The vestibular system includes the parts of the inner ear and brain that process the sensory information involved with controlling balance and eye movements. Two forms of vestibular disease exist:
- Peripheral vestibular disease (PVD); damage to the inner ear nerve.
- Central vestibular disease (CVD); damage to the brain (medulla).
Signs of vestibular disorders include nystagmus, head tilt, and/or loss of balance; change of mental status (depression, stupor, and coma) and gait abnormalities (falling, veering, leaning, rolling, and circling.
Congenital vestibular disorders have been reported in certain breeds of dogs (Doberman Pinscher, German Shepherd dog, Cocker spaniel, Beagle, and Akita) and oriental cats (Siamese, Tonkinese, and Burmese). Most of the affected animals recover within the first weeks of life. Deafness has been reported in some cases. Inflammation of the inner ear is the most common cause of PVD; others include viral infections such as distemper and feline infectious peritonitis virus; various bacterial, rickettsial, protozoal and fungal infections. Other rare cases of PVD include botfly (Cuterebra larva) migration through the ear canal to the inner ear in cats and hypothyroidism in dogs.3 PVD in which the cause cannot be established (idiopathic) is the second most common form of the disease which is seen in older dogs. Occasionally dogs will have vomiting. Most dogs will improve within 3 days and recover within 1 to 2 weeks without treatment. Sometimes, the head tilt persists.2,3
Congenital vestibular disorders have been reprorted in the Beagle breed