Dysautonomia is not a single disorder, the term describes a number of conditions which affect the autonomic nervous system. This section of the nervous system controls automatic body functions, like heart rate and breathing.
Despite the term being unfamiliar to many people, dysautonomia affects an estimated 70 million people worldwide.
In this article, we will describe some of the different types of dysautonomia, their symptoms, and treatments.
Contents of this article:
Fast facts on dysautonomia
Here are some key points about dysautonomia. More detail and supporting information is in the main article.
- The effects of dysautonomias range from lightheadedness to premature death
- Neurocardiogenic syncope and postural orthostatic tachycardia syndrome (POTS) are the most common dysautonomias
- Some researchers believe POTS may be an autoimmune condition
- Dysautonomias often go undiagnosed or they are misdiagnosed
What are dysautonomias?
Dysautonomia is a condition caused by malfunction of the autonomic nervous system.
Dysautonomias come in many forms, but they all involve the autonomic nervous system (ANS).
The ANS controls automatic activities in the body. For instance, the ANS is responsible for maintaining a constant internal temperature, regulating breathing patterns, a steady blood pressure and heart rate, and, appropriate pupil dilation, sexual arousal, and excretion.
Symptoms of dysautonomia, therefore, generally manifest themselves as problems in those particular body systems.
Dysautonomias are more common in females and often occur during puberty, but they can arise at any age.
Although there is a range of dysautonomias, they all share certain symptoms, including lightheadedness, fainting, unstable blood pressure, and an abnormal heart rate.
Some dysautonomias are inherited or due to a degenerative disease, these are called primary dysautonomias. Others are because of an injury or a separate condition, these are referred to as secondary dysautonomias. Common conditions that can lead to secondary dysautonomias include diabetes mellitus, multiple sclerosis, rheumatoid arthritis, Parkinson's disease, and celiac disease.
There is currently no cure for primary dysautonomias, but some medications and interventions can relieve the symptoms. Secondary dysautonomias often improve once the initial condition is treated.
Types of dysautonomia
There are at least 15 distinct dysautonomias; the most common are neurocardiogenic syncope and postural orthostatic tachycardia syndrome (POTS). Below is a summary of some of the more frequent dysautonomias.
Neurocardiogenic syncope (NCS) is the most common dysautonomia and affects tens of millions of people worldwide. The major symptom of NCS is fainting, also called syncope.
When standing, gravity pulls blood downward toward the lower extremities. This causes blood to drain from the brain. In a healthy person, the ANS tightens the muscles within the veins and alters the heart rate to make sure the blood does not pool in the feet and legs.
These mechanisms don't always work correctly for people with ANS. This means they are more likely to faint as the blood briefly leaves the brain.
Some individuals with NCS might only faint rarely, but others might have difficulty carrying out normal tasks because fainting is so frequent.
Most treatments or interventions for NCS are aimed at preventing the symptoms. The following changes to one's normal routine can make a big difference in those who have less serious cases of NCS:
- Increased fluid and salt intake can relieve most symptoms for some individuals
- Avoid standing in queues
- Take shorter, cooler showers
- Avoid saunas, hot baths, and sunbathing
- When standing, shift from one leg to the other and flex leg muscles
- Avoid alcohol
- Reduce caffeine intake
Postural orthostatic tachycardia syndrome
POTS is estimated to affect around 1 percent of all teenagers - somewhere between 1 and 3 million American teens. POTS is about five times more common in females than males.
POTS is normally caused by a secondary factor, but it is often difficult to work out what that is. Symptoms of POTS can include:
- Lightheadedness and fainting
- Tachycardia (abnormally fast heart rate)
- Chest pains
- Shortness of breath
- Stomach upset
- Easily exhausted by exercise
- Over-sensitivity to temperatures
The disorder has been associated with a range of other conditions and diseases, including:
- Autoimmune diseases.
- Ehlers Danlos Syndrome - a collagen protein disorder than can lead to joint hypermobility and "stretchy" veins.
- Genetic disorders or abnormalities.
- Infections such as Epstein Barr virus, Lyme disease, extra-pulmonary mycoplasma pneumonia and hepatitis C.
- Multiple sclerosis.
- Toxicity from alcoholism, chemotherapy, and heavy metal poisoning.
- Traumas, pregnancy, or surgery.
- The causes of POTS are still not understood, but researchers are investigating a number of avenues. Some scientists believe the condition might be due to a genetic mutation; others think it may be autoimmune (an individual's immune system attacking its own cells).
Multiple system atrophy
Multiple system atrophy is often mistaken for Parkinson's in the early stages.
Multiple system atrophy (MSA) is a much rarer condition than POTS and NCS and is slightly more common in males than in females. It is also more likely to occur in persons over the age of 50.
Approximately 25,000-100,000 Americans are estimated to have MSA at any given time. It is often mistaken for Parkinson's disease because the early symptoms are similar.
In the brains of people with MSA, certain regions slowly break down, namely the cerebellum, basal ganglia, and brainstem.
Little is known about the causes of MSA. In fact, experts know more about what it isn't than what it is. It is not hereditary, it is not contagious, and it is not related to multiple sclerosis.
At this time, there is no cure for MSA and treatment only manages symptoms and supports patients.
Autonomic dysreflexia (AD) is most often found in people with injuries to their spinal cord. AD normally occurs when something irritates the region below the level of a patient's injury. For instance an infection or constipation.
The patient's damaged spine prevents pain messages from reaching the brain. The ANS acts as if confused and reacts inappropriately, producing severe spikes in blood pressure.
Most treatments of AD aim to reduce the initial irritation, which prevents further attacks of AD.
The baroreflex mechanism is one of the body's many ways of maintaining the right blood pressure.
Baroreceptors are stretch receptors situated in important blood vessels. They detect stretching in the artery walls and send messages to the brainstem.
If these messages fail, blood pressure can be too low when resting or rise dangerously during times of stress or activity. Other symptoms include headaches, excessive sweating, and an abnormal heart rate that does not respond to medication.
Baroreflex failure sometimes occurs after surgery, radiation for cancer, and nerve injury. However, the cause is often not known.
Treatment for baroreflex failure involves medications to control heart rate and blood pressure, as well as interventions to improve stress management.
Diabetic autonomic neuropathy
Diabetic autonomic neuropathy affects an estimated 20 percent of people with diabetes, around 69 million people worldwide. The condition affects the nerves that control the heart, regulate blood pressure, and control blood glucose levels.
Symptoms can include the following:
- Resting tachycardia (fast heart rate)
- Orthostatic hypotension
- Breathing problems
- Gastroparesis (food not passing through the stomach normally)
- Erectile dysfunction
- Sudomotor (sweating) dysfunction
- Impaired neurovascular function
- "Brittle diabetes" (difficult to manage diabetes, usually type I, characterized by frequent episodes of hyperglycemia and hypoglycemia).
Treatment for diabetic autonomic neuropathy focuses on careful management of diabetes. In some cases, antioxidants and aldose reductase inhibitors can reduce symptoms.
Familial dysautonomia is a very rare version of dysautonomia. It only affects a very small group of people of Jewish decent. In all, there are an estimated 350 people in the world with familial dysautonomia.
Symptoms normally arrive at a young age and include:
- Feeding difficulties
- Slow growth
- A lack of tears
- Frequent lung infections
- Difficulty maintaining the right temperature
- Prolonged breath-holding
- Delayed development, including walking and speech
- Poor balance
- Kidney and heart problems
Familial dysautonomia is particularly serious, there is no cure, and it is almost always fatal.
Diagnosis and treatment of dysautonomia
Because there are so many types of dysautonomia, it is difficult to diagnose and is often missed. Sometimes, symptoms in a patient are mistaken for another condition that is already present.
A successful diagnosis often results from collaboration between a number of specialists.
This confusion also runs through to the treatment of dysautonomia. With such a wide spectrum of disorders and, because they often occur alongside other conditions, there is no single treatment that is safe and effective for all types of dysautonomia.