From the Guidelines
Autonomic dysfunction refers to a condition where the autonomic nervous system, which controls involuntary bodily functions, doesn't work properly, and can manifest as various symptoms including orthostatic hypotension, abnormal heart rate, and digestive problems. This condition can be primary or secondary, resulting from another condition like diabetes, Parkinson's disease, or certain medications 1. The autonomic nervous system plays a crucial role in maintaining homeostasis in the body, and its dysfunction can significantly impact quality of life. According to the 2018 ESC guidelines for the diagnosis and management of syncope, dysautonomia is used to describe any abnormal function of the autonomic nervous system, including neurogenic orthostatic hypotension, reflex syncope, and postural orthostatic tachycardia syndrome (POTS) 1. Some key points to consider in autonomic dysfunction include:
- The condition can cause a range of symptoms, from mild to debilitating, and can significantly impact quality of life
- Treatment typically addresses the underlying cause when possible and manages symptoms through lifestyle modifications and medications
- Referral for autonomic evaluation can be useful to improve diagnostic and prognostic accuracy in selected patients with syncope and known or suspected neurodegenerative disease 1
- Autonomic evaluation may determine the underlying cause of neurogenic OH, provide prognostic information, and have therapeutic implications 1. In terms of management, lifestyle modifications such as increased fluid and salt intake, compression garments, and careful position changes are often recommended, and medications like fludrocortisone, midodrine, or beta-blockers may be prescribed to manage symptoms 1. Overall, autonomic dysfunction is a complex condition that requires careful evaluation and management to improve patient outcomes and quality of life.
From the Research
Definition and Causes of Autonomic Dysfunction
- Autonomic dysfunction refers to a condition where the autonomic nervous system (ANS) is disrupted, leading to various symptoms involving the cardiovascular, gastrointestinal, and urogenital systems 2, 3.
- The ANS is designed to maintain physiologic homeostasis, and its widespread connections make it vulnerable to disruption by many disease processes, including primary and secondary etiologies such as Parkinson's disease, diabetes mellitus, and immune-mediated illnesses 3.
Symptoms and Diagnosis of Autonomic Dysfunction
- Patients with autonomic dysfunction may present with a variety of seemingly unrelated symptoms, including fatigue, difficulty concentrating, orthostatic intolerance, palpitations, constipation or diarrhea, early satiety, urinary retention or incontinence, and erectile dysfunction 2.
- Diagnosis of autonomic dysfunction involves evaluating symptoms, measuring supine and standing blood pressure, and conducting appropriate clinical tests to narrow the differential diagnosis and identify the cause of orthostatic hypotension (OH) 4.
- Heart rate and plasma norepinephrine responses to orthostatic stress are helpful in diagnosing impairment of the baroreflex in patients with OH and suspected autonomic dysfunction 3.
Treatment and Management of Autonomic Dysfunction
- Treatment of autonomic dysfunction involves a combination of nonpharmacologic and pharmacologic approaches, including increased salt and water intake, fludrocortisone, midodrine, and selective serotonin reuptake inhibitors 5, 4.
- Patients with orthostatic hypotension due to autonomic failure may benefit from treatment with alpha-adrenergic agonists, such as midodrine, which can increase standing blood pressure and decrease orthostatic symptoms 6, 5.
- Treatment algorithms should always be interpreted in the light of individual patient characteristics, and sound clinical judgment and close follow-up of patients should guide combination therapy 6.