What are Autonomic Disorders?
Autonomic disorders are conditions that affect the autonomic nervous system (ANS).
The ANS is a part of the peripheral nervous system that controls involuntary functions in the body - those that happen automatically without conscious effort like heart rate, blood pressure, digestion, temperature regulation, sweating, bladder and bowel function, and sexual function. The ANS is divided into two main branches: the sympathetic nervous system, which prepares the body for stress or emergency situations ("fight or flight"), and the parasympathetic nervous system, which promotes relaxation and recovery ("rest and digest"). Together, these systems work in balance to maintain internal stability, or homeostasis, ensuring the body responds appropriately to both internal and external changes.
Causes of Autonomic Disorders
Autonomic disorders can be caused by a variety of conditions that damage or disrupt the autonomic nervous system. Common causes include chronic diseases like diabetes, which can lead to nerve damage (autonomic neuropathy), and neurodegenerative disorders such as Parkinson’s disease or Multiple System Atrophy. Autoimmune diseases like lupus or Sjögren’s syndrome can also attack autonomic nerves. Genetic conditions, such as Familial Dysautonomia, are inherited and affect nerve development. Other causes include infections (e.g., HIV, Lyme disease), trauma, tumors, and toxic exposure (e.g., chemotherapy, heavy alcohol use). In some cases, the cause is idiopathic, meaning it's unknown.
Symptoms of Autonomic Disorders
Common symptoms of autonomic disorders include:
- Dizziness or fainting (especially when standing)
- Abnormal sweating (too much or too little)
- Difficulty regulating body temperature
- Digestive problems (bloating, constipation, diarrhea)
- Bladder issues (incontinence, retention)
- Heart palpitations
- Sexual dysfunction
- Fatigue
- Visual disturbances (blurry vision when standing)
Diagnosis of Autonomic Disorders
Diagnosis of autonomic disorders involves a combination of medical history, physical examination, and specialized tests to evaluate how the autonomic nervous system is functioning. Doctors typically begin by assessing symptoms like dizziness, fainting, abnormal sweating, or digestive issues. Common diagnostic tests include:
- Tilt Table Test – checks blood pressure and heart rate responses when moving from lying to standing.
- Heart Rate Variability Test – evaluates how heart rate changes with breathing or other stimuli.
- QSART (Quantitative Sudomotor Axon Reflex Test) – measures sweating response to assess nerve function.
- Thermoregulatory Sweat Test – shows sweating patterns on the body under heat stress.
- 24-hour Blood Pressure Monitoring – detects abnormal blood pressure fluctuations.
- Blood and Urine Tests – may be used to check for underlying causes like diabetes or autoimmune disease.
- Autonomic Reflex Screen – evaluates the integrity of the sympathetic and parasympathetic nervous systems.
Treatment for Autonomic Disorders
Treatment for autonomic disorders focuses on managing symptoms and addressing any underlying conditions causing the dysfunction. Since there is no universal cure, treatment is often individualized and may include:
- Lifestyle Changes: Increasing fluid and salt intake, wearing compression garments, avoiding triggers (like standing too long or heat), and elevating the head of the bed can help manage symptoms like low blood pressure and dizziness.
- Medications: Depending on the symptoms, drugs like midodrine or fludrocortisone may be used for low blood pressure, beta-blockers for heart rate control, and prokinetics for digestive issues. Pain relievers or anticholinergic drugs may be used for bladder or sweating problems.
- Physical Therapy: Gentle, regular exercise can improve circulation and prevent deconditioning, especially in patients with Postural Orthostatic Tachycardia Syndrome (POTS).
- Treating Underlying Conditions: Managing diabetes, autoimmune diseases, or infections can help reduce autonomic nerve damage.
- Immunotherapy: In autoimmune autonomic disorders, treatments like IVIG, steroids, or plasma exchange may be beneficial.
