Diskospondylitis in Dogs

Overview of Canine Discospondylitis

The spine contains many small bones called vertebrae. In between these bones are small cushions called intervertebral discs. Diskospondylitis is an infection of one or more vertebral discs and their adjacent vertebrae. Bacterial infection is the most common cause of diskospondylitis. Fungal infections are possible, but occur less commonly.

The disorder is more common in large and giant breeds of dog. It is rare in the cat. Any age dog may be affected and males are affected more often than females.

Any vertebrae may be affected, although the thoracic (chest area) and lumbar (lower back) areas are most commonly affected. The effects of the disease may be mild (slight pain and discomfort) to severe (spinal fracture and paralysis).

What to Watch For

Signs of diskospondylitis in dogs may include:

• Spinal pain
• Fever
• Recurrent urinary tract infections
• Lethargy
• Poor appetite
• Reluctance to move
• Incoordination
• Paralysis

Diagnosis of Diskospondylitis in Dogs

• X-rays
• Myelography
• Computed tomography (CT scan)
• Magnetic Resonance Imagine (MRI)
• Radionuclide Bone Imaging
• Laboratory tests
• Needle aspiration and biopsy

Treatment of Diskospondylitis in Dogs

• Antibiotics
• Cage rest
• Analgesics
• Surgery

Home Care and Prevention

There is no specific home care for diskospondylitis and this disease is not preventable.

In-depth Information on Diskospondylitis in Dogs

Diskospondylitis is an infection of the vertebral disk, most commonly by an infection in the bloodstream. The original infection may involve the heart (endocarditis), teeth, urinary tract or other sites. Bacteria causing infection in these other body systems will enter the bloodstream and cause infection of the intervertebral discs. The most common bacteria causing diskospondylitis is Staphylococcus, although many other bacteria and a few fungi can also be responsible.

A less common cause of disc infection is via a migrating foreign body, such as a grass awn. Grass awns have barbed ends that allow them to migrate forward through body tissues. Wheat, barley, and foxtails are examples of grasses that have this characteristic. The exact portal of entry for these grass awns is not known; however, there are several theories. Inhalation of the grass awn, and migration through the lungs, along the diaphragm, and finally to the spine is the most commonly suggested route of entry.

Previous trauma to the disc or to the vertebrae has also been suggested to play a role in the development of diskospondylitis. Diskospondylitis has also been reported as a complication after spinal surgery.

Clinical signs of pain, reluctance to stand or jump, poor appetite, fever, or spinal cord dysfunction is highly suggestive of diskospondylitis, however, other diseases may cause similar signs, such as:

• Trauma to the spine
• Meningomyelitis (inflammation of the spinal cord and the membranes)
• Neoplasia (cancer)
• Intervertebral disk disease (a rupture of a disc, with no infection)

Most dogs with diskospondylitis and minimal neurologic problems respond to appropriate medical therapy. Recurrence is always a possibility, especially in patients with compromised immune systems. For dogs who develop significant neurologic problems, the prognosis is guarded, but some of these patients do respond favorably, so treatment should be attempted.

In-depth Information on Diagnosis

• X-rays. Diagnosis is usually made based on X-ray findings. Development of X-ray abnormalities, however, may take 2 to 4 weeks after infection. Therefore, early on in the disease, X-ray abnormalities may not be seen.
• Myelography. This technique involves injecting a dye into the space surrounding the spinal cord, so that the spinal cord can be examined. It is performed in patients with substantial neurologic abnormalities, usually as a prelude to surgery. This procedure is usually performed at universities or referral centers.
• Computed tomography (CT scan). CT scans are excellent for detecting subtle irregularities at the edges of the infected vertebrae, compared to X-rays, and often detects early infections that would be missed on X-rays. The procedure is expensive and is only performed at universities and referral centers.
• Magnetic Resonance Imagine (MRI). This is the preferred method of diagnosing diskospondylitis in humans, allowing evaluation of large areas of the spine on a single set of images. It also identifies infected tissue earlier than X-rays can. This procedure is performed at universities and referral centers.
• Radionuclide Bone Imaging. This is another specialized technique for identifying infection of the discs and the adjacent vertebrae. Infected tissues show a positive radioactive scan, while healed tissues show a negative scan. This fact makes this technique a useful way to monitor if treatment has been successful. This procedure is only available at a few universities.
• Laboratory tests. Blood tests alone are not enough to make a diagnosis of diskospondylitis, however, they help support a diagnosis. White blood cell counts may be normal or they may be increased. Urinalysis may show evidence of a urinary tract infection. Blood cultures are positive in 45 to 75 percent of diskospondylitis cases, allowing identification of the responsible organism. Urine cultures identify the offending organism in 25 percent of cases. A bacterium called Brucella is occasionally responsible for causing diskospondylitis, and a blood test looking for antibodies to this bacterium should be performed; it is usually positive in approximately 10 percent of cases.
• Needle aspiration and biopsy. Insertion of a needle into the space where the disc resides and is a safe procedure for obtaining a sample of material for culture and microscopic analysis. The procedure requires general anesthesia, and is performed only if the patient does not respond to initial antibiotic therapy, in cases of suspected cancer, or when the diagnosis is otherwise unclear. This procedure is usually performed at universities or referral centers.

In-depth Information on Treatment

The initial treatment of diskospondylitis usually consists of antibiotics, cage rest and pain medication. Clinical signs such as spinal pain and fever usually resolve within five days of starting effective therapy, although neurologic problems, if present, resolve more slowly. If medical therapy is unsuccessful, surgery may be necessary.

• Antibiotics. Antibiotics are the mainstay of therapy. Antibiotic selection is based on the results of blood cultures, urine cultures, and the Brucella test. While waiting for these results, an antibiotic that is effective against the organism most commonly responsible for diskospondylitis (Staphylococcus) is chosen. Therapy for the first three to five days is usually intravenous. After that, oral antibiotics are usually administered.
• Cage rest. In addition to antibiotics, the patient’s activity should be restricted to minimize discomfort and the chance of fracturing or luxating (dislocating) the spine.
• Analgesics. Non-steroidal anti-inflammatory drugs may be needed to control pain in some cases, but should be used very carefully, as they may cause the clinical signs to temporarily go away despite the fact that the infection may be progressing. If analgesics are used, they should be discontinued after three to five days to assess the effectiveness of the antibiotic treatment.
• Surgery. If initial therapy is unsuccessful, a surgical biopsy may be necessary to confirm the diagnosis. Patients with severe neurologic deficits may need surgery to relieve pressure on the spinal cord that can occur if an infected disc ruptures, or if a spinal fracture or dislocation is compressing the spinal cord.

Follow-up Care for Dogs with Diskospondylitis

Optimal treatment for your dog requires a combination of home and professional veterinary care. Follow-up can be critical, especially if your dog does not rapidly improve. Administer all prescribed medications as directed. Alert your veterinarian if you are experiencing problems treating your dog.