Diagnosis
Koch's Spine.
Discussion
It is also the commonest form of skeletal tuberculosis with an incidence
of up to 50% of all skeletal tuberculosis. In general it is a disease
of the young adult in the developing countries. In developed countries
it affects more commonly, the elderly. The spinal disease is always secondary
to a primary lesion and occurs due to hematogenous spread. The primary
focus may be active or quiescent and may be in the lungs, mediastinal
lymph nodes, kidneys and other viscera.
Clinically there are four types :
1. Para discal lesion begins in the metaphysis, erodes the cartilage and
destroys the disc, resulting in narrowing of the disc space.
2. Central type begins in the midsection of the body which gets softened
and yields under gravity and muscle action, leading to compression, collapse
and bony deformation.
3. Anterior lesions lead to cortical bone destruction beneath the anterior
longitudinal ligament. Spread of the infection is in the subperiosteal
and sub ligamentous planes resulting in the loss of periosteal blood supply
to the body with resultant collapse. Other factors such as periarteritis
and endarteritis contribute to the collapses.
4. In appendicle type, the infection settles in the pedicles, the laminae,
the articular processes or the spinous processes and causes initial ballooning
of the structure followed by destruction.
Tuberculous spondylitis
commonly occurs in the thoracic, followed by lumbar and cervical spines
which more often occurs in the pediatrics group. With its high resolution,
direct multiplanar imaging, detection of early lesions and also associated
lesions such as abscesses, skip lesions and epi and intradural involvement,
MRI is the obvious choice of investigation. Contrast MRI aids in better
delineation and also in differentiating the lesion from the surrounding
edema. T1 images show decreased signal from the lesion within the 30 days
and narrowing of the disc space and also loss of signal from the nuclear
pulpous. T2 may show increased signal from the involved body and the disc
narrowing with normal decreased or increased signal higher than normally
seen.
Dr
Ashok Raghavan, Manipal Hospital, Bangalore
References
http://www.thamburaj.com/spinal_tuberculosis.htm
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