Bone Tuberculosis Book Review

BONE TUBERCULOSIS

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Cause: Mycobacterium tuberculosis.

Tuberculous osteomyelitis is almost always caused by the hematogenous spread of organism from an active focus of TUBERCULOSIS elsewhere in the body, usually the lungs and occasionally other sites (lympnodes, kidney, and bowel).Infection may occur at any age but it is most commonly seen in children. Most cases present 6 months to 3 years after the initial infection. Any bone may be affected but the most frequent site is the spine- lumber and thoracic vertebra (forming clinical syndrome called Pott’s disease-characterized by a presence of a swelling on the spice).Other sites are the metaphysis of long bones. The infection often begins in the anterior part of the vertebral disc and subsequently involves the anterior part of the adjacent vertebrae. Indeed the infection breaks through intervertebral discs to involve multiple vertebrae and extends into the soft tissues; forming abscess.

The usual presenting feature is a chronic back pain, often with stiffness and limitation of movement. The tuberculous destruction and collapse of the vertebral bodies and discs result in serious deformities (Kyphosis and Kyphoscoliosis) of the spine. In addition, vertebral collapse may compress the spinal cord and nerve roots resulting in pain, muscle spasms,weakness,paralysis and other neurological disorders in structures/organs located below the collapsed/compressed spinal cord segment; urinary incontinency for instant.

Tuberculous exudates may dissect along fascial planes and muscle sheaths and present itself at a more remote area/site as a “Cold abscess”. In Tuberculosis infection normally the exudates spread along the paravertebral muscles and psoas muscle sheath and localize in the inguinal regional, forming “Psoas abscess”.

Microscopic features of TB infection include the presence of epithelioid granulomas (tubercles) with central caseous necrosis and giant cells.

Diagnosis of the infection will rely on the clinical signs and symptoms (presence of swelling on the spine in a patient known to have pulmonary TB) and bacterial culture to isolate the implicating bacteria. However it is taking too long to culture for Mycobacterium species and may take at least 6 weeks to get the result.Th best option then is to take a biopsy and stain the biopsed tissue using Ziehl Nielsen (ZN stain) staining technique. Positive sample will show short, slender red rods indicative of Mycobacterium Tuberculosis.

Therapy for skeletal tuberculosis involves prolonged chemotherapy and in some cases surgical debridement of the affected bone site.