Dysautonomia refers to a disorder of autonomic nervous system (ANS) function that generally involves failure of the sympathetic or parasympathetic components of the ANS, but dysautonomia involving excessive or overactive ANS actions also can occur. Dysautonomia can be local, as in reflex sympathetic dystrophy, or generalized, as in pure autonomic failure. It can be acute and reversible, as in Guillain-Barre syndrome, or chronic and progressive. Several common conditions such as diabetes and alcoholism can include dysautonomia. Dysautonomia also can occur as a primary condition or in association with degenerative neurological diseases such as Parkinson’s disease. Other diseases with generalized, primary dysautonomia include multiple system atrophy and familial dysautonomia. Hallmarks of generalized dysautonomia due to sympathetic failure are impotence (in men) and a fall in blood pressure during standing (orthostatic hypotension). Excessive sympathetic activity can present as hypertension or a rapid pulse rate.
Signs and symptoms
The symptoms of dysautonomia are numerous and vary widely for each individual,symptoms of dysautonomia are due to inefficient or unbalanced efferent signals sent via both systems. The primary symptoms present in individuals with dysautonomia include:
- Orthostatic hypotension
- Dry mouth
- Rapid heart rate
- Tunnel vision
- Difficulty swallowing
- Bowel incontinence
- Blurry vision
- Urinary incontinence
- Sexual problems
Dysautonomia may be due to inherited or degenerative neurologic diseases (primary dysautonomia) or it may occur due to injury of the autonomic nervous system from an acquired disorder (secondary dysautonomia). The most common causes of dysautonomia include:
- Toxic causes
- Parkinson disease
- Multiple sclerosis Multiple sclerosis
- Guillan Barre syndrome
- HIV and AIDS
- Chronic alcohol misuse
- Lyme disease
- Spinal cord injury
- Surgery or injury involving the nerves
In the sympathetic nervous system predominant dysautonomia is common in fibromyalgia, chronic fatigue syndrome, irritable bowel syndrome and interstitial cystitis, raising the possibility that such dysautonomia could be their common clustering underlying pathogenesis.
The autonomic nervous system (ANS) is a component of the peripheral nervous system and is made up of two branches: the c (SNS) and the parasympathetic parasympathetic nervous system (PNS). The SNS controls the more active responses such as increasing heart rate and blood pressure. The PNS slows down the heart rate and aids in digestion,for example. Symptoms typically arise from abnormal responses of either the sympathetic or parasympathetic systems based on situation or environment.
The diagnosis of dysautonomia should include measurements of blood pressure and heart rate while lying flat, and after 3 minutes of standing. Additional tests and exams to determine dysautonomia (neuropathy diagnosis) includes the following:
- Cold presser
- Hyperventilation test
- Orthostatic intolerance
- Evaluate for acute (intermittent) porphyria.
- Deep breathing
- Valsalva maneuver
- Tilt table test
- Testing for abnormalities of BP
- Quantitative sudomotor axon reflex test (QSART)
- Thermoregulatory sweat test
- Evaluation of cerebrospinal fluid via lumbar puncture
- Small fiber neuropathy biopsy
There is usually no cure for dysautonomia. 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 hypotension include elevation of the head of the bed, water bolus (rapid infusion of water given intravenously), a high-salt diet, and drugs such as fludrocortisone and midodrine.
The outlook for individuals with dysautonomia depends on the particular diagnostic category. People with chronic, progressive, generalized dysautonomia in the setting of central nervous system degeneration have a generally poor long-term prognosis. Death can occur from pneumonia, acute respiratory failure, or sudden cardiopulmonary arrest.