VETgirl December 2023 Beat e-Magazine

TABLE 1: Localization

QUARTERLY BEAT / DECEMBER 2023 ///

/// QUARTERLY BEAT / DECEMBER 2023

PARADOXICAL (Subset of Central)

PERIPHERAL

CENTRAL

VESTIBULAR DISEASE Canine & Feline CENTRAL, PERIPHERAL, I DON’T NEURO?

Alert, but can be disoriented/ confused based on severity

Normal or abnormal (depressed, stuporous, comatose)

MENTATION

HEAD TILT

Ipsilateral

Contralateral

H/R>>V Doesn’t change with position Fast phase AWAY

H/R/V Can change with head position Fast phase any direction

H/R/V Can change with head position Fast phase TOWARDS the lesion

NYSTAGMUS

MISSY CARPENTIER , DVM, DACVIM (Neurology)

Vestibular ataxia +/- cerebellar ataxia Paresis possible

Vestibular ataxia GOOD STRENGTH

GAIT

SMALL ANIMAL WEBINAR

Know the difference between peripheral vs central vestibular? Learn the difference in this webinar! If you missed Dr. Missy Carpentier-Anderson’s webinar on October 24, 2023 entitled Canine and Feline Vestibular Disease, read the highlights below! Want to learn more about vestibular disease? Tune in to learn how to differentiate peripheral from central vestibular disease and, based on the neurolocalization, the most common differential diagnoses and treatments!

FACIAL NERVE

+/-

HORNER’S

+/-

+/-but is rare

OTHER CN DEFICITS SPECIFICALLY V-XII)

+/-

CP DEFICITS

YES (lesion side)

WATCH FULL WEBINAR

TABLE 2: Differential Diagnosis Based on Localization

Vestibular disease is a frequent presenting complaint for our patients. The question you should always be asking yourself once you evaluate your vestibular patient is, is it peripheral or central? Below you will find a brief description of vestibular disease, followed by two charts that will: 1) Help you determine if your neurologic findings point towards a peripheral or central localization (Table 1) AND 2) Provide differentials for a peripheral vs central localization (Table 2) The vestibular system refers to all parts of the body that set up balance and orientation. When we discuss the vestibular system, we divide it into peripheral (with the ear) and central (within the brain). With peripheral vestibular disease, we have a problem within the petrous temporal bone and our focus involves the middle and/ or inner ear. With central vestibular disease, we are focused on the brainstem or the cerebellum. Using your neurologic examination, you should be able to tell if your patient (more confidently with dogs than cats), neurolocalizes peripheral or central. When I look at a vestibular patient, they are all peripheral until proven otherwise. You don’t want your patient to have a central vestibular disturbance, so you use your evaluation to know if there is anything that tells you that you need to be more focused on the brainstem or cerebellum in that patient. THEN THERE ARE CATS… Every part of your exam can point to a peripheral vestibular problem in a cat, and they are central. Unless I have a very obvious middle ear infection or a severe upper respiratory infection with a cat, I would never bet that a cat is peripheral (and trust me early on I made this mistake many times, lesson learned!). They always have the potential to be central, simply because they are a cat.

Just like every neurologic patient, you are going to start with the signalment, history, and your physical evaluation. Then, you will move onto your hands off and on neurologic evaluation. The nice thing about vestibular disease is it is pretty easy to know that that is what you are dealing with if a head tilt is present. Is there a head tilt? Yes, well there you go your patient has vestibular disease. Now we need to figure out if it is peripheral or central with our examination. Below is a chart for determining peripheral vs central disease. You will also notice that there is a category for paradoxical. Paradoxical is a form of central vestibular disease due to a disturbance involving either the flocculonudular lobe of the cerebellum or the caudal cerebellar peduncle. Another category of peripheral vestibular disease that is not in the chart is bilateral peripheral – these patients will NOT have a head tilt, no pathologic or physiologic nystagmus, they do have side to side head excursions, and are found with a crouching posture due to decreased extensor tone. The most common presenting complaint for these animals (most commonly cats), is that they are anorexic or are vomiting due to the disequilibrium. The most common diagnosis is a bilateral otitis media (hopefully without intra-cranial extension, but again cats…). Webinar Highlights

PERIPHERAL

CENTRAL

DEGENERATIVE

Lysosomal storage diseases

Arachnoid cyst COMS (Caudal occipital malformation syndrome) Hydrocephalus

Congenital vestibular disease Idiopathic vestibular disease

ANOMOLOUS

METABOLIC

Hypothyroidism

Aural neoplasia Malignant nerve sheath tumor

NEOPLASTIC

Intracranial neoplasia (primary vs metastatic)

NUTRITIONAL

Thiamine deficiency

Otitis media/interna with intracranial extension MUO (meningoencephalitis of unknown origin) Infectious inflammatory (FIP)

Otitis media/interna nasopharyngeal polyps PSOM (Primary secretory otitis media)

INFLAMMATORY

Ototoxic (aminoglycosides, iodophors, diuretics, cisplatin, chlorhexidine)

TOXIC

+/-but is rare

TRAUMATIC

Inner ear trauma

Head trauma

VASCULAR

Cerebrovascular accident (paradoxical)

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