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 internal organs, smooth muscle and glands. The autonomic nervous system is a control system t ...

(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 to ...

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 en ...

, intestines,

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, 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, multiple system atrophy, dementia with Lewy bodies, 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 sys ...

, HIV/AIDS, 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 p ...

. 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 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 *

Bowel incontinence Fecal incontinence (FI), or in some forms encopresis, is a lack of control over defecation, leading to involuntary loss of bowel contents, both liquid stool elements and mucus, or solid feces. When this loss includes flatus (gas), it is referred ...

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 thi ...

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 * Difficulty swallowing *

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 post ...

* Insomnia * Low blood pressure *

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 hy ...

* Syncope * Tachycardia * Tunnel vision * Urinary incontinence or

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 (SNS), predominant dysautonomia is common along with fibromyalgia,

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, raising the possibility that such dysautonomia could be their common clustering underlying pathogenesis. 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 may misleadingly suggest anxiety for patients with dysautonomia.

Mechanism

The

is a component of the peripheral nervous system and comprises two branches: the sympathetic nervous system (SNS) and the parasympathetic nervous system (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 and heart rate 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 (f ...

, and testing of the sudomotor 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 b ...

by lumbar puncture

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 ...

and American civil war 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 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 b ...

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 pathw ...

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 ...

(a guanine monophosphate 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 syste ...

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 neuromu ...

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 atheroscleros ...

, a procedure referred to as

transvascular autonomic modulation Chronic cerebrospinal venous insufficiency (CCSVI or CCVI) is a term invented by Italian researcher Paolo Zamboni in 2008 to describe compromised flow of blood in the veins draining the central nervous system. Zamboni hypothesized that it might ...

, 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,

acute respiratory failure Respiratory failure results from inadequate gas exchange by the respiratory system, meaning that the arterial oxygen, carbon dioxide, or both cannot be kept at normal levels. A drop in the oxygen carried in the blood is known as hypoxemia; a rise ...

, 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.