Diagnosis is made by 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. Depending on the severity of the dysfunction, dysautonomia can range from being nearly symptomless and transient to disabling and/or life-threatening.[12]
Dysautonomia, a complex set of conditions characterized by autonomic nervous system (ANS) dysfunction, manifests clinically with a diverse array of symptoms, of which postural orthostatic tachycardia syndrome (POTS) stands out as the most common.[11]
The symptoms of dysautonomia, which are numerous and vary widely for each person, are due to inefficient or unbalanced efferent signals sent via both systems.[medical citation needed] Symptoms in people with dysautonomia include:
Dysautonomia may be due to inherited or degenerative neurologic diseases (primary dysautonomia)[5] or injury of the autonomic nervous system from an acquired disorder (secondary dysautonomia).[1][14] Its most common causes include:
In addition to sometimes being a symptom of dysautonomia, anxiety can sometimes physically manifest symptoms resembling autonomic dysfunction.[29][30][31] 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.[32] 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.[33]
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 digestion, for example. Symptoms typically arise from abnormal responses of either the sympathetic or parasympathetic systems based on situation or environment.[5][36][26]
Diagnosis of dysautonomia depends on the overall function of three autonomic functions—cardiovagal, adrenergic, and sudomotor. A diagnosis should at a minimum include measurements of blood pressure and heart rate while lying flat and after at least three minutes of standing. The best way to make a diagnosis includes a range of testing, notably an autonomic reflex screen, tilt table test, and testing of the sudomotor response (ESC, QSART or thermoregulatory sweat test).[37]
Additional tests and examinations to diagnose dysautonomia include:
Particularly in the Russian literature,[38] a subtype of dysautonomia that particularly affects the vascular system has been called vegetative-vascular dystonia.[39] The term "vegetative" reflects an older name for the autonomic nervous system: the vegetative nervous system.[citation needed]
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. In the case of autoimmune neuropathy, treatment with immunomodulatory therapies is done. If diabetes mellitus is the cause, control of blood glucose is important.[1] Treatment can include proton-pump inhibitors and H2 receptor antagonists used for digestive symptoms such as acid reflux.[41]
The prognosis of dysautonomia depends on several factors; people with chronic, progressive, generalized dysautonomia in the setting of central nervous system degeneration such as Parkinson's disease or multiple system atrophy generally have poorer long-term prognoses. Dysautonomia can be fatal due to pneumonia, acute respiratory failure, or sudden cardiopulmonary arrest.[5] Autonomic dysfunction symptoms such as orthostatic hypotension, gastroparesis, and gustatory sweating are more frequently identified in mortalities.[46]
^McIntosh RC (August 2016). "A meta-analysis of HIV and heart rate variability in the era of antiretroviral therapy". Clin Auton Res (Review). 26 (4): 287–94. doi:10.1007/s10286-016-0366-6. PMID27395409. S2CID20256879.
^Sakakibara R, Uchiyama T, Kuwabara S, Mori M, Ito T, Yamamoto T, Awa Y, Yamaguchi C, Yuki N, Vernino S, Kishi M, Shirai K (2009). "Prevalence and mechanism of bladder dysfunction in Guillain-Barre Syndrome". Neurourol Urodyn. 28 (5): 432–437. doi:10.1002/nau.20663. PMID19260087. S2CID25617551.
^Loganovsky K (1999). "Vegetative-Vascular Dystonia and Osteoalgetic Syndrome or Chronic Fatigue Syndrome as a Characteristic After-Effect of Radioecological Disaster". Journal of Chronic Fatigue Syndrome. 7 (3): 3–16. doi:10.1300/J092v07n03_02.
^Ivanova ES, Mukharliamov FI, Razumov AN, Uianaeva AI (2008). "[State-of-the-art corrective and diagnostic technologies in medical rehabilitation of patients with vegetative vascular dystonia]". Voprosy Kurortologii, Fizioterapii, I Lechebnoi Fizicheskoi Kultury (1): 4–7. PMID18376477.
^Stallkamp Tidd SJ, Nowacki AS, Singh T, et al. (2024). "Comorbid anxiety is associated with more changes in the Management of Postural Orthostatic Tachycardia Syndrome". Gen Hosp Psychiatry. 87: 1–6. doi:10.1016/j.genhosppsych.2024.01.003. PMID38224642. S2CID266997580.
Brading A (1999). The autonomic nervous system and its effectors. Oxford: Blackwell Science. ISBN978-0-632-02624-1.
Goldstein D (2016). Principles of Autonomic Medicine(PDF) (free online version ed.). Bethesda, Maryland: National Institute of Neurological Disorders and Stroke, National Institutes of Health. ISBN978-0-8247-0408-7.
Jänig W (2008). Integrative action of the autonomic nervous system : neurobiology of homeostasis (Digitally printed version. ed.). Cambridge: Cambridge University Press. ISBN978-0-521-06754-6.
