Discussion
This patient had a final diagnosis of an epidural abscess secondary to tuberculous spondylitis (also known as "Pott disease" or "spinal tuberculosis"). The lumbar plain-film radiographs revealed a compression fracture of the T11 vertebra (Figure 1). A subsequent MRI (Figure 2; sagittal T2-weighted image) revealed severe pathologic compression fractures, multilevel osteomyelitis, and an epidural abscess extending from T10 to T12. Although increased disk signal was noted, particularly in the T10-T11 disk space, the signal was also present at uninvolved levels; this finding was believed to be secondary to normal hydration, because enhancement consistent with diskitis was not demonstrated in contrast-enhanced images (not available) of the involved disk spaces. These radiologic findings suggested tuberculous spondylitis, which was definitively diagnosed after cultures revealed pansusceptible Mycobacterium tuberculosis.
Figure 1.
Figure 2.
Tuberculous spondylitis results from hematogenous spread of M tuberculosis. Percival Pott first described spinal tuberculosis in 1779; however, evidence of the disease can be seen in ancient mummies from Egypt and Peru. Although rare in industrialized countries, this disease continues to be seen in developing countries.
Tuberculosis is the world's deadliest infection. Because humans are the only carriers of M tuberculosis, eradication is possible, but tuberculosis control programs have had varied success; not surprisingly, some of the more successful countries include the United States and other industrialized nations. It is particularly important to consider the diagnosis when examining patients from Southeast Asia, India, China, and other endemic regions.
Tuberculous spondylitis is seen in approximately 8%-9% of cases of extrapulmonary tuberculosis. The vertebral bodies of the spine are susceptible to seeding from tuberculosis because of high blood flow throughout adulthood. The distribution of the vertebral blood supply also allows multiple adjacent vertebrae to be affected.
Pott disease is more commonly associated with late reactivation of tuberculosis than with primary infection. In the United States, Pott disease primarily occurs in adults and most commonly affects the lower thoracic and lumbar regions. In approximately 10% of cases, the cervical region is affected. Cervical and upper thoracic involvement is potentially more disabling[1] and can present with dysphagia, stridor, torticollis, hoarseness, and other neurologic deficits.
In tuberculous spondylitis, the infection leads to inflammatory bone destruction and caseating necrosis within the vertebral body.[2] It then spreads via the anterior/posterior longitudinal ligaments to adjacent vertebral bodies; typically, two or more contiguous vertebrae are involved (which is unlike the bony lesions seen in most cancers). This destruction can cause collapse of the vertebral bodies, producing spinal instability, spinal cord compression, and herniation of the disk. Involvement of the anterior and lateral portions of the vertebral body typically causes vertebral collapse, with kyphosis and gibbous deformity; cavitation and extradural masses more often result when the posterior vertebral body is affected.
A tuberculous abscess in the epidural region can also compress the spinal cord, frequently causing bilateral symptoms. Abscess formation or bony destruction may cause serious morbidity and permanent neurologic deficits. Uncommonly, cervical involvement can result in extension of disease into the neck or retropharynx. Lumbar disease can similarly track along fascial planes and form calcifications within psoas abscesses or extradural abscesses[3]; this finding is nearly pathognomonic for tuberculous infection.
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Cite this: Tami O Tiamfook-Morgan, Daniel M. Lindberg. A 39-Year-Old Man With Debilitating Back Pain - Medscape - Apr 27, 2016.
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