Dysautonomia presents in a number of forms, but all of them involve dysfunction of the autonomic nervous system (ANS), usually manifesting as failure of the sympathetic or parasympathetic components of the ANS. Less commonly, dysautonomia occurs due to overactivity of the ANS.
The ANS is the division of the nervous system that orchestrates unconscious homeostatic operations, i.e. activities that the body carries out automatically without input from higher brain centers.
In particular, the ANS is responsible for maintaining a constant internal temperature, regular breathing patterns, steady blood pressure, appropriate pupil dilation, sexual arousal and excretion. Symptoms of dysautonomia, therefore, generally manifest themselves as errors in those particular areas of physiology.
Dysautonomia is more common in females and often occurs during puberty, although these conditions can arise at any age.
There are a number of dysautonomia subtypes, and so symptoms vary. Some of the more common symptoms are lightheadedness, fainting, unstable blood pressure and an abnormal heart rate.
In the most serious cases, death can occur from pneumonia, acute respiratory failure or sudden cardiopulmonary arrest.
Dysautonomia secondary to another disease or condition can be treated by resolving or managing the underlying causes of the illness.
It is worth noting that dysautonomias can develop as part of other diseases such as diabetes, multiple sclerosis, rheumatoid arthritis, celiac disease, Sjögren’s syndrome (an autoimmune system that attacks glands), lupus and Parkinson’s disease.
Fast Facts on Dysautonomia3>
Here are some key points about dysautonomia.
- Dysautonomia describes a range of conditions that affect the autonomic nervous system.
- The autonomic nervous system is responsible for unconscious control of bodily functions.
- The effects of dysautonomias range from lightheadedness through to premature death.
- Neurocardiogenic syncope and postural orthostatic tachycardia syndrome (POTS) are the most common dysautonomias.
- Research suggests POTS may be an autoimmune condition.
- There is usually no cure for primary dysautonomia (symptoms of secondary dysautonomia can improve by treating underlying disease).
- Dysautonomias often go undiagnosed or are misdiagnosed.
- Hallmarks of dysautonomia include impotence and orthostatic hypotension (a sudden drop in blood pressure upon standing).
Neurocardiogenic syncope (NCS) is the most common of the dysautonomias and is thought to affect tens of millions of people worldwide. The major symptom of NCS is fainting, otherwise known as syncope.
When standing, gravity pulls blood downward toward the lower extremities. This can cause partial drainage of blood from the head and thorax. In a healthy individual, the ANS increases vascular tone, heart rate and cardiac output to counteract the changes.
In people with NCS, these mechanisms do not always work correctly, resulting in fainting as the brain is deprived of blood and the oxygen it supplies.
The severity of NCS varies significantly, with some sufferers experiencing a single fainting episode and others having difficulty functioning during their normal lives due to regular fainting episodes.
The following, simple measures often make big differences to those who are at the milder end of the scale of symptoms:
One of the most common of all the dysautonomias, postural orthostatic tachycardia syndrome (POTS) is estimated to affect around 1% of all teenagers – somewhere between 1 and 3 million American teens. POTS is about five times more prevalent in females than males.
As POTS is a syndrome rather than a disease, this means that it is caused by something else, although it is usually difficult to figure out the cause(s) of any individual case. The disorder has, however, been associated with a range of other conditions and diseases, including:
Researchers now believe that POTS encompasses a range of clinical disorders with similar characteristics. The symptoms can include, but are not limited to:
There is evidence that the hormone norepinephrine plays a role in the etiology of POTS.
Potential mechanisms of action include mutations in the genes that code for norepinephrine transportation, impaired vascular innervation, high plasma norepinephrine concentrations and alpha receptor sensitivity (alpha receptors are targets of norepinephrine).
Other research indicates that POTS may be an autoimmune condition. Antibodies to adrenergic receptors (receptors that react in the presence of norepinephrine) and other relevant structures have been identified in patients with POTS.
A range of lifestyle interventions can help patients manage the symptoms of POTS, and there are several medications that may also help. The important thing is for patients to consult a physician who has experience in treating autonomic disorders as every individual case is different.