Overview of Canine Degenerative Myelopathy
Degenerative myelopathy is a slow, progressive spinal cord disorder of unknown cause that is most commonly seen in aging German shepherds and a few other large breeds of dogs. Effective therapy has not been reported. Most dogs deteriorate over the course of 6 to 12 months and are eventually euthanized.
The cause of the condition is unknown, although it is believed to be an autoimmune disease – a condition in which the body’s immune system begins to attack its own nerve cells. The age of onset is 5 to 14 years, with an average age of 9 years. Males are affected more than females.
The disorder is seen almost exclusively in German shepherds, although it has been diagnosed in a few other large breed dogs, such as Belgian shepherds, Rhodesian ridgebacks, standard poodle, Boxer, Chesapeake Bay retriever, Irish Setter, collies and Weimaraners. Other breeds affected include Pembroke and Cardigan Welsh corgi. The high incidence in German shepherds suggests a genetic basis for the disease.
The disease is slowly progressive. Affected dogs get progressively weaker and more uncoordinated as the disease process progresses. Many dogs progress over 4 to 6 months from the time of initial diagnosis.
What to Watch For
Signs of degenerative myelopathy in dogs may include:
Progressive weakness of the hind limbs
Knuckling of the toes
Wearing of the inner digits of the rear paws
Loss of muscle in the rear legs
Tremors of rear legs
Eventual urinary and fecal incontinence
The front legs can be affected in late stages of the disease
Diagnosis of Degenerative Myelopathy in Dogs
Diagnostic tests are needed to identify degenerative myelopathy and rule out other diseases with similar clinical symptoms. Diagnostic tests include:
Complete medical history and physical examination. Degenerative myelopathy should be suspected in any middle aged German shepherd with progressive weakness and loss of coordination in the rear legs.
A complete neurologic examination including assessment reflexes and pain sensation is key to making a diagnosis of degenerative myelopathy.
Routine x-rays should be taken to rule out orthopedic problems that may have similar signs.
X-ray contrast studies in which a dye is injected around the spinal cord may be necessary to rule out other causes of progressive weakness and loss of coordination.
A spinal tap may give some useful information for making a diagnosis.
Treatment of Degenerative Myelopathy in Dogs
There is no effective treatment for degenerative myelopathy. A few treatments have been recommended, but no controlled studies have been performed to show any proven benefit.
These treatments include:
Vitamins and other supplements
Special homemade diet
Exercise and physical therapy program
Excellent nursing care including padded surfaces, slings, good traction and keeping your dog clean and dry.
Give all medications and supplements as prescribed. Exercise appears to be helpful in delaying the progression of the disease. Dogs should be placed on an increasing, alternate-day exercise program including walking and swimming, if possible.
In-depth Information on Degenerative Myelopathy in Dogs
Degenerative myelopathy is a slowly progressive neurologic disorder mainly affecting German shepherds between the ages of 5 and 14 years. The condition bears many similarities to multiple sclerosis in people. The initial clinical sign is usually an increased difficulty standing up. The rear legs become progressively weaker, and the dog becomes more and more uncoordinated. The rear legs may cross during walking, and the paws may begin to knuckle, causing the nails to be worn from dragging and scuffing. If forced to turn quickly, affected dogs will often fall. The front legs remain normal, as does pain sensation. Late in the course of disease, bowel and bladder incontinence develops.
The diagnostic tests recommended will help differentiate degenerative myelopathy from the following:
Hip dysplasia. This is a hereditary orthopedic condition of the hips commonly seen in large breed dogs
Intervertebral disc disease. Intervertebral discs are structures located between the vertebrae that act as a cushion against excessive movement or trauma. Damage to a disc can cause neurologic signs that may mimic those seen in degenerative myelopathy.
Cancer. Slowly progressive tumors involving the spinal cord may also show signs resembling degenerative myelopathy.
In-depth Information on Diagnosis
Diagnostic tests for degenerative myelopathy are performed mainly to rule out other causes of slowly progressive weakness and lack of coordination. Tests may include:
A complete medical history and physical examination. Middle-aged German shepherds with progressive neurologic dysfunction in the rear legs are highly suspicious for degenerative myelopathy. The physical examination is done to rule out orthopedic causes.
A complete neurologic exam. This is necessary to assess strength, reflexes, pain perception and other neurologic parameters.
Routine x-rays. These are taken of the spine and hips to help rule out hip dysplasia and intervertebral disc disease as a cause of the symptoms.
Myelography. This is a specialized radiographic procedure in which a dye is injected around the spinal cord to make the cord more visible on x-rays. This test may be necessary to rule out intervertebral disc disease and spinal cancer as a cause of the symptoms.
A spinal tap. This is a procedure in which a sample of the fluid that bathes the brain and spinal cord is taken. It is performed low on the spinal cord and may give information supporting a diagnosis of degenerative myelopathy. Many dogs with degenerative myelopathy may have an increased protein concentration in the spinal fluid.
Electrophysiologic testing. Tests to determine nerve function may be suggested to rule out other neurologic disorders.
Advanced imaging. Computerized tomography and or magnetic resonance image may be used to rule out other causes of the clinical signs.
Routine blood work is also recommended to assess overall health. Routine laboratory work may include a complete blood count, diagnostic profile and urinalysis. The results are generally unremarkable in dogs with degenerative myelopathy and without and secondary diseases..