The vestibular system is composed of portions of an animal's brain and its inner ear and is responsible for maintaining the sense of balance. When disease affects these structures, pets develop very characteristic symptoms. Causes of vestibular disease include infections, tumors, inflammatory diseases, the use of some types of drugs, and hypothyroidism, but many animals, particularly older dogs, develop symptoms without an identifiable underlying reason.
A head tilt, circling, abnormal eye movements, and difficulty walking are the most characteristic clinical signs associated with vestibular disease. In severe cases, animals may vomit, be unable to stand, and roll across the floor. A veterinarian can diagnose vestibular disease based on a physical exam and an animal's clinical signs, but searching for a cause may entail x-rays, CT scans, MRIs, and other tests. If an older dog suddenly develops signs of vestibular disease and no other problems are evident, a veterinarian will often assume that it is suffering from the idiopathic form of the condition (i.e., no underlying cause is identifiable) and simply monitor for improvement in the animal's condition.
If an inner ear infection is responsible for a pet's symptoms, long-term use of an appropriate antibiotic will usually take care of the problem. Tumors or other conditions are more difficult to treat and may require surgery. Idiopathic vestibular disease in older dogs improves without treatment over the course of several days to weeks. If vomiting persists it can usually be controlled with anti-nausea medications until the animal's condition stabilizes. Keeping the dog confined so it doesn't fall and injure itself and offering food and water by hand may be necessary for a period of time. Most individuals recover completely, while others maintain a mild head tilt and unsteadiness while walking, but these problems rarely adversely affect the dog's quality of life.
Written by: Jennifer Coates, DVM
Last reviewed: October 2, 2008