Vestibular disease is a condition in which the cat develops incoordination due to several disorders affecting the vestibular apparatus in the inner ear or brainstem. The vestibular system is responsible for providing the brain with vital information about orientation and direction relative to gravity. This information means your cat is aware if he is turning, upside down, right side up, walking, running or falling.
Many of us have temporarily disrupted the vestibular system when we have spun around fast or been on a merry-go-round, as soon as you stop, you may remember staggering, losing your balance or tilting to one side for a few seconds until the vestibular system catches up.
The peripheral system is divided into two systems:
- Peripheral – Inner ear and pathways to the brainstem
- Central – Brainstem
Central vestibular disease is more serious than peripheral; thankfully, most cases of vestibular disease arise from the peripheral system.
Peripheral vestibular disease:
- Otitis interna, inflammation of the inner ear due to infection is the most common cause of vestibular disease in cats. This often develops from otitis externa (inflammation or infection of the outer ear).
- Congenital which affects Burmese and Siamese cats, affected cats may also be deaf
- Aminoglycoside antibiotics (gentamicin, enrofloxacin, orbifloxacin, zeniquin), cisplatin (a chemotherapy drug) and furosemide (a diuretic) and chlorhexidine
- Nasopharyngeal polyps
- Cancers including fibrosarcoma, squamous cell carcinoma, chondrosarcoma and osteosarcoma
- Idiopathic (no known cause)
- Drooping eyelid (Horner’s syndrome)
Central vestibular disease:
- Neoplasia – Meningioma, glioma, choroid plexus tumour and ependymoma)
- Inflammation or infection of the brain stem – Viral (FIP, FeLV, rabies), protozoal (toxoplasma, neospora), bacterial (anaplasma, Ehrlichia, Listeria, Rocky Mountain spotted fever), fungal (cryptococcosis)
- Abnormal cuterebra migration
- Thiamine deficiency
- Hydrocephalus – Accumulation of cerebrospinal fluid within the brain
- Drugs and toxins such as metronidazole and lead
- Head trauma
- Alert but disoriented
- Involuntary rhythmic movement of the eyes (nystagmus)
- Head tilt on the affected side
- Circling in one direction
- Falling to one side
- Wobbly gait (ataxia)
Proprioception is the sense of one’s self, for example, if you have an itch on your ear, you can scratch it without looking, or touch the tip of your nose with your eyes closed. There is a decline in this ability in intoxicated people. Cats with central vestibular disease display the following symptoms:
- Abnormal mental status
- Head tilt on the affected or opposite side
- Unnatural limb position
- Limb weakness
Your veterinarian will obtain a thorough history and perform a physical and neurological exam which can help to differentiate between central and peripheral vestibular disease. During the examination, your veterinarian will perform an otoscopic examination of the ears to evaluate infection or masses.
- Baseline tests such as biochemical profile, complete blood count, and urinalysis can evaluate the overall health of your cat, but results are often normal
- X-rays of tympanic bullae and brain
- MRI or CT of the ear and brain
- Blood tests to evaluate for FeLV and FIP
- Cerebrospinal fluid tap to evaluate for infection
The goal of treatment is to address the underlying cause as well as provide supportive care, which may include:
- Nutritional support. As most cats with vestibular disease have difficulty eating due to nausea and poor coordination.
- Anti-nausea medication such as meclizine.
- Antibiotics to treat an ear infection.
- Anti-fungal medications such as itraconazole to treat fungal infections.
- Miticide drugs to kill ear mites, which are a common cause of ear infections in cats due to trauma from scratching.
- Surgery and/or radiotherapy for malignant tumours.
- Surgery or laser therapy to remove polyps.
- Corticosteroids to reduce brain swelling.
- It is not possible to remove cuterebra and treatment is aimed at management of symptoms such as anti-seizure medications, ivermectin to kill the parasite, antihistamines to prevent an allergic reaction and corticosteroids to reduce inflammation.
- Discontinue any medication which brought on vestibular disease.
Most cats with vestibular disease will improve within 2-3 days and full recovery by three weeks.
Once your cat has been discharged from the hospital he will need to be cared for at home until he has fully recovered. Pet owners will need to make some adaptations if symptoms are still present. Keep the cat indoors in a well-padded area during the recovery period and block access to stairs and windows to prevent falls. Food, water and litter trays should be kept close, and hand-feed if the cat is not showing an interest in food. Administer medication as prescribed.