By Jay McDonnell, DVM, MS, Diplomate ACVIM (Neurology)
1. What is Feline idiopathic vestibular disease?
Feline idiopathic vestibular disease (IVD) is a disease of uncertain cause that affects the peripheral (outside the brain) vestibular system.
Although the origin of the disease has yet to be determined, it is speculated that it occurs due to an inflammatory process that affects the peripheral vestibular apparatus of the labyrinth – a sensory system located deep within your cat’s ear that is responsible for maintaining balance and movement.
2. What does it look like?
The hallmark of unilateral vestibular disease is a head tilt. It is nearly always to one side or the other. The head tilt is described as towards which side of the cat’s head that is pointing towards the floor. The head tilt is present and constant in all positions. The kitty illustrating this article has a head tilt to the left even when he is laying down.
3. When does it occur?
There does seem to be a seasonal increase in IVD during the summer months in our area.
4. Who does it affect?
There doesn’t seem to have any predeliction for age or sex. IVD has been seen in all breeds of cats.
5. What signs will I see in my cat?
The onset is acute, and your cat may develop signs very quickly (within an hour). You will notice head tilt, disorientation, falling, rolling and nystagmus. Nystagmus is a rapid, repetitive, involuntary movement of the eyes in a side-to-side or circular. Most cats show an incoordinated, wobbly walk. Some cats are unable to stand, and may constantly roll or fall to one side or the other. Other cats can become so disoriented that they either don’t move, vomit or vocalize loudly. Some people report that it looks like their kitty is having a seizure, which it can resemble.
6. What is bilateral IVD?
In these cases, your cat may not exhibit much of a tilted head, but may instead swing its head from side to side and remain in a crouched posture.
7. How is IVD diagnosed?
There is no definitive test for IVD like there is for Parvo virus or heartworm disease. Instead to make a diagnosis, your veterinarian rule outs other diseases such as ear infections, middle ear polyps, feline infectious periotonitis and some forms of cancer.
She will begin by performing a complete physical and neurological exam on your cat. One hallmark of IVD is lack of other neurological signs that point to the brain. No abnormalities in conscious proprioception (your cat’s ability to be aware of his/her own body position and movement) are typically noted, although this may be difficult to assess, especially during the first 24-48 hours, when signs are often most severe. Weakness is usually not present. The other nerves to the face and head are also not affected.
Your veterinarian may want to perform other tests in conjunction with a neurological exam to rule out other possible causes of vestibular signs. These may include an ear exam, x-rays of your cat’s skull, spinal tap and a brain-skull MRI. If these diagnostics return normal results and your cat’s history and neurological exam are consistent with peripheral vestibular disease, a diagnosis of IVD is considered.
8. What about treatment?
Currently, no specific treatment has been proven to be beneficial in all cases. However, certain drugs (such as sedatives, anti-vomiting, and motion sickness-relieving medications) may be prescribed at your veterinarian’s discretion. Supportive therapy is the mainstay of treatment until signs resolve. This involves assisting your cat with eating and drinking, and keeping him in a safe environment where essentials (food, water, and litterbox) are located within a safe distance and at ground-level, in order to prevent your cat from sustaining secondary injuries by wandering while uneasy on his feet or by jumping from a high level. It is also important to ensure your cat remains hydrated.
The majority of cats return to normal over the course of several weeks. The prognosis is excellent, as cats rarely have any remaining vestibular dysfunction upon recovery.