Case study: Discospondylitis
Charlie is a 9 year old English Springer Spaniel. This lovely lad visited us with a two-week history of finding it difficult to get up from rest, being reluctant to climb the stairs, and stumbling during walks particularly with his left hindlimb.
Head vet David examined Charlie, and found that he had a good range of pain-free motion in all of the hindlimb joints. However, he was not bearing as much weight through his left hindlimb as he should be, and some of his reflexes were slow in this leg compared with his right hindlimb. Charlie also showed signs of discomfort on spinal palpation and had a high temperature of 40.2℃.
Imaging and Diagnosis
David advised a CT scan with contrast to examine the thoracolumbar and lumbosacral spine (from his chest to his tail), plus the pelvis and hips. A CT scan is like a series of X-rays that are stacked together to form a 3-D image. Using contrast means injecting a substance that helps different tissues show up better on the scan. This was performed at our clinic and the scans were sent to be interpreted by an imaging expert.
The intervertebral disc space between the 13th thoracic vertebra (T13) and 1st lumbar vertebra (L1) is narrower than it should be. The pink arrows on the images below show a speckled appearance in the bone on the caudal (back) surface of T13 and cranial (front) surface of L1. Underneath these pink arrows we can see areas of new, abnormal bone growth. These findings were suggestive of discospondylitis – inflammation associated with infection of the intervertebral disc.
The blue arrows show that the soft tissues sitting below the spine are taking up quite a bit of the contrast which suggests that there is still an active infection in this region. The green arrows show a region of material sitting outside the spinal cord (extradural), which is also enhanced by contrast. This can suggest a mild ‘slipped disc’, but in this case it indicated inflammation consistent with the suspected discospondylitis.
Other findings on the CT scans showed suspected early signs of discospondylitis between the first two lumbar vertebrae. There were also signs of suspected chronic (long-term) discospondylitis within the lumbosacral region of the spine (lower down the back towards the tail) with evidence of soft tissue inflammation or fibrotic material, plus inflammation of the lumbosacral nerve roots. The hips and pelvis showed no abnormal signs on CT scan.
Treatment and follow-up
Charlie was treated with broad spectrum antibiotics, cefalexin and clindamycin, for 6 weeks.
Charlie was checked at 3 and 6 weeks post initial diagnosis. At 3 weeks his temperature was normal, his nerve reflexes had returned to normal and pain in his back was decreased. The owners reported that he was much brighter and had started jumping on the furniture. At the 6 weeks check he was clinically normal and the owners reported that he was extremely bright and back to his old self and wanting to go on long walks with no adverse effects.
A follow up CT scan was performed at 6 weeks post diagnosis.
The main finding of note on the follow-up CT scan was that the extradural material and neighbouring soft tissues are no longer taking up the contrast. This suggests that the infection and inflammation are settling down and treatment has been effective. While the bony changes remain (green arrows), these will reduce over time due as the bones continue to remodel, although are unlikely to become totally normal again.
We are delighted by Charlie’s progress so far and his long-term prognosis is good.
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