Inner Ear Disorders: Tinnitus & Vertigo

Inner Ear (Tinnitus & Vertigo)

• Tinnitus is any sound perceived by a listener that does not originate from an external sound source for more than five minutes.
• Tinnitus is often not originating from an external source for a time period of more than five minutes.
• Two types of tinnitus exist:
  • Subjective: only the patient can hear it (95%).
  • Objective: even examiners can hear, often pulsatile (synchronous with heartbeat).
• Disturbing tinnitus affects 3-5% of individuals.
• Causes of subjective tinnitus can be:
  • Otologic: impacted wax, middle ear fluid, acute/chronic otitis media, Ménière's disease, presbycusis, noise-induced hearing loss, acoustic neuroma, idiopathic sudden SNHL
  • Metabolic: hypothyroidism, hyperthyroidism, obesity, hyperlipidaemia, vitamin deficiency (e.g., B12)
  • Neurologic: head injury (labyrinthine concussion), temporal bone fractures, whiplash injury, multiple sclerosis, postmeningitic, brain haemorrhage, brain infarct
  • Cardiovascular: hypertension, hypotension, anaemia, cardiac arrhythmias, arteriosclerosis
  • Pharmacologic: certain drugs, ototoxic drugs
  • Psychogenic: anxiety and depression.
• Causes of objective tinnitus can be:
  • Vascular: arteriovenous (AV) shunts, AV malformations, glomus tumor of middle ear, arterial bruit, carotid aneurysm, carotid stenosis, vascular loop pressing on VII nerve, high-riding carotid artery, venous hum, dehiscent jugular bulb
  • Temporomandibular joint (TMJ) disorders
  • Palatal myoclonus
  • Foreign objects (e.g. insects) in the ear
  • Dental: clicking of TM joint
• Causes of tinnitus relating to some change in the auditory system:
  • 80% of patients with sensorineural hearing loss (SNHL) have tinnitus.
  • Hearing loss impacts neural activity within the auditory system, leading the brain to interpret the activity for sound.
  • Areas of the cochlea with hair cell damage cease to amplify sound. Phantom sounds can be perceived in damaged regions by the brain.
• Vertigo is defined as an illusion of movement, either of the patient or of their surroundings.
• Patients with vestibular system damage typically experience dizziness, not vertigo.
• Often, vertigo isn't a permanent, constant symptom. The central nervous system adapts to vestibular lesions, eventually causing it to subside over days or weeks.
• Constant dizziness that lasts for months likely isn't a vestibular-related condition.
• Causes of vertigo by duration:
  • Seconds: Benign paroxysmal positional vertigo (BPPV)
  • Minutes: Migraine, Vertebrobasilar insufficiency
  • Hours: Meniere's disease, Otic syphilis
  • Weeks: CNS disorder, Multiple sclerosis, Acoustic neuroma, Autoimmune
  • Variable duration: Inner ear fistula, Lyme disease, Labyrinthine concussion, Blast trauma, Barotrauma, Superior semi-circular canal dehiscence syndrome
  • Days: Vestibular neuritis, Labyrinthitis

Vertigo Types

• Peripheral: More severe, short-lived, symptoms include tinnitus, diminished hearing, ear discharge, otalgia. Associated with peripheral nystagmus.
• Central: Milder, long-lived and chronic, symptoms include diplopia, slurred speech, dysarthria, and dysphoria. Associated with central nystagmus.

Diagnosis

• Diagnosis primarily depends on a patient's history (onset, character, duration, relationship to head movements, other symptoms such as tinnitus or hearing loss), along with physical examination.
• The diagnosis of inner ear diseases is by exclusion, beginning by excluding central causes first.
• Neurological symptoms, such as loss of consciousness, weakness, numbness, dysarthria, and diplopia, may be considered.

Diagnostic Tests

• Tympanometry (tests middle ear function) may show myoclonic activity and a patent Eustachian tube.
• Pure tone audiometry may detect conductive hearing loss, secondary to vascular lesions affecting the middle ear.
• Imaging using gadolinium-enhanced CT and MRI (in many cases) is necessary to diagnose the root cause.

Management

• Treat tinnitus by identifying and treating the underlying cause.
• Reassurance and psychotherapy (especially if no cause can be found), relaxation, and biofeedback techniques.
• Sedation and tranquillizers may be needed initially to help patients adapt to tinnitus.
• Masking (using noise to cover up tinnitus) can be a useful technique (especially when traditional hearing aids are insufficient).
• Consider sound machines or white noise generators for masking during the night.

BPPV (Benign paroxysmal positional vertigo)

• Characterized by sudden vertigo, lasting seconds, triggered by specific head positions.
• No associated hearing loss.
• Characteristic nystagmus present on the Dix-Hallpike test.
• Most commonly involves the posterior semicircular canal (PSC).
• Typically affects patients in their 50s.
• Recurrence rates are 10-15% a year.
• May involve canalithiasis (ear stones).

Predisposing Factors of BPPV & Dix-Hallpike Test

• Circumstances in which the head is placed in an inverted position (dental procedures).
• Age, inactivity, and family history.
• Head trauma/vestibular neuritis.
• Other ear diseases/Meniere's syndrome.
• Lateral positioning/lying/getting up/looking up/bending.
• Dix-Hallpike test: 1-5 seconds latent period with minimal symptoms, followed by acute vertigo with rotatory nystagmus towards the affected side. The nystagmus typically lasts 10-40 seconds.

Treatment of PSC BPPV

• Repositioning is the first-line therapy.
• Use gravity to reposition ear stones (canalith debris) from the affected canal into the vestibule.
• Epley maneuver is the most common repositioning technique. This is repeated until no nystagmus occurs. (90% effective at treatment).

Meniere's Disease

• Excessive endolymph buildup.
• Associated with episodic vertigo (lasting hours), fluctuating hearing loss, tinnitus and aural pressure.
• Characteristically starts unilaterally, but approximately 25% of cases are bilateral.

• Idiopathic (unknown cause).

• Often associated with other inner-ear disorders, systemic conditions, or allergies.

Meniere's Disease Management

• Stabilize fluid and electrolyte levels in the body (hydrops diet regimen).
• Minimize the intake of solutes and sugars.
• Adequate fluid intake (6-8 glasses daily).
• Caffeine and alcohol restriction.
• Potential for diuretic prescriptions to identify and treat underlying conditions.
• Creating safe and quiet physical environments to mitigate symptoms. 

• Manage persistent symptoms (e.g. aminoglycoside and intratympanic gentamicin therapy) but these have a risk of worsening hearing loss (10%).

Vestibular Neuritis

• Characterized by vertigo lasting days after an upper respiratory infection.
• No hearing loss.

• May experience postural instability towards the infected ear, but typically able to walk.

• Potential etiologies include viral infection, vascular occlusion and/or immunologic mechanisms.

Labyrinthitis

• Often linked to viral causes and is usually not life-threatening.

• Secondary to middle ear infection can be fatal if suppurative labyrinthitis/meningitis occur. 

• Characterized by vertigo, severe vertigo, (and hearing loss occurring simultaneously), may need to rule out middle ear problems in emergencies.

• Post-stapes surgery may weaken the oval window membrane, and congenital abnormalities may cause dehiscent oval windows. 

• Spread is possible through an abnormal cholesteatoma from the middle ear. (e.g., a cholesteatoma can cause a semi-circular canal fistula).

Diffuse Suppurative Labyrinthitis

• Likely related to suppurative otitis media.
• Pathogens are commonly S. pneumoniae, H. influenzae and Neisseria meningitides.
• Management includes hospitalization and intravenous antibiotics to prevent the spread and potential intracranial issues.

Explore the complexities of tinnitus and vertigo in this quiz. Learn about the different types of tinnitus, their causes, and the impact on individuals. Test your knowledge on this important aspect of inner ear health.