Today’s case is a 2-year-old male neutered Boxer with one-month history of thoracolumbar pain and two weeks of paraparesis. The patient cries when getting up and has a poor appetite.
On the sagittal MR images, there is destruction of the endplates of the L2-L3 and L7-S1 vertebrae with hyperintense tissue ventral to the intervertebral disc spaces. On T2 and post-contrast images (3,4,6,7,9), the vertebral bodies and ventral tissue are hyperintense and contrast-enhancing. The axial images through the affected disc spaces show the enhancing tissue within the vertebral bodies. There is no evidence of spinal cord compression at these sites.
On abdominal ultrasound, there were enlarged medial iliac lymph nodes lateral to the aorta (images 10,11).
Image one was taken during fluoroscopic aspirate of the L2-3 lesion. There is destruction of the endplates of L2 and L3, and widening of the intervertebral disc space. The spondylosis deformans at this site and adjacent disc spaces is irregular, but there was no evidence of discospondylitis cranial to L2-3 on MR. Image 12 was taken 1 month after initiating treatment, and there is better definition of the endplates at both sites with surrounding sclerosis. Image 13 was taken 2 months after starting treatment and shows further healing of the lesions.
Discospondylitis – Staphylococcus intermedius
The lesions in this dog are classic for discospondylitis. It is the only disease that affects the intervertebral disc space in a symmetric fashion. The diagnosis was obtained by aspirate of the L2-3 disc space with fluoroscopic guidance. The L5-7 disc spaces are much more difficult to access because of the ilial wings.
Blood and urine cultures were negative, however this disease is usually a result of bacteremia. The CBC and high globulins were supportive of an infectious process.
Healing of these lytic lesions usually results in fusion of the two vertebral bodies with ventral spondylosis. Radiographic healing can lag behind clinical improvement by 3 weeks.
This dog had radiographic signs of discospondylitis; symmetrical lysis in the vertebral bodies adjacent to the end-plates – you see this sign in L1-L2 -, but you can see spondylosis in other vertebral bodies. Discospondylitis most often affects the thoracic and lumbar vertebrae of young and middle-aged, large-breed male dogs. Single or multiple-site lesions occur. Staphylococcus aureus and Brucella species have been reported as causative bacterial agents.