Balance disorders Notes

NOTES NOTES BALANCE DISORDERS GENERALLY, WHAT ARE THEY? PATHOLOGY & CAUSES DIAGNOSIS ▪ Disorders of inner ear (vestibular portion) → disequilibrium (balance loss) DIAGNOSTIC IMAGING CAUSES OTHER DIAGNOSTICS ▪ Inner ear infections, injuries; genetic disorders, others SIGNS & SYMPTOMS ▪ Vertigo ▫ Spinning sensation of oneself/ surroundings ▪ Hearing loss, tinnitus ▪ CT scan, MRI ▪ Audiometric test ▪ Neurologic examination ▪ Clinical manifestation TREATMENT MEDICATIONS ▪ Antibiotics (causitive) ▪ Antihistamines, antiemetics, anticholinergics (symptomatic) SURGERY ▪ Causative treatment OTHER INTERVENTIONS ▪ Vestibular rehabilitation therapy 476 OSMOSIS.ORG

Chapter 63 Balance Disorders LABYRINTHITIS osms.it/labyrinthitis PATHOLOGY & CAUSES ▪ Inner ear (labyrinth) inflation ▪ Damage of auditory, vestibular-end organs responsible for hearing, retaining balance (rotational, linear-motion sensation) CAUSES ▪ Viral infection (rubella virus, cytomegalovirus, mumps virus) ▪ Bacterial infection ▫ Streptococcus pneumoniae, Haemophilus influenzae, Neisseria meningitidis; most commonly meningitis/ otitis media complication ▪ Head injury, stress, allergy, medication RISK FACTORS ▪ Upper respiratory tract infection COMPLICATIONS ▪ Permanent hearing loss SIGNS & SYMPTOMS ▪ Severe vertigo (oneself/surroundings seem spinning), associated symptoms ▪ Fatigue, nausea, vomiting ▪ Rotational motion signalization impairment → nystagmus ▪ Tinnitus, hearing loss ▪ Gait impairment DIAGNOSIS OTHER DIAGNOSTICS ▪ Head, neck examination ▫ Nystagmus ▪ Neurologic examination ▫ Positive Romberg’s test: inability to maintain postural control ▫ Abnormal tandem gait: inability to walk in straight line with one foot in front of other (heel-to-toe) ▪ Head impulse, Nystagmus, and Test of skew (HiNTs) examination ▫ Positive head-thrust test: inability to maintain visual fixation when head turned rapidly toward side of lesion by examiner ▫ Negative test of skew ▫ Direction-changing nystagmus TREATMENT MEDICATIONS ▪ Inflammation ▫ Corticosteroids ▪ Bacterial infection ▫ Antibiotics ▪ Symptomatic treatment ▫ Antihistamines, antiemetics, anticholinergics OTHER INTERVENTIONS ▪ Self-limiting ▫ Recovery in 1–6 weeks ▪ Vestibular rehabilitation therapy ▫ Head, eye movement, postural change, walking exercise OSMOSIS.ORG 477

MENIERE'S DISEASE osms.it/menieres-disease PATHOLOGY & CAUSES ▪ Idiopathic inner-ear disorder ▫ Vertigo, progressive hearing loss CAUSES ▪ Exact cause unknown ▫ Likely abnormal fluid, ion homeostasis in inner ear (endolymphatic hydrops) ▪ Possibly due to endolymphatic sac/ duct blockage, viral infection, vestibular aqueduct hypoplasia, vascular constriction RISK FACTORS ▪ Children ▫ Congenital inner-ear malformations ▪ Family history (10% familial) SIGNS & SYMPTOMS ▪ Spontaneous vertigo episodes (last 20 minutes–24 hours), associated symptoms (fatigue, nausea, vomiting); tinnitus, progressive hearing loss ▪ Less common ▫ Drop attack (sudden fall with preserved consciousness) 478 OSMOSIS.ORG DIAGNOSIS OTHER DIAGNOSTICS ▪ Diagnostic criteria ▫ Two/more unprovoked vertigo episodes (each last > 20 minutes) ▫ Audiometrically-confirmed sensorineural hearing loss in affected ear on at least one occasion before/during/after vertigo episode ▫ Tinnitus/fullness feeling in ear TREATMENT MEDICATIONS ▪ Symptomatic treatment ▫ Antihistamines, antiemetics, anticholinergics SURGERY ▪ Symptoms do not improve ▫ Surgical decompression of endolymphatic sac OTHER INTERVENTIONS ▪ Sodium restriction, diuretics may alleviate symptoms (unknown efficacy)

Chapter 63 Balance Disorders SCHWANNOMA osms.it/schwannoma PATHOLOGY & CAUSES ▪ Benign nerve-sheath Schwann cell tumor ▪ Involves any peripheral nerve ▫ Most commonly affects head, neck nerves; vestibular nerve (vestibular schwannoma) ▪ Associated with neurofibromatosis type II (presents with bilateral schwannomas) ▫ Caused by loss-of-function mutation in neurofibromin 2 (NF2) gene that encodes tumor-suppressor protein merlin (schwannomin) RISK FACTORS ▪ Childhood radiation treatment OTHER DIAGNOSTICS ▪ Neurologic examination ▫ Cranial nerve deficit ▪ Audiometry ▫ Confirms sensorineural hearing loss TREATMENT SURGERY ▪ Excision OTHER INTERVENTIONS ▪ Radiation therapy ▫ Stereotactic radiosurgery, stereotactic radiotherapy, proton beam therapy COMPLICATIONS ▪ Very rarely become malignant (neurofibrosarcoma degeneration) ▪ Left untreated ▫ Brainstem compression, cerebellar tonsil herniation, hydrocephalus SIGNS & SYMPTOMS ▪ Cochlear nerve involvement → hearing loss, tinnitus ▪ Vestibular nerve involvement → walking disequilibrium ▪ Trigeminal nerve involvement → facial paresthesia, hypoesthesia, pain ▪ Facial nerve involvement → facial paresis, gustatory disturbances; xerophthalmia, paroxysmal lacrimation, xerostomia Figure 63.1 The histological appearance of a Schwannoma demonstrating characteristic Antoni A and Antoni B areas. DIAGNOSIS DIAGNOSTIC IMAGING MRI ▪ Mass detection Figure 63.2 The gross pathology of an excised schwannoma. OSMOSIS.ORG 479

VERTIGO osms.it/vertigo PATHOLOGY & CAUSES SIGNS & SYMPTOMS ▪ Sensation that oneself/surroundings are spinning ▫ Symptom, not disease ▪ Labyrinth, vestibular nerve, vestibular centers (in brainstem) damage/dysfunction ▪ Peripheral vertigo ▫ Mild–moderate disequilibrium (dizziness, lightheadedness) ▫ Spinning sensation; fatigue, nausea, vomiting; hearing loss, tinnitus, fullness, ear pain ▪ Central vertigo ▫ Severe disequilibrium ▫ Less prominent spinning sensation, nausea than peripheral vertigo ▫ May be accompanied by neurologic deficits, nystagmus CAUSES ▪ Peripheral vertigo ▫ Calcified otoliths in posterior semicircular canal (canalithiasis) → benign paroxysmal positional vertigo (most common) ▫ Labyrinthitis, Ménière disease, herpes zoster oticus ▪ Central vertigo ▫ Vestibular migraine; brainstem ischemia; cerebellar infarction, hemorrhage; multiple sclerosis MNEMONIC: VOMITS Causes of vertigo Vestibulitis: labyrinthitis or vestibular neuronitis Ototoxic drugs Meniere’s disease Injury Tumor Spin: benign paroxysmal positional vertigo 480 OSMOSIS.ORG DIAGNOSIS DIAGNOSTIC IMAGING MRI/CT scan ▪ Suspected central vertigo ▫ Central nervous system abnormalities OTHER INTERVENTIONS Vestibular system function tests ▪ Differentiate vertigo from other dizziness causes ▪ Electronystagmography ▪ Dix–Hallpike maneuver ▫ Individual sits, head rotated 45° towards ear being tested → individual lowered to supine past bed’s end, extends neck 20° below horizontal → vertigo, nystagmus reproduced → test positive ▪ Head-thrust test ▫ Individual fixates on target while head is rotated quickly → catch-up saccades, nystagmus → test positive

Chapter 63 Balance Disorders ▪ Rotation test ▫ Individual accelerates, decelerates in rotating chair → analyze postrotatory nystagmus → test positive ▪ Caloric reflex test ▫ Cold/warm water/air irrigation into external auditory canal Audiometry ▪ Assess hearing loss TREATMENT MEDICATIONS ▪ Vestibular migraines (underlying cause) ▫ Anticonvulsants, beta blockers ▪ Symptomatic treatment ▫ Antihistamines, antiemetics, anticholinergics, benzodiazepines OTHER INTERVENTIONS ▪ Vestibular rehabilitation therapy OSMOSIS.ORG 481