Skeletal tuberculosis in children.

The objective of this review is to present the imaging findings of skeletal tuberculosis in children. The incidence of tuberculosis is increasing and skeletal tuberculosis accounts for 10-20% of all extra-pulmonary cases. The most common manifestations of skeletal tuberculosis in children are spondylitis, arthritis and osteomyelitis. Tuberculous spondylitis involves the intervertebral disc only late in the disease. Subligamentous spread of the infection may lead to multiple levels of vertebral body involvement that may either be continuous or skipped. Extension of the disease into the paravertebral or extra-dural space may occur. Tuberculous arthritis usually occurs as a result of metaphyseal spread to the joint. Tuberculous osteomyelitis may appear as cystic, well-defined lesions, infiltrative lesions or spina ventosa. The latter is a term used to describe a form of tuberculous osteomyelitis where underlying bone destruction, overlying periosteal reaction and fusiform expansion of the bone results in cyst-like cavities with diaphyseal expansion. Radiographs are still the mainstay of evaluation of patients with bony lesions. Ultrasonography can detect soft-tissue extension of the bony lesions and guide drainage or biopsy procedures. CT accurately demonstrates bony sclerosis and destruction, especially in areas difficult to assess on radiographs such as the posterior elements of the vertebral body. MRI is the modality of choice in evaluating early marrow involvement and soft-tissue extension of the lesion.