Head Tilt - triakoso

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Head
Tilt
Nusdianto Triakoso
Veterinary Teaching Hospital
Airlangga University
triakoso - head tilt 2010

Definition
• Tilting of the head away from its normal
orientation with the trunk and limbs;
associated with disorders of the vestibular
system


Pathophysiology
• Vestibular system—coordinates position
and movement of the head with that of the
eyes, trunk, and limbs by detecting linear
acceleration and rotational movements of
the head; includes vestibular nuclei in the
rostral medulla of the brainstem, vestibular
portion of the vestibulocochlear nerve
(cranial nerve VIII), and receptors in the
semicircular canals of the inner ear

Pathophysiology
• Head tilt—most consistent sign of
diseases affecting the vestibular system
and its projections to the cerebellum,
spinal cord, cerebral cortex, reticular
formation, and extraocular eye muscles
via the medial longitudinal fasciculus;
usually directed toward the same side as
the lesion

Risks factor
• Hypothyroidism
• Administration of ototoxic drugs
• Thiamine-deficient diet (e.g., exclusively
fish diet)
• Otitis externa, media, and interna


Signs
• Be sure that abnormal head posture is not
head turning (turning the head and neck to
the side as if to turn in a circle), which is of
thalamocortical origin and is not
associated with other vestibular signs
(e.g., abnormal nystagmus).


Signs
• Head tilt
• Paralisis fasialis, Horner’s syndrome
Falling
• Leaning
• Turning


Cause – Peripheral disease
• Anatomic—congenital head tilt
• Metabolic—hypothyroidism; pituitary
chromophobe adenoma; paraneoplastic
disease; cranial nerve polyneuropathy
• Neoplastic—nerve sheath tumor of cranial
nerve VIII; neoplasia of the bone and
surrounding tissue (e.g., osteosarcoma,
fibrosarcoma, chondrosarcoma, and squamous
cell carcinoma)

Cause – Peripheral disease
• Inflammatory—otitis media and interna;*
primarily bacterial but also related to parasitic
(e.g., Otodectes), mycotic, and fungal origins;
foreign body; nasopharyngeal polyps
• Idiopathic—canine geriatric vestibular disease;*
feline idiopathic vestibular disease*
• Immune mediated—polyneuropathy
• Toxic—aminoglycosides; lead;
hexachlorophene
• Traumatic—tympanic bulla or petrosal bone
fracture; ear flush

Cause – Central disease
• Degenerative—storage disease; demyelinating
disease; vascular event
• Anatomic—hydrocephalus
• Neoplastic—glioma; choroid plexus papilloma;
meningioma; lymphosarcoma; nerve sheath
tumor; medulloblastoma; skull tumor (e.g.,
osteosarcoma); metastasis (e.g.,
hemangiosarcoma and melanoma)
• Nutritional—thiamine deficiency

Cause – Central disease
• Inflammatory, infectious—viral (e.g., FIP, canine
distemper virus); protozoal (e.g., toxoplasmosis); fungal
(e.g., cryptococcosis, blastomycosis, histoplasmosis,
coccidioidomycosis, and nocardiosis); bacterial (e.g.,
central erosion caused by otitis media and interna);
parasitic (e.g., Cuterebra larvae); rickettsial (e.g.,
ehrlichiosis); algae (protothecosis)
• Inflammatory, noninfectious—granulomatous
meningoencephalomyelitis
• Trauma—petrosal bone fracture with brainstem injury
• Toxic—metronidazole


Vestibular disease
•

Unilateral disease—head tilt usually directed toward the side of the
lesion; may be accompanied by other vestibular signs; abnormal
nystagmus (resting, positional) with fast phase usually in the
direction opposite the tilt; mild ventral deviation of the eye (vestibular
strabismus) ipsilateral to the tilt that is exacerbated by elevation of
the head; ataxia and disequilibrium with a tendency to fall, lean, or
circle toward the side of the tilt
• Bilateral disease—head tilt may be absent or mild in the direction
of the more severely affected side; abnormal nystagmus may be
seen; physiologic nystagmus (e.g., normal vestibular nystagmus or
conjugate eye movements) may be depressed or absent with wide
side-to-side swaying movements of the head (especially evident in
cats); may note a wide-based stance, especially in the thoracic
limbs, or a crouched posture with reluctance to move
• Head tilt—must be localized in the peripheral (e.g., vestibular
portion of cranial nerve VIII or receptors in the inner ear) or central
(e.g., vestibular nuclei and their neuronal pathways) nervous system

Vestibular disease
•

Peripheral deficits—horizontal or rotatory nystagmus with fast
phase always in the direction opposite the head tilt; patient may
have concomitant ipsilateral facial nerve paresis or paralysis or
Horner syndrome, because of the close association of cranial
nerves VIII and VII in the petrosal bone and the sympathetic
nervous system in the tympanic bulla.
• Central deficits—vertical, horizontal, or rotatory nystagmus that
can change with the position of the head; altered mentation;
ipsilateral paresis or proprioceptive deficits; other signs related to
the cerebellum, rostral medulla, and caudal pons; in some patients,
multiple cranial nerve involvement other than cranial nerve VII.
• Paradoxical vestibular syndrome—caused by lesions in the
cerebellar peduncles, cerebellar medulla, or flocculonodular lobes of
the cerebellum; vestibular signs (e.g., head tilt and nystagmus) are
opposite the side of the lesion, whereas the cerebellar signs and the
proprioceptive deficits are ipsilateral to the lesion.


Peripheral

Central

Postural reactions

Normal

Abnormal

Mental status

Normal

May be depressed

7

5-12

Symphatetic

-

Cranial nerve deficits
Other nerves
Nystagmus

Fast phase is opposite
Fast phase can be any
the side of the head
direction. If vertical or
tilt, either horisontaly
changes direction, it is
or rotary
usually central


Non Vestibular Head Tilt
and Head Posture
• Uncommon
• Must be differentiated from vestibular head tilt
• Unilateral lesions of the midbrain—cause severe
rotation of the head (rare) of > 90° toward the side
opposite the lesion; no other vestibular signs; tilt corrects
when the patient is blindfolded
• Circling of adversive syndrome (secondary to rostral
thalamic lesions)—the head turn, lean, or neck curvature
can be misinterpreted as a vestibular tilt; no vestibular
signs; contralateral postural, menace, or sensory deficits
reflect a thalamic lesion; compulsive turning, usually in
large circles and without the disequilibrium of vestibular
circling

CBC/Biochemistry
• Usually normal
• Mild anemia—hypothyroidism
• Leucocytosis with neutrophilia—otitis
media or interna
• Thrombocytopenia—ehrlichiosis
• Hypercholesterolemia—hypothyroidism
• High serum globulin concentration—FIP

Treatment
• Inpatient vs. outpatient—depends on severity of the
signs (especially vestibular ataxia), size, and age of the
patient, and need for supportive care
• Supportive fluids—replacement or maintenance fluids
(depend on clinical state); may be required in the acute
phase when disorientation, nausea, and vomiting
preclude oral intake; especially important in geriatric
patients
• Activity—restrict (e.g., avoid stairs and slippery
surfaces) according to the degree of disequilibrium
• Diet—usually no need for modification unless the cause
is thiamine deficiency (e.g., exclusively fish diet without
vitamin supplementation); oral intake may need to be
restricted with nausea and vomiting

Treatment
• CAUTION: be aware of aspiration secondary to
abnormal body posture in patients with severe
head tilt and vestibular disequilibrium or
brainstem dysfunction.
– Advise client that the prognosis for central vestibular
disorders is usually poorer than that for peripheral
disorders.
– Inform client of the risks associated with biopsy,
surgery, and radiation of a brainstem mass.
– Surgical treatment—may be required to drain bulla
with otitis media or interna, to remove
nasopharyngeal polyps in cats, and to resect tumor, if
accessible

Medications
• Otitis media or interna—broad-spectrum antibiotic
(parenteral or oral) that penetrates bone while awaiting
culture results; trimethoprim-sulfa (15 mg/kg PO q12h or
30 mg/kg PO q12–24h); first-generation cephalosporins,
such as cephalexin (10–30 mg/kg PO q6–8h) and
amoxicillin/clavulanic acid (12.2–25 mg/kg PO q12h for
dogs or 62.5 mg/cat PO q12h); treatment often required
for 4–6 weeks
• Hypothyroidism—T4 replacement (dogs, levothyroxine
22 mg/kg PO q12h) should be introduced gradually in
geriatric patients, especially with cardiac disease;
response varies, partly depending on the duration of
signs (e.g., in some patients, neuropathy is not
reversible)

Medications
• Drug affecting vestibular function—discontinue
offending agent; signs are usually, but not always,
reversible.
• Infectious—specific treatment, if indicated; for bacterial
diseases, antibiotic that penetrates the blood–brain
barrier (e.g., trimerhoprim-sulfa, 15 mg/kg PO q12h); for
protozoal diseases, sulfa or clindamycin (12.5–25 mg/kg
PO q12h); for fungal diseases, itraconazole (dogs, 2.5
mg/kg PO q12h or 5 mg/kg PO q24h; cats, 5 mg/kg PO
q12h); prognosis usually grave for protozoal, fungal, and
viral diseases (e.g., canine distemper and FIP)


Medications
• Granulomatous meningoencephalomyelitis—usually
initially treated with steroids: dexamethasone (dogs, 0.25
mg/kg PO, IM q12h for 3 days; then 0.25 mg/kg PO q24h
for 3 days), followed by prednisone (1 mg/kg PO q24h
for 1–2 weeks; then decrease slowly); depending on
progress, may need stronger immunosuppression—
azathioprine (dogs, 2 mg/kg PO q24h initially; then 0.5–1
mg/kg PO q48h)—or radiation
• Trauma—supportive care (e.g., antiinflammatory drugs,
antibiotics, intravenous fluid administration); specific
fracture repair or hematoma removal is difficult,
considering the location.

Medications
• Canine geriatric and feline idiopathic vestibular
disease—supportive care only
• Cranial polyneuropathy—response to prednisone
usually good if the patient has a primary immune
disorder
• Thiamine deficiency—diet modification and thiamine
replacement


Medications
• CONTRAINDICATIONS
– Drugs potentially toxic to the vestibular
system—aminoglycoside antibiotics;
prolonged high-dose metronidazole

• PRECAUTIONS
– Long-term trimethoprim sulfa administration—
keratoconjunctivitis sicca (dry eye)
– Avoid topical drugs (especially oil based) if
the tympanic membrane is ruptured

Head Tilt - triakoso

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