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Dysautonomia
The autonomic nervous system
Specialty	Neurology
Causes	Inadequacy of sympathetic, or parasympathetic, components of autonomic nervous system[1]
Risk factors	Alcoholism and Diabetes[2]
Diagnostic method	Ambulatory Blood pressure, as well as EKG monitoring[3]
Treatment	Symptomatic and supportive[1]

Dysautonomia or autonomic dysfunction is a condition in which the autonomic nervous system (ANS) does not work properly. This may affect the functioning of the heart, bladder, intestines, sweat glands, pupils, and blood vessels. Dysautonomia has many causes, not all of which may be classified as neuropathic.^[4] A number of conditions can feature dysautonomia, such as Parkinson's disease, HIV/AIDS, multiple system atrophy, autonomic failure, postural orthostatic tachycardia syndrome, and autonomic neuropathy.^{[citation needed]}

The diagnosis is achieved through functional testing of the ANS, focusing on the affected organ system. 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.^[5]

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

Causes

Vincristine

Dysautonomia may be due to inherited or degenerative neurologic diseases (primary dysautonomia)^[4] or it may occur due to injury of the autonomic nervous system from an acquired disorder (secondary dysautonomia).^[6][8] The most common causes of dysautonomia include

In the sympathetic nervous system (SNS), predominant dysautonomia is common along with fibromyalgia, chronic fatigue syndrome, irritable bowel syndrome, and interstitial cystitis, raising the possibility that such dysautonomia could be their common clustering underlying pathogenesis.^[11]

In addition to sometimes being a symptom of dysautonomia, anxiety can sometimes physically manifest symptoms resembling autonomic dysfunction.^[12][13][14] 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.^[15] For such patients, the anxiety sensitivity index may have better predictivity for anxiety disorders, while the Beck anxiety inventory may misleadingly suggest anxiety for patients with dysautonomia.^[16]

Mechanism

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.^[4][17]

Diagnosis

Valsalva maneuver

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, and testing of the sudomotor response (QSART or thermoregulatory sweat test).^[18]

Additional tests and examinations to determine a diagnosis of dysautonomia include

Vegetative-vascular dystonia

Particularly in the Russian literature,^[19] a subtype of dysautonomia which particularly affects the vascular system has been called vegetative-vascular dystonia.^{[20][21][22][23][24]} The term "vegetative" reflects an older name for the autonomic nervous system: the vegetative nervous system.^{[citation needed]}

Management

H₂- receptor antagonist

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 is important.^[6] Treatment can include proton-pump inhibitors and H2 receptor antagonists used for digestive symptoms such as acid reflux.^[25]

For the treatment of genitourinary autonomic neuropathy medications may include sildenafil (a guanine monophosphate type-5 phosphodiesterase inhibitor). For the treatment of hyperhidrosis, anticholinergic agents such as trihexyphenidyl or scopolamine can be used, also intracutaneous injection of botulinum toxin type A can be used for management in some cases.^[26]

Balloon angioplasty, a procedure referred to as transvascular autonomic modulation, is specifically not approved for the treatment of autonomic dysfunction.^[27]

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, or sudden cardiopulmonary arrest.^[4]

Autonomic dysfunction symptoms such as orthostatic hypotension, gastroparesis, and gustatory sweating are more frequently identified in mortalities.^[28]

See also

References

Further reading

Books

• 
  Brading, Alison (1999). The autonomic nervous system and its effectors. Oxford: Blackwell Science. ISBN 978-0632026241.
  


• 
  Goldstein, David (2016). Principles of Autonomic Medicine (PDF) (free online version ed.). Bethesda, Maryland: National Institute of Neurological Disorders and Stroke, National Institutes of Health. ISBN 9780824704087.
  


• 
  Jänig, Wilfrid (2008). Integrative action of the autonomic nervous system : neurobiology of homeostasis (Digitally printed version. ed.). Cambridge: Cambridge University Press. ISBN 978-0521067546.
  

Journal articles

• 
  Lara, Aline; Damasceno, Denis D.; Pires, Rita; Gros, Robert; Gomes, Enéas R.; Gavioli, Mariana; Lima, Ricardo F.; Guimarães, Diogo; Lima, Patricia (2010-04-01). "Dysautonomia Due to Reduced Cholinergic Neurotransmission Causes Cardiac Remodeling and Heart Failure". Molecular and Cellular Biology. 30 (7): 1746–1756. doi:10.1128/MCB.00996-09. ISSN 0270-7306. PMC 2838086. PMID 20123977.
  


• 
  Schiffer, Randolph B.; Rao, Stephen M.; Fogel, Barry S. (2003-01-01). Neuropsychiatry. Lippincott Williams & Wilkins. ISBN 9780781726559.
  

External links

• PubMed