Why Dysautonomia Is Often Misdiagnosed

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Dysautonomia refers to a group of disorders involving nerves that control heart rate, breathing, and other involuntary functions. Dysautonomia can be difficult to diagnose, in part because symptoms are linked to a range of health issues. Some causes are common, such as neuropathies that occur with diabetes. Others are rare genetic disorders.

Symptoms occur when the autonomic nervous system (ANS) doesn’t send or receive nerve signals as it should. Some people report dysautonomia associated with long COVID, and research to better understand the relationship is ongoing. Others experience it with Parkinson's disease, heart problems, lupus, or for no clear reason at all—sometimes making it hard to diagnose the condition and cause.

A fatigued woman sitting at a table
JGI / Jamie Grill / Getty Images

Symptoms and the Autonomic Nervous System

The autonomic nervous system (ANS) controls involuntary body processes. These functions are regulated by different parts of the ANS, with systems that include:

  • The sympathetic nervous system to direct the "flight-or-fight" response during moments of stress, causing the widening of your pupils and speeding up your heart and breathing.
  • The parasympathetic nervous system, which counters the sympathetic nervous system and normalizes body functions. This can result in the narrowing of your pupils and slowing down of heart and breathing rate as you recover from stress.
  • The enteric nervous system to direct the movement, blood flow, and secretion of mucus in the gastrointestinal tract.

There are many conditions that affect these systems of the ANS, either as a primary cause of dysautonomia or as a secondary cause due to a health condition. The varied causes and emerging diagnoses, such as long COVID or postural orthostatic tachycardia syndrome (POTS), remain difficult to diagnose.

POTS, for example, can take more than five years on average to diagnose. Symptoms related to heart rate need to persist for three to six months before even considering the POTS diagnosis.

Dysautonomia symptoms are specific to the ANS dysfunction. They can include:

  • Dizziness
  • Heart palpitations
  • Blood pressure changes
  • Fainting
  • Pale or blue-tinged skin
  • Feeling cold
  • Changes in sweating
  • Vision changes
  • Dry eyes or mouth
  • Digestive problems (nausea, diarrhea, constipation)
  • Erectile dysfunction
  • Balance problems
  • Chronic fatigue
  • Pain syndromes
  • Cognitive and mood changes
  • Sleep disruptions

Not all people will experience the same symptoms of dysautonomia. Complicating the diagnosis is the fact that symptoms like orthostatic hypotension can be a serious and late-stage finding of cardiac disease, or a side effect of medication that resolves with drug changes.

In some cases, healthcare providers may suspect anxiety or stress as a cause of dizziness before a dysautonomia is accurately diagnosed.

What the Autonomic Nervous System Controls

The bodily functions that ANS regulates include:

  • Bladder and bowel function
  • Heart rate and blood pressure
  • Breathing
  • Saliva glands and digestion
  • Pupils dilating and tear production in eyes
  • Sexual function
  • Temperature regulation, including sweating

What Causes Dysautonomia?

Dysautonomia arises from the malfunction of any part of the ANS. There are many causes of dysautonomia that can be broadly classified as being primary or secondary.

Primary Dysautonomia

Primary dysautonomia occurs on its own in the absence of any other disease. It may be the result of the deterioration of the ANS by a known condition (such as familial dysautonomia). Primary dysautonomia also describes when functions regulated by the ANS fail for no known reason (referred to as idiopathic dysautonomia).

There are at least 15 different types of primary dysautonomia, the most common of which are neurocardiogenic syncope (NCS) and POTS.

An inherited form of dysautonomia, known as Riley-Day syndrome, was first described in 1949. In later years, genetic testing identified this as an inherited form of familial dysautonomia.

Secondary Dysautonomia


Secondary dysautonomia is the malfunction of the ANS due to another disease. Also known as intrinsic dysautonomia, it occurs when a disease damages nerves of the ANS.

The possible causes of secondary dysautonomia are many and include:

Toxic exposure to chemicals and vitamin deficiencies also can lead to dysautonomia symptoms.

Types of Primary Dysautonomia

Researchers have identified at least 15 distinct types of primary dysautonomia. Some are common and may affect millions of people worldwide. Others are rare and may only be seen in certain groups.

Neurocardiogenic Syncope (NCS)

Neurocardiogenic syncope (NCS) is the most common form of dysautonomia, also known as vasovagal syncope. NCS causes fainting spells that occur either occasionally or frequently.

Orthostatic hypotension, also known as postural hypotension, is a steep drop in blood pressure while standing or rising. It is a feature of neurocardiogenic syncope and other forms of dysautonomia that causes dizziness and fainting spells.

Under normal circumstances, the ANS will counteract the effects of gravity by narrowing blood vessels in the lower limbs to deliver more blood to the brain. When this does not occur as it is supposed to, fainting can occur.

NCS is thought to affect tens of millions of people worldwide. The condition is also sometimes triggered by stress, dehydration, alcohol, and overheated environments.

Postural Orthostatic Tachycardia Syndrome (POTS)

Postural orthostatic tachycardia syndrome (POTS) causes your heart to beat too fast when you stand up, leading to chest pain, shortness of breath, and fainting.

Some researchers have speculated that POTS may be the result of an underlying autoimmune condition (in which the immune system attacks certain tissues, such as those of the nervous system). It affects females more often than males, and people with POTS may also have:

Familial Dysautonomia (FD)

Familial dysautonomia (FD) is an inherited form of dysautonomia that causes decreased pain sensitivity, the absence of tears, and problems regulating body temperature. Other symptoms include:

  • Prolonged breath-holding
  • Poor bladder control
  • Delayed growth
  • Loss of balance
  • Frequent lung infections

FD is a rare condition that mainly affects people of Ashkenazi Jewish descent. It is caused by a specific genetic mutation (called the IKBAP mutation) that is passed down from parents to children. FD is a serious condition and can be fatal.

Symptoms commonly develop during childhood. In some cases, FD can lead to a dysautonomic crisis, which causes rapid fluctuations in blood pressure and heart rate, dramatic changes in personality, and the complete shutdown of digestion.

Multiple System Atrophy (MSA)

Multiple system atrophy (MSA) is a severe form of dysautonomia that tends to affect people over 40. Symptoms of MSA include:

  • Irregular heartbeats
  • Problems with muscle control
  • Loss of balance
  • Speech problems
  • Loss of bladder control
  • Vomiting episodes

MSA is a rare condition that is commonly mistaken for Parkinson's disease. The cause of MSA is unknown but does not appear to be genetic. What scientists have found is that certain parts of the brain break down over time in people with MSA.

MSA progresses rapidly and is often fatal. Sudden death often occurs during sleep due to paralysis of the lungs.

Pure Autonomic Failure (PAF)

Pure autonomic failure (PAF) is a non-fatal form of dysautonomia that commonly affects people in their 40s and 50s. It is caused by the excessive accumulation of a protein called synuclein that helps transmit nerve signals. The cause of the accumulation is unknown.

The buildup of synuclein is seen with other conditions such as Parkinson's disease. But unlike Parkinson's, only certain body functions are affected. Symptoms include:

  • Dizziness when standing
  • Heat intolerance
  • Bladder control problems
  • Less sweating
  • Blurred vision (due to the pupils not opening or closing fully as they should)

PAF is thought to be rare and tends to affect females more than males. The disorder may progress and lead to multiple symptom atrophy (MSA) in some people.

Prognosis

Primary dysautonomia, the type that occurs on its own in the absence of any other disease, is not curable. Secondary dysautonomia, caused by a variety of diseases from Lyme's disease to multiple sclerosis, may or may not be curable, depending on the cause and how treatable the condition is.

The prognosis for dysautonomia varies by the cause. If dysautonomia is related to a progressive degenerative disorder like Parkinson's or multiple sclerosis, the outlook is usually poor. Death is often the result of pneumonia, acute respiratory failure, or sudden cardiac arrest.

Keep in mind that research continues into dysautonomia linked to emerging causes like COVID-19, and much remains to be known about what causes ANS symptoms.

Managing Symptoms

For people with primary dysautonomia, the treatment is focused on managing symptoms. The options can vary by the condition and the type and severity of symptoms involved.

Examples include:

  • Neurocardiogenic syncope: A drug called Florinef (fludrocortisone acetate), which is used to treat low blood pressure, can help prevent orthostatic hypotension and fainting spells. Compression socks can improve circulation by preventing blood from pooling in the legs. Severe cases may require a pacemaker when all other treatments fail.
  • Postural orthostatic tachycardia syndrome: Medications are used to treat POTS, but whether they are effective remains under study; a beta blocker called propranolol has the most research support. Salt and water balance may play an underlying role. Routine exercise is also recommended.
  • Familial dysautonomia: Multiple medications may be needed to manage blood pressure, breathing problems, and vomiting episodes. People with severe swallowing problems may require a feeding tube. Genetic screening for the IKBAP mutation is recommended if both parents are of Ashkenazi heritage so that they can make an informed decision about having children.
  • Multiple system atrophy: Along with Florinef, the drugs Mestinon (pyridostigmine) and Orvaten (midodrine) can raise blood pressure quickly. Drugs used to treat Parkinson-like symptoms, such as levodopa, may also be prescribed. A mechanical ventilator and feeding tube may be needed in severe cases. A urinary catheter may be also required if the loss of bladder control is severe.
  • Pure autonomic failure: Many of the same treatments used for NCS may be prescribed to people with PAF. Medications like Flomax (tamsulosin) may help people with overactive bladder.

Testing for Dysautonomia

Diagnostic testing depends on the type. Postural orthostatic tachycardia syndrome (POTS) can be diagnosed based on your heart rate while lying on a tilt table. Neurocardiogenic syncope (NCS) is diagnosed based on the exclusion of other possible causes. Familial dysautonomia (FD) can be diagnosed with an injection of histamine, which causes a specific skin reaction.

Summary

Dysautonomia is the malfunctioning of the autonomic nervous system (ANS) that regulates involuntary bodily functions. Dysautonomia is a common condition but it can be difficult to diagnose because the patterns and symptoms are so diverse.

Some people have primary dysautonomia in which there is a problem with the ANS itself. Others have secondary dysautonomia caused by an underlying disease or medical condition.

Because the ANS regulates so many different functions—from breathing and heart rate to temperature regulation and sexual function—the possible symptoms of dysautonomia are vast. As a result, it can take time for a healthcare provider to identify dysautonomia as the cause of the symptoms.

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Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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Richard N. Fogoros, MD

By Richard N. Fogoros, MD
Richard N. Fogoros, MD, is a retired professor of medicine and board-certified in internal medicine, clinical cardiology, and clinical electrophysiology.