What is dysautonomia?
Dysautonomia is a term used to describe a wide range of conditions caused by our autonomic nervous system not functioning properly. There are around 15 different types of dysautonomia, and it is estimated to affect more than 70 million people worldwide. The most common types of dysautonomia are neurocardiogenic syncope and Postural orthostatic tachycardia syndrome (POTS).
We have two main nervous systems in our brain, our central nervous system (which consists of our brain and spinal cord) and our peripheral nervous system (which consists of all the nerves that branch out from the brain or spinal cord and extends to all the muscles and organs in the body). The autonomic nervous system is part of our peripheral nervous system and is largely under involuntary control, and is responsible for regulating vital physiologic processes such as heart rate, blood pressure, respiration, digestion, and sexual arousal.
What causes dysautonomia?
The autonomic nervous system contains three anatomically distinct divisions: the sympathetic, parasympathetic and enteric nervous systems. Dysautonomia generally involves the failure of the sympathetic or parasympathetic components of the autonomic nervous system, but dysautonomia that involves an excessive or overactive autonomic nervous system can also occur.
Our autonomic nervous system has many functions, such as maintaining a constant internal temperature, regulating breathing patterns, maintaining good blood pressure control, and maintaining heart rate. Many other functions, such as pupil dilation, sexual arousal, and excretion are also under the control of our autonomic nervous system.
Dysautonomia can be classified as either primary, which is generally inherited or due to degenerative disease; or secondary, which can result from another condition or injury.
Primary Dysautonomia
- Familial dysautonomia (Riley-Day syndrome)
- Idiopathic orthostatic hypotension (progressive autonomic failure)
- Multiple system atrophy with autonomic failure (Shy-Drager syndrome)
- Parkinson’s syndrome with autonomic failure
Secondary Dysautonomia
- Amyloidosis
- Autoimmune neuropathies (Guillain-Barre syndrome, Myasthenia gravis, Rheumatoid arthritis)
- Carcinomatous autonomic neuropathy
- Central nervous system disease (hypothalamic lesions, posterior fossa tumors, syringomyelia, tertiary syphilis, Wernicke’s syndrome
- Diabetes mellitus
- Metabolic diseases (Fabry’s disease, pernicious anemia, porphyria, Tangier disease)
- Drug-related (eg, due to alcohol, antidepressants, antihypertensives, or antipsychotics)
What are the symptoms of dysautonomia?
Symptoms generally reflect a problem with one of the functions under autonomic system control. Symptoms may be mild and subtle and may go unnoticed or may be attributed to another condition. It is usually a combination of symptoms that establishes that dysautonomia is present.
Symptoms may come and go and vary in their severity. Sometimes physical activity can trigger more severe symptoms. The most common symptom (affecting 94% of all people with dysautonomia) is postural hypotension (which is when your blood pressure suddenly falls when you stand up quickly after lying down or sitting), causing a person to feel dizzy, lightheaded, or to faint.
Symptoms may include:
- An irregular, fast, or slow heartbeat
- Anxiety
- Breathing difficulties
- Concentration or memory problems
- Decreased sweating
- Difficulty staying upright or an unsteady gait
- Difficulty coping with noise and light
- Chest pain
- Exercise intolerance
- Fatigue
- Gastrointestinal problems (such as nausea, diarrhea)
- Low blood pressure
- Migraines
- Mood swings
- Poor appetite
- Sexual dysfunction (such as impotence, loss of libido, retrograde ejaculation)
- Sleep disturbances
- Slurred speech
- Temperature regulation problems
- Tremors
- Urinary problems (such as frequent urination)
- Visual field disturbances
- Weakness
How is dysautonomia diagnosed?
See your doctor if you have any persistent symptoms or collection of symptoms typical of dysautonomia. Your doctor will need to take a thorough history and perform a physical examination and possibly conduct tests to determine if an underlying condition is present.
Classical symptoms of generalized dysautonomia due to sympathetic failure are impotence in men and postural hypotension. Excessive sympathetic activity can cause high blood pressure or a rapid heart rate.
How is dysautonomia treated?
There is no single treatment that helps with all dysautonomias. For most, there is no cure, although symptoms may improve in some secondary dysautonomias if the underlying cause is treatable.
For many dysautonomias, treatment is symptomatic and supportive and may consist of:
- Elevation of the head of the bed
- A high-salt diet
- Medications such as fludrocortisone or midodrine
