Edema By Andrea D Thompson, MD, PhD, University of Michigan; Michael J Shea, MD, Michigan Medicine at the University of Michigan Reviewed / Revised Jul 2022 | Modified Sep 2022 View Patient Education Pathophysiology Etiology Evaluation Treatment Geriatrics Essentials: Edema Key Points Topic Resources Lower Extremity Edema Scrotal Edema Some Causes of Edema Edema is swelling of soft tissues due to increased interstitial fluid.