Pleural effusionFrom Wikipedia, the free encyclopediaIt has been suggested thatParapneumonic effusionbemergedinto this article. (Discuss)Proposed since January 2014.

Pleural effusion

Diagram of fluid buildup in the pleura

Classification and external resources

ICD-10J90-J91

ICD-9511.9

MedlinePlus000086

MeSHD010996

Pleural effusionis excess fluid that accumulates in thepleural cavity, the fluid-filled space that surrounds thelungs. This excess can impairbreathingby limiting the expansion of the lungs. Various kinds of pleural effusion, depending on the nature of the fluid and what caused its entry into the pleural space, arehydrothorax(serous fluid),hemothorax(blood),urinothorax(urine),chylothorax(chyle), orpyothorax(pus).Pneumothoraxis the accumulation ofairin the pleural space.Contents[hide] 1Types 2Causes 2.1Transudative 2.2Exudative 2.3Other/ungrouped 3Pathophysiology 4Diagnosis 4.1Imaging 4.2Thoracentesis 4.3Light's criteria 5Treatment 6See also 7References 8External linksTypes[edit]Five types of fluids can accumulate in the pleural space: Serous fluid(hydrothorax) Blood(hemothorax) Chyle(chylothorax) Pus(pyothoraxorempyema) Urine(urinothorax)On the basis of fluid present - Transudative pleural effusion Exudative pleural effusionOn the basis of associated infection- Parapneumonic effusion(pneumonia,lung abscess) Tuberculous effusion( pulmonary tuberculosis) Malignant effusion (brochogenic carcinoma)Causes[edit]Transudative[edit]The most common causes oftransudativepleural effusions in the United States arebiventricular failure, andcirrhosis(causinghepatichydrothorax). Nephrotic syndrome leading to increased loss of albumin and resultant 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 be exudative[1]The mechanism for the exudative pleural effusion is probably related to increased permeability of the capillaries in the lung, which results from the release of cytokines or inflammatory mediators (e.g. vascular 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] Congestive Heart Failure(CHF) Livercirrhosis Hypoproteinemia Nephrotic syndrome Acute atelectasis Myxedema Peritoneal dialysis Meigs syndrome Obstructive uropathy End-stage kidney diseaseExudative[edit]

Pleural effusionChest x-ray of a pleural effusion. The arrow A shows fluid layering in the right pleural cavity. The B arrow shows the normal width of the lung in the cavityOnce identified asexudative, 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 amylase is elevated in cases of esophageal rupture,pancreatic pleural effusion, or cancer. Glucose is decreased with cancer, bacterial infections, orrheumatoid pleuritis. Pleural fluid pH is low in empyema ( 45 IU/L,interferon gamma> 140 pg/mL, or positivepolymerase chain reaction(PCR) for tuberculous DNA).The most common causes of exudative pleural effusions are bacterialpneumonia, cancer (withlung cancer,breast cancer, andlymphomacausing approximately 75% of all malignant pleural effusions), viral infection, andpulmonary embolism.Conditions associated with exudative pleural effusions:[2] Malignancy Infection Trauma Pulmonary infarction Pulmonary embolism Autoimmune disorders Pancreatitis Ruptured esophagus ( orBoerhaave's syndrome) Rheumatoid Pleurisy Drug-induced Lupus TuberculosisOther/ungrouped[edit]Other causes of pleural effusion includetuberculosis(though pleural fluid smears are rarely positive for AFB, this is the most common cause of pleural effusion in some developing countries),autoimmunedisease such assystemic lupus erythematosus, bleeding (often due to chest trauma),chylothorax(most commonly caused by trauma), 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 benignovarian tumor), andovarian hyperstimulation syndrome.Pleural effusions may also occur through medical/surgical interventions, including the use of medications (pleural fluid is usuallyeosinophilic),coronary artery bypass surgery, abdominal surgery,endoscopic variceal sclerotherapy,radiation therapy,liverorlung transplantation, and intra- or extravascular insertion ofcentral lines.Pathophysiology[edit]Pleural fluid is secreted by parietal layer of thepleuraand reabsorbed by the lymphatics in the most dependent parts of the parietal pleura, primarily the diaphragmatic and mediastinal regions.Diagnosis[edit]

A large left sided pleural effusion as seen on an upright chest X-rayPleural effusion is usually diagnosed on the basis ofmedical historyandphysical exam, and confirmed bychest x-ray. Once accumulated fluid is more than 300 ml, there are usually detectableclinical signsin the patient, such as decreased movement of the chest on the affected side, stony dullness to percussion over the fluid, diminishedbreath soundson the affected side, decreased vocal resonance andfremitus(though this is an inconsistent and unreliable sign), andpleural friction rub. Above the effusion, where the lung is compressed, there may be bronchial breathing andegophony. A large effusion there may causetrachealdeviation 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 effusion (summary positivelikelihood ratio, 8.7; 95%confidence interval, 2.233.8), while the absence of reduced tactile vocal fremitus made pleural effusion less likely (negative likelihood ratio, 0.21; 95% confidence interval, 0.120.37).[4]Imaging[edit]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 pleural 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, it will gravitate towards the lower portions of thepleural cavity. The pleural effusion behaves according to basic fluid dynamics, conforming to the shape of the lung and chest cavity. If the pleural cavity contains both air and fluid, then the fluid will have a "fluid level" that is horizontal instead of conforming to the lung space.[6]Chest radiographs acquired in the lateraldecubitusposition (with the patient lying on his side) are more sensitive and 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., bluntedcostophrenic angles). Massive left-sided pleural effusion (whiteness) in a patient presenting with lung cancer. CTscan of chest showing left sided pleural effusion. Effusion fluid often settles at the lowest space due togravity; here at the back as the patient is lying under scanner. The lung expanding within an area of pleural effusion as seen by ultrasound Micrographof a pleural fluidcytopathologyspecimen showingmalignant mesothelioma, one cause of a pleural effusion.Thoracentesis[edit]Once a pleural effusion is diagnosed, the cause must be determined. Pleural fluid is drawn out of the pleural space in a process calledthoracentesis, and it should be done in almost all patients who have pleural fluid that is 10mm in thickness on CT, ultrasonography, or lateral decubitus x-ray and that is new or of uncertain etiology. In general, the only patients who do not require thoracentesis are those who haveheart failurewith symmetric pleural effusions and no chest pain or fever; in these patients,diuresiscan be tried, and thoracentesis avoided unless effusions persist for 3 days.[7]In thoracentesis, a needle is inserted through the back of the chest wall in the sixth, seventh, or eighth intercostal space on the midaxillary line, into the pleural space. The fluid may then be evaluated for the following:1. Chemical composition includingprotein,lactate dehydrogenase(LDH),albumin,amylase,pH, andglucose2. Gram stainand culture to identify possible bacterial infections3. Cellcount and differential4. Cytopathologyto identify cancer cells, but may also identify some infective organisms5. Other tests as suggested by the clinical situationlipids,fungal culture,viral culture, specificimmunoglobulinsLight's criteria[edit]Transudatevs.exudate view talk edit

TransudateExudate

Main causesIncreasedhydrostaticpressure,Decreasedcolloidosmotic pressureInflammation-Increased Vascular Permeability

AppearanceClear[8]Cloudy[8]

Specific gravity1.020

Proteincontent2.9 g/dL[9]

fluid protein/serum protein< 0.5> 0.5[10]

Differenceofalbumincontentwith blood albumin> 1.2 g/dL< 1.2 g/dL[11]

fluidLDHupper limit for serum< 0.6 or 0.6[9]or >23[10]

Cholesterolcontent< 45 mg/dL> 45 mg/dL[9]

Instruments for needle biopsy of the pleura.[12]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 between cells.Transudative pleural effusions are defined as effusions that are caused bysystemicfactors that alter the pleural equilibrium, orStarling forces. The components of the Starling forceshydrostatic pressure, permeability, and oncotic pressure (effective pressure due to the composition of the pleural fluid and blood)are altered in many diseases, e.g.,left ventricular failure, kidney failure, liver failure, andcirrhosis. Exudative pleural effusions, by contrast, are caused by alterations inlocalfactors that influence the formation and absorption of pleural fluid (e.g.,bacterial pneumonia,cancer,pulmonary embolism, and viral infection).[13]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 (Light, et 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 0.63. Pleural fluid LDH is greater than 0.6[9]or23[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 studies 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 casesalbuminlevels in blood and pleural fluid are measured. If the difference between the albumin level in the blood and the pleural fluid is greater than 1.2 g/dL (12 g/L), this suggests that the patient has a transudative pleural effusion.[11]However, pleural fluid testing is not perfect, and the final decision about whether a fluid is a transudate 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, investigators 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 local (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 bilateral effusions, symmetric and asymmetric, are the most common distribution in heart failure (60% of effusions in heart failure will be bilateral). When there is asymmetry in heart failure-associated pleural effusions (either unilateral or one side larger than the other), the right side is usually more involved than the left.[4]Treatment[edit]Treatment depends on the underlying cause of the pleural effusion.Therapeutic aspiration may be sufficient; larger effusions may require insertion of anintercostal 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 in residual fluid left behind when the chest tube is removed. This fluid can lead to complications such as hypoxia 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 surgicalpleurodesis, in which the two pleural surfaces are scarred to each other so that no fluid can accumulate between them. This is a surgical procedure that involves inserting a chest tube, then either mechanically abrading the pleura or inserting the chemicals to induce a scar. This requires the chest tube to stay in until the fluid drainage stops. This can take days to weeks and can require prolonged hospitalizations. If the chest tube becomes clogged, fluid will be left behind and the 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 connect it to a simple vacuum tube and remove from 600 cc to 1000 cc of fluid. This can be repeated daily. When not in use, the tube is capped. This allows patients to be outside the hospital. For patients withmalignant pleural effusions, it allows them to continue chemotherapy, if indicated. Generally, the tube is in for about 30 days and then it is removed when the space undergoes a spontaneous pleurodesis.See also[edit] Empyema Heart failure Pulmonary embolism Subpulmonic effusion ThoracentesisReferences[edit]1. Jump up^Porcel JM, Light RW (2008). "Pleural effusions due to pulmonary embolism.".Current Opinion in Pulmonary Medicine14(4): 33742.doi:10.1097/MCP.0b013e3282fcea3c.PMID18520269.2. ^Jump up to:abGalagan et al. Color Atlas of Body Fluids. CAP Press, Northfield, 20063. Jump up^de Menezes Lyra R (July 1997)."A modified outer cannula can help thoracentesis after pleural biopsy"(PDF).Chest112(1): 296.doi:10.1378/chest.112.1.296.PMID9228404.4. ^Jump up to:abWong CL, Holroyd-Leduc J, Straus SE (Jan 2009). "Does this patient have a pleural effusion?".JAMA301(3): 30917.doi:10.1001/jama.2008.937.PMID19155458.5. Jump up^Corne et al. (2002).Chest X-Ray Made Easy. Churchill Livingstone.ISBN0-443-07008-3.6. Jump up^Squire, Lucy Frank; Novelline, Robert A. (2004).Squire's fundamentals of radiology. Cambridge: Harvard University Press. pp.1323.ISBN0-674-01279-8.7. Jump up^Light, Richard W."Pleural Effusion".Merck Manual for Health Care Professionals. Merck Sharp & Dohme Corp. Retrieved21 August2013.8. ^Jump up to:abThe University of Utah Spencer S. Eccles Health Sciences Library > WebPath images >"Inflammation".9. ^Jump up to:abcdHeffner J, Brown L, Barbieri C (1997). "Diagnostic value of tests that discriminate between exudative and transudative pleural effusions. Primary Study Investigators".Chest111(4): 97080.doi:10.1378/chest.111.4.970.PMID9106577.10. ^Jump up to:abLight R, Macgregor M, Luchsinger P, Ball W (1972). "Pleural effusions: the diagnostic separation of transudates and exudates".Ann Intern Med77(4): 50713.doi:10.7326/0003-4819-77-4-507.PMID4642731.11. ^Jump up to:abRoth BJ, O'Meara TF, Gragun WH (1990). "The serum-effusion albumin gradient in the evaluation of pleural effusions".Chest98(3): 5469.doi:10.1378/chest.98.3.546.PMID2152757.12. Jump up^de Menezes Lyra R (1997). "A modified outer cannula can help thoracentesis after pleural biopsy.".Chest112(1): 296.doi:10.1378/chest.112.1.296.PMID9228404.13. Jump up^Light, Richard W. "Ch. 257: Disorders of the Pleura and Mediastinum". In Fauci AS, Braunwald E, Kasper DL, Hauser SL, Longo DL, Jameson JL, Loscalzo J.Harrison's Principles of Internal Medicine(17th ed.).14. ^Jump up to:abLight RW, Macgregor MI, Luchsinger PC, Ball WC (1972). "Pleural effusions: the diagnostic separation of transudates and exudates".Ann Intern Med77(4): 50713.doi:10.7326/0003-4819-77-4-507.PMID4642731.15. ^Jump up to:abJoseph J, Badrinath P, Basran GS, Sahn SA (November 2001)."Is the pleural fluid transudate or exudate? A revisit of the diagnostic criteria".Thorax56(11): 86770.doi:10.1136/thorax.56.11.867.PMC1745948.PMID11641512.16. Jump up^Joseph J, Badrinath P, Basran GS, Sahn SA (2002)."Is albumin gradient or fluid to serum albumin ratio better than the pleural fluid lactate dehydroginase in the diagnostic of separation of pleural effusion?".BMC Pulmonary Medicine2: 1.doi:10.1186/1471-2466-2-1.PMC101409.PMID11914151.[1]17. Jump up^Romero S, Martinez A, Hernandez L, Fernandez C, Espasa A, Candela A, Martin C (2000). "Light's criteria revisited: consistency and comparison with new proposed alternative criteria for separating pleural transudates from exudates.".Respiration; international review of thoracic diseases67(1): 1823.doi:10.1159/000029457.PMID10705257.18. Jump up^Porcel JM, Pea JM, Vicente de Vera C, Esquerda A (Feb 18, 2006). "[Reappraisal of the standard method (Light's criteria) for identifying pleural exudates].".Medicina clinica126(6): 2113.doi:10.1157/13084870.PMID16510093.External links[edit] Pleural Effusion - Definition, Causes, Diagnosis and Treatment. MedlinePlus EncyclopediaPleural Effusion Pleural EffusionImages from MedPix[show] v t ePathologyofrespiratory system(J,460519),respiratory diseases

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