Tuberculous osteomyelitis

Tuberculous osteomyelitis is rare and occurs following haematogenous spread from the primary focus in the lung or in the gut. In the spine it is usual for two adjacent vertebral bodies to be involved (Pott’s disease). The vertebrae collapse but the posterior structures remain intact, so the spine angulates into a kyphos. An abscess forms, which may put pres­sure on to the spinal cord or the nerve roots, but which also tracks forward in the prevertebral space. From there it follows fascia, and in the case of low thoracic or lumbar tuber­culosis may follow the psoas muscle from its original origin to its insertion in the lesser trochanter of the femur. There    the pus may track through the subcutaneous fat and discharge through the skin. There is little inflammation because the abscess cavity is remote from the point of discharge so it is a ‘cold’ abscess.

In the developed world, tuberculosis is again on the increase in patients who are immunocompromised either because of diseases such as acquired immunnodeflciency syndrome (AIDS) or because they have been immunosuppressed. The organism is becoming increasingly resistant to standard antibiotics such as rifampicin. The failure of some patients, such as drug addicts, to comply fully with the treatment regime, further increases the risk of spread of antibiotic-resistant tuberculosis.