This posts talks about common but difficult neurological presentation in a cat with a strange head movement from side to side and balance problem. Some people might even think it’s a vision problem, like the cat can’t focus. So what could this be?

What is the vestibular system and how does it work?

The vestibular system is the system that controls the balance and allow the animal to know where the body is within the space. The vestibular system is extremely important in cats as they are very dexterous using their paws. The more fine movements the animal has with their hands/fingers/paws, the more developed the cerebellum will be.

The vestibular system can be divided into two main components: the peripheral vestibular system and the central vestibular system.

The peripheral vestibular system includes the vestibular organs, which are located in the inner ear, and the vestibular nerve, which transmits information from the vestibular organs to the brainstem. The vestibular organs include the utricle, saccule, and three semicircular canals, which are filled with fluid and sensory cells.

When the head moves, the fluid in the vestibular organs moves as well, which in turn activates the sensory cells. The sensory cells have hair-like projections called stereocilia that are embedded in a gelatinous matrix called the cupula. The movement of the fluid causes the cupula to bend, which in turn causes the stereocilia to bend. This bending of the stereocilia triggers an electrical signal that is transmitted to the vestibular nerve and then to the brainstem.

The central vestibular system includes the vestibular nuclei, which are located in the brainstem, and their connections to other parts of the brain, such as the cerebellum, thalamus, and cortex. The vestibular nuclei receive information from the vestibular nerve and process it to generate appropriate motor responses and to maintain balance and spatial orientation

Recognising a dysfunction within the vestibular system can be easy as the majority of the cases with a lesion within one part of the peripheral or central vestibular system will have very obvious clinical signs like vestibular or cerebellar ataxia, head tilt, nystagmus and/or strabismus. THE PROBLEM, is that we don’t always have all these signs AND sometimes some of these signs are also seen on pathologies NOT affecting the vestibular system,,,but don’t you worry,,,,we will keep talking about this on further cases.

What do we see on this video is a tricky case: This cat as an affection of both peripheral vestibular systems, this is why you can see this abnormal head position, wondering from side to side. The cat is hesitant to jump but doesn’t seem obviously ataxic.

What other vestibular signs can you see? A mild head tilt to the right, but you can’t see nystagmus or strabismus.

This is a very tricky case because being the problem bilateral is not that obvious to see the typical asymmetric vestibular signs.

Why do I know this is peripheral? For few reasons:

1. The cat is bright and alert: a lesion on both sides of the brainstem will produce severe obtundation
2. The cat has no proprioceptive deficits

Remember that 50% of the cats with a vestibular syndrome will have an ear disease being infectious otitis and nasopharyngeal polyps the most common pathologies.