Paralysis in dogs can have a number of causes, including injury, disease, and exposure to toxins. Congenital diseases, injury, and tumors of the central nervous system are common causes of paralysis in dogs. A number of medical conditions, some infectious, some not, can cause paralysis in dogs. Even bites from ticks can lead to canine paralysis in some cases.
Injury to the brain, spinal cord or spine may be one of the most common causes of paralysis in dogs. Damage to the nerves or spine can cause partial or total paralysis, and this paralysis is often permanent. The canine nervous system is often capable of recovering somewhat from damage done by trauma, but most dogs recover only some of their prior range of movement. Dogs experiencing shock from a severe injury may display temporary paralysis, even if the nervous system itself is undamaged. Tumors of the spine and brain can have similar affects on motility, but, in many cases, paralysis can be reversed if the tumor is successfully excised.
Exposure to toxins, pesticides and rodenticides can be a common cause of paralysis. Some ticks carry a salivary toxin that can cause life-threatening paralysis in dogs. Poisoning with botulinum toxin can also lead to life-threatening canine paralysis. Dogs are most likely to ingest botulinum toxin in contaminated food. The toxin may also enter open wounds that aren't kept clean and bandaged.
Many dogs experience some degree of paralysis due to congenital disorders. Intervertebral disk disease, atlantoaxial subluxation, and caudal cervical spondylomyelopathy are some of the inherited conditions that can cause paralysis. Peripheral vestibular disorder, which can cause paralysis of the face and loss of motor control, may have a genetic component, though often this disease occurs after viral or bacterial infection. Degenerative disk disease, another congenital canine condition, can cause gradual paralysis, as it causes the protective membrane around the spinal cord to break down.
Infectious diseases, including distemper and rabies, can cause canine paralysis. Diseases that cause inflammation of the brain or spinal cord may result in paralysis if allowed to become severe. These conditions can include granulomatous meningoencephalomyelitis and fibrocartilagenous embolism. Even ear infections, when left untreated, can reach the inner ear and contribute to canine facial paralysis.