neuro.vetmed.ufl.edu/neuro/vestibular/vestibular.ppt

Copyright University of Florida 1997

New tilt on an old problem.


Cardinal Signs of V.D.

• Head Tilt• Nystagmus

– Horizontal– Rotatory– Vertical– Positional

• Circling (tight)

• Imbalance & Incoordination


Nystagmus

• Horizontal– Fast-Phase away from head tilt

– Fast Phase toward head tilt

• Rotatory

• Vertical

• Positional

• Peripheral V.D.

• Central V.D.


Vestibular Diseases

Vestibular Disease

Idiopathic V.D. Inner Ear Disease Central V.D.

8th Nerve only

8th Nerve,

7th Nerve &

Horner’s SyndromeAnything Else


Idiopathic V.D.

• Acute Onset of Vestibular Signs– Head tilt

– Horizontal or Rotatory nystagmus with fast-phase away from head tilt

– Nothing else

• Can Be Very Severe


Idiopathic V.D.Minimum Data Base

• Physical Examination

• Neurologic Examination– Only 8th nerve signs

• Odoscopic Examination

• Other tests as indicated– Heartworm Check– Fecal

– Chest and Abdominal Radiographs


Idiopathic V.D.

• Re-check in one week– Ought to be better

• Re-check in one month– Should still be

improving

• Re-check again if any signs persist– Head tilt may be

permanent

• Thought to be secondary to an immune act on the 8th nerve– Remember each

cranial nerve is antigenically distinct

• Can re-occur

Summary of Case Management


Vestibular Diseases

Vestibular Disease


8th Nerve only

8th Nerve,

7th Nerve &



Inner Ear Disease

• 8th Nerve Signs• 7th Nerve Signs

– ear & lip droop– lack of palpebral

reflex– nose turn– nostril flaring

• Horner’s Syndrome


Inner Ear Disease

• Facial nerve dysfunction– diminished ear and

lip reflexes

– lack of palpebral reflex with inability to blink

– diminished tear production


Horner’s Syndrome

• Small Animals– Ptosis– Myosis

– Enophthalmos

• Large Animals– Facial sweating

(horse)– Lack of muzzle

sweating (cow)


Inner Ear Disease

• Most cases are secondary to bacterial infection (otitis media & interna)– extension from otitis

externa

– pharyngitis with extension up the eustachian tube

– hematogenous spread


Inner Ear Disease

• Remainder are– fungal infections– ear polyps

– neoplasia

• Major rule:– “Treat for the Treatable”

• Therefore, most need antibiotics!


Diagnosis of Inner Ear Disease

• PE, NE, OE– Schirmer’s tear test

• CBC

• UA• Skull Radiographs• Other (if indicated)

– Chest & Abdominal Radiographs

– Ear Culture– Cardiac Exam

Minimum Data Base

Normal bulla radiographNote: sharp bone edges with symmetrical

appearance.


Inner Ear InfectionRadiographic Findings

Right-lateral and DV radiograph of dog with unilateral otitis interna showing

sclerosis of the tympanic bulla on the right side with loss of detail in the region

of the osseous petrous-temporal bone.

RR

L


Inner Ear Infection

• Treat with bacterio-cidal drugs which penetrate bone and blood-tissue barriers– Combination therapy

• cephalosporins

• sulfa drugs

– Enrofloxacin

• Must treat 6-8 weeks


Ear Polyps in Cats

• Benign growth in the external ear canal which causes signs by extension.

• Can also be pharyngeal mass which grows into middle ear via the eusthasian tube.


Ear Polyps in Cats

• Treatment is surgical removal.

• Damage can be permanent, if pressure necrosis has destroyed the inner ear structure.


Inner Ear Disease

• Other Neoplasia– neurofibromas– osteosarcomas

– FeLV

• Prognosis is Poor

• Other Infections– Fungal

• Prognosis Guarded to Poor


Inner Ear Disease

• Consider Advanced Imaging Techniques– Bone Scan

– MRI Scan

• Consider Surgical Drainage of Bulla

• If owner can not afford additional tests or referral, may try changing antibiotics.

• Main reason for failure is not treating long enough.

What if Antibiotics Fail ?


I.E.D. (Special Dx- -Imaging)

• Bone Scan– demonstrates

enhanced uptake of radioisotope in region of infection.

• MRI Scan– shows fluid levels or

soft tissue proliferation.


I.E.D.- -MRI Scan

MRI Scan showing osseous proliferation and soft tissue density

in the osseous bulla.


B.A.E.R. test

Provides indication of the ability of the auditory portion of the 8th nerve to function and relay that information through the brainstem toward the cerebral cortex.


Bilateral I.E. Disease

• No Head Tilt• No Nystagmus

– spontaneous or– physiologic

• Wide head excursions due to inability to fix eyes on vertical with movement.

Open mouth radiograph with

chronic changes in both bullas


Bilateral I.E. Disease

• MRI image shows bilateral disease in middle and inner ear.

• May respond to aggressive antibiotic therapy.

• Some patients will also be deaf.


Inner Ear Disease

• Treat with antibiotics and recheck in 2 weeks– if better, continue– if worse, reassess

• Recheck in 1 month– if normal, stop

antibiotics

– if still residual problems, continue 2 more weeks

• Recheck at 6 months– re-examine any

abnormalities (such as abnormal bulla radio-graphs)

• If problems worsens or persists without change for 4 weeks, consider referral.

Summary of Case Management


Central Vestibular Disease


Vestibular Diseases

Vestibular Disease


8th Nerve only

8th Nerve,

7th Nerve &


The referral line


Nystagmus

• Horizontal– Fast-Phase away from head tilt

– Fast Phase toward head tilt

• Rotatory

• Vertical

• Positional

• Peripheral V.D.

• Central V.D.


Diagnosis of C.V.D.

• PE, NE, OE, FE– NE shows weakness,

postural response changes, and/or reflex changes

• CBC, Chemistry, UA• Skull Radiographs• CSF tap

– CSF titers

• BAER test• Advanced Imaging

– CT Scan– MRI Scan– Bone or Brain Scan

• Surgical Biopsy

Minimum Data Base

The Referral Line



• Postural Changes– CP Deficit– Dysmetria

• Reflex Changes– hyperactive reflexes– crossed-extensor

reflexes– Babinski’s sign

Conscious proprioceptive deficit

may be on the same or opposite side

of the lesion.

Long Tract Signs



• CSF Analysis– may be normal or

show increased pressure, protein and/or cells.

• CSF Titers– species specific tests– many must be paired

with serum titers.

CSF Tap and Analysis

CSF cytology form a dog exhibiting

a mixed reaction with neutrophils,

lymphocytes and macrophages.



• Inflammatory or Infectious Diseases– canine distemper

– toxoplasmosis and neosporiosis

– fungal– rickettsial– GME– SRME

Common Causes of Diseases in Dogs



• Trauma or Vascular– remember dogs don’t

get atherosclerosis !

• Neoplasia– meningiomas– choroid plexus

papillomas– oligodendrogliomas

– astrocytomas– metastatic neoplasia

Common Causes of Diseases in Dogs


Central Vestibular DiseaseMRI of Brainstem Meningioma


Central Vestibular DiseasePrimary Neoplasia

Oligodendroglioma Choroid Plexus Papilloma



• Can be:– peracute– acute & progressive

– chronic

• In brainstem, tends to be a multifocal inflammatory disorder

• Responds temporarily to steroids.

Granulomatous Meningoencephalitis

Patient with GME presenting with

vertical nystagmus, long tract signs,

and circling with incoordination.


Central Vestibular DiseaseGranulomatous Meningoencephalitis

GME histologically causes multifocal meningoencephalitis due to proliferation

of reticulohistiocytic cells. Lesions also show multinucleated giant cells.


• Neoplasia– meningiomas


• Infectious Diseases– FIP– FeLV

– toxoplasmosis– cryptococcosis

• Trauma• Metabolic

– thiamine deficiency

• Toxicity– organophosphates

Common Causes of Diseases in Cats


Central Vestibular DiseaseCommon Causes of Diseases in Cats

Don’t Forget Thiamine Deficiency !!!

Brainstem hemorrhages secondary to thiamine deficiency.



• Most Common Cause is Infection of Brainstem by Listeria monocytogenes– 50-75% respond to anti-

biotic therapy

• May result from invasion of infection into blood sinuses, resulting in Basillar Empyema

Common Causes of Diseases in Ruminants



• Listeriosis is common in adult cattle and goats.

• Culture is difficult, requires cold-enhancement.

• Treat with penicillins and sulfas for 2-4 weeks.

Multifocal areas of hemorrhage due to

Listeriosis-induced meningoencephalitis.

Common Causes of Diseases in Ruminants



In Horses……

think

EPM!!!!!

(Equine Protozoal Myelitis)

Common Causes of Diseases in Horses



• Signs include head tilt– paradoxical (head tilt is

away from the lesion)

• If horizontal nystagmus exists, the fast-phase is toward the head tilt

• Also signs of dysmetria and whole body tremors (including head)

Cerebellar Disorders



The output of the cerebellum is through the activation of the Purkenjie cells. This output is inhibitory. When the cerebel-lum is damaged, the result is disinhibition of brainstem nuclei. Asymmetrical damage cause increased in motor tone on the side of the lesion, leading to the head tilting away from the damage.

Paradoxical Head Tilt in Cerebellar Disorders



• Chronic distemper in dogs

• FIP in cats

• Thiamine deficiency in cats, horses, and ruminants

• OP intoxication in dogs and cats

• Lead poisoning in all animals

• Meningiomas in dogs and cats

Causes of Cerebellar Disorders


Central Vestibular DiseaseMRI of Cerebellar Meningioma



• Corticosteroids– prednisolone @ 1

mg/kg/day in 3 divided doses for 3-7 days

– reduce prednisolone dose to 1/3 mg/kg twice a day

– find minimum daily dose and go to alternate-day therapy (over weeks)

• Misoprostol– 3-4 µg/kg twice a day– may stop when at

alternate-day steroids

• Doxycycline– 5-10 mg/kg once a day

for 2 weeks

• Sulfadimethoxine– 15 mg/kg twice a day

When Referral is Not an Option.TREAT FOR THE TREATABLE !!!

neuro.vetmed.ufl.edu/neuro/vestibular/vestibular.ppt

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