- Discussion:
- although the disease is generally more likely to be chronic, acute mycobacterial arthritis has been reported;
- periarticular bone lesions may accompany the synovial involvement;
- pulmonary tuberculosis is evident in only half the patients with skeletal involvement;
- pulmonary TB signs vary with stage of dz, few early on;
- later high fever, wt loss, prolonged, productive cough, anemia, high count of acid-fast in sputum;
- note the high prevalence of HIV in tuberculosis patients and vice versa (5-10% of HIV patients will have TB);
- tuberculous spondylitis:
- ref: Images in Clinical Medicine. Pott's Disease of the Thoracic Spine
- appendicular involvement:
- look for metaphyseal lytic lesions with little or no sclerosis, and no periosteal reaction;
- juxta-articular / joint involvement:
- hips and knees are affected most frequently;
- may present as gradually worsening arthritis but is often mistaken for some other form of arthritis (such as "mono-articular rheumatoid arthritis" or PVNS);
- peri-articular osteopenia is common;
- unlike most forms of arthritis, TB joint involvement is most often mono-articular;
- note that in TB arthropathy, the joint space will often be maintained (unlike RA);
- phalangeal tuberculous osteitis:
- look for soft tissue swelling, cortical thinning, medullary destruction, and periosteal
reaction involving the middle and distal phalanx;
- diff dx:
- transient phalangeal osteolysis:
- Myobacterium marinum:
- reference:
- Tuberculosis of the hand and wrist.
- Lytic lesions of distal radius in children: a rare tubercular presentation.

- Protection of Health Care Personel:
- historically transmission rate has been high;
- in the past, when strict prevention measures were not manditory, there have been some reports of nearly half of health care
students becoming PPD positive after 1 year;
- patients known or suspected to be infected need to wear a HEPA mask and need to be placed in respiratory isolation;
- respiratory isolation should include a room w/ special ventilation, optimally with HEPA filters;
- elective surgery on actively infected patients should be delayed until the disease is treated and enters a latent phase;

- Skin Testing:
- in the U.S. about 10-15% of the population will have positive test;
- patients who have been given the bacille Calmette Guerin vaccine will have positive tests;
- w/ infection, skin tests are usually, but not always, positive;
- false negative tests will occur in malnourished patients and AIDS patients;
- skin testing in a patient w/ an active infection may result in skin slough;

- Laboratory Diagnosis:
- bacterium is a thin rod w/ rounded ends;
- classic histologic pattern reveals central necrotic area surrounded by histiocytes and occasional giant cells with nuclei
positioned at the margin of the cell;
- Ziehl-Neelsen Staining Method:
- note potential false negative results are a frequent occurance;
- tuberculum is acid fast (resist decolorization w/ acids)
- diff dx: Myobacterium marinum:
- Culture:
- requires use of enriched medium and adequate oxygenation;
- cultures visible at 2-4 weeks;
- note that joint aspiration may not produce positive culture, and w/ suspected joint infection, a synovial biopsy may be required;

- Medical Treatment of Tuberculosis Infection:
- preventive therapy:
- preventive therapy with insoniazid given for 6-12 months is effective in decreasing the risk of future tuberculosis;
- persons for whom preventitive therapy is indicated include: household members and other close contacts of potentially
infectious persons;
- newly infected persons; persons with past tuberculosis or with a significant tuberculin reaction and abnormal chest films in
whom current TB has been excluded;
- infected persons in special clinical situations such as sillicosis, diabetes mellitus, adrenocorticosteroid therapy;
- persons at high risk of developing severe forms of tuberculosis, if infected due to contact w/ a person having INH resistant
organisms, should be treated with rifampin rather than INH;
- acute infection:
- isoniazid, rifampin, and pyrazinamide (20-25 mg / kg / day) given for 2 months, after which time isoniazid and rifampin for 4
months is effective treatment in patients with fully susceptible organisms who comply with the treatment regimen;
- 9 month regimen consisting of isoniazid and rifampin is also highly successful;
- need for additional drug in initial phase is not certain unless isoniazid resistance is suspected;
- w/ suspected INH resistance, consider the addition of ethambutol in initial phase;
- children should be treated in essentially the same way as adults using appropriately adjusted doses of the drugs;
- dormant infection:
- rifampin (10 mg/kg/day) and pyrazinamide are most effective

References

Tuberculous spondylitis in adults

Spinal tuberculosis in a developed country. A review of 26 cases with special emphasis on abscesses and neurologic complications.

Progressive kyphosis following solid anterior spine fusion in children with tuberculosis of the spine. A long-term study.

Controlled trial of short-course regimens of chemotherapy in the ambulatory treatment of spinal tuberculosis. Results at three years of a study in Korea. Twelfth report of the Medical Research Council Working Party on Tuberculosis of the Spine.

Imaging in children with spinal tuberculosis. A comparison of radiography, computed tomography and magnetic resonance imaging.

Comparison of tuberculous and pyogenic spondylitis. An analysis of 122 cases.

Cytological Diagnosis of Vertebral Tuberculosis with Fine-Needle Aspiration Biopsy.

Radiology of skeletal tuberculosis.