can occur at any age. There is no sex predilection for the disease.

Pathology

The primary causative organism is mycobacterium tuberculosis, however atypical mycobacteria i.e. Mycobacterium kansasii,  M. xenopi and M. avium intracellulare are also isolated in immunocompromised individuals.

The organism reaches the bone and remains dormant until recrudescence occurs. Any factor which modifies the state of local resistance and resultant activation of dormant tubercle bacilli, microtrauma has been proposed as a mechanism, however no case could it be established that trauma was an etiological factor.

Location

The most common form of articular tuberculosis is spondylitis followed by arthritis of weight bearing joints (especially knee and hip ). The spine is the most common site followed by the hip joint which constitutes approximately 15% of all cases.

Tubercular arthropathy can affect any joint but frequently reported in knee, ankle, sacroiliac joint, sternaoclavicular joint, shoulder, elbow and wrist. Tubercular arthropathy is usually monoarticular.

Several variants of tuberculosis in the shoulder have been described and are discussed separately in the article shoulder tubercular arthropathy.

Laboratory investigation

Initial acid-fast bacilli smears are often negative and synovial culture is positive in ~80% of cases .

Radiographic features

Plain radiograph

Plain films are reliable to detect and follow up of treatment for tubercular arthropathy. A triad of radiologic abnormalities (Phemister's triad) include:

• peri-articular osteoporosis
• peripherally located osseous erosion
• gradual diminution of the joint space

By radiological features, tubercular arthropathy can be divided into early and late stages:

• early stages (stage of synovitis and arthritis) - radiographic features include
  • periarticular demineralization
  • joint space widening (due to joint effusion)
  • mild subchondral erosion
• late stages (stage of erosion and destruction)
  • gradual narrowing of joint space (there is involvement of articular cartilage)
  • severe subchondral erosion and destruction
  • pathological subluxation and dislocation
  • fibrous ankylosis - in contrast to pyogenic arthritis, the development of bone ankylosis is uncommon in tuberculous arthritis and, when present, is more likely to be secondary to prior surgical intervention
  • atrophic changes in bones may occur and lead to atrophic arthropathy (seen in shoulder joint as carries sicca)             

Ultrasound

Joint effusion may be the only finding but is non-specific.

CT

CT can establish the degree of bone destruction or rarely sequestrum. Extension of infection in surroundings or any sinus tract formation can also be demonstrated on the post-contrast scan.

MRI

The lesions are typically:

• T1: hyperintense
• T2: hypointense
• T1 C+ (Gd): brilliant enhancement

This may be as a result of  presence of blood degradation products, inflammation, necrosis and fibrosis which is seldomly seen in other proliferative arthropathies.

MRI can assess associated abnormalities (e.g. osteomyelitis, myositis, cellulitis, para-articular abscess, tenosynovitis, bursitis, skin ulceration or sinus tract formation):

• sinus tracts appear linear T2 hyperintensity with marginal ‘tram-track enhancement’
• para-articular abscesses have thin, smooth and enhancing wall

Treatment and prognosis

Complete course of chemotherapy is the most important therapeutic approach. In advanced cases surgical treatment can be indicated if the deformity is limiting.

Differential diagnosis

Differential diagnosis of tubercular arthropathy may include causes of erosive arthritis, monoarticular arthropathy and arthropathies resulting in ankylosis and joint destruction such as:

• rheumatoid arthritis; synovial thickening is more uniform and bone erosions are much larger with defined rim enhancement in tuberculous arthritis also extraarticular cystic masses are more frequent and more numerous
  • symmetrical polyarticular distribution
• septic arthritis
• ankylosing spondylitis
• osteoarthritis
• synovial osteochondromatosis
• pigmented villonodular synovitis
• gout
• haemophilic arthropathy

Siehe auch:

• Rheumatoide Arthritis
• Juvenile idiopathische Arthritis
• Arthritis
• muskuloskelettale Tuberkulose
• chronic pyogenic arthritis
• Phemister triad

und weiter:

• Rice bodies (musculoskeletal)
• rice bodies rheumatoide Arthritis
• differential diagnosis of epiphyseal overgrowth
• tuberculous arthritis of the knee