Veterinary Voice, May 2013 – Vestibular Disease in the Cat and Dog

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May 2013, Issue 55


Neurology Update!

Many of you have expressed that there is a need for a local neurologist…

Dr. Maggie Vandenberg, her nurse Cassie Talbot and Bruno

 

On February 18th, 2013 we set in motion a full neurology service, including advanced imaging with both a 1.5 T MRI Magnet and a 32 slice Helical CT, as well as Neurologic Surgery and Medical Neurology.     

 

 

 

Bruno

 

 

 

For more information about our neurology service or if you have questions regarding a case please call our board certified Neurologist, Maggie Vandenberg, DVM, DACVIM (Neurology) at 303-678-8844.

 

 


Event Updates!

It has been a busy couple of weeks at AMVS for events! One of our favorites so far was the first aid presentation for a couple of the local police departments that Dr. Crystal Connor hosted last week. Canine officers from Westminster, Longmont, and Frederick police departments all came, and it was so great to have them! These presentations are a great way for local officers to learn the basics of triage, so animals injured in the field have a better chance of survival. Dr. Connor will be providing more of these courses throughout the summer for other local police departments.

On Thursday, May 23rd the Emergency Procedures & Wet Lab CE with Dr. Dana Dietrich had a really good turn out. The Weld County Humane Society generously provided cadavers for the Wet Lab portion. The AECC Emergency doctors set up five stations to practice chest tubes, abdominocentesis, nasal cannulas, female urinary catheters, and tracheostomies. Thank you to the folks who participated – we hope to see you at our next event!


Friday, May 17th was a fun filled evening at the first Longmont Art Walk of the year. Don’t worry if you missed this event as there are 2 more art walks scheduled this summer. Please enjoy the pictures below courtesy of the Longmont Times call.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Upcoming Events!

  For a complete and updated listing of all of our upcoming events,
please visit our events calendar by clicking the paw print.

 

Thursday, June 13th at 6:00pm 

Located at Aspen Meadow Veterinary Specialists
104
S. Main St. Longmont CO 80501 

Join AMVS and Leave No Trace for a presentation on canine first aid and enjoying the outdoors responsibly.      

The Leave No Trace traveling trainers will give an interactive presentation and discussion focusing on the elements of the Leave No Trace minimum impact program. They will highlight the Leave No Trace outdoor skills and ethics program, which is applicable to all outdoor enthusiasts and all environments.

  

Following, AMVS will give a presentation introducing the basics of canine first aid, including obtaining vitals, triaging, and bandage placement. This information will provide you with some of the basic knowledge and supplies if your dog develops an injury while enjoying the outdoors.   

Upcoming Police Dog Presentations


Wednesday, June 5th at 6:00pm &
Wednesday, June 19th at 6:00pm

 

For more information on this event please call us at

 Upcoming CE’s!

 
Saturday, June 10th at 6:00pm
Located at Aspen Meadow Veterinary Specialists
104 South Main Street, Longmont CO 80501
 
CRCG (Canine and Conditioning Rehabilitation Group) is offering a series of CE approved seminars this summer with this seminars topic being Rehabilitation and Prevention for Neurologic Issues. 
 
Neurological physical therapy in people addresses neurological disorders or diseases. These include but are not limited to brain injury, spinal cord injury, and stroke. Outcomes of neurological disorders can include paralysis, vision impairment, poor balance, and inability to ambulate. These same beneficial techniques can be applied to these conditions in dogs and cats. There are many ways that rehabilitation compliments the care that you are already giving your client and can improve the outcome.
 
To register this event visit CRCG’s Contact Us page or by calling 303-762-(SWIM) 7946
  
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Vestibular Disease In the Cat and Dog

By Dr. Maggie Vandenberg DVM, DACVIM  

Neurology

 

Practice Points

  • In central vestibular disease concurrent mental dullness and dysfunction, as well as other cranial nerve deficits are often observed.
  • The most common causes of peripheral vestibular disease in dogs and cats are otis media/interna and idiopathic vestibular disease
  • Magnetic resonance imaging is the gold standard diagnostic test for soft tissue imaging and preferred imaging for vestibular disease.
  • Computed tomography (CT) should be considered in patients with otic disease causing vestibular signs.
  • Patients with otitis media/interna will have a history of head shaking, bulla pain, and/or ear infection.

 

7 year old, female spayed lab with right peripheral CN VIII signs
7 year old, female spayed lab with
right peripheral CN VIII signs

 

     Vestibular disease is one of the most commonly seen neurologic condition seen in general and/or specialty practice. This is a general term for neurologic conditions affecting the balance center. The balance center is located within the brainstem, cerebellum, first three cervical spinal segments, or inner ear. Animals with vestibular disease often have several neurologic abnormalities. These abnormalities include head tilt, abnormal nystagmus, dull mentation, vomiting, ataxia, proprioceptive deficits, and/or become unable to stand or walk. Oftentimes, due to the severity of clinical signs, it is very difficult to determine by neurologic exam where the location of or what is the underlying cause of the vestibular dysfunction. Careful observation, attention to historical information, and a systematic approach is crucial in order to appropriately treat and determine the underlying cause of dysfunction in our patients.

 

     Vestibular disease is separated into two main categories based on the disease localization. The two categories of disease are peripheral and central. With peripheral vestibular disease the underlying problem is occurring within the bony and membranous labyrinth of the petrous temporal bone (inner ear). With peripheral vestibular disease you can additionally observe ipsilateral dysfunction of the post-ganglionic sympathetic innervation to the eye, and/or dysfunction in cranial nerve VII. In central vestibular disease the underlying problem is occurring within the brain (brainstem, cerebellum) or first three cervical spinal cord segments. With central vestibular disease concurrent mental dullness and dysfunction in other cranial nerves (cranial nerves V, VII, IX, XII) is often observed.

 

     Cats and dogs have very different etiologies of vestibular dysfunction. Peripheral vestibular disease has many underlying causes. The two most common causes of peripheral vestibular dysfunction in both species include: otitis media/interna and idiopathic peripheral vestibular disease. Patients with otitis media/interna will have a history of head shaking, bulla pain, and/or otic discharge/infection. Otic examination will be abnormal. If there are not any apparent abnormalities on otic examination than another cause should be sought out. It is very important to recognize that topical otic medications can be extremely ototoxic especially when the integrity of the tympanic membrane is compromised. So ideally they should not be used at all. Additionally, horner syndrome or facial nerve paralysis is commonly seen along with otitis media/interna as these nerves pass within the inner ear in close association with the vestibular receptors. Idiopathic vestibular disease is seen in both cats and dogs. In both species it’s onset is acute and clinical signs (head tilt, ataxia, vomiting) can be quite severe. In this disorder cranial nerve VII and/or horner syndrome will not be seen. It is seen in dogs over 5 years of age and can occur in cats of any age.   Aural neoplasms are seen in both species and tend to be more malignant (85% of the time) in cats. Nasopharygeal polyps are found in young cats (1-5 years of age). They are usually unilateral and removal by traction polypectomy through the mouth or external ear canal typically results in a 30-40% recurrence rate. A bulla osteotomy can reduce recurrence to ~10%. Hypothyroidism is a condition that causes peripheral cranial neuropathy in dogs. Commonly cranial nerves VII and VIII are affected together. Supplementation with thyroid hormones usually results in improvement within a few months.

 

     Central vestibular disease should definitely be considered if proprioceptive deficits, dull mentation, and/or other brainstem signs are observed. These conditions are often more insidious and/or chronic in nature. They can be acute though with cerebrovascular disease. Conditions that cause central vestibular dysfunction are hypothyroidism (dog), intracranial tumors, non-infectious inflammatory disease (granulomatous meningoencephalitis), infectious disease (fungal, protozoal, viral, rickettsial), metronidazole toxicity (dogs), metabolic diseases (portosystemic shunts, hypothyroidism), cerebrovascular disease (more commonly in the dog), and degenerative diseases (lysosomal storage diseases).

 

     Work up for both forms of vestibular disease is similar. Getting a baseline blood chemistry, complete blood count, urinalysis, and blood pressure is essential in every patient. Typically patients are not in a life-threatening situation and taking the time to adequately assess your patient is essential. Supportive therapy should be initiated as soon as possible. Typically patients have vertigo and may be vomiting. In these patients it is recommended to start intravenous fluid support, anti-emetics, and appropriate nursing (turning, passive range of motion, supported ambulation).   Steroids are not indicated in the initial nursing period. In many instances they are not necessary and if given they will interfere with future diagnostic testing (i.e., cerebrospinal fluid analysis, magnetic resonance imaging). If an otic infection is confirmed, appropriate testing (myringotomy, culture, cytology) and administration of antibiotic therapy should be performed.   In the persistently hypertensive patient, underlying causes of hypertension should be sought out. Testing such as protein:creatinine, ACTH stimulation test, abdominal ultrasound, +/- echocardiography can be considered if indicated by the laboratory results and initial assessment.

 

     If the initial diagnostics do not reveal an underlying cause, a neurologic consultation should be performed. At that time magnetic resonance imaging (MRI) of the brain (FIGURE 1) +/- cerebrospinal fluid (CSF) analysis should be considered. Computed tomography (CT) could be considered for otic disease causing only peripheral signs but is not ideal in patients with central vestibular disease. With CT, the beam hardening artifacts caused by the bone can preclude visualization of small lesions within the brainstem, cerebellum. Thus MRI is the preferred method of imaging for vestibular disease as it is the gold standard diagnostic test for soft tissue imaging.

 

FIGURE 1: CT Scan of otitis externa, media, and interna

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