Meningomyelitis in Dogs

The central nervous system is composed of the brain and spinal cord. These bundles of nervous tissue are encased in and protected by sheathes called the meninges. Rarely, an infection, trauma or autoimmune reaction can target this protective tissue and cause inflammation, leading to neurological problems and impaired movement. Meningomyelitis refers to the more serious condition where the protective meninges and the nerves themselves are inflamed. This can cause severe weakness, abnormal behavior and rob an animal of their coordination. If your dog shows any signs of difficulty walking, breathing, urinating/defecating, or any behavior unlike their usual demeanor, see a veterinarian immediately, as permanent neurological damage can occur if meningomyelitis is not treated swiftly.

• Difficulty walking
• Abnormal behavior
• Dilated or constricted pupils incongruent with ambient light
• Trouble controlling urination or defecation
• Reduction in reflexes
• Trouble swallowing
• Pain tracing back to spinal column
• Fever

Types

• Steroid-responsive
• Infectious
• Trauma

• Autoimmune reaction erroneously attacking the meninges
• Infection of the spinal column
• Trauma to the spinal column or spinal cord.

Owners who notice their pet displaying signs of neurological problems (such as suddenly bumping into objects or stumbling), running a fever, or failing to urinate should contact their veterinarian immediately. The veterinarian will make a physical examination of your dog, including checking their reflexes. Just as a human leg will kick when the knee is tapped, dogs have reflexes of their own. Often, dogs with meningomyelitis will exhibit impaired or absent reflexes, an important clue for the diagnosis. The veterinarian will also check for swelling and pain, which if localized to the spinal region could indicate the source of the problem.

Next, the veterinarian will run a CBC (blood count), a urinalysis, and conduct a spinal tap. A spinal tap involves collecting some of the fluid in the spinal column with a needle. Your dog will likely be sedated for this to avoid injury, and a portion of its back shaved and sterilized to prevent infection from the test. Analysis of this fluid will reveal whether or not there is an infection, and if so, what kind.

The veterinarian may employ an ultrasound to check your pet’s abdominal cavity and spinal region for cancer or evidence of trauma. Ultrasound is a simple, non-invasive procedure that can be performed in a veterinarian's office. Often, a veterinarian may refer your dog to an animal hospital for an MRI, which produces a more detailed image.

If signs of inflammation are present along with severe neurological symptoms, the veterinarian will diagnose the dog with meningomyelitis and formulate a treatment plan.

The type of treatment given will depend on the cause of the inflammation. Most common is an infection, whether viral or bacterial. Bacterial infections will be treated with antibiotics, given orally if the condition is not too severe, or intravenously if the dog cannot swallow. Supportive care such as IV fluids and nutrition may be given to keep the dog’s strength up. Viral meningitis will usually involve supportive care until the animal has cleared the infection on its own. Canine antiviral drugs are not widely available and have mixed efficacy.

If the injury is due to autoimmune disease or trauma leading to excessive inflammation, a course of anti-inflammatory steroids will be given. These steroids will need to be taken with food and/or a gastrointestinal protectant medication as they can irritate the gastrointestinal systems of many patients. Treatment with steroids in the case of autoimmune or inflammatory reaction usually produces a quick improvement of symptoms.

Animals who are not infected with antibiotic-resistant strains of bacteria usually make a full recovery in two weeks if the infection is caught early. Proper administration of the medication, including taking the full course of antibiotics even after symptoms have resolved, is critical. Viral strains of meningomyelitis carry a more guarded outlook, as the supportive care offered by a veterinarian’s office may not be enough to counter the infection, but in many cases animals do make a recovery.

Steroid-responsive meningomyelitis responds well to high doses of prednisone administered over the course of several weeks and tapered off gradually. Many dogs can be discharged from the animal hospital after a week. Medium to large breed dogs seem particularly susceptible to this condition, and are most affected while under the age of 2. This mechanism by which this syndrome arises is poorly understood, and is diagnosed more often by the animal responding to treatment than by a definitive lab test.