What is Dysautonomia (Autonomic Nervous System Dysfunction)?

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Last updated: April 14, 2025View editorial policy

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From the Guidelines

Dysautonomia is a complex disorder of the autonomic nervous system that requires a comprehensive management approach to reduce morbidity, mortality, and improve quality of life, and the most effective management strategy is to address specific symptoms and may include increased salt and fluid intake, compression garments, and medications such as fludrocortisone, midodrine, or beta-blockers, as well as lifestyle modifications, as recommended by the 2018 ESC guidelines for the diagnosis and management of syncope 1.

Definition and Causes

Dysautonomia is a disorder of the autonomic nervous system that controls involuntary bodily functions like heart rate, blood pressure, digestion, and temperature regulation. It occurs when nerves of this system are damaged or malfunction, causing a wide range of symptoms including dizziness, fainting, rapid heartbeat, blood pressure fluctuations, digestive problems, and exercise intolerance.

Symptoms and Diagnosis

The symptoms of dysautonomia can vary widely and may include orthostatic intolerance, orthostatic tachycardia, orthostatic hypotension, and postural orthostatic tachycardia syndrome (POTS) 1. Diagnosis is based on a thorough history, physical examination, and eyewitness observation, if available.

Treatment and Management

Treatment typically involves addressing specific symptoms and may include:

  • Increased salt and fluid intake
  • Compression garments
  • Medications such as:
    • Fludrocortisone (0.1-0.2 mg daily) to increase blood volume
    • Midodrine (2.5-10 mg three times daily) to raise blood pressure
    • Beta-blockers like propranolol (10-40 mg twice daily) to manage tachycardia
  • Lifestyle modifications, including:
    • Gradual position changes
    • Avoiding triggers like heat or prolonged standing
    • Small frequent meals
    • Structured exercise programs

Prognosis and Quality of Life

While often chronic, many patients experience significant improvement with proper management focused on maintaining blood pressure stability and reducing symptom severity. Dysautonomia can be primary (like POTS) or secondary to conditions such as diabetes, autoimmune disorders, or certain infections 1.

From the Research

Definition and Classification of Dysautonomia

  • Dysautonomia covers a range of clinical conditions with different characteristics and prognoses, including Reflex Syndromes, Postural Orthostatic Tachycardia Syndrome (POTS), Chronic Fatigue Syndrome, Neurogenic Orthostatic Hypotension (nOH), and Carotid Sinus Hypersensitivity Syndrome 2.
  • Cardiovascular Autonomic Neuropathy (CAN) is a term used to define dysautonomia with impairment of the sympathetic and/or parasympathetic cardiovascular autonomic nervous system, which can be idiopathic or secondary to systemic pathologies 2.

Diagnosis and Management of Dysautonomia

  • The diagnosis of CAN involves the use of Valsalva, Respiratory, and Orthostatic tests (30:15), which are the gold standard methods, and can be associated with RR Variability tests to increase sensitivity 2.
  • Treatment of patients with dysautonomia is complex and often refractory, requiring specialized and multidisciplinary evaluation, and there is no cure for most types of dysautonomia at a late stage 2.
  • Lifestyle measures, such as postural care, good hydration, and higher salt intake, are important treatment steps, and various drugs can be used for symptomatic treatment, including fludrocortisone, midodrine, and droxidopa 2, 3.

Specific Conditions Related to Dysautonomia

  • Postural Orthostatic Tachycardia Syndrome (POTS) is characterized by sustained elevation of heart rate in an orthostatic position, and its management involves lifestyle measures, beta-blockers, ivabradine, fludrocortisone, and midodrine 3.
  • Chronic Fatigue Syndrome is a form of dysautonomia, characterized by unexplained fatigue, feeling ill after exercising, non-restorative sleep, and cognitive impairment or orthostatic intolerance 2.
  • Exercise and a multidisciplinary holistic approach can improve symptoms and quality of life in patients with dysautonomia, as shown in a study where adolescents with dysautonomia completed an eight-week strength training program and reported significant improvements in quality of life and endurance time 4.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Dysautonomia: A Forgotten Condition - Part 1.

Arquivos brasileiros de cardiologia, 2021

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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