Head Tilt - triakoso

triakoso - head tilt 2010

Head Head TiltTilt

Nusdianto Triakoso

triakoso.wordpress.com

Veterinary Teaching Hospital

Airlangga University


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

Cranial nerve deficits 7 5-12

Other nerves Symphatetic -

Nystagmus Fast phase is opposite the side of the head tilt, either horisontaly or rotary

Fast phase can be any direction. If vertical or changes direction, it is usually central


Non Vestibular Head Tiltand 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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