effusion
(ĕ-fū'zhŭn 
)
[L. effusio, a pouring out, shedding]
Escape of fluid into a part, such as the pleural cavity, as by empyema (pus), hydrothorax (serum), hemothorax (blood), chylothorax (lymph), pneumothorax (air), hydropneumothorax (serum and air), and pyopneumothorax (pus and air).
joint e.Increased fluid within a joint cavity. There may be increased production of synovial fluid following trauma, with some arthritic disease processes, or blood accumulating in the joint following trauma or surgery or due to hemophilia. Excessive amounts of synovial fluid, pus, or blood accumulate in many arthritic diseases (such as gout or rheumatoid arthritis), after trauma, in joint infections, following joint surgery, or in hemophilia.
pericardial e.The abnormal accumulation of fluid in the pericardial cavity, between the visceral and the parietal pericardium. Its causes include cardiac trauma; and immune, infectious, and inflammatory diseases. Symptoms produced by the effusion include chest pain, difficulty breathing, anxiety, and palpitations.
pleural e.Fluid in the thoracic cavity between the visceral and parietal pleura. It may be seen on a chest radiograph if it exceeds 300 mL.
Fluid in the pleural space is sometimes well tolerated and asymptomatic, but most patients report some degree of dyspnea, cough, or pain on inspiration.
X-rays of the chest reveal opacification of the base of the lung compatible with fluid retention. If this opacification “layers out” when the patient rests on one side, fluid is present. Fluid can also be identified with ultrasound, CT, or MRI of the thorax. Thoracentesis is used to obtain fluid for microbiological, cytological, and chemical analysis.
Exudative pleural fluid should be removed with a chest tube or with repeated thoracentesis, along with treatment of the underlying cause. Some examples of exudative effusions are those adjacent to a pneumonia (parapneumonic effusion), which are treated with antibiotic therapy; or those caused by cancer (malignant pleural effusions), which may require surgical debulking and radiation or chemotherapy. Transudative effusions may sometimes improve with diuretic therapy, i.e. with control of heart, kidney, or liver failure contributing to generalized fluid retention.
The patient with an effusion is educated about and prepared for any needed diagnostic, radiographical, or invasive procedures.
SEE: thoracentesis.
e., pleural, of extravascular origin
ABBR: PEEVO
Fluid in the pleural space that arrives there from another source, e.g., from a surgical puncture of the urinary bladder, a fistula, or shunt from the cerebrospinal fluid space, or a misplaced catheter or feeding tube.