Dysautonomia or autonomic dysfunction is a condition in which the

autonomic nervous system The autonomic nervous system (ANS), formerly referred to as the vegetative nervous system, is a division of the peripheral nervous system that supplies viscera, internal organs, smooth muscle and glands. The autonomic nervous system is a control ...

(ANS) does not work properly. This may affect the functioning of the

heart The heart is a muscular organ in most animals. This organ pumps blood through the blood vessels of the circulatory system. The pumped blood carries oxygen and nutrients to the body, while carrying metabolic waste such as carbon dioxide t ...

bladder The urinary bladder, or simply bladder, is a hollow organ in humans and other vertebrates that stores urine from the kidneys before disposal by urination. In humans the bladder is a distensible organ that sits on the pelvic floor. Urine enters ...

intestines The gastrointestinal tract (GI tract, digestive tract, alimentary canal) is the tract or passageway of the digestive system that leads from the mouth to the anus. The GI tract contains all the major organs of the digestive system, in humans ...

sweat glands Sweat glands, also known as sudoriferous or sudoriparous glands, , are small tubular structures of the skin that produce sweat. Sweat glands are a type of exocrine gland, which are glands that produce and secrete substances onto an epithelial sur ...

pupils The pupil is a black hole located in the center of the iris of the eye that allows light to strike the retina.Cassin, B. and Solomon, S. (1990) ''Dictionary of Eye Terminology''. Gainesville, Florida: Triad Publishing Company. It appears black ...

, and blood vessels. Dysautonomia has many causes, not all of which may be classified as

neuropathic Peripheral neuropathy, often shortened to neuropathy, is a general term describing disease affecting the peripheral nerves, meaning nerves beyond the brain and spinal cord. Damage to peripheral nerves may impair sensation, movement, gland, or o ...

. A number of conditions can feature dysautonomia, such as

Parkinson's disease Parkinson's disease (PD), or simply Parkinson's, is a long-term degenerative disorder of the central nervous system that mainly affects the motor system. The symptoms usually emerge slowly, and as the disease worsens, non-motor symptoms becom ...

multiple system atrophy Multiple system atrophy (MSA) is a rare neurodegenerative disorder characterized by autonomic dysfunction, tremors, slow movement, muscle rigidity, and postural instability (collectively known as parkinsonism) and ataxia. This is caused by progr ...

dementia with Lewy bodies Dementia with Lewy bodies (DLB) is a type of dementia characterized by changes in sleep, behavior, cognition, movement, and regulation of automatic bodily functions. Memory loss is not always an early symptom. The disease worsens over time ...

, Ehlers-Danlos syndromes,

autoimmune autonomic ganglionopathy Autoimmune autonomic ganglionopathy (AAG) is a rare form of dysautonomia in which the immune system produces ganglionic anti-nicotinic acetylcholine receptor (AChR) antibodies, inhibiting ganglionic AChR currents and impairing transmission in aut ...

and

autonomic neuropathy Autonomic neuropathy (AN or AAN) is a form of polyneuropathy that affects the non-voluntary, non-sensory nervous system (i.e., the autonomic nervous system), affecting mostly the internal organs such as the bladder muscles, the cardiovascular s ...

HIV/AIDS Human immunodeficiency virus infection and acquired immunodeficiency syndrome (HIV/AIDS) is a spectrum of conditions caused by infection with the human immunodeficiency virus (HIV), a retrovirus. Following initial infection an individual ...

, autonomic failure, and

postural orthostatic tachycardia syndrome Postural orthostatic tachycardia syndrome (POTS) is a condition characterized by an abnormally large increase in heart rate upon standing. Symptoms may include lightheadedness, brain fog, blurred vision, weakness, fatigue, headaches, heart ...

. The diagnosis is achieved through functional testing of the ANS, focusing on the affected

organ system An organ system is a biological system consisting of a group of organs that work together to perform one or more functions. Each organ has a specialized role in a plant or animal body, and is made up of distinct tissues. Plants Plants have ...

. Investigations may be performed to identify underlying disease processes that may have led to the development of symptoms or autonomic neuropathy.

Symptomatic treatment Symptomatic treatment, supportive care, supportive therapy, or palliative treatment is any medical therapy of a disease that only affects its symptoms, not the underlying cause. It is usually aimed at reducing the signs and symptoms for the comfor ...

is available for many symptoms associated with dysautonomia, and some disease processes can be directly treated.

Signs and symptoms

The symptoms of dysautonomia, which are numerous and vary widely for each individual, are due to inefficient or unbalanced efferent signals sent via both systems. The primary symptoms in individuals with dysautonomia include: *

Anhydrosis Hypohidrosis is a disorder in which a person exhibits diminished sweating in response to appropriate stimuli. In contrast with hyp''er''hidrosis, which is a socially troubling yet often benign condition, the consequences of untreated hypohidrosi ...

Anxiety Anxiety is an emotion which is characterized by an unpleasant state of inner turmoil and includes feelings of dread over anticipated events. Anxiety is different than fear in that the former is defined as the anticipation of a future threat wh ...

* Blurry or

double vision Diplopia is the simultaneous perception of two images of a single object that may be displaced horizontally or vertically in relation to each other. Also called double vision, it is a loss of visual focus under regular conditions, and is often v ...

* Bowel incontinence *

Brain fog Clouding of consciousness (also known as brain fog or mental fog) occurs when a person is slightly less wakeful or aware than normal. They are not as aware of time or their surroundings and find it difficult to pay attention. People describe this ...

Constipation Constipation is a bowel dysfunction that makes bowel movements infrequent or hard to pass. The stool is often hard and dry. Other symptoms may include abdominal pain, bloating, and feeling as if one has not completely passed the bowel movement ...

Dizziness Dizziness is an imprecise term that can refer to a sense of disorientation in space, vertigo, or lightheadedness. It can also refer to disequilibrium or a non-specific feeling, such as giddiness or foolishness. Dizziness is a common medical c ...

Difficulty swallowing Dysphagia is difficulty in swallowing. Although classified under "symptoms and signs" in ICD-10, in some contexts it is classified as a condition in its own right. It may be a sensation that suggests difficulty in the passage of solids or liqui ...

Exercise intolerance Exercise intolerance is a condition of inability or decreased ability to perform physical exercise at the normally expected level or duration for people of that age, size, sex, and muscle mass. It also includes experiences of unusually severe pos ...

Insomnia Insomnia, also known as sleeplessness, is a sleep disorder in which people have trouble sleeping. They may have difficulty falling asleep, or staying asleep as long as desired. Insomnia is typically followed by daytime sleepiness, low energy, ...

Low blood pressure Hypotension is low blood pressure. Blood pressure is the force of blood pushing against the walls of the arteries as the heart pumps out blood. Blood pressure is indicated by two numbers, the systolic blood pressure (the top number) and the dia ...

Orthostatic hypotension Orthostatic hypotension, also known as postural hypotension, is a medical condition wherein a person's blood pressure drops when standing up or sitting down. Primary orthostatic hypertension is also often referred to as neurogenic orthostatic hyp ...

* Syncope *

Tachycardia Tachycardia, also called tachyarrhythmia, is a heart rate that exceeds the normal resting rate. In general, a resting heart rate over 100 beats per minute is accepted as tachycardia in adults. Heart rates above the resting rate may be normal (su ...

Tunnel vision Tunnel vision is the loss of peripheral vision with retention of central vision, resulting in a constricted circular tunnel-like field of vision. Causes Tunnel vision can be caused by: Eyeglass users Eyeglass users experience tunnel vision t ...

Urinary incontinence Urinary incontinence (UI), also known as involuntary urination, is any uncontrolled leakage of urine. It is a common and distressing problem, which may have a large impact on quality of life. It has been identified as an important issue in geria ...

urinary retention Urinary retention is an inability to completely empty the bladder. Onset can be sudden or gradual. When of sudden onset, symptoms include an inability to urinate and lower abdominal pain. When of gradual onset, symptoms may include loss of bladd ...

Vertigo Vertigo is a condition where a person has the sensation of movement or of surrounding objects moving when they are not. Often it feels like a spinning or swaying movement. This may be associated with nausea, vomiting, sweating, or difficulties w ...

Weakness Weakness is a symptom of a number of different conditions. The causes are many and can be divided into conditions that have true or perceived muscle weakness. True muscle weakness is a primary symptom of a variety of skeletal muscle diseases, i ...

Causes

Dysautonomia may be due to inherited or degenerative neurologic diseases (primary dysautonomia) or it may occur due to injury of the autonomic nervous system from an acquired disorder (secondary dysautonomia). The most common causes of dysautonomia include: In the

sympathetic nervous system The sympathetic nervous system (SNS) is one of the three divisions of the autonomic nervous system, the others being the parasympathetic nervous system and the enteric nervous system. The enteric nervous system is sometimes considered part of th ...

(SNS), predominant dysautonomia is common along with

fibromyalgia Fibromyalgia (FM) is a medical condition defined by the presence of chronic widespread pain, fatigue, waking unrefreshed, cognitive symptoms, lower abdominal pain or cramps, and depression. Other symptoms include insomnia and a general hyp ...

chronic fatigue syndrome Chronic fatigue syndrome (CFS), also called myalgic encephalomyelitis (ME) or ME/CFS, is a complex, debilitating, long-term medical condition. The causes and mechanisms of the disease are not fully understood. Distinguishing core symptoms are ...

irritable bowel syndrome Irritable bowel syndrome (IBS) is a "disorder of gut-brain interaction" characterized by a group of symptoms that commonly include abdominal pain and or abdominal bloating and changes in the consistency of bowel movements. These symptoms may ...

, and

interstitial cystitis Interstitial cystitis (IC), a type of bladder pain syndrome (BPS), is chronic pain in the bladder and pelvic floor of unknown cause. It is the urologic chronic pelvic pain syndrome of women. Symptoms include feeling the need to urinate right awa ...

, raising the possibility that such dysautonomia could be their common clustering underlying

pathogenesis Pathogenesis is the process by which a disease or disorder develops. It can include factors which contribute not only to the onset of the disease or disorder, but also to its progression and maintenance. The word comes from Greek πάθος ''pat ...

. In addition to sometimes being a symptom of dysautonomia,

anxiety Anxiety is an emotion which is characterized by an unpleasant state of inner turmoil and includes feelings of dread over anticipated events. Anxiety is different than fear in that the former is defined as the anticipation of a future threat wh ...

can sometimes physically manifest symptoms resembling autonomic dysfunction. A thorough investigation ruling out physiological causes is crucial, but in cases where relevant tests are performed and no causes are found or symptoms do not match any known disorders, a primary anxiety disorder is possible, but should not be presumed. For such patients, the

anxiety sensitivity Anxiety sensitivity (AS) refers to the fear of behaviours or sensations associated with the experience of anxiety, and a misinterpretation of such sensations as dangerous. Bodily sensations related to anxiety, such as nausea and palpitations, are mi ...

index may have better predictivity for anxiety disorders, while the

Beck anxiety inventory The Beck Anxiety Inventory (BAI), created by Aaron T. Beck and other colleagues, is a 21-question multiple-choice self-report inventory that is used for measuring the severity of anxiety in adolescents and adults ages 17 and older. The questions ...

may misleadingly suggest anxiety for patients with dysautonomia.

Mechanism

The

is a component of the

peripheral nervous system The peripheral nervous system (PNS) is one of two components that make up the nervous system of bilateral animals, with the other part being the central nervous system (CNS). The PNS consists of nerves and ganglia, which lie outside the brain ...

and comprises two branches: the sympathetic nervous system (SNS) and the

parasympathetic nervous system The parasympathetic nervous system (PSNS) is one of the three divisions of the autonomic nervous system, the others being the sympathetic nervous system and the enteric nervous system. The enteric nervous system is sometimes considered part of ...

(PSNS). The SNS controls the more active responses such as increasing heart rate and blood pressure. The PSNS slows down the heart rate and aids in digestion, for example. Symptoms typically arise from abnormal responses of either the sympathetic or parasympathetic systems based on situation or environment.

Diagnosis

The diagnosis of dysautonomia depends on the overall function of three autonomic functions – cardiovagal, adrenergic, and sudomotor. A diagnosis should, at a bare minimum, include measurements of

blood pressure Blood pressure (BP) is the pressure of circulating blood against the walls of blood vessels. Most of this pressure results from the heart pumping blood through the circulatory system. When used without qualification, the term "blood pressure" r ...

and

heart rate Heart rate (or pulse rate) is the frequency of the heartbeat measured by the number of contractions (beats) of the heart per minute (bpm). The heart rate can vary according to the body's physical needs, including the need to absorb oxygen and excr ...

while lying flat, and after at least 3 minutes of standing. The best way to achieve a diagnosis includes a range of testing, notably an autonomic reflex screen,

tilt table test A tilt table test (TTT), occasionally called upright tilt testing (UTT), is a medical procedure often used to diagnose dysautonomia or syncope. Patients with symptoms of dizziness or lightheadedness, with or without a loss of consciousness (fa ...

, and testing of the

sudomotor Sudomotor function refers to the autonomic nervous system control of sweat gland activity in response to various environmental and individual factors. Sweat production is a vital thermoregulatory mechanism used by the body to prevent heat-related ...

response ( ESC, QSART or thermoregulatory sweat test). Additional tests and examinations to determine a diagnosis of dysautonomia include: Valsalva maneuver

Tests to elucidate the cause of dysautonomia can include: * Evaluation for acute (intermittent) porphyria. * Evaluation of

cerebrospinal fluid Cerebrospinal fluid (CSF) is a clear, colorless body fluid found within the tissue that surrounds the brain and spinal cord of all vertebrates. CSF is produced by specialised ependymal cells in the choroid plexus of the ventricles of the bra ...

lumbar puncture Lumbar puncture (LP), also known as a spinal tap, is a medical procedure in which a needle is inserted into the spinal canal, most commonly to collect cerebrospinal fluid (CSF) for diagnostic testing. The main reason for a lumbar puncture is to ...

Vegetative-vascular dystonia

Particularly in the Russian literature, a subtype of dysautonomia which particularly affects the vascular system has been called vegetative-vascular dystonia. The term "vegetative" reflects an older name for the autonomic nervous system: the vegetative nervous system. Similar form of this disorder has been historically noticed in various wars, like

Crimean war The Crimean War, , was fought from October 1853 to February 1856 between Russia and an ultimately victorious alliance of the Ottoman Empire, France, the United Kingdom and Piedmont-Sardinia. Geopolitical causes of the war included the de ...

and

American civil war The American Civil War (April 12, 1861 – May 26, 1865; also known by other names) was a civil war in the United States. It was fought between the Union ("the North") and the Confederacy ("the South"), the latter formed by states th ...

and among British troops who colonized India, this disorder was referred to as "irritable heart syndrome" (

Da Costa's syndrome Da Costa's syndrome (also known as "soldier's heart", cardiac neurosis, chronic asthenia, effort syndrome, functional cardiovascular disease, neurocirculatory asthenia, primary neurasthenia, subacute asthenia and irritable heart) is a psychiatri ...

) in 1871 by American physician Jacob DaCosta.

Management

The treatment of dysautonomia can be difficult; since it is made up of many different symptoms, a combination of drug therapies is often required to manage individual symptomatic complaints. Therefore, if an autoimmune neuropathy is the case, then treatment with immunomodulatory therapies is done, or if

diabetes mellitus Diabetes, also known as diabetes mellitus, is a group of metabolic disorders characterized by a high blood sugar level ( hyperglycemia) over a prolonged period of time. Symptoms often include frequent urination, increased thirst and increased ap ...

is the cause, control of

blood glucose Glycaemia, also known as blood sugar level, blood sugar concentration, or blood glucose level is the measure of glucose concentrated in the blood of humans or other animals. Approximately 4 grams of glucose, a simple sugar, is present in the blo ...

is important. Treatment can include

proton-pump inhibitor Proton-pump inhibitors (PPIs) are a class of medications that cause a profound and prolonged reduction of stomach acid production. They do so by irreversibly inhibiting the stomach's H+/K+ ATPase proton pump. They are the most potent inhibitors ...

s and

H2 receptor antagonists H2 antagonists, sometimes referred to as H2RAs and also called H2 blockers, are a class of medications that block the action of histamine at the histamine H2 receptors of the parietal cells in the stomach. This decreases the production of stom ...

used for digestive symptoms such as

acid reflux Gastroesophageal reflux disease (GERD) or gastro-oesophageal reflux disease (GORD) is one of the upper gastrointestinal chronic diseases where stomach content persistently and regularly flows up into the esophagus, resulting in symptoms and/ ...

. For the treatment of

genitourinary The genitourinary system, or urogenital system, are the organs of the reproductive system and the urinary system. These are grouped together because of their proximity to each other, their common embryological origin and the use of common pathwa ...

autonomic neuropathy medications may include

sildenafil Sildenafil, sold under the brand name Viagra, among others, is a medication used to treat erectile dysfunction and pulmonary arterial hypertension. It is unclear if it is effective for treating sexual dysfunction in women. It is taken by ...

guanine monophosphate Guanosine monophosphate (GMP), also known as 5′-guanidylic acid or guanylic acid (conjugate acid, conjugate base guanylate), is a nucleotide that is used as a monomer in RNA. It is an ester of phosphoric acid with the nucleoside guanosine. GMP ...

type-5 phosphodiesterase inhibitor). For the treatment of

hyperhidrosis Hyperhidrosis is a condition characterized by abnormally increased sweating, in excess of that required for regulation of body temperature. Although primarily a benign physical burden, hyperhidrosis can deteriorate quality of life from a psychologi ...

anticholinergic Anticholinergics (anticholinergic agents) are substances that block the action of the neurotransmitter called acetylcholine (ACh) at synapses in the central and peripheral nervous system. These agents inhibit the parasympathetic nervous system ...

agents such as

trihexyphenidyl Trihexyphenidyl (THP, benzhexol, trihex, marketed as Artane and others) is an antispasmodic drug used to treat stiffness, tremors, spasms, and poor muscle control. It is an agent of the antimuscarinic class and is often used in management of Pa ...

or scopolamine can be used, also intracutaneous injection of

botulinum toxin Botulinum toxin, or botulinum neurotoxin (BoNT), is a neurotoxic protein produced by the bacterium ''Clostridium botulinum'' and related species. It prevents the release of the neurotransmitter acetylcholine from axon endings at the neuromusc ...

type A can be used for management in some cases.

Balloon angioplasty Angioplasty, is also known as balloon angioplasty and percutaneous transluminal angioplasty (PTA), is a minimally invasive endovascular procedure used to widen narrowed or obstructed arteries or veins, typically to treat arterial atherosclero ...

, a procedure referred to as transvascular autonomic modulation, is specifically not approved for the treatment of autonomic dysfunction.

Prognosis

The prognosis of dysautonomia depends on several factors; individuals with chronic, progressive, generalized dysautonomia in the setting of central nervous system degeneration such as Parkinson's disease or multiple system atrophy have a generally poorer long-term prognosis. Consequently, dysautonomia could be fatal due to

pneumonia Pneumonia is an inflammatory condition of the lung primarily affecting the small air sacs known as alveoli. Symptoms typically include some combination of productive or dry cough, chest pain, fever, and difficulty breathing. The severity ...

, acute respiratory failure, or sudden

cardiopulmonary arrest Cardiac arrest is when the heart suddenly and unexpectedly stops beating. It is a medical emergency that, without immediate medical intervention, will result in sudden cardiac death within minutes. Cardiopulmonary resuscitation (CPR) and possib ...

. Autonomic dysfunction symptoms such as orthostatic hypotension,

gastroparesis Gastroparesis (gastro- from Ancient Greek γαστήρ – gaster, "stomach"; and -paresis, πάρεσις – "partial paralysis"), also called delayed gastric emptying, is a medical disorder consisting of weak muscular contractions (peristalsis) ...

, and gustatory sweating are more frequently identified in mortalities.