- Clinical science
Ménière disease is an idiopathic condition affecting the inner ear. For unknown reasons, the resorption of endolymphatic fluid is impaired, resulting in its accumulation within the membranous labyrinth (endolymphatic hydrops). The disease usually presents with a triad of symptoms consisting of vertigo, hearing loss, and tinnitus. These episodes often last from minutes to hours and decrease in frequency as patients age. Hearing loss, on the other hand, tends to worsen with every episode. Diagnostic tests show low-frequency hearing loss, typically with a horizontal nystagmus. Acute episodes are treated with bed rest and vestibular suppressants, while long-term therapy focuses on lifestyle changes such as adopting a low-sodium diet and reducing alcohol consumption and stress. In those who do not respond to these measures, interventional and/or surgical treatment may be necessary to shut down the vestibular organ.
- Peak incidence: 40–60 years
Epidemiological data refers to the US, unless otherwise specified.
- Endolymph hydrops: accumulation of fluid in the endolymphatic sac.
All patients with Ménière disease have impaired endolymph resorption, the cause of which is not fully understood. However, not all patients with endolymphatic hydrops have symptoms of Ménière disease. There are currently two theories about why some patients develop symptoms:
- Rupture theory: Fluid accumulation in the endolymphatic sac can cause a tear in the Reissner's membrane, which usually separates the endolymph (rich in potassium) from the perilymph (rich in sodium). The resulting increase in perilymphatic potassium levels depolarizes the afferent acoustic nerve fibers, causing the characteristic symptoms.
- Compression theory: Impaired endolymph resorption leads to compression of the semicircular canal, which is crucial for balance and hearing.
Physiologically, endolymph is rich in potassium, whereas perilymph is rich in sodium. In Ménière disease, the concentration of potassium in the perilymph increases!
Acute, unilateral symptoms that last from minutes to hours. The frequency of these episodes decreases with increasing age. In 30% of patients, the disease eventually affects both sides.
- Ménière triad
- Ear fullness
- Often notable for a horizontal nystagmus
Central Vertigo (CV)
Peripheral Vertigo (PV)
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- Tuning fork tests
- Pure tone audiometry: low-frequency hearing loss
- Suprathreshold audiometry: : displays positive recruitment (outer hair cells are damaged by endolymph hydrops)
- Electroencephalography (EEG): normal auditory evoked potentials (AEP)
The differential diagnoses listed here are not exhaustive.
- Intratympanic gentamicin injection: repeated application of gentamicin to the middle ear cavity through a small incision in the eardrum (paracentesis)
- Sacculotomy: The endolymphatic sac and duct (part of the vestibular organ) is surgically exposed in order to promote drainage of endolymph.
- Vestibular neurectomy: Surgical lysis of the vestibular bundle entering the internal auditory canal. In some cases, the procedure is associated with hearing loss.