Dysautonomia or autonomic dysfunction is a condition in which the autonomic nervous system does not work properly. 

The autonomic nervous system regulates internal organs, controls heart rate, blood pressure, sweating, digestion, respiration, pupillary reactivity, urination, and sexual arousal.

Autonomic fibers are small, lightly myelinated and unmyelinated.

The autonomic nervous system acts unconsciously via efferent motor fibers and autonomic dysfunction manifests as an organ malfunction.

It 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).

Generalized autonomic failure is a type of dysautonomia with autonomic hyperactivity due to damage of both sympathetic and parasympathetic systems.

A restricted sympathetic or parasympathetic failure leads to unopposed actions of each other.

Autonomic symptoms can be divided into orthostatic, non-orthostatic, and diffuse.

Orthostatic symptoms are typically related to cerebral hypo perfusion manifesting as lightheadedness.

Frequent nonorthostatic symptoms include constipation, bladder problems, cold or hot intolerance, excessive sweating or loss of sweating, and erectile dysfunction.

Common complaints of autonomic symptoms include fatigue, headaches, and insomnia.

Reduced or elevated core temperatures may indicate abnormal hypothermic function.

Pupillary abnormalities, dry mouth and dry eyes may be present and dysautonomia.

Autonomic overactivity can be generalized or restrictive.

Dysautonomia can be continuous or paroxysmal, acute, subacute, or chronic preganglionic, postganglionic, or mixed.

Many small sensory fibers are located in close proximity with autonomic fibers and frequently are damaged together.

Damage of small sensory fibers is typically associated with burning pain on the feet or hands, and  frequently with lightning like or  lancinating pain, aching or uncomfortable paresthesias (dysesthesias) or with pain to nonpainful stimuli (allodynia).

Vibration sensing proprioception are modalities transmitted by large fibers and they should be normal aim, while pain temperature sensation at the distal leg is abnormal in small fiber neuropathy.

Deep tendon reflexes should be normal, and there should not be muscle weakness in small fiber neuropathy.

Dysautonomia may affect the functioning of the heart, bladder, intestines, sweat glands, pupils, and blood vessels.


Has many causes, not all of which may be classified as neuropathic.


Dysautonomia seen in Parkinson’s disease, HIV/AIDS, multiple system atrophy, autonomic failure, postural orthostatic tachycardia syndrome, Ehlers-Danlos syndrome, autoimmune autonomic ganglionopathy, and autonomic neuropathy.


Caused by inadequacy of sympathetic, or parasympathetic, components of autonomic nervous system.


Risk factors:


Alcoholism and Diabetes


The diagnosis of dysautonomia requires functional testing of the autonomic nervous system.


Testing requires focusing on the affected organ systems and identifying underlying disease processes that may have led to the development of autonomic neuropathy.

A medical history including review of medications is necessary, and emphasis placed on the problem onset  of acute, subacute, or chronic nature, and its rapid or slow progression, and severity from mild to severe.

The use of drugs, alcohol, diet, supplements, toxic exposures, history of Lyme disease, history of travel, or risk behavior need to be analyzed.

Dysautonomia features include simultaneous involvement of multiple organ systems and fluctuations of symptoms from day to day or from position to position.

A voiding and gastrointestinal history and complaints are required for adequate assessment of neurogenic bladder and gastric motility disorders.

Treatment varies from supportive care to to specific and direct actions in some disease processes.


The symptoms vary widely for each individual, and are due to inefficient or unbalanced efferent signals sent via The autonomic sympathetic and parasympathetic nervous systems.


The primary symptoms include: 






Blurry or double vision


Bowel incontinence


Brain fog






Difficulty swallowing


Exercise intolerance






Orthostatic hypotension






Tunnel vision


Urinary incontinence or urinary retention





Physical examination findings including postural variations in blood pressure, heart rate, pupillary light reflex, skin temperature, skin color, and patterns of sweating.

Blood pressure and heart rate are measured in supine position and during standing.

The pressure and pulse should be checked for at least 10 minutes after standing as orthostatic hypotension without a compensatory increase in heart rate usually indicates autonomic  failure.

Causes of dysautonomia: 



The most common causes of dysautonomia include: 









Autoimmune diseases



Craniocervical instability






Eaton-Lambert syndrome



Ehlers-Danlos syndrome



Guillain-Barré syndrome






Lyme disease



Multiple sclerosis



Multiple system atrophy



Paraneoplastic syndrome



Parkinson’s disease



Spinal cord injury



Surgery or injury involving the nerves



Toxicity (vincristine)



Sympathetic nervous system (SNS) predominant dysautonomia is common along with: fibromyalgia, chronic fatigue syndrome, irritable bowel syndrome, and interstitial cystitis.



Anxiety can sometimes physically manifest symptoms resembling autonomic dysfunction.



The autonomic nervous system 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.



Dysautonomia diagnosis depends on the function of three autonomic functions – cardiovagal, adrenergic, and sudomotor. 



To make a diagnosis: measurements of blood pressure and heart rate while lying flat, and after at least 3 minutes of standing, autonomic reflex screen, tilt table test, and testing of the sudomotor response.



Additional tests and examinations: 



Ambulatory blood pressure and EKG monitoring



Cold pressor test



Deep breathing 



Hyperventilation test



Nerve biopsy for small fiber neuropathy



Quantitative sudomotor axon reflex test 



Testing for orthostatic intolerance



Thermoregulatory sweat test



Tilt table test



Valsalva maneuver



The treatment of dysautonomia  is difficult, due to its different symptoms.



A combination of drug therapies is often required to manage the process symptomatically.



Immunomodulatory therapy is used for autoimmune induced dysautonomia.



Control of blood glucose is important for diabetes.



Proton-pump inhibitors and H2 receptor antagonists used for digestive symptoms such as acid reflux.



Genitourinary autonomic neuropathy medications may include a guanine monophosphate type-5 phosphodiesterase inhibitor.



For hyperhidrosis, anticholinergic agents such as trihexyphenidyl or scopolamine can be used.



Intracutaneous injection of botulinum toxin type A can be used for management of hyperhidrosis, in some cases.



The prognosis of dysautonomia depends on the underlying cause.



Dysautonomia due to central nervous system degeneration such as Parkinson’s disease or multiple system atrophy have a generally poorer long-term prognosis. 



Dysautonomia could lead to pneumonia, acute respiratory failure, or sudden cardiopulmonary arrest.



Autonomic dysfunction symptoms such as orthostatic hypotension, gastroparesis, and gustatory sweating are associated with more severe disease.



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