Meniere's Disease

Meniere's disease most commonly affects adults aged 40–60. The diagnosis is clinical, based on a classic tetrad: spontaneous episodes of rotational vertigo, fluctuating low-frequency sensorineural hearing loss (SNHL), tinnitus, and a sensation of fullness in the affected ear. In the early stages, hearing often recovers between attacks, but as the disease progresses, permanent SNHL develops, often flattening out across all frequencies. Attacks can be preceded by 'auras' of increased tinnitus or pressure. 'Drop attacks' (Tumarkin's otolithic crises) can occur in late-stage disease where the patient suddenly falls without losing consciousness. Management aims to reduce the frequency and severity of attacks. While not life-threatening, the unpredictable nature of the vertigo can lead to significant psychological distress and occupational impairment. The Driver and Vehicle Licensing Agency (DVLA) must be notified of the diagnosis.

The underlying cause is 'endolymphatic hydrops', which refers to the distension of the endolymphatic compartment of the inner ear. The inner ear contains two fluids: endolymph (high K+) and perilymph (high Na+). In Meniere’s, there is either an overproduction or, more likely, an under-resorption of endolymph in the endolymphatic sac. This leads to increased pressure, which eventually causes a rupture in Reissner's membrane (which separates the two fluids). The mixing of potassium-rich endolymph with perilymph bathes the vestibular nerve fibres, causing depolarization and the acute vertigo attack. The hearing loss results from damage to the delicate hair cells in the cochlea over time due to repeated pressure fluctuations and biochemical changes.

Patients present with discrete 'attacks'. During an attack, there is severe vertigo, often with nausea and vomiting, nystagmus, and a subjective drop in hearing. Between attacks, the patient may be asymptomatic early on. Aural fullness is often the first sign of an impending attack. It is crucial to exclude Mimics: Vestibular Migraine (very common, may have photophobia/headache), Acoustic Neuroma (progressive SNHL/tinnitus, rarely episodic vertigo), and Multiple Sclerosis. Permanent hearing loss starts in the low frequencies (125-1000Hz) which is rare for other causes of SNHL.

- Bedside: Otoscopy (normal in Meniere's), Rinne’s and Weber’s tests (will show SNHL - Weber's lateralises to the 'better' ear).
- Audiology: Pure tone audiometry is essential, showing a low-frequency sensorineural hearing loss.
- Imaging: MRI Internal Auditory Meatus (IAM) is mandatory in patients with unilateral SNHL or tinnitus to exclude a vestibular schwannoma (acoustic neuroma).
- Special tests: Caloric testing or VEMP (Vestibular Evoked Myogenic Potentials) may be performed in specialist balance clinics.

Acute attack: Buccal or IM Prochlorperazine (Stemetil) to control nausea and vertigo. Prophylaxis: First-line is lifestyle modification (low-salt diet, Caffeine/Alcohol avoidance). First-line Medical: Betahistine (16mg TDS). Second-line: Intratympanic steroid injections or Gentamicin injections (note: Gentamicin is ototoxic and carries a risk of permanent hearing loss). Surgical: Endolymphatic sac decompression or Vestibular nerve section (rarely performed now). Safety: DVLA notification is mandatory for vertigo.