By Lauren R. Talarico, DVM, DACVIM (Neurology/Neurosurgery)
Neurologic diseases are rather common illnesses that affect canine brains and spinal cords. Mostly commonly, dogs have either seizures (a disease in the brain) or herniated or “slipped” discs (a disease of the spinal cord). If your dog suffers from a neurological disease or you fear she may be experiencing brain or spinal-cord problems, it’s important to understand what’s happening and speak with your veterinarian right away. Treatments are available to ensure your dog can live a long and healthy life.
Seizures occur when the cells comprising the brain, known as neurons, fire uncontrollably. When this occurs, a dog’s brain loses the ability to inhibit certain bodily functions. Dogs often lose consciousness and do not respond when their names are called, and their muscles become rigid and often begin convulsing. Dogs may also urinate and defecate during or immediately after a seizure.
There are three main phases of a seizure: the pre-ictal, ictal, and post-ictal phases. The pre-ictal phase occurs minutes or hours prior to the actual seizure event. During this time, many dogs become excessively “clingy” to their owners or other pets in the house. Alternatively, some dogs will appear anxious or sometimes lethargic. The ictus is the actual seizure event, when the brain’s electrical activity is uncontrollable. The actual seizure occurs from the time a dog loses consciousness to the time when she regains it. The post-octal phase is sometimes called “the aftermath.” It can last for several minutes, hours, or upwards of two weeks. Common post-ictal behaviors can include transient blindness, lethargy, excitement, aggression, pacing, agitation and increased appetite.
The most common cause of seizures in dogs is idiopathic epilepsy. Other causes can include: toxin exposure; metabolic or endocrine diseases; autoimmune, inflammatory or infectious diseases; brain tumors; congenital brain malformations; and strokes.
To diagnose a seizure patient, your vet will order routine bloodwork, a brain MRI, and a spinal tap. An MRI allows us to fully evaluate the brain for an underlying cause of seizure activity. A spinal tap is sometimes used to rule out underlying autoimmune causes, infectious diseases and some forms of cancer.
There are many different anti-seizure medications approved for use in dogs and cats, which your veterinarian will recommend. Every pet is different in the combination and type of medication needed to help control their seizures.
The goal of anti-seizure medications is not to “cure” the patient of seizures, but rather to help decrease the frequency and/or severity of their seizures by at least 50 percent. So proper medication can likely improve the quality of life for your dog.
Intervertebral Disc Disease
The most common cause of spinal cord compression in dogs is intervertebral disc disease (IVDD). IVDD is analogous to a herniated or “slipped disc” commonly diagnosed in humans. The intervertebral disc normally resides between the bones in the spine known as the vertebrae. The disc is shaped exactly like a jelly donut. When the jelly part of the “disc donut” moves out of place, the spinal cord that is positioned above the disc is compressed.
The spinal cord is like a highway that transmits messages from your dog’s toes to their brains and back down again. If the spinal cord is compressed, it’s like there’s traffic on a highway. Messages can no longer travel fast enough to the brain, and animals begin walking with a wobbly gait. In very severe cases of spinal cord compression, dogs can become paralyzed.
A dog’s back and/or neck can be affected by IVDD. The most common signs of spinal cord disease in dogs include dragging or scuffing their paws on the ground, walking with an uncoordinated or weak gait, and developing a hunched-over posture. Some dogs with spinal cord disease affecting their necks will hold their necks in a stiff position and are reluctant to bend when eating or drinking. If the primary site of compression is in the back, only the hind limbs are affected. Conversely, if the compression is located in the neck, all four legs will be abnormal.
The diagnosis of spinal cord disease is time sensitive in dogs. Prognosis is directly related to the time between when the incident occurs and treatment is started. The earlier spinal cord disease is diagnosed and treated, the more favorable the prognosis. IVDD can be diagnosed by either a CT scan or an MRI.
Treatment options involve either medical management, or surgical decompression of the spinal cord and removal of the herniated disc material. Medical management typically consists of 4-6 weeks of strict crate rest, anti-inflammatory medication, pain medications and muscle relaxants. The surgical treatment option affords removal of the disc and decompresses the spinal cord. Deciding between medical management versus surgical decompression is based on the severity of a dog’s neurologic signs as well as their CT or MRI findings. ND
If you believe you dog has been diagnosed with seizures or IVDD or if you are concerned your dog may be suffering from any neurologic disease, please feel free to contact Dr. Talarico at VCA Southpaws Veterinary Specialty and Emergency Center in Fairfax, Va. You can also visit her website at www.theneurovet.com.