Penyakit Meniere

01Pathophysiology

Meniere's disease results from endolymphatic hydrops, a condition where excess endolymph accumulates within the membranous labyrinth of the inner ear. Under normal conditions, endolymph is produced by the stria vascularis in the cochlea and reabsorbed by the endolymphatic sac. When reabsorption fails or production is excessive, the membranous labyrinth distends.

This distension has two consequences. First, the swollen endolymphatic compartment mechanically distorts the basilar membrane and organ of Corti, impairing cochlear transduction. Because the apical turn of the cochlea (responsible for low-frequency sound) is most compliant and therefore most susceptible to pressure changes, low-frequency hearing loss appears first. This is a hallmark finding and the reason audiometry in early Meniere's disease shows a characteristic rising pattern on the audiogram.

Second, periodic rupture of the distended Reissner's membrane allows potassium-rich endolymph to mix with perilymph. This sudden ionic shift bathes the vestibular hair cells and nerve fibers in high-potassium fluid, causing depolarization blockade. The result is a sudden, intense episode of vertigo with nystagmus as the brain receives asymmetric vestibular input. The affected labyrinth initially fires excessively (irritative phase), then becomes temporarily paralyzed (paralytic phase). This explains why the nystagmus may initially beat toward the affected ear and then reverse direction.

The tinnitus and sensation of aural fullness correlate directly with the degree of endolymphatic pressure. As the membrane heals and ionic gradients normalize, symptoms resolve, which is why the disease is episodic and self-limiting per attack but progressive over years. Repeated membrane ruptures cause cumulative damage to both cochlear and vestibular hair cells, leading to permanent hearing loss and eventual burnout of the vestibular organ in late-stage disease.

02Classification and Clinical Manifestation

Staging by Hearing Loss

Clinical Manifestation by Symptom

Definite vs. Probable Meniere's Disease (2015 Classification Criteria)

03Diagnostic Workup

Pure tone audiometry is the cornerstone of the workup and should be the first test ordered when Meniere's disease is suspected. The classic finding is a low-frequency sensorineural hearing loss pattern, often described as a rising audiogram. Serial audiometry is valuable because the hallmark of early disease is fluctuation: hearing may be normal between attacks. During or immediately after an episode, audiometry will capture the characteristic dip.

Electrocochleography measures the ratio of the summating potential (SP) to the action potential (AP) at the cochlear nerve. An SP/AP ratio exceeding 0.4 is considered abnormal and suggests endolymphatic hydrops. This test is particularly useful when audiometry alone is inconclusive.

Gadolinium-enhanced MRI of the inner ear (using intratympanic or intravenous gadolinium with delayed imaging) has become the gold standard for directly visualizing endolymphatic hydrops. It also serves a critical role in excluding vestibular schwannoma (acoustic neuroma), which can mimic Meniere's disease with unilateral hearing loss and tinnitus. Any patient with asymmetric sensorineural hearing loss should receive MRI to rule this out.

Videonystagmography (VNG) with caloric testing assesses the function of each horizontal semicircular canal independently. In Meniere's disease, the affected ear typically shows a reduced caloric response (unilateral weakness). This test does not confirm the diagnosis on its own but quantifies the degree of vestibular damage.

The glycerol dehydration test (oral glycerol followed by repeat audiometry) can provide supportive evidence. If hearing improves by at least 10 dB after the osmotic challenge, it suggests that reversible hydrops is present.

04Management and Treatment

Acute management focuses on symptom control. During an episode, the patient should be placed in a quiet, dark room. Meclizine (an antihistamine with anticholinergic properties) is the most commonly used vestibular suppressant. Benzodiazepines such as diazepam suppress the vestibular nucleus directly and are effective for severe episodes. These medications should not be used long-term because they impair central vestibular compensation.

Long-term prophylaxis begins with dietary sodium restriction, which is the most consistently recommended intervention. Reducing sodium intake lowers the osmotic gradient driving fluid into the endolymphatic space. Thiazide diuretics (hydrochlorothiazide 25 mg daily, often combined with triamterene to prevent hypokalemia) are added when lifestyle changes alone are insufficient. Patients on thiazides require periodic monitoring of electrolytes and renal function. Betahistine, a histamine H1 agonist and H3 antagonist, improves microcirculation in the stria vascularis and is widely prescribed in Europe and Asia, though it is not FDA-approved in the United States.

For patients who fail medical therapy, intratympanic dexamethasone injections are the preferred next step because they offer anti-inflammatory benefit without risk to hearing. If vertigo remains uncontrolled, intratympanic gentamicin is the ablative option of choice. Gentamicin is preferentially vestibulotoxic (more toxic to vestibular than cochlear hair cells), so it can eliminate vertigo episodes while partially preserving hearing. However, there is a 15-30% risk of further hearing loss, so this must be discussed with the patient.

Surgical options are reserved for truly refractory cases. Endolymphatic sac decompression is the least invasive surgical approach and preserves both hearing and vestibular function, though its efficacy is debated. Vestibular nerve section (translabyrinthine or retrosigmoid approach) has the highest vertigo cure rate among hearing-preserving surgeries. Labyrinthectomy is definitive but sacrifices all hearing in the operated ear and is only appropriate when the ear has no serviceable hearing remaining.

Contraindications and cautions: Avoid meclizine and anticholinergics in elderly patients due to sedation and fall risk. Benzodiazepines carry dependence risk. Gentamicin is contraindicated if the contralateral ear also has hearing loss (risk of bilateral deafness). Diuretics require caution in patients with renal insufficiency or electrolyte abnormalities.

05Differential Diagnosis and Distractors

06Traps and High-Yield Pearls

The most common way students miss Meniere's disease questions is by confusing it with BPPV or vestibular migraine. The discriminator is duration: BPPV episodes last seconds, Meniere's episodes last 20 minutes to 12 hours, and vestibular migraine episodes can overlap in duration but lack progressive audiometric hearing loss. When a vignette describes episodic vertigo, the first reflex should be to check the duration and whether hearing loss is documented.

Another frequent trap involves the diagnostic workup. Students often select "MRI" as the first test when they see unilateral hearing loss and tinnitus, thinking of vestibular schwannoma. While MRI is indeed necessary to rule out a schwannoma, the best initial test for a patient presenting with the classic Meniere's triad is audiometry. MRI comes into the workup to exclude structural pathology, not as the first-line diagnostic step for Meniere's itself.

A third pitfall involves management sequencing. Test-writers will present a Meniere's patient who has failed dietary modification and diuretics, then ask for the next step. The answer is intratympanic dexamethasone (non-ablative, hearing-preserving), not intratympanic gentamicin (ablative). Gentamicin is reserved for patients who have failed steroid injections. Jumping to gentamicin too early is a common error, as is jumping directly to surgery.

Finally, remember the "burnt-out" Meniere's concept. A late-stage patient may present with chronic disequilibrium and severe hearing loss but few vertigo attacks. This occurs because the vestibular end organ has been destroyed by repeated injury. Students may not recognize this as Meniere's because the classic episodic vertigo is absent, but the history of prior recurrent episodes and the audiometric pattern will point to the diagnosis.

The core competency being tested is the ability to recognize the full clinical tetrad (episodic vertigo, fluctuating sensorineural hearing loss, tinnitus, aural fullness), correctly sequence the diagnostic workup, and apply a stepwise escalation of therapy from conservative to ablative to surgical.