Tuberculosis Study Guide - M.M. Savula 2002

Extrapulmonary tuberculosis
Bone and joint tuberculosis

Among Extrapulmonary tuberculosis cases, Bone and joint Tuberculosis accounts for 35.5%. Tuberculous involvement of the spine is most frequently observed (40%), with Tuberculosis of the Hip and knee joints ranking second and third, respectively. Other Bones and joints are affected less frequently.

Pathogenesis. Tuberculous lesions of bones and joints occur most commonly in children and adolescents As a result of hematogenous dissemination of MTB from a primary focus in the Lymph Nodes, and in adults during late generalization due to the reactivation of old, seemingly healed foci. Predisposing factors may include past childhood infections, trauma, hypothermia, poor Nutrition, etc.

Pathogenesis and Clinical presentation. Three phases of bone and joint tuberculosis development are distinguished:

1. Pre-arthritic, pre-spondylitic, or primary osteitis phase. Tuberculous involvement begins in the metaphyses and epiphyses of long bones or in the vertebral body. Tuberculous granulations develop, replacing Bone tissue in a specific area. The process spreads through the Haversian canals to the compact bone layer, causing its destruction. This results in The formation of a sequestrum, which abuts the joint with a wide base in the case of long bone involvement, and the periosteum in the case of vertebral involvement. In this stage of the disease, which sometimes lasts for several weeks or months, clinical symptoms are mild. Mild signs of intoxication may occur, including general weakness, sweating, decreased appetite, and occasional low-grade fever.

2. The arthritic or spondylitic phase begins with the spread of the process to the synovial membrane and articular surfaces of the joint, or adjacent vertebrae (Fig. 24 - see Appendix). In this phase, In addition to worsening systemic symptoms, local symptoms depending on the localization of the tuberculous process are clearly pronounced: pain, functional impairment, soft tissue Swelling, joint deformity, Muscle guarding, and muscle atrophy. The process can spread to adjacent Tissues, forming cold abscesses and fistulas. A complication of chronic bone and joint tuberculosis can be Amyloidosis of internal Organs.

3. In the post-arthritic or post-spondylitic phase, the process stabilizes and symptoms of intoxication disappear, but skeletal deformities remain, along with fibrous and, subsequently, bony ankylosis of the joint.

Diagnosis. To establish a diagnosis, key factors include a history of gradual disease onset, mild signs of intoxication, contact with a tuberculosis patient, recent tuberculin conversion, or strongly positive tuberculin Skin tests. X-ray and tomographic (including computed tomography and Magnetic Resonance imaging) examinations of bones and joints are crucial, revealing increased bone porosity (Osteoporosis), joint space narrowing, destruction of the articular ends of bones, destruction and flattening of vertebral bodies, and shadows of cold abscesses. Diagnosis is simplified if other sites of tuberculosis (Lungs, lymph nodes, etc.) are detected. The Etiology of bone and joint involvement is confirmed by detecting MTB in joint aspirate or fistula discharge. If the diagnosis remains unclear, histological examination of biopsy specimens from the affected tissue is performed.