TO THE EDITOR:
With reference to "Current Concepts Review. Tuberculosis of Bones and Joints" (78-A: 288—298, Feb. 1996), Watts and Lifeso mentioned that diminished intervertebral space is a late sign of tuberculosis of the spine.
I tend to disagree, as it is a well known fact that the reduction in intervertebral space is the earliest sign, even without any evidence of osseous destruction, according to the work of Mukhopadhyaya2 and that of Tuli3. This point was well supported in Mercer's Orthopaedic Surgery1.
K. Sudarshan, M.S.(Orth): Pt. J.N.M. Medical College and D.K. Hospital, M-1, Rajiv Nagar, Raipur (M.P.) 492007, India
Dr. Watts and Dr. Lifeso reply:
We agree that the loss of height of the disc space is a sign of septic discitis in an adult patient. However, we believe that it is more of a late finding. We think that, especially with the increased use of magnetic resonance imaging, the earliest finding, at least in an adult, is rarefaction of the end plate.
We believe that septic discitis in an adult begins as an inflammatory process in paravertebral soft tissues and probably in the adjacent vertebral body. The end plates of the vertebral body are then most likely penetrated by either inflammatory granulation tissue or actual septic foci manifested, at least on magnetic resonance images, as loss of definition of the end plate. With increasing use of magnetic resonance imaging, we are noting that changes in the end plate are often accompanied by paravertebral soft-tissue swelling and even soft-tissue abscesses in the paravertebral region. As the disease progresses, there is increasing loss of the disc space. Whether that actually represents destruction of disc tissue or herniation of the disc into the adjacent vertebral body varies somewhat from patient to patient.
Consequently, if a patient is seen early in the course of the disease, we believe that the initial findings involve loss of definition of the end plate. If the patient is seen later, the findings involve increasing loss of height of the disc space.
Hugh G. Watts, M.D.: Shriners Hospital for Crippled Children, 3160 Geneva Street, Los Angeles, California 90020
Robert M. Lifeso, M.D.: Erie County Medical Center, 462 Grider Street, Buffalo, New York 14215