dysautonomia

Dysautonomia refers to disorders of the autonomic nervous system (ANS), which controls involuntary functions such as heart rate, blood pressure, digestion, temperature regulation, and bladder control. It can occur as a standalone condition or as part of another disorder. Included are syndromes such as postural orthostatic tachycardia syndrome (POTS), neurocardiogenic syncope, autoimmune autonomic ganglionopathy, and degenerative conditions like pure autonomic failure and multisystem atrophy.

Symptoms vary but commonly include orthostatic intolerance with dizziness or fainting on standing, atypical heart rate responses, fatigue, and digestive problems (nausea, bloating, gastroparesis, constipation or diarrhea), urinary symptoms, abnormal sweating, and temperature sensitivity.

Causes may be primary (idiopathic or autoimmune) or secondary to diseases such as diabetes, amyloidosis, Parkinson disease with autonomic involvement, vitamin deficiencies, infections, or certain medications.

Diagnosis relies on medical history and specialized tests of autonomic function, including tilt-table testing, heart rate response to deep breathing, the Valsalva maneuver, and quantitative sudomotor axon reflex testing (QSART), along with evaluation for underlying conditions.

Management centers on symptom relief and treating underlying causes when possible. Nonpharmacologic strategies include hydration, increased salt intake where appropriate, compression garments, and graded exercise. Medications such as midodrine, fludrocortisone, and pyridostigmine may help orthostatic symptoms; autoimmune forms may respond to immunotherapy. Treatment is individualized and supervised by specialists.

Prognosis varies with cause and severity. Some individuals achieve stability with management; others experience progressive autonomic dysfunction. Ongoing research aims to clarify mechanisms and improve targeted therapies.