Why Dysautonomia Is Often Misdiagnosed

Dysautonomia is the malfunctioning of nerves that regulate involuntary functions such as heart rate, breathing, blood pressure, digestion, and sweating. It happens when the autonomic nervous system (ANS) doesn’t send or receive nerve signals as it should, which can happen for any number of reasons.

Dysautonomia is often misdiagnosed, in large part because it is not one diagnosis but a group of medical conditions with a variety of symptoms that mimic those of other health issues. While relatively common, affecting more than 70 million people worldwide, it can sometimes take years to get a diagnosis.

This article looks at the causes and symptoms of dysautonomia and why the condition is so frequently misdiagnosed. It also describes the different types of dysautonomia and how they are managed or treated.

The History of Dysautonomia

Dysautonomia has been known by different names over the centuries. As far back as the 10th century BC, symptoms described in King David appear consistent with dysautonomia, namely his inability to maintain equilibrium (balance) or a normal body temperature.

An inherited form of dysautonomia, known as Riley-Day syndrome, was first described in 1949. The condition causes many different symptoms, including difficulty swallowing, insensitivity to pain, instability when standing up, and excessive sweating while eating or when excited.

In later years, genetic testing revealed that Riley-Day syndrome was one of several inherited forms of dysautonomia, known collectively as familial dysautonomia (FD). The condition was traced back to a genetic mutation that arose in a small Jewish population in Eastern Europe back in the 1500s.

Why Dysautonomia Is Often Misdiagnosed

According to Dysautonomia International, only 25% of people with symptoms of dysautonomia are diagnosed on their first visit, while others will wait for years before the condition is identified.

Because dysautonomia involves a broad and variable range of non-specific symptoms, both physical and psychological, healthcare providers will often attribute the symptoms to anxiety.

Others have been known to attribute dysautonomia to neurological conditions like Parkinson's disease. While dysautonomia is a common feature of Parkinson's, it can occur in people without the disease. Misdiagnoses like these can expose people to inappropriate and needless treatments.

The Autonomic Nervous System

The autonomic nervous system (ANS) regulates involuntary body processes. It is part of the peripheral nervous system.

The bodily functions that ANS regulates include:

• Bladder function
• Blood pressure
• Bowel function
  
• Breathing
• Digestion
• Eye tearing
• Heart rate
• Pupil dilation
• Respiration
• Salivation
• Sexual function
• Temperature regulation, including sweating

How the ANS Works

Involuntary body functions are regulated by different parts of the ANS, some of which act in opposition to the other. There are three distinct parts:

• The sympathetic nervous system directs 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 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 directs the movement, blood flow, and secretion of mucus in the gastrointestinal tract.

There are many different conditions that can affect the ANS, either on their own or as the result of a disease. These all fall under the category of dysautonomia.

Dysautonomia Symptoms

Because the ANS has so many functions, the possible symptoms of dysautonomia are expansive.

Symptoms can vary from one person to the next. Some people may have only occasional symptoms, while others may experience them frequently. Some symptoms may appear on their own, while others may occur in clusters.

Possible symptoms of dysautonomia include:

• Balance problems
• Blurred vision
• Brain "fog"
• Chest pain
• Changes in blood pressure
• Changes in body temperature
• Difficulty swallowing
• Dizziness or lightheadedness
• Dry eyes or excessive tearing
• Erectile dysfunction
• Fainting
• Fast or slow heartbeat
• Frequent urination
• Irregular heartbeats
• Light sensitivity
• Loss of bowel or bladder control
• Migraines
• Mood swings
• Nausea and vomiting
• Noise sensitivity
• Ongoing fatigue or tiredness
• Shortness of breath
• Sleep problems
• Sweating heavily or not at all
• Vertigo
• Weakness

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 postural orthostatic tachycardia syndrome (POTS).

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:

• Amyloidosis
• Celiac disease
• Chiari malformation
• Chronic fatigue syndrome
• Crohn’s disease
• Ehlers-Danlos syndrome
• Fibromyalgia
• Guillain-Barre syndrome
• HIV
• Irritable bowel syndrome
  
• Lupus
• Lyme disease
• Muscular sclerosis
• Parkinson's disease
• Rheumatoid arthritis
• Sarcoidosis
  
• Sjogren's syndrome
• Toxic exposure to chemicals
• Traumatic injury
• Ulcerative colitis
• Vitamin deficiencies
  

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.

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. Tachycardia is the word used to describe abnormally fast heartbeats.

POTS is thought to affect between one and three million people in the United States. Females are at greater risk than males.

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).

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, and 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.

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.

FD is a serious condtion and can be fatal.

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, and 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, and blurred vision (due to the pupils not opening or closing fully as they should). A person with PAF may also have bladder control problems and not sweat much.

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

There is no cure for primary dysautonomia. The treatment is mainly focused on the management of symptoms, such as dizziness and fainting.

Secondary dysautonomia may improve with treatment of the underlying condition. Other cases may recur, particularly with autoimmune diseases like lupus or Sjogren's syndrome that cause occasional flare-ups.

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.

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: In addition to Florinef, drugs called beta-blockers can help regulate blood pressure and reduce the risk of rapid heartbeats. Increasing your sodium intake and drinking 2 to 2-1/2 liters of water per day can also help. 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.
  

Summary

Dysautonomia is the malfunctioning of the autonomic nervous system (ANS) that regulates involuntary bodily functions. Dysautonomia is a common condition that affects around 70 million people worldwide. But it can be difficult to diagnose because the patterns and symptoms are so diverse and non-specific.

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.

A Word From Verywell

As common as dysautonomia is, it can be frustratingly difficult to diagnose. If you have symptoms you cannot explain and all efforts to pinpoint a cause have failed, ask your primary care provider for a referral to a board-certified neurologist.