Medical management of Meniere's disease

Introduction:

Medical management of Meniere's disease includes:

1. Dietary management

2. Physiotherapy

3. Psychological support

4. Pharmacologic intervention

Dietary management:

This includes reduction of sodium in the diet. Infact it was Frustenberg in 1934 who introduced a low salt diet for patients with Meniere's disease. Pathophysiology of Meniere's disease is enlargement of membranous labyrinth due to excess accumualtion of endolymphatic fluid. Any attempt to reduce this fluid level will help in alleviate the symptoms of the patient. Medical managment is mainly used to treat patients during the acute phase of the attack. Vestibular suppresants are commonly used. Drugs used to control attacks of vertigo have varying levels of anticholinergic, antiemetic and sedative properties. Drugs used to alleviate symptoms include phenothiazines (prochlorpherazineand perphenazine), antihistamines like ( cinnarizine, cyclizine, dimenhydrinate, and meclizine hydrochloride), benzodiazepines like (lorazepam and diazepam).

Vestibular suppressants:

Diazepam: when used acts as vestibular depressant. It also alleviates the anxiety associated with this disorder. The beneficial effects of diazepam ib vestibular system is presumed to be due to an increase in the cerebellar GABA-ergic system. Stimulation of cerebellar GABA-ergic system mediates inhibition on the vestibular response. This drug is very useful in alleviating vertigo especially when associated with anxiety. Usual dose is 5 mg administered orally every 3 hours. The initial dose may also be administered intravenously.

Antiemetic drugs:

Drugs belonging to this group helps to alleviate vomiting in Meniere's disease.

Anticholinergic drugs:

Glycopyrrolate an anticholinergic drug when combined with diazepam is helpful in controlling inner ear symptoms of nausea and vomiting. In adults it is administered in doses of 1-2 mg. It may also be administered as intramuscular injection (0.1 - 0.2 mg) every 4 hours. Side effects (reversible) of this drug includes dry mouth, distortion of visual acuity, exacerbation of symptoms in patients with prostatic hypertrophy. This drug is contraindicated in patients with glaucoma and prostatic hypertrophy.

Antidopaminergic drugs:

Droperidol: This is an antidopaminergic drug used to alleviate the symptoms of Meniere's disease. This drug is aministered in doses of 2.5 - 10 mg orally in adults. If administered intravenously it is given as 5 mg bolus. This drug has fewer incidence of side effects like extrapyramidal symptoms / sedation / hypotension. Prochlorperazine: This drug belongs to phenothiazine group. It is used as an antiemetic and a potentiator of analgesic and hypnotic drugs. Usual recommeded dose is 10 mg given orally or intramuscularly every 4 - 6 hours in adults. This drug has excellent antiemitic effect.

Antihistamines:

Dimenhydrinate: is useful in preventing and treating vertigo associated with Meniere's disease. It is also very effective in controlling nausea and vomiting. Only side effect of this drug is its propensity to cause drowsiness. It is administered as 50 - 100 mg doses thrice a day. This drug can also be adminsitered intramuscularly / intravenously. Diphenhydramine: This drug is not useful in treating acute vertigo. It may be useful in prevention of vertigo. The usual duration of action is 4-6 hours. Usually this drug is administered as an initial loading dose of 50 mg orally. Meclizine: This drug is one of the most useful antiemetics to prevent / treat nausea and vomiting assocaited with vertigo of vestibular origin. It has a slower onset and a longer duration of action (24 hours). For vertigo the usual dose administered in adults is 25 - 100 mg daily in divided doses. Side effects of this drug include: drowsiness, blurred vision, drowsiness. Promethazine: This drug has pronounced antihistaminic activity in addition to its strong central cholinergic blocking activity. It is effective in the treatment of vertigo and motion sickness. It is adminsitered usually in doses of 25 mg every 4 to 6 hours. One major advantage of this drug is that it can be administered rectally, when severe vomiting prevents its effective oral administration. Most common side effect of this drug is sedation.

Maintenance therapy:

The goal of maintenance therapy is

1. To prevent acute attacks of vertigo

2. To maintain hearing in Meniere's disease

This therapy usually includes dietary modifications combined with pharmacological intervention. Dietary modifications: The mainstay of diet modifications is to reduce sodium intake. A very low sodium intake or low sodium diet is usually recommended. A strict low sodium diet means a daily allowance of 1500 mg. This is a very stringent diet and patients find it very difficult to comply with this diet. A more practical approach would be to advise the patient to avoid excessively salty food. Restrictions are also imposed on the intake of caffeine, nicotine and alcohol.

Diuretics:

The use of diuretics in the maintenance therapy is based on the supposition that these drugs can alter the fluid balance of inner ear, leading to a depletion of endolymph and a correction of hydrops. In 1934 Furstenburg demonstrated that the symptoms of Meniere's disease were due to retention of sodium. He went on to recommend a low sodium diet / use of diuretics to control Meniere's disease. Boles in 1975 demonstrated that most patients had their vertigo controlled with an 800 - 1000 mg of sodium diet / day. Hydrochlorthiazide: This diuretic causes natriuresis and kaliuresis by blocking sodium reabsorption in the loop of Henle. Potassium supplementation is required in patients using this drug. Side effects of this drug include: hypokalemia, hyperglycemia, hypotension, and hyperuricemia. It is usually adminstered as 50 mg tabs orally / day in adults. Potassium supplements is usually required in these patients. Dyazide: Is a potassium sparing diuretic. It can be convenietly administered as a single daily dose. Frusemide: This is a loop diuretic. It is a very potent diuretic. It can cause electrolyte and volume depletion more rapidly than other diuretics. It usually causes hypokalemia. Usual adult dose is 10 - 80 mg/day. The duration of action lasts for about 4 hours. Amiloride: This is a potassium sparing diuretic acting on the distal tube of Henle. Its diuretic potency is highly limited. It is usually used in combination with other diuretics in order to minimize potassium loss.

Carbonic anhydrase inhibitors:

Acetazolamide: Is a carbonic anhydrase inhibitor. It causes a decrease in the sodium - hydrogen exchange in the renal tubule inducing diuresis.

Methazolamied: Is another carbonic anhydrase inhibitor shown to be effective in controlling symptoms of Meniere's disease. This drug is usually administered in doses of 50 mg / day, 5 days a week for 3 months.

Medical ablative therapy:

Aminoglycosides: Ototoxic effects of aminoglycosides are well documented. Streptomycin and gentamycin are predominantly vestibulotoxic. Intramuscular injections of streptomycin administered twice daily for periods of days to weeks have been used in patients with debilitating bilateral disease / unilateral disease in the only hearing ear. Complete ablation causes disabling oscillopsia. Many authors have suggested lower doses and fewer injections to achieve partial ablation, thereby reducing the incidence of severe ataxia. Currently the recommended daily dose is 1 g of streptomycin intramuscularly 5 days a week until vestibular ablation occurs as manifested by absence of ice water caloric test. Intratympanic injections of these drugs have also been used with success.

Vasodilators:

The use of vasodilators is based on the idea that Meniere's disease results from ischemia of the stria vascularis. Betahistine has been used with varying degrees of success. This drug can be used for short term control of vertigo and for maintenance therapy. Nicotinic acid is another vasodilator which when administered 30 minutes before meals in doses of 50 - 400 mg helps in resolving the acute crisis associated with Meniere's disease.

Calcium channel blockers:

Nimodepine a highly lipophilic drug is very useful in the medical management of Menierie's disease. It readily crosses the blood brain barrier. This drug is useful in patients who have failed diuretic medical therapy.

ACE inhibitors:

These are very effective vasodilators. These drugs block the rening angiotensin aldosterone system. They produce vasodilatation by blocking angiotensin II induced vasoconstriction.

Lipoflavins and vitamins:

Combination of lipoflavins and vitamins have been tried as a managment modality with varying degrees of success.