Pathophysiology
Endolymph is the fluid found within the membranous labyrinth. It is produced within a region of the cochlear duct known as the stria vascularis. This region contains specialised epithelial cells which produce and secret endolymph fluid. It is also known as endolymphatic hydrops.
The exact pathophysiology is not well known. However, it is believed that dysfunctioning sodium channels set up an osmotic gradient that encourages endolymph movement into the membranous labyrinth.
😷 Presentation
- Most common in middle-aged adults.
- It has a classical triad of:
- Episodic vertigo attacks lasting >20 minutes.
- Fluctuant or permanent sensorineural hearing loss.
- Tinnitus
- There may be a sensation of aural fullness and the patient may fall to one side.
Symptoms tend to be unilateral with episodes lasting minutes-hours (resolving within 24 hours). During periods of remission, the sensorineural hearing loss tends to worsen over time.
🔍 Investigations
It is predominantly a clinical diagnosis on the basis of Meniere’s triad.
- Otoscopy - normal ear drum.
- Audiometry - sensorineural hearing loss.
- Tympanometry - normal (type A).
🧰 Management
- Management requires sufficient prophylaxis between attacks:
- Suitable lifestyle advice (reducing salt or avoiding chocolate and caffeine)
- Regular betahistine medication (H1 agonist that functions as a vestibular sedative)
- Acute vertigo and nausea are managed with prochlorperazine (another vestibular sedative/ anti-emetic)
May be warranted if prophylactic management is insufficient:
Intra-tympanic gentamicin injections
Intra-tympanic steroid injections
Endolymphatic sac destruction
Labyrinthectomy (rare)