What is Vestibular Disease?

[Music] so today we're going to talk about vestibular disease vestibular disease it refers to a problem in the balanced systems so we often use the word vestibular and balance interchangeably so sometimes I'll say that stimulus system sometimes I'll say balance system the vestibular system is the part of the nervous system responsible for maintaining balance in general there are two parts of the balanced system that we think of the two parts of the balanced system are what we call the peripheral vestibular system and the central vestibular system the peripheral vestibular system is the parts associated with the inner ear whereas the parts of the central vestibular system are the parts of the balanced system that are within the brain and the brain stem so what I've kind of drawn schematically here this is the dog's ears the top of the head the other ear and what we have here is the ear canal there's basically a vertical part in a horizontal part and then we get to the eardrum which is this little line there what I've tried to draw here is what we call the middle ear or the tympanic bulla and then the balanced system actually starts inside of that so the parts of the peripheral vestibular system are the receptors in the inner ear and the nerve what we call cranial nerve 8 or the vestibulocochlear nerve the parts within the brain are the central vestibular system so that's the vestibular nuclei that are in the medulla oblongata and the cerebellum so it's important for us as veterinarians to determine is the problem more likely to be in the central vestibular system or the peripheral vestibular system because it affects one what the possible causes are that affects what the treatment is and it also affects the prognosis or the likelihood of us helping that pet so one of the most important things we do when presented with a dog that is showing signs of vestibular disease is to determine is it a central versus a peripheral problem what are the symptoms of a balanced problem in dogs and cats the most common symptom is a head tilt so a head tilt is the head is cocked to one side where one eyes lower than the other one ears lower than the other if the animal is able to walk it might walk like a drunken sailor so it might list or lean or roll or fall to one side sometimes animals can be very affected and they'll actually alligator roll in one direction the next symptom of a balance problem is what we call nystagmus nystagmus refers to involuntary rapid eye movements or involuntary jerks of the eyes usually they have a slow phase in one way and a fast jerk in the opposite direction so we describe nystagmus based off of the direction of the the rapid jerk or what we call the fast phase and then the next symptom of a balance problem is what we call strabismus or an abnormal eye position so we can use this and this to help us better say is the problem inside the inner ear or is it inside of the brain because again that affects the possible causes it affects the the tests that we choose and it affects the prognosis and the treatment so when we're presented with an animal that's showing symptoms of a balanced problem we evaluate the head tilt we evaluate the character of the nystagmus we evaluate for other cranial nerve abnormalities we evaluate the level of meditation and the postural reactions or the the CPS the conscious proprioception in an animal that has a peripheral vestibular problem so again out here in the inner ear so it's not affecting the brainstem at all it's just affecting the inner ear the head tilt is typically toward the side of where the problem is nystagmus is usually horizontal or rotary with the fast phase away from the side of the problem we might have other cranial nerve abnormalities specifically cranial nerve seven the facial nerve cranial nerve seven is responsible for muscles of facial expressions so we might see a facial droop or inability to blink on the same side as the head tilt in animals with peripheral vestibular disease just because cranial nerve seven and cranial nerve eight are right next to each other similarly while it's not a cranial nerve the sympathetic innervation to the eye so the information that causes the pupil to get bigger or or dilate that nerve can be affected in certain causes of peripheral vestibular disease so sometimes we might see a small pupil on the same side as the head tilt because it's not affecting the brain mentation should be normal level of consciousness should be normal and again because the problems in the inner ear and not affecting the brain stem our postural reactions should be normal for animals with peripheral vestibular disease in contrast animals that have a problem inside of the brain or central vestibular disease their head tilt can be toward or away from the side of the problem the nystagmus can be toward or away from the side of the problem and we might also see things like vertical nystagmus so in peripheral vestibular disease we do not expect the eyes to have up-and-down movements we only expect side-to-side or what we call horizontal nystagmus or rotary where the eye rotates just a little bit but we do not expect vertical nystagmus where the eyes go up and down so vertical and I stagg miss is a symptom of a central problem sometimes we can have other cranial nerve problems so since the problem in central vestibular disease is affecting the brain stem we might see other problems of other cranial nerves that are right near the vestibular nuclei many times we could see decreased facial sensation sometimes we can see atrophy of the tongue so cranial nerve 5 cranial nerve seven and cranial nerve 12 are often affected at the same time in a central vestibular localization mentation may be abnormal so the level of consciousness is affected by many of the parts of the brain that are in this same area where the vestibular nuclei are so a problem here can also cause things like changes in level of consciousness and then finally postural reactions so knowledge of where the limb is in space that information travels through this area of the brain so sometimes dogs with central vestibular disease may have postural reaction deficits but it's typically on the same side as where the problem is lastly sometimes we can have problems affecting the cerebellum so cerebellar signs include intention tremor hyper metria or high stepping of the limbs so recognition of cerebellar signs tells us that the problem is affecting the brain or the central vestibular system what are the possible causes of peripheral vestibular disease so the most common thing that we see that causes peripheral vestibular disease is an ear infection so something affecting the middle or inner ear we can also have tumors of the the inner ear hypothyroidism can affect the peripheral vestibular system and one of the other common causes of peripheral vestibular disease is idiopathic old dog vestibular disease that typically happens in older dogs comes on suddenly is usually very severe but usually improves on its within a few days examples of diseases that affect the central vestibular system or the brain stem are things like strokes we can get strokes in the brainstem we can get inflammation in the brainstem we can get tumors in the brainstem sometimes ear infections can be so severe that they actually invade through the bone and affect the brain so in general the things that affect the central vestibular system like brain tumors meningitis encephalitis strokes and brain infections are much more serious than things like idiopathic and inner ear infections how do we tell what the cause is so looking at the pet we can often tell the difference of peripheral versus central and that changes our list of possible causes or we call our differential diagnosis so we can come up with that list but the way that we find out which one it is is by doing tests usually the first tests involve blood tests so a complete blood count a chemistry panel so complete blood count is going to look at the red blood cells the white blood cells the platelets a chemistry panel is going to look at the internal organs so the blood sugar the liver or the kidneys and then we also often do a thyroid profile because low thyroid can be associated with certain causes a vestibule ER disease the next step is often x-rays of the chest while the x-rays of the chest aren't necessarily going to tell us what's going on in the brain certain causes such as metastatic cancer or strokes sometimes we can see abnormalities in the heart and lungs on our x-rays additionally prior to moving towards an MRI x-rays of the chest are important to make sure that your pet is a good anesthetic candidate and many times we'll do a blood pressure just because strokes are a relatively common cause of festive or their disease it's very important for us to check the blood pressure so assuming that one two and three do not give us an answer the next step is typically anesthesia and an MRI and an MRI is going to be the best way for us to get a picture of the brain and the inner ear and tell us is it an inner ear infection is it a tumor is it a stroke is it inflammation of the brain etc and by knowing which one of those it is we have the best chance of treating your pet specifically and aggressively many times a spinal tap is necessary to look for inflammation of the brain or certain infections and certain types of cancer a spinal tap is usually done only after an MRI because sometimes the MRI will give us the answer and tell us that we don't need to do the spinal tap sometimes the MRI will tell us that a spinal tap would be too risky so we always do it the MRI prior to deciding on whether to do a spinal tap or not so in summary the vestibular system is the part of the neurological system responsible for maintaining balance and posture the symptoms of a balanced problem include head tilt leaning falling listing and rolling to one side abnormal eye movements what we call nystagmus abnormal eye position will be called strabismus there are two basic parts of the vestibular system the parts outside of the brain what we call the peripheral vestibular system and the parts inside of the brain what we call the central vestibular system it's important for us to tell the difference of central versus peripheral because it affects the possible causes it affects the tests that we recommend it affects the treatment and it affects the prognosis most patients with vestibular disease we require an MRI to know what the cause is but sometimes we can find it before doing an MRI [Music]

Channel: Southeast Veterinary Neurology

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Keywords: vestibular disease in dogs, what is vestibular disease, off balance dog, off balance cat, dog rolling over, central vestibular, peripheral vestibular system, mri, southeast veterinary neurology, nystagmus, abnormal eye movements dogs, dogs health, inner ear, idiopathic geriatric vestibular disease, ear infections, strabismus, encephalitis, treatment of vestibular disease, vestibular disease symptoms, veterinary medicine, dog balance problem, dog off balance

Id: v5MEn7uR_70

Length: 12min 52sec (772 seconds)

Published: Wed Jul 03 2019