Vestibular Dysfunctions in Dogs and Cats

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Vestibular Dysfunctions in Dogs and Cats | W. Jean Dodds, DVM

Head tilt? Walking in circles? Your companion dog or cat is likely trying to regain his sense of balance or his spatial orientation is off. The cause is more than likely a vestibular dysfunction. Most often it is an inner ear infection, but several other diseases and conditions can cause vestibular problems.

Classification

The two broad categorizations of vestibular dysfunctions are peripheral (inner ear) and central (brain stem/central nervous system) because of their locations. Peripheral vestibular disorders are the most common.

Signs & Diagnosis

The most common signs for both peripheral and central vestibular disorders are:

  • Head tilt
  • Vestibular ataxia – loss of coordination
  • Tight circling, falling, or rolling
  • Nystagmus – uncontrolled eye movements
  • Nausea
  • Strabismus – eyes do not align; and squinting often occurs

Three additional signs – proprioception (sense of where the body is, in relation to itself), mentation (mental activity), and certain cranial nerve deficits – are indicators of possible central vestibular dysfunction.

The first step is a complete neurological examination that puts a companion pet through a series of physical tests. However, it is not perfect. For instance, Troxel et al. conducted a comparative study to help veterinarians distinguish between the two types and analyzed the dysfunctions individually. Of the 20 dogs with central vestibular dysfunction, 95% of the dogs had abnormal postural reactions, 45% of the dogs had mentation change, and 60% of dogs had cranial nerve deficits other than central nerve VIII. These results are good, but ultimately definitive diagnosis of both vestibular dysfunctions is best done with an MRI (magnetic resonance imaging). Spinal fluid taps are also a part of the standard protocol for central vestibular dysfunction.    

But, as I always say, “What is causing this bodily system to not function properly?” We know of several other causes of vestibular dysfunction. So, we need to rule them in or out with blood and other tests.

Peripheral Vestibular Causes

  • Inner ear infections – Most of the time, these ear infections occur because a bacterial or fungal (often yeast) infection has spread from the outer ear to the inner, so a course of antibiotics or other antimicrobials will need to be given. Personally, I do not support the prolonged or continuous use of antibiotics, so I would want to dig deeper to search for any underlying causes or predispositions. Recurring ear infections are quite often caused by a food sensitivity/intolerance, environmental inhalant (atopy) or contact sensitivity/allergy. So, we need to test for these two conditions to lessen or stop the dependence on antimicrobials.
  • Congenital vestibular disease is reported in German Shepherds, Doberman Pinschers, English Cockers, and Siamese and Burmese cats. Since it is present early in life, many companion pets adapt to it.
  • Tumors (cancer)
  • Hypothyroidism – The thyroid affects so many different pathways in the body that testing for it should be annual. Thyroid medication, if warranted, should lessen or stop the vestibular symptoms.
  • Overly enthusiastic ear cleaning that can cause irritation and inflammation and might even rupture the eardrum.
  • Idiopathic – Also known as “old dog vestibular disease” and often thought incorrectly to be caused by a stroke. The signs often disappear within a few days with supportive care.
  • Idiopathic cat – Most cases arise in the northeast portion of the United States during the summer months. The signs often disappear within a few days with supportive care.
  • Inflammatory polyps – Commonly seen in cats and can be removed.
  • Trauma
  • Ototoxicity – Caused by medications; treatment is to discontinue the use of the drug. Some medications may also cause permanent hearing loss.

Central Vestibular Causes

As previously mentioned, central vestibular dysfunction is rarely seen compared to the peripheral dysfunction.

  • Thiamine deficiency – Generally seen in cats fed all-fish diets.
  • Cysts
  • Hypothyroidism
  • Cushing’s Disease
  • Tumors
  • Infectious disease
  • Granulomatous Meningoencephalomyelitis; Necrotizing Leukoencephalitis; Necrotizing Meningoencephalitis – Prognosis is poor.
  • Syringomyelia – most common in the Cavalier King Charles Spaniel; also in the Pug, French bulldog and Chihuahua
  • Embolism  
  • Metronidazole toxicosis – Metronidazole (Flagyl) is an antibiotic used to treat bacterial infections including those of the vagina, bowel, skin, joints, and respiratory tract. Seizures may also be present.
  • Stroke is a common cause of central vestibular dysfunction, and may occur secondary to blood vessel infarction or hemorrhage into the brain.
  • Trauma – Vestibular signs may be due to primary damage, or secondary to raised intracranial pressure, brain herniation or hemorrhage.

Treatment

The best treatment protocol is to figure out the primary or underlying condition, if possible, such as a food sensitivity, hypothyroidism or use of medications.

Secondly, these patients will need varying degrees of supportive care, but that really depends on location and severity.

  • Motion sickness medications can alleviate nausea and vomiting.
  • Homeopathic or Chinese medicinal herbs can be given.
  • Physical or rehabilitation therapy can improve stability.

W. Jean Dodds, DVM
Hemopet / NutriScan
11561 Salinaz Avenue
Garden Grove, CA 92843

References

LeCouteur, Richard A. “Vestibular Disorders of Dogs and Cats (Proceedings).” Veterinary Calendar. DVM360, 01 Apr. 2009. Web. 29 Jan. 2017. http://veterinarycalendar.dvm360.com/vestibular-disorders-dogs-and-cats-proceedings?id=&sk=&date=&%0A%09%09%09&pageID=5.

Mariani, Christopher L., DVM. “Full Tilt! Diagnosing and Managing Vestibular Dysfunction in Dogs and Cats (Proceedings).” Veterinary Calendar. DVM360, 01 May 2011. Web. 29 Jan. 2017. http://veterinarycalendar.dvm360.com/full-tilt-diagnosing-and-managing-vestibular-dysfunction-dogs-and-cats-proceedings?id=&sk=&date=&pageID=2.

Rylander, Helena, DVM. “Vestibular Syndrome: What’s Causing the Head Tilt and Other Neurologic Signs?” Veterinary Medicine. DVM360, 1 July 2012. Web. 29 Jan. 2017. http://veterinarymedicine.dvm360.com/vestibular-syndrome-whats-causing-head-tilt-and-other-neurologic-signs?id=&pageID=1&sk=&date=.

Troxel, MT, KJ Drobatz, and CH Vite. “Signs of Neurologic Dysfunction in Dogs with Central versus Peripheral Vestibular Disease.” Journal of the American Veterinary Medical Association 227.4 (2005): 570-74. U.S. National Library of Medicine. Web. 29 Jan. 2017. http://www.ncbi.nlm.nih.gov/pubmed/16117064.

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