Vertigo is a disorder of the central and external ear canal, where the vestibular apparatus exists; the vestibular apparatus exists in the inner ear. The vestibular system regulates balance, proper head position and normal eye movements. Dogs with acute onset of vertigo are usually older and don’t have previous evidence of brain disease.
Idiopathic vestibular disease occurs in dogs older than 7. Sometimes the disease is referred to as old-age vestibular disease. The term “idiopathic” indicates that the cause of the disease is unknown. Often, blood tests, urinalysis and X-rays of the spine are done. Those are commonly not definitive for the cause of severe vertigo. Onset of clinical signs is sudden, and severity can vary from mild to severe. The head is tilted to one side, making it look as if the animal is listening to the ground. Affected animals may have abnormal eye movements in which the eyes move rapidly side to side. This is called nystagmus. The animal may stumble, fall or circle to the same side as the head tilt. Walking and gait may be uncoordinated.
Balance is abnormal. Severely affected animals may continually roll over and be unable to walk. Some animals may be nauseated, and refuse to eat. Importantly, all other evidence of neurological disease is absent. This is strictly a disease of the inner ear, the vestibular system.
Vertigo is horrific in human beings, but is especially horrific in our beloved dogs. There is no specific treatment for this disorder. Affected animals usually show improvement within several days. Severely affected animals may initially require hospitalization for intravenous fluids and anti-nausea drugs. Good nursing care is often required at home until the animal can walk normally. The animal may need to be hand-fed if it is too uncomfortable to stand.
Hospitalized animals are monitored with repeated neurological exams during the first few days until improvements are observed. Complete recovery may take several weeks, and some dogs may have a persistent head tilt and incoordination.
We don’t know why this disease occurs to the inner ear. Idiopathic vestibular disease is still a conundrum to all vets.
Dr. Karsten Fostvedt is a veterinarian at St. Francis Pet Clinic in Ketchum.