Ménière's disease is a disorder of the inner ear. The exact causes of the condition are still unknown.
There are number of factors that affect the risk of this disease that include:
- trauma related
- endocrinal or hormonal problems
- blood vessel related
- genetic variations
The disease affects the inner ear.
Physiology of the inner ear
There are two major organs in the inner ear:
- the cochlea - a spiral shell shaped organ that contains two fluid-filled chambers and is the main organ for hearing
- the vestibular apparatus - this contains a set of complexly positioned tubes called the membranous labyrinth that help in maintenance of balance.
The fluid inside the inner ear is called endolymph.
Pathophysiology of Ménière's disease
In patients with Ménière's disease the pressure of the endolymph fluid is altered. In some patients there is too much fluid and this may create a swelling and affect the surrounding structures.
If it affects the cochlea there is hearing loss and if it affects the labyrinth there are balance problems and dizziness. The cause of this endolymph fluid pressure change is unknown.
The primary problem thus is obstruction in the ducts that carry endolymph. A mechanical block due to fibrous deposits, viral infections, inflammation due to over activity of the immune system or lack of blood supply (ischemia) of the ducts may all be causes of the condition.
Risk factors that predispose to Ménière's disease
Risk factors that predispose to Ménière's disease include genetic association, viral infections and so forth.
Ménière's disease is seen to run in families in some 10% of the cases. This indicates that there may be genetic association with the disease and the diseased or faulty genes are often passed down in families.
There are findings in studies that a defective gene that codes for a calcium gene may be the link between this disease and families suffering from it.
Viral infections that lead to meningitis or infection of the membranes that surround the brain and spinal cord are also linked in causation of Ménière's disease.
Other infections that may cause the condition include otosyphilis or syphilis affecting the ears and infections with Herpes simplex virus.
Other risk factors that predispose to Ménière's disease
Other risk factors that predispose to Ménière's disease include:
- Allergic tendencies to certain foods
- Chemical imbalance in the fluid in the inner ear with too little or too much sodium or potassium
- Since Ménière's disease and Migraine headaches seem to have an association there are hypotheses that suggest that there may be an underlying problem with blood vessels. Migraines are caused by narrowing and widening of blood vessels of the head.
- Cogan's syndrome (non-syphilitic interstitial keratitis and bilateral audiovestibular deficits) is also linked to the condition
- Stress and anxiety may also bring upon attacks but are not direct causes of the disease. (1-8)
Ménière's disease and Autoimmune conditions
Normally the body’s immunity detects what is its own and what is foreign. When it encounters something foreign it attacks the cells with the help of white blood cells.
In patients with autoimmune diseases the fighter cells fail to recognize the cells of the body and attack them. Patients of Ménière's disease may develop antiphospholipid antibodies, rheumatoid arthritis and lupus.