RT Journal
A1 Hildreth CJ, Lynm C, Glass RM
T1 PLeural effusion
JF JAMA
JO JAMA
YR 2009
FD January 21
VO 301
IS 3
SP 344
OP 344
DO 10.1001/jama.301.3.344
UL http://dx.doi.org/10.1001/jama.301.3.344
AB 
When an abnormal amount of fluid accumulates in the space between the 2 layers of the pleura  (the membrane that lines the surface of the lungs), it is called a pleural effusion . It is estimated that 1 million people in the United States develop a pleural effusion each year. About 20% to 60% of the people who develop pneumonia have a pleural effusion. A pleural effusion can also occur due to an extrapulmonary  (outside the lungs) cause. Treatment depends on the underlying cause. The January 21, 2009, issue of JAMA includes an article about diagnosing pleural effusions.