Tuberculosis

- 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.   



Original Text by Clifford R. Wheeless, III, MD.

Last updated by Data Trace Staff on Friday, December 2, 2016 9:02 am