Intervertebral disc disease (IVDD) is one of the most common spinal conditions in dogs and is especially prevalent in dogs with a long back and short legs.
Your dog’s spinal column is made up of a series of backbones (vertebrae) with disc-shaped cushions between them. These cushions, which are known as intervertebral discs, act as shock absorbers for the spine and also provide stability.
Each cushioning disc has a thick covering on the outside, with a softer, gel-like core. Over time, the outer portion of the disc breaks down while the inner portion hardens. If the outer portion breaks down too much, the hardened interior can bulge or burst into the spinal canal and put pressure on the spinal cord or nerves as they branch off the spinal cord. This is commonly referred to as a herniated disc or slipped disc, and it can cause a wobbly walk, back or neck pain, nerve damage, and even hind limb paralysis.
Generally speaking, there are two types of IVDD:
Type I primarily affects young to middle-aged dogs. It occurs mainly in chondrodystrophic breeds, which are the dogs with the long back and short legs. In these dogs, breakdown of the disc (or discs) tends to begin early in life, leaving the disc vulnerable to damage from activities that usually would be considered normal. If an at-risk dog jumps off a couch or takes a sharp turn while chasing a ball, the hardened disc may bulge against the spinal cord causing sudden pain or gait changes.
Type II primarily affects older large breed dogs such as Labrador retrievers and German shepherds, and signs tend to appear more gradually. In type II IVDD, breakdown of the disc causes it to bulge into the spinal canal over a period of weeks or months causing slow and gradual loss of the ability to walk normally.
IVDD can occur anywhere in the spine but is most common in the middle of it (between the shoulders and hips) or in the neck. When it occurs in the middle of the spine, only the hindlimbs are affected while all four limbs may be affected if the problem exists in the neck.
Caudal occipital malformation syndrome (COMS) is a congenital disorder in which the skull is too small to accommodate the brain. Consequently, the part of the brain nearest the neck, called the cerebellum, is pushed from its normal position and starts to exit the skull. This can lead to a buildup of spinal fluid, which puts pressure on the back of the brain and spinal cord, causing pain. Dogs with this syndrome scratch at their face and ears, thought to be due to pain from nerve compression.
Seizures are sudden neurologic events that cause involuntary movements and may result in your dog becoming unresponsive. They may last anywhere from a few seconds to several minutes before the brain resets itself. Seizures are classified as being generalized (involving the whole body) or partial (involving one area of the body). Even though seizures don’t last long, watching your pet lose consciousness, twitch, jerk, and possibly lose bowel and bladder control is frightening.
If your dog has a seizure, make sure he is not in an area where he can get hurt. If he is on the couch, move him to the floor or a padded area away from objects that could be knocked over. Do not attempt to place any objects in his mouth, especially your fingers, as dogs often cannot control their chewing movements during a seizure.
Seizures are classified into three categories:
Intracranial: Caused by a problem inside the skull and disturbing normal brain function. Examples include structural brain disorders including tumors, inflammatory diseases, infections, strokes, birth defects, such as hydrocephalus (water on the brain), traumatic brain injuries, and degenerative brain diseases.
Extracranial: Caused by metabolic problems or toxins that affect brain function. Metabolic disorders associated with seizures include severe liver and kidney disease, electrolyte disorders, low blood sugar, and hormonal disorders. Accidental consumption of prescription or over-the-counter drugs and toxins like antifreeze may also cause seizures.
Idiopathic epilepsy: If a dog is having recurrent seizures and an intracranial or extracranial cause cannot be identified, the dog is diagnosed with idiopathic epilepsy. This type of condition occurs most often in younger, purebred dogs.
Veterinarians take into account, the age and breed of the dog, neurologic examination findings, and a description of the seizure event when evaluating a dog with seizures.