Dr. Charles "Pat" Davis, MD, PhD, is a board certified Emergency Medicine doctor who currently practices as a consultant and staff member for hospitals. He has a PhD in Microbiology (UT at Austin), and the MD (Univ. Texas Medical Branch, Galveston). He is a Clinical Professor (retired) in the Division of Emergency Medicine, UT Health Science Center at San Antonio, and has been the Chief of Emergency Medicine at UT Medical Branch and at UTHSCSA with over 250 publications.
Steven Doerr, MD, is a U.S. board-certified Emergency Medicine Physician. Dr. Doerr received his undergraduate degree in Spanish from the University of Colorado at Boulder. He graduated with his Medical Degree from the University Of Colorado Health Sciences Center in Denver, Colorado in 1998 and completed his residency training in Emergency Medicine from Denver Health Medical Center in Denver, Colorado in 2002, where he also served as Chief Resident.
A pleural effusion is a buildup of fluid in the pleural space, an area
between the layers of tissue that line the lungs and the chest cavity. It may
also be referred to as effusion or pulmonary effusion. The type of fluid that
forms a pleural effusion may be categorized as either transudate or exudate.
Transudate is usually composed of ultrafiltrates of plasma due to an imbalance
in vascular hydrostatic and oncotic forces in the chest (heart failure,
cirrhosis), while exudate is typically produced by inflammatory conditions (lung
infection, malignancy). Exudative pleural effusions are usually more serious and
difficult to treat.
The development of a pleural effusion occurs from fluid seeping into the
pleural space, a thin area between the visceral and pleural membranes in the
chest cavity, which normally contains a small amount of fluid to facilitate smooth
lung movement. Fluid under pressure, malignant cells, and infectious agents can
occasionally enter this space and cause it to expand with abnormal amounts of
fluid and other compounds (see diagnosis section).