6/15/15, 2:08 Pleural e!usion - Wikipedia, the free encyclopedia Page 1 of 9 https://en.wikipedia.org/wiki/Pleural_e!usion Pleural effusion Diagram of fluid buildup in the pleura Classification and external resources ICD-10 J90 (http://apps.who.int/classifications/icd10/browse/2015/en#/J90)-J91 (http://apps.who.int/classifications/icd10/browse/2015/en#/J91) ICD-9 511.9 (http://www .icd9data.com/getICD9Code.ashx?icd9=511.9) MedlinePlus 000086 (http://www.nlm.nih.gov/medlineplus/ency/ar ticle/000086.htm) MeSH D010996 (https://www .nlm.nih.gov/cgi/mesh/2015/MB_cgi? field=uid&term=D010996) Pleural effusion From Wikipedia, the freeencyclopedia Pleural effusionis excess fluid that accumulates in the pleural cavity, the fluid-filled space that surrounds the lungs. This excess can impair breathing by limiting the expansion of the lungs. Various kinds ofpleural effusion, depending on the nature of the fluid and what caused its entry into the pleural space, are hydrothorax (serous fluid), hemothorax (blood), urinothorax (urine), chylothorax (chyle), or pyothorax (pus). Pneumothorax is the accumulation of air in the pleural space. Contents 1 Types 2 Causes 2.1Transudative 2.2 Exudative 2.3 Other/ungrouped 3 Pathophysiology 4 Diagnosis 4.1 Imaging 4.2 Thoracentesis 4.3 Light's criteria 5 Treatment 6 See also 7 References 8 External links Types Five types of fluids can accumulate in the pleural space: Serous fluid (hydrothorax) Blood (hemothorax) Chyle (chylothorax)
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The most common causes of transudative pleural effusions in the United States are biventricular failure, andcirrhosis (causing hepatic hydrothorax). Nephrotic syndrome leading to increased loss of albumin and resulta
hypoalbuminemia and thus reducing colloid osmotic pressure is another less common cause. Pulmonary
embolisms were once thought to be associated with transudative effusions but have been recently shown to b
exudative[1] The mechanism for the exudative pleural effusion is probably related to increased permeability
he capillaries in the lung, which results from the release of cytokines or inflammatory mediators (e.g. vascul
endothelial growth factor) from the platelet-rich thrombi. The excessive interstitial lung fluid traverses the
visceral pleura and accumulates into the pleural space.
Conditions associated with transudative pleural effusions:[2]
Once identified as exudative, additional evaluation is needed to determine the cause of the excess fluid, and
pleural fluid amylase, glucose, pH and cell counts are obtained.
Pleural fluid red cell counts are elevated in cases of bloody effusions (for example after heart surgery ohemothorax from incomplete evacuation of shed blood)
fluid layering in the right pleuralcavity. The B arrow shows the norm
width of the lung in the cavity
Pleural fluid amylase is elevated in cases of esophageal rupture, pancreatic pleural effusion, or cancer.Glucose is decreased with cancer, bacterial infections, or rheumatoid pleuritis.Pleural fluid pH is low in empyema (<7.2) and may be low in cancer.If cancer is suspected, the pleural fluid is sent for cytology. If cytology is negative, and cancer is still
suspected, either a thoracoscopy, or needle biopsy[3] of the pleura may be performed.The fluid is also sent for Gram staining and culture, and, if suspicious for tuberculosis, examination for TB markers(adenosine deaminase > 45 IU/L, interferon gamma > 140 pg/mL,or positive polymerase chain reaction (PCR) for tuberculousDNA).
The most common causes of exudative pleural effusions are bacterial
pneumonia, cancer (with lung cancer, breast cancer, and lymphoma
causing approximately 75% of all malignant pleural effusions), viral
nfection, and pulmonary embolism.
Another common cause is after heart surgery. Patient's with
ncompletely drained blood can have retained blood that leads to an
nflammatory response that drives a bloody, exudative pleural fluid thatpresents as an effusion.
Conditions associated with exudative pleural effusions:[2]
Post Heart Surgery (from incomplete evacuation of shed blood)MalignancyInfectionTraumaPulmonary infarction
Pulmonary embolismAutoimmune disordersPancreatitisRuptured esophagus ( or Boerhaave's syndrome)Rheumatoid PleurisyDrug-induced LupusTuberculosis
Other/ungrouped
Other causes of pleural effusion include tuberculosis (though pleural fluid smears are rarely positive for AFB
his is the most common cause of pleural effusion in some developing countries), autoimmune disease such asystemic lupus erythematosus, bleeding (often due to chest trauma), chylothorax (most commonly caused by
rauma), and accidental infusion of fluids.
Less common causes include esophageal rupture or pancreatic disease, intra-abdominal abscess, rheumatoid
arthritis, asbestos pleural effusion, Mesothelioma, Meigs syndrome (ascites and pleural effusion due to a ben
ovarian tumor), and ovarian hyperstimulation syndrome.
Pleural effusions may also occur through medical/surgical interventions, including the use of medications
pleural fluid is usually eosinophilic), coronary artery bypass surgery, abdominal surgery, endoscopic varicea
sclerotherapy, radiation therapy, liver or lung transplantation, and intra- or extravascular insertion of central
ines.
Pathophysiology
Pleural fluid is secreted by parietal layer of the pleura and reabsorbed by the lymphatics in the most dependeparts of the parietal pleura, primarily the diaphragmatic and mediastinal regions.
Diagnosis
Pleural effusion is usually diagnosed on the basis of medical history and
physical exam, and confirmed by chest x-ray. Once accumulated fluid is
more than 300 ml, there are usually detectable clinical signs in the
patient, such as decreased movement of the chest on the affected side,
stony dullness to percussion over the fluid, diminished breath sounds onhe affected side, decreased vocal resonance and fremitus (though this is
an inconsistent and unreliable sign), and pleural friction rub. Above the
effusion, where the lung is compressed, there may be bronchial
breathing and egophony. A large effusion there may cause tracheal
deviation away from the effusion. A systematic review (2009) published
as part of the Rational Clinical Examination Series in the Journal of the
American Medical Association (JAMA) showed that dullness to
conventional percussion was most accurate for diagnosing pleural
nterval, 2.2–33.8), while the absence of reduced tactile vocal fremitus made pleural effusion less likelynegative likelihood ratio, 0.21; 95% confidence interval, 0.12–0.37).[4]
Imaging
A pleural effusion will show up as an area of whiteness on a standard posteroanterior X-ray.[5] Normally the
space between the two layers of the lung, the visceral pleura and the parietal pleura, cannot be seen. A pleura
effusion infiltrates the space between these layers. Because the pleural effusion has a density similar to body
fluid or water, it can be seen on radiographs. Since the effusion has greater density than the rest of the lung, i
will gravitate towards the lower portions of the pleural cavity. The pleural effusion behaves according to bas
fluid dynamics, conforming to the shape of the lung and chest cavity. If the pleural cavity contains both air an
fluid, then the fluid will have a "fluid level" that is horizontal instead of conforming to the lung space. [6] Che
radiographs acquired in the lateral decubitus position (with the patient lying on his side) are more sensitive a
can pick up as little as 50 ml of fluid. At least 300 ml of fluid must be present before upright chest films can
pick up signs of pleural effusion (e.g., blunted costophrenic angles).
Once a pleural effusion is diagnosed, the cause must be determined. Pleural fluid is drawn out of the pleural
space in a process called thoracentesis, and it should be done in almost all patients who have pleural fluid tha
! 10 mm in thickness on CT, ultrasonography, or lateral decubitus x-ray and that is new or of uncertain etiolo
n general, the only patients who do not require thoracentesis are those who have heart failure with symmetri
pleural effusions and no chest pain or fever; in these patients, diuresis can be tried, and thoracentesis avoided
unless effusions persist for!
3 days.
[7]
In thoracentesis, a needle is inserted through the back of the chest wan the sixth, seventh, or eighth intercostal space on the midaxillary line, into the pleural space. The fluid may
hen be evaluated for the following:
1. Chemical composition including protein, lactate dehydrogenase (LDH), albumin, amylase, pH, andglucose
2. Gram stain and culture to identify possible bacterial infections3. Cell count and differential4. Cytopathology to identify cancer cells, but may also identify some infective organisms5. Other tests as suggested by the clinical situation – lipids, fungal culture, viral culture, specific
immunoglobulins
Light's criteria
Definitions of the terms "transudate" and "exudate" are the source of much confusion. Briefly, transudate is
produced through pressure filtration without capillary injury while exudate is "inflammatory fluid" leaking
An accurate diagnosis of the cause of the effusion, transudate versus exudate, relies on a comparison of the
chemistries in the pleural fluid to those in the blood, using Light's criteria. According to Light's criteria (Lighet al. 1972), a pleural effusion is likely exudative if at least one of the following exists:[14]
1. The ratio of pleural fluid protein to serum protein is greater than 0.52. The ratio of pleural fluid LDH and serum LDH is greater than 0.6
3. Pleural fluid LDH is greater than 0.6 [9] or 2 ⁄ 3
[14] times the normal upper limit for serum. Different
laboratories have different values for the upper limit of serum LDH, but examples include 200[15] and
300[15] IU/l.[16]
The sensitivity and specificity of Light's criteria for detection of exudates have been measured in many studi
and are usually reported to be around 98% and 80%, respectively.[17][18] This means that although Light's
criteria are relatively accurate, twenty percent of patients that are identified by Light's criteria as having
exudative pleural effusions actually have transudative pleural effusions. Therefore, if a patient identified by
Light's criteria as having an exudative pleural effusion appears clinically to have a condition that usually
produces transudative effusions, additional testing is needed. In such cases albumin levels in blood and pleur
fluid are measured. If the difference between the albumin level in the blood and the pleural fluid is greater th
1.2 g/dL (12 g/L), this suggests that the patient has a transudative pleural effusion.[11] However, pleural fluid
esting is not perfect, and the final decision about whether a fluid is a
ransudate or an exudate is based not on chemical analysis of the fluid,
but on accurate diagnosis of the disease that produces the fluid.
The traditional definitions of transudate as a pleural effusion due to
systemic factors and an exudate as a pleural effusion due to local factors
have been used since 1940 or earlier (Light et al., 1972). Previous to
Light's landmark study, which was based on work by Chandrasekhar,
nvestigators unsuccessfully attempted to use other criteria, such as
specific gravity, pH, and protein content of the fluid, to differentiate
between transudates and exudates. Light's criteria are highly statistically
sensitive for exudates (although not very statistically specific). More
recent studies have examined other characteristics of pleural fluid that
may help to determine whether the process producing the effusion is
ocal (exudate) or systemic (transudate). The chart to the right, illustrates
some of the results of these more recent studies. However, it should be
borne in mind that Light's criteria are still the most widely used criteria.
The Rational Clinical Examination Series review found that bilateraleffusions, symmetric and asymmetric, are the most common distribution
n heart failure (60% of effusions in heart failure will be bilateral). When
here is asymmetry in heart failure-associated pleural effusions (either
unilateral or one side larger than the other), the right side is usually more
nvolved than the left.[4]
Treatment
Treatment depends on the underlying cause of the pleural effusion.
Therapeutic aspiration may be sufficient; larger effusions may require insertion of an intercostal drain (either
pigtail or surgical). When managing these chest tubes, it is important to make sure the chest tubes do not
become occluded or clogged. A clogged chest tube in the setting of continued production of fluid will result i
residual fluid left behind when the chest tube is removed. This fluid can lead to complications such as hypox
due to lung collapse from the fluid, or fibrothorax, later, when the space scars down. Repeated effusions may
require chemical (talc, bleomycin, tetracycline/doxycycline), or surgical pleurodesis, in which the two pleura
surfaces are scarred to each other so that no fluid can accumulate between them. This is a surgical procedure
hat involves inserting a chest tube, then either mechanically abrading the pleura or inserting the chemicals to
nduce a scar. This requires the chest tube to stay in until the fluid drainage stops. This can take days to weekand can require prolonged hospitalizations. If the chest tube becomes clogged, fluid will be left behind and th
pleurodesis will fail.
Pleurodesis fails in as many as 30% of cases. An alternative is to place a PleurX Pleural Catheter or Aspira
Drainage Catheter. This is a 15Fr chest tube with a one-way valve. Each day the patient or care givers conne
o a simple vacuum tube and remove from 600 cc to 1000 cc of fluid. This can be repeated daily. When not in
2. Galagan et al. Color Atlas of Body Fluids. CAP Press, Northfield, 20063. de Menezes Lyra R (July 1997). "A modified outer cannula can help thoracentesis after pleural biopsy"
5. Corne et al. (2002). Chest X-Ray Made Easy. Churchill Livingstone. ISBN 0-443-07008-3.
6. Squire, Lucy Frank; Novelline, Robert A. (2004). Squire's fundamentals of radiology. Cambridge: Harvard Universit
Press. pp. 132–3. ISBN 0-674-01279-8.
7. Light, Richard W. "Pleural Effusion"
(http://www.merckmanuals.com/professional/pulmonary_disorders/mediastinal_and_pleural_disorders/pleural_effushtml). Merck Manual for Health Care Professionals. Merck Sharp & Dohme Corp. Retrieved 21 August 2013.
8. The University of Utah • Spencer S. Eccles Health Sciences Library > WebPath images > "Inflammation"
Retrieved from "https://en.wikipedia.org/w/index.php?title=Pleural_effusion&oldid=666111426"
Categories: Disorders of fascia Diseases of pleura
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