Pleural effusion , also called effusion for short in jargon , is a term from medicine and describes an excessive accumulation of fluid in the pleural cavity , also known as the pleural space, between the pleural leaves due to a disrupted relationship between fluid formation and removal (absorption) . The fluid is located in the chest between the lungs and the ribs , more precisely between the pleura (pleura visceralis) and the pleura or pleura (pleura parietalis). The lungs are therefore surrounded by fluid.
The causes of a pleural effusion are varied and accordingly its treatment depends on a careful diagnosis. Pleural effusions are relatively common , with an annual incidence of about 450,000.
A pleural effusion represents a space-displacing process in the chest and, depending on its size, reduces all lung volumes .
In a healthy adult, the pleural cavities are each filled with around 5 ml of protein-rich fluid, which is normally replenished within an hour, and which acts as a sliding layer to give the lungs freedom of movement when breathing in and out. There is a balance between formation and absorption. The amount of fluid exchanged is 0.2 ml / kg / h.
Classification and causes
Based on the pleural fluid obtained by puncture , pleural effusions are divided into low-protein transudates caused by pressure differences in the circulatory system and high-protein exudates caused by increased tissue permeability (the further diagnostic and therapeutic procedure essentially depends on this classification). Furthermore, the effusion can be bloody, purulent or milky. It can either run freely around the lungs or be enclosed by adhesions. Pleural effusions can occur with many different underlying diseases. The most common causes are heart failure , malignant tumors (malignancies) , pneumonia and pulmonary embolism . Pleural effusions can also occur in the context of renal or hepatic insufficiency . In multimorbid , especially older patients, as in 30% of all pleural effusions, several causes can be present. In young patients, the cause is often tuberculosis .
Possible causes of a pleural effusion are:
oncotic - hydrostatic , i.e. due to the pressure difference between hydrostatic and oncotic pressure and the liquid filtration, for example:
- in the context of heart failure (one of the most common causes of pleural effusion as a transudate)
- In left heart failure, the difference in pressure between the systemic and pulmonary circulation and the pleural space causes the effusion of the visceral pleura, while the lymphatic vessels of the parietal pleura, if they are sufficiently open, absorb the fluid
- In (idiopathic and familial) pulmonary hypertension , mostly on the right side
- Constrictive pericarditis
- Hypoalbuminemia (resulting in decreased oncotic pressure), such as in nephrotic syndrome
- Pulmonary embolism with transudate (with increased pulmonary capillary pressure ) or exudate (20 to 55% of patients with pulmonary embolism have a pleural effusion. The frequency depends on the severity of the pulmonary embolism and the occurrence of a pulmonary infarction ).
- in the context of heart failure (one of the most common causes of pleural effusion as a transudate)
- Inflammatory- infectious when the pleura is infected, as exudate ( pleurisy exudativa ), for example
- Viruses (for example in pleurisy ) and mycoplasma
- Fungi and parasites
- parapneumonic (i.e. in pneumonia (inflammation of the lungs) due to the transfer of bacteria, for example pneumococci , in the lung tissue to the pleura)
- as non-specific purulent empyema or pleural empyema (immediate treatment with antibiotics and pleural drainage is required here)
- intra-abdominal abscess
- neoplastic, i.e. in the context of cancer ( malignant pleural effusion , an exudate, is most common in lung cancer (37.5%), second most common in breast cancer (16.8%), followed by malignant lymphoma (11.5%), less common in gastrointestinal, gynecological, urological and other primary tumors. The larger a unilateral pleural effusion, the more likely a tumor can be the cause. The risk of a poor prognosis can be classified using the so-called LENT score.)
- vascular (concerning blood vessels) for example:
- autoimmunological, examples:
- traumatic for example:
If there is significant bleeding, it is a hemothorax .
Smaller effusions (up to around 500 ml in adults) are often not noticed and, in harmless cases, can be an accompanying finding of viral pneumonia. In the case of larger effusions, the main symptom is shortness of breath (the most common complaint in patients with pleural effusion), which initially occurs during physical exertion, and with increasing effusion even at rest. However, the severity of the shortness of breath is not necessarily related to the size of the pleural effusion, but can also be attributed to a limitation of the lung mechanics or a disruption of gas exchange caused by the underlying disease. Accelerated breathing (tachypnea) can also occur with larger effusions. Throat irritation or dry cough is common with larger effusions; breath-dependent chest pain can occur as so-called pleuritic pain with simultaneous inflammation of the parietal pleura (the visceral does not convey pain) (pleuritic chest pain occurs in about three quarters of patients with pulmonary embolism and pleural effusion ). Pressure pain in the chest area that does not depend on breathing can occur with pleural casts as a result of pleural empyema, malignant tumors or pleural carcinosis. It can also lead to significant sleep disorders.
Pleural effusions can be present on one side or (mostly in congestive heart failure) on both sides, which is usually assessed on the basis of an X-ray. One can suspect an effusion when "dragging" one side, widened and possibly also bulging intercostal spaces during breathing, a dampening of the knocking sound and a (basal) weakening or an absence of the breathing noise as well as the vocal fremitus , which like the bronchophony is severely weakened is lifted over a section of the lung.
With bilateral basal weakening, congested neck veins, peripheral edema, tachycardia and a third heart sound, a cardiac pleural effusion is suspected. A pleural rubbing can be heard at the beginning of an effusion as part of an inflammation of the lungs (pneumonia) with inflammation of the pleura (pleurisy). With unilateral damping, the probability of exudate is higher and diagnosis is usually more difficult. The fastest and most accurate way to detect a pleural effusion is to perform an ultrasound scan of the chest, which makes certain structures (pleural septa) more visible than a computer tomography . In the case of intensive care patients, especially those who are ventilated, the ultrasound examination is also more advantageous than a chest X-ray performed in the supine position .
On the chest x-ray recommended if a pleural effusion is suspected , pleural effusions can be seen on the p.a. thorax image from a volume of 200–300 ml, and from 50 ml on the lateral image. Typically, in an image taken while standing, shading that rises laterally (outwards) (represented by the Damoiseau-Ellis line , also known as the Ellis-Damoiseau line , which delimits the effusion ).
A computed tomography of the chest can also reveal smaller pleural effusions, enables the distinction between pleural fluid and pleural tissue proliferation and can provide information on the cause of the effusion (e.g. pneumonia, tumor or pulmonary embolism). In addition, other findings related to the pleural effusion can be identified. For example a pleural empyema or a lung abscess as well as benign and malignant pleural changes.
In order to clarify the often unclear cause of an effusion, it should be punctured and the effusion fluid obtained (about 50 ml, more if this can alleviate symptoms related to the effusion such as shortness of breath) laboratory , bacteriological or microbiological ( Gram stain , Polymerase chain reaction ) and cytologically (to determine a causal tumor disease) (see pleural puncture ). If there is pneumonia, an effusion should also be punctured to rule out pleural empyema. If the puncture is performed under ultrasound guidance, the resulting pneumothorax is less likely . Before a CT examination, an effusion should also be punctured, if possible, in order to better visualize changes in the pleura or lungs.
In pleural effusions, transudates (e.g. due to heart failure or liver cirrhosis ) or exudates in active pleural diseases (e.g. pleural mesothelioma ) can occur. The Light criteria help to differentiate between a transudate and an exudate, which is important for diagnosis and therapy . If one or more of the following criteria are met, one speaks of an exudate (otherwise it is a transudate):
- Ratio of protein in pleural effusion to protein in serum> 0.5
- Ratio of lactate dehydrogenase (LDH) in pleural effusion to LDH in serum> 0.6
- LDH in the pleural effusion> 200 units per liter (over 2/3 of the upper limit of normal serum LDH).
If the evaluation of the Light criteria reveals an exudate, which would also be indicated by a cholesterol concentration of over 55 mg / dL, a pneumological consultation, a computer tomography, further laboratory tests, a tuberculosis diagnosis or the search for other infections are available to further clarify the cause to disposal.
If the diagnosis can be clarified, the underlying diseases are treated, otherwise invasive diagnostic procedures such as pleural biopsy (a CT- guided needle biopsy is more sensitive in diagnosing malignant pleural changes than an earlier biopsy with the Abrams needle), thoracoscopy or video-assisted thoracoscopy (VATS), especially before treatment of lung cancer with surgery or radiation, and (in the case of hemoptysis , bronchial obstruction or intrapulmonary mass) a bronchoscopy .
If, on the other hand, it is a transudate, the biomarker NTproBNP can be determined to confirm heart failure . If the cause of the transudate is cirrhosis , the transaminases are pathologically changed, if renal insufficiency is the cause, the urine proteins determined in the laboratory provide an indication of this.
If the pH of the pleural fluid is low ( acidosis ), it could indicate a complicated pleural infection, tuberculosis, rheumatoid arthritis, or a malignant effusion. Therefore, the pH value should be determined from the fluid obtained by puncturing the effusion, even in the case of non-purulent pleural effusions and suspicion of an infection causing the effusion.
The determination of tumor markers in the pleural puncture generally does not provide any further information.
A small pleural effusion is often only a symptom and does not require any therapy itself and it can be observed in a wait-and-see manner (in the case of parapneumonic effusion [see above], an empyema that develops may have to be treated). In the case of a small effusion, as well as a (cardiac-related) pleural effusion that can be safely attributed to a heart failure ( cardiac insufficiency ) or any other bilateral effusion (e.g. existing in the case of nephrotic syndrome) without chest pain, the focus is on the treatment of the underlying disease and, if necessary, a diagnostic Pleural puncture can be omitted prior to therapy. If a pleural puncture has been carried out and a (purulent) infection has already been detected through the routine examination of the pleural fluid, this underlying disease is treated, otherwise further differential diagnosis is carried out using the Light criteria.
In the case of larger pleural effusions (over about 1 liter in adults), therapy usually consists of relieving the pressure by emptying the pleural space using a pleural puncture ( thoracentesis ). A heavier effusion, especially with respiratory or cardiac decompensation due to the expansion of the effusion, is usually treated with a chest drain . If all of the fluid cannot be emptied as a result - which can be checked by radiological examinations - an operation may be necessary to compensate for the respiratory and cardiac functions again and because parts of the effusion can become encapsulated. The procedure is carried out, if necessary with the involvement of a thoracic surgeon , via thoracoscopy or minimally invasive via video-assisted thoracoscopy (keyhole surgery), which leaves hardly any scars.
Chemical or surgical pleurodesis (gluing of the pleural leaves) may be necessary if the effusions continue to run . The aim of both procedures is to scar the pleural leaves so that fluid cannot accumulate again between them. In chemical pleurodesis, an inflammatory fluid (e.g. tetracycline / doxycycline) is temporarily introduced into the pleural space through a chest tube or pleural drainage. The intended consequence of the inflammatory reaction is the scarring of the pleural leaves. In surgical pleurodesis, the inflammatory stimulus is set mechanically as part of a minimally invasive procedure (thoracoscopy), e.g. B. by roughening the pleural leaves under thoracoscopic control. Both procedures require a pleural catheter (thoracic tube) that must remain in place until no or only a minimal amount of effusion occurs. Consequently, a longer hospital stay must be taken into account. In one study, however, the scarring of the pleural leaves did not work in every fourth patient.
In the case of malignant effusions without significant chambering, pleurodesis can be achieved within five weeks by introducing talc into the pleural space in 43% of cases. Cases in which the lungs are prevented from developing, for example by fibrosis, are not suitable.
An alternative can be the creation of a drainage tube, which can be left in the chest as a catheter (pleural catheter ) for a long time or permanently. A thin drainage tube with a valve mechanism (indwelling catheter) can be placed in the pleura on an outpatient basis under local anesthesia.
Every day the patient or the nursing staff can connect the hose to a vacuum bottle and drain up to one liter of effusion. This allows patients to maintain mobility at home. In the majority of patients, the pleural leaves stick together spontaneously after about a month (2; 3). Then the silicone tube can be removed.
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- Carol Tan, Artyom Sedrakyan, John Browne, Simon Swift, Tom Treasure: The evidence on the effectiveness of management for malignant pleural effusion: a systematic review. In: European Journal of Cardio-Thoracic Surgery . 29, 5, May 2006, pp. 829-838, online (PDF; 697 kB) .
- A. Tremblay, C. Mason, G. Michaud: Use of tunneled catheters for malignant pleural effusions in patients fit for pleurodesis. In: The European Respiratory Journal. 30, 2007, doi: 10.1183 / 09031936.00164706 , pp. 759-762,
- Marianne Abele-Horn: Antimicrobial Therapy. Decision support for the treatment and prophylaxis of infectious diseases. With the collaboration of Werner Heinz, Hartwig Klinker, Johann Schurz and August Stich, 2nd, revised and expanded edition. Peter Wiehl, Marburg 2009, ISBN 978-3-927219-14-4 , pp. 97-99 ( pleural effusion / pleural empyema ).
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- G Miserocchi: Mechanisms controlling the volume of pleural fluid and extravascular lung water . In: European Respiratory Review: An Official Journal of the European Respiratory Society . tape 18 , no. 114 , 2009, ISSN 1600-0617 , p. 244-252 , doi : 10.1183 / 09059180.00002709 , PMID 20956149 .
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- Percentages according to M. E Robert, BC Kahan, CE Hooper u. a .: Management of malignant pleural effusion: British Thoracic Society pleural disease guideline 2010. In: Thorax. Volume 65, Supplement 2, 2010, pp. Ii32-40.
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- Named after C. Ellis (1826–1883) from Boston and ZH Damoiseau (1815–1890) from Paris.
- Klaus Holldack, Klaus Gahl: Auscultation and percussion. Inspection and palpation. Thieme, Stuttgart 1955; 10th, revised edition ibid 1986, ISBN 3-13-352410-0 , pp. 93-95 and 97.
- Richard W. Light, M. Isabelle MacGregor, Peter C. Luchsinger Jr., Wilmot C. Ball: Pleural Effusions: The Diagnostic Separation of Transudates and Exudates . In: Annals of Internal Medicine . tape 77 , no. 4 , October 1, 1972, ISSN 0003-4819 , p. 507-513 , doi : 10.7326 / 0003-4819-77-4-507 .
- When therapy for heart failure is initiated, the concentrations of proteins, LDH and lipids in the pleural fluid are increased, so that a transudate can be misclassified as exudate.
- A. Tremblay, C. Mason, G. Michaud: Use of tunneled catheters for malignant pleural effusions in patients fit for pleurodesis. 2007.
- Rahul Bhatnagar, Emma K Keenan, Anna J Morley, Brennan C Kahan, Andrew E Stanton: Outpatient Talc Administration by Indwelling Pleural Catheter for Malignant Effusion . In: New England Journal of Medicine . tape 378 , no. 14 , April 5, 2018, ISSN 0028-4793 , p. 1313–1322 , doi : 10.1056 / NEJMoa1716883 ( nejm.org [accessed August 11, 2019]).