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Neuroradiology Case of the Week

Case 117

Clinical Presentation: A 50-year-old female presented with history of neck ache and low-grade fever for two months.

Radiological Findings: Axial T1 weighted post contrast image of the craniocervical junction shows destruction and erosion of atlantoaxial joint with an enhancing soft tissue mass. Small epidural component is seen causing pressure on the thecal sac. Sagittal T1 weighted image of the cervical spine shows destruction of C1 and C2 with a soft tissue mass.

Discussion: Tuberculous spondylitis is a frequent cause of infectious spondylitis in endemic regions and is increasing in prevalence because of the resurgence of tuberculosis during the past decade, especially in patients who are immunocompromised. Tuberculous involvement of the spine has the potential for serious morbidity including permanent neurological deficits and severe deformity. In adults, most occurrences of infectious spondylitis resulting from a hematogenous source (e.g. bacteremia, intravenous drug abuse) begins in lumbar or thoracic vertebral body subjacent to the vertebral endplate by seeding of septic emboli via small, penetrating end arteries. Infection enters the disc space by contiguous involvement and by neurovascular proliferation.
     Pott's disease (Spinal Tuberculosis) is the most dangerous form of musculoskeletal tuberculosis because it can cause bone destruction, deformity and paraplegia. The condition most commonly involves thoracic and lumbosacral spine. Subligamentous spread to three or more vertebral levels is frequently seen.
     Nonpyogenic organisms such as tuberculosis lack proteolytic enzymes this tends to spare the disc. However, these infections are characterized by large paraspinal collections disproportionate to the amount of local bone destruction. Pott's disease is usually secondary to an extra spinal source of infection. Typically, more than one vertebra is involved. The area usually affected is the anterior aspect of vertebral body adjacent to the subchondral plate. Tuberculosis may spread from that area to adjacent intervertebral discs. Progressive bone destruction leads to vertebral collapse and kyphosis. The spinal canal can be narrowed by abscesses, granulation tissue or direct dural invasion. Abscesses in the lumbar region may descent down the sheath of the psoas to the femoral trigone region and eventually erode into the skin. Cervical, thoracic and thoracolumbar involvement is higher than lumbar involvement in patients with tuberculous spondylitis.
      Pott's disease presents with different complications like neurologic deficits, abscesses or sinus tracts. Back pain is the earliest and the most common symptom. Neurologic compression occurs in 50% of the cases and includes spinal cord compression with paraplegia, paresis, and impaired sensation and nerve root pain or cauda equina symptoms. Severe neurologic complications occur in cervical spine tuberculosis. Spine deformity of some degree occurs in almost every patient.

References:

1. Griffith JF, Kumta SM, Leung PC, Cheng JC, Chow LT, Metreweli C. Imaging of musculoskeletal tuberculosis: a new look at an old disease. Clin Orthop 2002; 398:32-39 [Medline]
2. Thrush A, Enzmann D. MR imaging of infectious spondylitis. AJNR 1990; 11:1171-1180 [Medline]
3. Alothman A, Memish ZA, Awada A, et al. Tuberculous spondylitis: analysis of 69 cases from Saudia Arabia. Spine 2001; 26:E565-570 [Medline]
4. Akman S, Sirvanci M, Talu U, Gogus A, Hamzaoglu A. Magnetic resonance imaging of tuberculous spondylitis. Orthopedics 2003; 26:69-73 [Medline].