Ear II

Question 1

Conductive hearing loss

• Mechanisms
• Pathophysiology
• Etiology

Answer 1

Conductive hearing loss

• Air conduction measures the ability of the external and middle ear to transmit sound to the cochlea
• Mechanisms
  
  • Obstruction
  • Mass effect (something blocking)
  • Stiffness effect (TM not moving)
  • Discontinuity (TM perforation)
• Often temporary

Pathophysiology

• Think external ear and middle ear problems
• Amount of sound transmitted to inner ear is limited

Etiology

• MC: cerumen
• Eustachian tube dysfunction
• E.g. ear wax, OE, FB, trauma, effusion, tumor, ETD

Question 2

Sensorineural hearing loss

• 2 types of mechanisms
• Etiology

Answer 2

Sensorineural hearing loss

• Think inner ear
• Mechanisms
  
  • Sensory loss - dysfunction of the cochlea, often from loss of hair cells
  • Neural loss - dysfunction of CN VIII or central auditory pathway

Etiology

• MC: presbycusis (old age)
• Loud noise (acoustic trauma)
• Meniere’s disease
• Head trauma
• Systemic diseases
• Acoustic neuroma
• MS
• Auditory neuropathy

Question 3

Tinnitus

• What is it
• 2 types
• Epidemiology
• Pathology
• Evaluation and PEx
• Diagnostics
• Treatment
• Experimental therapy
• Prognosis

Answer 3

Tinnitus

• Perception of sound in the ear or head
• Mild, high pitched sounds - usually ringing, buzzing, and hissing
• Continuous or intermittent (sec to min)
• Often associated with sensory hearing loss

Types

• Pulsatile tinnitus
  
  • Hearing one’s own heartbeat
  • Usually indicates a vascular abnormality
• Staccato tinnitus
  
  • Rapid serious of pops or clicks with sensation of ear fluttering
  • Occurs from middle ear muscle spasm

Epidemiology

• Men > women
• 50 million people in the US
• 12 million have some degree of disability due to condition
• Prevalence increases with age

Pathology

• May come from somatic sounds near the cochlea
• Many theories involving disruption of the normal neural firing patterns along the auditory pathway
  
  • Loss of cochlear input to neurons in central auditory pathways can cause abnormal neural activity in auditory cortex
  • Development of alternative neural synapses that lack normal inhibitory pathways
  • Auditory “seizure” (abnormal auditory-evoked potentials)
  • Neurotransmitter abnormalities (serotonin, GABA)

Evaluation

• History
  
  • Full hearing loss history
  • Ask about medical hx: HTN, neurologic dz, depression, anxiety, insomnia, etc
  • Assess for clues to vascular tinnitus
• Physical exam
  
  • Complete head, ear, and neck exam
  • Include CNs
• Audiometry

Diagnostics

• If unilateral without obvious etiology, then consider MRI
• If pusatile, consider MRA, MRV, or temporal bone CT

Treatment

• Patient education
• Tx underlying condition (e.g. HTN, depression)
• Stop ototoxic medications
• Avoid exposure to excessive noise
• Behavioral therapy
• Masking (listen to music)

Experimental therapy

• Transcranial magnetic stimulation of the central auditory system
• Transcranial direct current stimulation
• Deep brain stimulation
• Brain surface implants
• Vagus nerve stimulation

Prognosis

• When severe and persistent, can interfere with sleep and concentration
• Can cause significant psychologic distress

Question 4

Dizziness

• Differental diagnosis
• Evaluation

Answer 4

Dizziness

Differential diagnosis

• Vertigo (peripheral and central)
• Disequilibrium
  
  • Peripheral neuropathy
  • MSK disorders that affect gait
  • Vestibular
  • Cerebellar
  • Cervical spondylosis
  • Parkinson dz
  • Visual impairment
• Presyncope (feeling like you’re going to pass out)
  
  • Cardiac dysrhythmia
  • Orthostatic hypotension
  • Med side effects
  • Other causes of brain hypoperfusion
• Nonspecific dizziness
  
  • Psychiatic disorders
  • Fibromyalgia
  • Hyperventilation
  • S/p head trauma or whiplash injury
  • Hypoglycemia
  • Med side effects

Evaluation

• History
  
  • Description of dizziness
  • First attack, duration, provoking factors, associated symptoms
• Physical exam
  
  • Vitals
  • Orthostatics
  • General, HEENT, cardiac, neurologic

Question 5

Vertigo

• What is it
• Peripheral vs central causes
• Clinical presentation for both
• Diagnositcs
• Vestibular disorders

Answer 5

Vertigo

• Sense of motion when there is no motion
  
  • Spinning sensation
  • Sense of tumbling forward
  • Falling forward or backward
• Primary symptom of vestibular dz
• It is critical to differentiate between central and peripheral causes

Peripheral vertigo causes

• Vestibular neuritis/Labyrinthitis
• Meniere disease
• Benign positional vertigo
• Ethanol intoxication
• Inner ear barotrauma
• Semicircular canal dehiscence

Central vertigo causes

• Seizure
• Multiple sclerosis
• Wernicke encephalopathy
• Chiari malformation
• Cerebellar ataxia syndromes

Peripheral and central causes

• Migraine
• Stroke
• Vascular insufficiency
• Cerebellopontine angle tumors
• Infections (Lyme, syphilis)
• Vascular compression
• Hyperviscosity syndromes
• Endocrinopathies (hypothyroidism)

Clinical presentation

• Central vertigo
  
  • Gradual onset
  • Progressive increase in severity
  • Gait and posture impaired significantly
  • Nystagmus – any direction, nonfatigable, no latency, no suppression with visual fixation
  • NO auditory symptoms
• Peripheral vertigo
  
  • Sudden onset
  • Acutely severe symptoms
  • N/V
  • Tinnitus
  • Hearing loss
  • Horizontal nystagmus with rotatory component
  • Eye motion in response to head turning

Diagnostics

• Dix Hallpike maneuver
  
  • Positive test: delayed onset fatigable nystagmus in most peripheral causes
  • If nystagmus is non fatigable, this indicates central cause
• Audiometry
• ENG/VNG (electronystagmogrophy/videonystagmography)
• Caloric stimulation
• VEMP
• MRI

Vestibular disorders

• BPPV
• Labryinthitis
• Meniere’s dz

Question 6

Benign paroxsmal positional vertigo (BPPV)

• What is it
• Treatment

Answer 6

Benign paroxsmal positional vertigo (BPPV)

• Caused by sediment in semicircular canals (otoconia, otoliths, cannalith)
• Provoked by changes in head position
  
  • “I roll over and become dizzy”
  • Acute vertigo x 10-60 seconds
  • Imbalanced x several hours
• Episodes are brief in duration, often recurrent
• Appear in clusters lasting for several days

Treatment

• Epley maneuver
• PT or OT referral
• Drugs - vestibular suppressents (meclizine)
• Bed rest may be needed if severe
• Patient education - risk for falls

Question 7

Labyrinthitis

• AKA
• Etiology
• Clinical presentation
• Diagnostics
• Treatment
• Patient education

Answer 7

Labyrinthitis

AKA

• Vestibular neuritis
• Vestibular neuronitis
• Neurolabyrinthitis
• Acute peripheral vestibulopathy

Etiology

• Inflammatory disorder of the vestibular portion of CN VIII
• Often occurs post viral infection
• Do not miss cerebellar hemorrhage or infarct!!!! Always have good neuro eval and hx when pt has symptoms like this

Clinical presentation

• Acute onset of continuous, severe vertigo
• Commonly seen with hearing loss and tinnitus
• N/V
• Gait impairment

Diagnostics

• Neuroimaging with MRI/MRA (if you cannot r/o with history)

Treatment

• Abx if pt is febrile or with sxs of bacterial infection
• Vestibular suppressents (for symptom control)
  
  • Anticholinergics
  • Antihistamines
  • Benzos
• Antiemitcs (zofran)
• Corticosteroids (benefit is unclear)

Patient education

• Reassure that it is benign
• Recovery is gradual, over several weeks
• All about symptom control
• May need vestibular rehabilitation referral

Question 8

Meniere Disease

• AKA
• What is it
• Pathophysiology
• Clinical presentation
• What is the triad of sxs
• Diagnosis
• Treatment

Answer 8

Meniere Disease

• AKA endolymphatic hydrops
• Vertigo syndrome due to a peripheral lesion

Pathophysiology

• Distention of endolymphatic compartment of inner ear
• Symptoms wax and wane as endolymphatic pressure rises and falls
• Can permanently damage inner ear structures

Clinical presentation

• Episodic vertigo with discrete spells lasting 20 min to several hours
• Fluctuating sensorineural hearing loss
• Low frequency! (unqiue to Meniere)
• Tinnitus – low tone, blowing/roaring quality
• Sensation of unilateral ear pressure (aural fullness)
• Vertigo + hearing loss + tinnitus = Meniere

Diagnosis

• Dx of exclusion, there is no definitive positive test
• Refer to ENT / audiology
• Caloric testing

Treatment

• Difficult to tx, aimed at decreasing endolymph fluid pressure in inner ear
• Diuretics (acetazolamide)
• Low salt diet
• Refractory cases
  
  • Intratympanic corticosteroid injections
  • Endolymphatic sac decompression
  • Vestibular ablation (transtympanic gentamicin, vestibular nerve section, or labyrinthectomy)

Question 9

​Vestibular schwannoma

• AKA
• What is it
• Pathophysiology
• Clinical presentation
• Diagnosis
• Treatment

Answer 9

Vestibular schwannoma

• AKA acoustic neuroma
• One of the most common intracranial tumors
• Unilateral hearing loss with no other sxs = think vestibular schwannoma!

Pathophysiology

• Benign tumor of cranial nerve VIII
• Begins in internal auditory canal
• Gradually grows to compress pons and cause hydrocephalus

Clinical presentation

• Unilateral hearing loss
• Continuous dysequilibrium
• Tinnitus

Diagnosis

• Audiometry
• MRI with contrast

Treatment

• Observation
• Surgical excision
• Radiotherapy