Dysautonomia

Overview
Dysautonomia is any disease or malfunction of the autonomic nervous system. This includes postural orthostatic tachycardia syndrome (POTS), neurocardiogenic syncope, mitral valve prolapse dysautonomia, pure autonomic failure, multiple system atrophy (Shy-Drager syndrome), Autonomic Instability and a number of lesser-known disorders.

In some cases, dysautonomia results in a reduction in the ability of the heart and circulatory system to compensate for changes in posture, causing dizziness or syncope (fainting) when one, e.g., stands suddenly. In other cases, the heart may race (tachycardia) for no apparent reason (known as Inappropriate sinus tachycardia), or the kidneys may fail to properly retain water (diabetes insipidus).

The effects of dysautonomia may be minor, only limiting the patient's activities slightly, or they may be totally disabling, leaving the patient bedridden.

History
In the nineteenth and earlier twentieth centuries, a diagnosis that was almost solely given to women was called "neurasthenia," or a "weak nervous system." These women would present symptoms of fatigue, weakness, dizziness and fainting, and the doctor's orders would simply be bed rest. Some of these women died, while many others recovered. No one understood where the problems came from.

Nowadays, diagnostic criteria and treatment for various forms of dysautonomia have sharpened, and doctors have realized that some men have it, too.

Causes
Causes of dysautonomias include viral illness, genetic factors, exposure to chemicals, pregnancy, autoimmune disorders, and a trauma or injury which damages the autonomic nervous system.

Treatment
There is no cure for dysautonomia. There are medications to assist in stabilization, but are often needed on a long-term basis. Secondary forms may improve with treatment of the underlying disease. In many cases treatment of primary dysautonomia is symptomatic and supportive. Measures to combat orthostatic intolerance include elevation of the head of the bed, frequent small meals, a high-salt diet, fluid intake, and compression hose. Drugs such as fludrocortisone, midodrine, ephedrine, and SSRIs can also be used to treat symptoms. Treating dysautonomia can be difficult. Treatment that helps one individual may actually worsen the symptoms of another. Often drugs and measures that are helpful are found through trial and error.

Prognosis
The outlook for patients with dysautonomia depends on the particular diagnostic category. Patients with chronic, progressive, generalized dysautonomia in the setting of central nervous system degeneration have a generally poor long-term prognosis. Death can occur in young children and the elderly. Younger patients can die from pneumonia, acute respiratory failure, or sudden cardiopulmonary arrest.

There is some evidence that dysautonomia may be a factor in SIDS (sudden infant death syndrome).