Tuberculous ArthritisDz

Synonyms: TB, consumption, Pott’s disease.

ICD9 Code:  TB arthritis 015.9;  TB spinne (Pott’s disease) 015.00
ICD10 Code:  TB arthritis  A18.2;  TB spine (Pott’s disease) A18.01

Definition: Tuberculous arthritis is a subacute, or occasionally chronic, arthritis secondary to Mycobacterium tuberculosis infection.

Etiology: Tuberculosis spreads from pulmonary sites to peripheral joints hematogenously or via lymphatic channels. Peripheral joints are usually infected by contiguous spread from adjacent tuberculous osteomyelitis. Spinal tuberculosis may originate from contiguous spread from the lungs or via blood or lymphatic routes. Because tuberculosis does not produce collagenase, joint destruction is slower than in bacterial arthritides.

Pathology: Synovial biopsy specimens may stain positively for the tuberculosis bacillus. Histologic findings include synovial proliferation, granulation tissue, and pannus.

Demographics: The prevalence of tuberculosis has declined considerably in the past 50 years, However, between 1985 and 1993, there was a resurgence of multi drug-resistant tuberculosis in the United States associated with the increase in AIDS (with a relative risk for tuberculosis 500 times that of the general population) and an increase in tuberculosis among some ethnic minorities and immigrants from underdeveloped countries. African Americans may be at higher risk of tuberculosis owing to both genetic and socioeconomic factors. Osteoarticular tuberculosis is seen in <5% of all patients with tuberculosis; 4- to 5-month delays in the diagnosis of osteoarticular tuberculosis are common in low-risk populations.

Cardinal Findings: After an insidious onset, the diagnosis of tuberculosis arthritis is often suggested by a chronic monarthritis (less commonly an oligoarthritis). Large weight-bearing joints may be preferentially affected in more endemic areas. Swollen joints may lack other manifestations of inflammation, such as warmth and erythema. Tuberculous spondylitis, or Pott disease, frequently begins in a thoracic disc space. It accounts for ~50% of osteoarticular tuberculosis. Spinal lesions may lead to severe kyphosis owing to vertebral destruction. Pulmonary disease is seldom active at the time of joint manifestations, although the chest radiograph remains abnormal in half of patients. Constitutional symptoms such as fever and weight loss are frequently present at the time of bone or joint disease.

Uncommon Findings: There are rare reports of tenosynovitis and fasciitis. Sacroiliac infection is present in ~7% of patients with skeletal tuberculosis. Poncet’s syndrome describes a reactive polyarthritis of the hands and feet in patients with a current or past tuberculosis infection. Atypical mycobacteria may also cause arthritis or other musculoskeletal manifestations, particularly in patients with HIV infection. There are rare reports of reactive arthritis after intravesical bacille Calmette-Guérin immunotherapy.

Diagnostic Testing: Culture of M. tuberculosis from synovial fluid and/or synovial biopsy is positive in ~90% of cases. An acid-fast smear of synovial fluid alone has a yield of <10%. Improved culture techniques and the use of PCR may detect organisms in a much shorter time. Synovial biopsy demonstrating noncaseating granulomas by histopathology is a less specific diagnostic option. CT-guided needle biopsy of spinal lesions may prove diagnos- tic. Nonspecific synovial fluid findings include neutrophilic pleocytosis (to- tal WBC count is usually 10,000–20,000 cells/mm3), elevated protein, and low synovial fluid glucose (detected in >50% of patients). Some (90%) of people with osteoarticular disease exhibit a positive purified protein derivative test result.

Imaging: Radiographs of peripheral joints with late-stage tuberculous arthritis may reveal destructive arthropathy without significant reactive bone formation.

Keys to Diagnosis: Look for a chronic monarthritis in an at-risk host, with acid-fast bacilli identified on joint fluid culture or synovial biopsy.

Differential Diagnosis: Fungal arthritis, inflammatory OA, and pseudogout should be considered.

Therapy: Multi-drug regimens for osteoarticular tuberculosis are usually the same as those for pulmonary tuberculosis; however, at least 6 to 9 months (3 months beyond negative culture in non-AIDS hosts and 6 months beyond negative cultures in patients with AIDS) of treatment is required. Therapy is usually initiated with isoniazid (5 mg/kg to as much as 300 mg/day), pyrazinamide (15–30 mg/kg to as much as 2 g daily), and rifampin (10 mg/kg to as much as
600 mg orally daily). Pyrazinamide can be discontinued after 8 weeks. If the incidence of multidrug resistance is <4%, it is recommended that ethambutol (5–25 mg/kg) or streptomycin (15 mg/kg) be added until resistances are known. Treatment regimens are dictated by the resistance patterns in the community and the immune status of the host. Surgery may be necessary if extensive bone destruction has occurred or if the spinal cord is compromised in Pott disease.

Prognosis: If there is minimal bone involvement, articular disease is successfully managed with drug therapy alone. Pott’s disease may result in neurologic damage, and in older series, mortality was as high as 20%. More recent reports sug- gest almost 80% resolution of even severe disease with appropriate drug therapy.

BIBLIOGRAPHY

American Thoracic Society, Centers for Disease Control and Prevention. Targeted tuberculin testing and treatment of latent tuberculosis infection.Am J Respir Crit Care Med 2000;161:S221–S247. PMID:10764341

Harrington JT. Mycobacterial and fungal arthritis. Curr Opin Rheumatol 1998;10:335–338. PMID:9725095