The term “dysautonomia” describes dysfunction of the autonomic nervous system (ANS). It is an umbrella term, meaning there are several types of dysautonomia with similar and different features.

Different medical conditions involving ANS malfunction all fall under the label of dysautonomia.

The ANS controls involuntary, or automatic, functions in the body. This includes digestion, kidney function, breathing, and temperature control.

When someone has dysautonomia, they may have trouble regulating one or more of these functions.

There are at least 15 distinct forms of dysautonomia. Many of the conditions have overlapping symptoms. Throughout the world, more than 70 million people have some form of dysautonomia.

Read on to learn more about some of the types of dysautonomia.

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POTS causes a variety of symptoms when moving from lying down to standing. It is one of the morecommon forms of dysautonomia.

People with POTS have an excessively reduced volume of blood returning to the heart when transitioning from lying down to standing. This causes several symptoms, such as:

Anyone can develop POTS. But it appears most common in females between the ages of 15 and 50 years.

Orthostatic hypotension means decreased blood pressure when changing positions from sitting or lying to standing. It occurs in about 6% of the population, according to the Dysautonomia Support Network.

However, that number increases with age and comorbidities, which are other health conditions that occur at the same time. It happens in about 20% of people over age 65, the organization says.

When someone with orthostatic hypotension stands up, they do not maintain sufficient blood pressure to send blood to the brain. The diagnostic criteria include a drop in systolic blood pressure of more than 20 millimeters of mercury (mm Hg) or a drop in diastolic blood pressure of more than 10 mm Hg within 3 minutes of standing.

This can cause a variety of symptoms, such as:

Vasovagal syncope describes any form of fainting due to an issue regulating blood pressure. It leads to decreases brain perfusion, meaning reduced blood flow to the brain. This causes a temporary loss of consciousness.

Vasovagal syncope can occur due to emotional upset or pain. But in many cases, doctors do not identify specific triggers.

Symptoms along with fainting may include:

IST describes a persisting but unexplained increase in heart rate greater than 100 beats per minute. It can occur in anyone of any age. But it is most common in females between the ages of 15 and 45 years.

The increase in heart rate also occurs with other distressing symptoms, including:

AAG is a very rare type of dysautonomia. In the United States, only about 100 people receive a diagnosis of AAG each year.

The condition occurs due to the body’s immune system damaging the receptors in part of the peripheral autonomic nerve fiber. The symptoms may come on suddenly or gradually and get worse over time.

Symptoms may include the following:

Baroreflex failure is an uncommon condition that can lead to significant shifts in blood pressure. At times, blood pressure and heart rate can severely increase in response to pain, exercise, and stress.

In addition, individuals with baroreflex failure may also develop low blood pressure during times of rest. Doctors often do not know the cause of baroreflex failure.

Symptoms may include:

  • increased heart rate that does not respond to medication
  • sweating
  • headache

Familial dysautonomia is an inherited condition that can cause dysfunction of the autonomic and sensory nervous systems. It is a rare condition.

Researchers estimate that familial dysautonomia occurs in roughly 350 people worldwide, and it mostly affects people of Ashkenazi Jewish descent.

Symptoms may vary and can include:

Pure autonomic failure is a rare type of dysautonomia. In the United States, it affects fewer than 200,000 people, according to the Dysautonomia Support Network.

The condition occurs due to a deterioration of the ANS cells and leads to overall dysfunction of the ANS. It is more common in males, and onset is most often in middle age, the Dysautonomia Support Network reports.

Orthostatic hypotension is one of the main features of pure autonomic failure. Additional symptoms may include:

  • urinary dysfunction
  • bowel issues
  • difficulty with temperature regulation

Multiple system atrophy is a progressive and fatal form of dysautonomia. It involves a neurodegenerative disease that affects the central nervous system and the ANS.

Multiple system atrophy usually occurs in people over age 50. Symptoms quickly progress over 5–10 years. Many people immobile in a few years.

Symptoms may include:

Dysautonomia involves malfunction or failure of the autonomic nervous system (ANS). The ANS controls many different functions in the body that are involuntary. For example, the ANS controls breathing, digestion, and blood pressure.

There are many types of dysautonomia. Researchers have identified at least 15 different forms.

One type of dysautonomia is POTS, which is one of the more common forms of dysautonomia. Other types of dysautonomia are orthostatic hypotension and vasovagal syncope, as well as rarer forms, such as pure autonomic failure and autoimmune autonomic ganglionopathy.