Visiting Vet: Diskospondy…what? Easy for you to say

Visiting Vet: Diskospondy…what? Easy for you to say

Michelle-JasnyMichelle Gerhard Jasny, V.M.D. has been practicing veterinary medicine on the Vineyard since 1982 and writing the Visiting Vet column for more than 25 years. She lives and works in West Tisbury. She can be reached at: drjasny@comcast.net. 

Almost one year old, the playful Bernese mountain dog weighed in at nearly 90 pounds. When he first started behaving as though his back hurt, we weren’t too concerned. “He probably just strained something running around,” we said, prescribing rest and anti-inflammatory pain medication. When that didn’t help, we tried a muscle relaxant, but his symptoms continued. He began to whine and pace at night, sometimes yelping or leaping up suddenly when anyone brushed past him.

Here in the clinic, Bernie walked normally but was anxious, jumping around, and making it hard for us to pinpoint the source of his discomfort. We ruled out Lyme disease with a blood test and added a second pain medication. We discussed radiographs, but since he was so bouncy and would probably need sedation for that, we decided to wait a while longer.

One week later, Bernie slipped and fell on the ice. Immediately after, he developed “posterior paresis,” a weakness in the hind legs resulting in an abnormal gait usually indicative of a spinal cord problem, but we still couldn’t localize any particular place that hurt. “Let’s take those pictures,” I advised.

My main differentials for Bernie at that point included intervertebral disc disease (IVD) or fibrocartilagenous embolism (FCE). In simple English, IVD is a “slipped disc.” FCE is an embolism compromising the blood supply to the spinal cord. It typically affects large breed young dogs. Despite his youth, we also had to consider cancer, as Bernese mountain dogs are very prone to it.  Bernie was now sufficiently subdued to allow us to X-ray without sedation. The films looked normal, but that didn’t rule out anything. It just meant that whatever was causing Bernie’s pain was not visible on plain X-rays.

If it was FCE, there was no rush. FCE is not progressive. There is no specific treatment other than supportive care. The neurological deficits often resolve with time. If it was IVD, that often responds to corticosteroids and rest. As long as he could feel and move his legs, IVD wasn’t urgent, although surgery might ultimately be indicated to relieve pressure on his spinal cord. If it was cancer? Well, that would be a much bigger bridge to cross, should we come to it. We gave Bernie intravenous corticosteroids, prescribed more orally to give at home along with his pain medications, and added tranquilizers to keep him quiet and give his back a chance to heal.

But it was not to be that simple. Bernie’s condition worsened. It was time to consult the specialists.

On initial exam, the neurologist also could not localize Bernie’s pain. That made me feel better. At least I had not missed anything obvious. She and I spoke each day as they gathered information. New radiographs were suspicious for a fracture of Bernie’s third thoracic vertebral body.  No, the fracture wasn’t visible on the films we had taken earlier, and it wasn’t the kind of clean break one would expect from simple trauma. Besides, it would be unlikely for a big healthy puppy to fracture a vertebra just from slipping on the ice — and some of Bernie’s symptoms pre-dated his fall.

The radiologist reported a “moth-eaten” appearance to the bone consistent with either tumor or infection. Either of those might have weakened the bone, resulting in a “pathological fracture” when Bernie slipped. “I’m really concerned it may be a tumor,” the neurologist confided. “Or diskospondylitis, which is almost as difficult to treat.”

Diskospondylitis is a bacterial or fungal infection of the intervertebral disks and adjacent vertebrae. Most often seen in medium to giant breed dogs, especially German shepherds and great Danes, any breed can be affected. It is even occasionally diagnosed in cats. It typically occurs in young to middle-aged individuals, with males being affected twice as often as females. Symptoms vary depending on exact location and severity of the lesion and may develop slowly or suddenly.  Signs may include pain especially when trying to get up, reluctance to jump, a stiff gait, incoordination, weakness, weight loss, poor appetite, lameness, and fever. Radiographs may appear normal for up to a month after the infection starts, but eventually they reveal changes in the intervertebral disk space and adjacent bone. The bacteria are usually spread via the blood, though the primary source of the infection often cannot be determined. It may start as a urinary tract infection, a wound, a foreign body like a grass awn, even dental disease.

Bernie needed more tests — MRI, CT, biopsies, cultures. While waiting for results, the specialists started him on antibiotics. We all held our breath, fingers and toes crossed, that it would not be cancer. The CT confirmed the pathologic fracture and mild spinal cord compression consistent with either diskospondylitis or tumor. The  biopsy showed no cancer.  Urine cultures were negative. Blood cultures, however, were positive for staphylococcus, confirming the diagnosis of bacterial diskospondylitis. The concurrent “sensitivity panel” listed the best antibiotics to combat this specific infection.

Due to the location of his fracture and the presence of infection, surgical stabilization was not advised. We had to depend on Mother Nature to heal the break, and, with our help, to stop the infection. Bernie came home on long-term antibiotics, gradually decreasing corticosteroids, and a cocktail of pain medications. He was outfitted with an elegant vest with handles on the top so his family could easily assist him getting up and walking, though his exercise still needed to be restricted for many weeks as he heals.

This is only the third case of diskospondylitis I have knowingly seen in 30-plus years of practice. We have a saying in medicine — you can’t find something if you don’t look for it. It wasn’t on my initial differential list (that won’t happen again) and it required extensive sophisticated  testing to establish the definitive diagnosis and treatment.

The prognosis for diskospondylitis depends on the degree of spinal cord damage and the organism involved, but Bernie has been improving steadily and we are very hopeful he will make a full recovery.

 

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