Clinical Laboratory Evaluation of Chronic Autonomic Failure

Background: The autonomic nervous system controls automatic body functions. Researchers want to improve the tests used to diagnose autonomic failure. Orthostatic hypertension is a drop in blood pressure when a person stands up. Researchers want to focus on this sign of autonomic failure. Objective: To improve testing for conditions that cause autonomic nervous system failure. Eligibility: People ages 18 and older in one of these categories: - Their blood pressure drops when they get up. - They have had a heart transplant or bilateral endoscopic thoracic sympathectomies or have had or will have renal sympathetic ablation Design: All participants will be screened with: - Medical history - Physical exam - Blood and urine tests Some participants will be screened with: - Heart and breathing tests - IV placement into an arm vein - Tilt table testing: Participants lie on a table that tilts while an IV is used to draw their blood. Participants may stay in the hospital for up to 1 week depending on their tests. Tests may include repeats of screening tests and: - Sweat testing: A drug is placed on the skin to cause sweating. Sensors on the skin measure moisture. - Lumbar puncture: A needle is inserted between the bones in the back to collect fluid. - MRI and PET/CT scan: Participants lie on a table that slides into a scanner. For the PET/CT, a small amount of a radioactive chemical will be injected with a small amount of a radioactive chemical. - Bladder catheter placement to collect urine - Skin biopsies: A punch tool removes a small skin sample. - Tests to see how the pupils react to light - Smelling tests - Thinking and memory tests - Questionnaires Participants may have a visit about 2 years later to repeat tests.