Rheumatoid pleurisy. observations on the development of low pleural fluid pH and glucose level.

A patient with rheumatoid pleurisy provided the opportunity to observe the time course of development of the low glucose level and low pH characteristic of these pleural effusions. During six days, the effusion evolved from one with a normal glucose value and pH to one with a glucose value of 20 mg/dL and a pH of 6.78. The mechanisms responsible for these phenomena probably are (1) a selective block to glucose transport from blood to pleural fluid, (2) enhanced glucose use by rheumatoid pleura, and (3) an efflux block to the end products of pleural space glucose metabolism. Once the low glucose value-low pH rheumatoid effusion develops, it seems not to revert to an effusion with a normal glucose level and pH.