• Clinical science
  • Clinician

Pleural effusion

Summary

Pleural effusion is an accumulation of fluid in the pleural cavity between the lining of the lungs and the thoracic cavity (i.e., the visceral and parietal pleurae). The pleural fluid is called a transudate if it permeates (transudes) into the pleural cavity through the walls of intact pulmonary vessels. It is called an exudate if it escapes (exudes) into the pleural cavity through lesions in blood and lymph vessels, e.g., as caused by inflammation and tumors. The accumulation of transudate is typically due to increased hydrostatic pressure (e.g., in congestive heart failure) and/or decreased oncotic pressure (e.g., in cirrhosis or nephrotic syndrome). Since transudate is a filtrate, it is typically a clear fluid with a low protein and cell content. By contrast, the lesions responsible for the outflow of exudate allow larger molecules and even solid matter to pass into the pleural cavity. For this reason, exudate is a cloudy fluid with a high protein and cell content. The effusion follows gravity and, unless the patient is bedridden, collects in the lower margins of the pleural cavity. Percussion over the area of effusion generates a dull tone, and breath sounds are diminished or completely absent on auscultation. Chest x-ray and ultrasound are usually performed as first-line tests to diagnose pleural effusion, but chest CT is sometimes required (e.g., for very small effusions). Thoracentesis with pleural fluid analysis is required to establish the underlying diagnosis in most pleural effusions and can also serve a therapeutic role. Treatment should focus on correcting the underlying condition.

Overview

  • Definition: an excessive amount of fluid between pleural layers that impairs the expansion of the lungs

Transudative pleural effusion

Exudative pleural effusion
Pathophysiology
Common causes of pleural effusion [1][2]
Rare causes [1][2]
Light's Criteria

Pleural fluid protein:serum protein ratio

  • ≤ 0.5
  • > 0.5

Pleural fluid LDH:serum LDH ratio

  • ≤ 0.6
  • > 0.6

Pleural fluid LDH

  • < ⅔ the upper limit of normal serum LDH
  • > ⅔ the upper limit of normal serum LDH

References:[3][4][5]

Clinical features

Symptoms [2]

Physical exam findings

  • Inspection and palpation
  • Auscultation
  • Percussion: dullness over the area of effusion

Diagnostics

Approach

  • Imaging is necessary to confirm the diagnosis
  • Consider diagnostic thoracentesis if the diagnosis is uncertain or management requires additional information (e.g., culture, cytology)
  • Consider invasive testing (e.g., bronchoscopy, VATS) if the diagnosis remains unclear

Imaging [6][2]

Chest x-ray [6][7]

Ultrasound [6][8]

  • Indications
  • Procedure: The imaging sequence is similar to the FAST protocol commonly used for trauma assessment.
  • Supportive findings: hypoechoic/anechoic structures in the lower margins of the pleural cavity (costodiaphragmatic recess)
    • Very sensitive: can detect fluid amounts as low as 20 mL
    • Hemothorax and empyema may appear heterogeneous.
    • Pleural fluid septations may be present.
    • Allows for detection of pleural thickening and pleural nodules

Chest CT [6][8]

  • Indications: gold standard but use is limited due to radiation and contrast exposure
    • Guiding placement of indwelling pleural catheters
    • Directed thoracentesis of a loculated effusion
    • Suspected parenchymal or pleural pathology
    • Better quantification of the amount of fluid (compared to CXR) is desired
  • Procedure: Chest CT without IV contrast is usually sufficient
    • With IV contrast: allows for the detection of underlying malignancy (e.g., metastases and/or primary tumor)
    • CT angiogram: helps to identify vascular pathology (e.g., dissection or AVM)
  • Supportive findings
    • Similar to CXR; can detect > 3–5 mL of fluid
    • Fluid density measurement can help differentiate pleural effusion from empyema and hemothorax [9]
    • Disease-specific signs: See pleural empyema.

Diagnostic thoracentesis [2][10]

Analysis of the pleural fluid (via thoracentesis) is usually required to definitively establish the underlying etiology but may not be necessary if there is already a clear diagnosis of an underlying condition (e.g., known CHF or connective tissue disease).

Description

Indications [2][10]

Contraindications to thoracentesis

Pleural fluid studies to order

See tables below for analysis and interpretation.

Complications

See therapeutic thoracentesis.

Pleural fluid analysis [8][2][11]

Differentiating transudates from exudates (incl. Light's criteria) [12][13]

Primary pleural fluid analysis
Laboratory parameters Transudative effusion Exudative effusion
Light's criteria Pleural fluid protein:serum protein ratio
  • ≤ 0.5
  • > 0.5
Pleural fluid LDH:serum LDH ratio
  • ≤ 0.6
  • > 0.6
Pleural fluid LDH
  • < ⅔ the upper limit of normal serum LDH
Pleural fluid cholesterol
  • < 55 mg/dL
  • > 55 mg/dL
Pleural fluid LDH
  • < 200 U/L
  • > 200 U/L
Pleural fluid cholesterol:serum cholesterol ratio
  • < 0.3
  • > 0.3
Adjunctive pleural fluid analysis [2][8][11]
Pleural fluid parameter Suggests transudative effusion Suggests exudative effusion
Physical appearance
  • Clear fluid
  • Does not froth or form clots
  • Cloudy or straw-colored fluid (may be hemorrhagic in rare cases)
  • Froths when shaken and forms clots when left standing
Specific gravity
  • ≤ 1.016
  • > 1.016

pH

Normal pH ∼ 7.6

  • 7.4–7.55
  • < 7.3–7.45
Glucose
  • ≥ 60 mg/dL
  • < 60 mg/dL
Total protein gradient
  • > 3.1 g/dL lower than serum total protein
  • < 3.1 g/dL lower than serum total protein
Albumin gradient
  • > 1.2 g/dL lower than serum albumin
  • < 1.2 g/dL lower than serum albumin

Narrowing the differential diagnosis of exudative effusions

Pleural fluid parameter Associated conditions [10][1][14]
Cell count and differential WBC count > 10,000 cells/mm3
Neutrophils > 50% of total leukocytes
Lymphocytes > 50% of total leukocytes
RBC count > 5,000 cells/μL
Hematocrit > 0.5 × peripheral hematocrit
pH < 7.2 [14]

Glucose < 60 mg/dL

Positive Gram stain or culture

Adenosine deaminase > 50 mcg/L

Positive AFB smear microscopy

  • Tuberculous effusion
Abnormal cytology
Amylase > 200 mcg/dL
Positive rheumatoid factor, ANA
Lipids Triglycerides > 110 mg/dL

Total cholesterol > 200 mg/dL

Total cholesterol:triglyceride ratio > 1

Cholesterol crystals

Total cholesterol 55–200 mg/dL

Chylomicrons and fat-soluble vitamins

Appearance Cloudy, milky
Purulent
Bloody


Transudate is usually clear, has a decreased cell count, and has low levels of protein, albumin, and LDH. Exudate typically appears cloudy, has an increased cell count, and has high levels of protein, albumin, and LDH.

Think of MEAT to memorize causes of pulmonary effusion associated with low glucose levels: Malignancy, Empyema, Arthritis (rheumatoid pleurisy), Tuberculosis.

Pleural fluid with a bloody appearance suggests a malignant etiology or hemothorax!

Additional serum laboratory studies and invasive diagnostic tests [12]

Management

Approach [10][12][14]

Treat the underlying cause [12]

Therapeutic thoracentesis [10]

The goal of a therapeutic thoracentesis is to remove fluid (especially in exudate because of increased risk of infection). Removal of 400–500 mL of fluid is usually sufficient to relieve symptoms (e.g., dyspnea).

Indications

Contraindications

See contraindications to thoracentesis.

Complications

Therapeutic thoracentesis should be halted if patients develop chest discomfort, cough, or hypoxia, which could represent re-expansion pulmonary edema.

Indwelling pleural catheter [21][22][23][24]

  • Goal: recurrent pleural fluid removal without repeated puncture
  • Indication: rapidly reaccumulating pleural effusions (e.g., malignant effusions ) [23][24]
  • Contraindications: See contraindications to thoracentesis.
  • Procedure [25]
    • A pleural catheter is inserted under the guidance of interventional radiology.
    • Similar to thoracentesis, except that the catheter is tunneled into the skin and can remain in situ for months.
  • Complications [25][26]

Surgical procedures [12]

Consultation with a thoracic surgeon and/or chest physician is recommended.

Tube thoracostomy

  • Indications
    • For recurrent pleural effusion or urgent drainage of infected and/or loculated effusions [27][28]
    • Drainage of high-viscosity fluid that is likely to clog [29][30]
  • Procedure: See tube thoracostomy.

Video-assisted thoracoscopic surgery (VATS)

Pleurodesis [22][23]

  • Definition: chemical or surgical obliteration of the pleural space
  • Indication
  • Contraindications [21]
    • Predicted survival < 3 months
    • Trapped lung
  • Procedure
    • After draining the pleural effusion, a substance (e.g., talc) is introduced into the pleural cavity.
    • This induces an inflammatory reaction that causes the pleural layers to bind together.
    • Alternatively, thoracoscopic pleurodesis with partial resection of the pleural layers may be performed.
  • Complication: fibrothorax

A chest x-ray should be performed after each of these procedures to rule out iatrogenic pneumothorax!

Acute management checklist

Subtypes and variants

Pleural fluid analysis is necessary in almost all cases to distinguish between the various subtypes of pleural effusion. Treatment depends on the underlying cause. Subtypes of pleural effusion include the following:

Parapneumonic effusion

Definition [36][2]

  • Accumulation of exudative fluid in the pleural cavity in response to pneumonia
    • Uncomplicated: without direct bacterial invasion
    • Complicated: extension of bacterial infection into the pleural space

Distinguishing features [36][6][14][10]

Treatment [10][37][38][39][28]

Pleural empyema

Definition [36]

Etiology [36][14]

Classification [40][41]

  • Stage I (exudative): accumulation of fluid and pus
  • Stage II (fibrinopurulent): aggregation of fibrin deposits that form septations and pockets
  • Stage III (organizing): formation of thick fibrous peel on pleural surface that restricts lung movement

Distinguishing features [36]

Treatment of pleural empyema

Empiric antibiotic therapy for pleural infection [37][38][39][28]

All patients should receive empiric antibiotics adjusted to their needs, local resistance patterns, and institutional guidelines.

Definitive treatment [40]

  • Stage I
    • Chest tube (thoracostomy) to remove empyema fluid
    • Consider intrapleural administration of fibrinolytic agents.
  • Stage II or mixed stage II/III
  • Stage III

Nontraumatic hemothorax

Definition [43][34]

  • Spontaneous or nontraumatic accumulation of blood in the pleural cavity

Etiology [34]

Distinguishing features

Treatment of nontraumatic hemothorax [43][34]

  • Stabilize the patient.
  • Identify and treat the underlying cause.
  • Consult surgery or interventional radiology for bleeding from tumors or vascular pathology.

A hemothorax, however small, must always be drained because blood in the pleural cavity will clot if not evacuated, resulting in a trapped lung or an empyema.

Malignant pleural effusion

Description [45]

  • Definition: accumulation of exudative fluid and malignant cells in the pleural cavity
  • Pathophysiology: cancer-related barrier dysfunction of the capillary walls → increased permeation of plasma protein, blood cells, and tumor cells

Etiology [45]

Distinguishing features [45]

  • Clinical: symptoms of underlying malignancy (e.g., constitutional symptoms, cachexia, hemoptysis)
  • Diagnostics
    • Imaging: associated underlying malignancy
    • Pleural fluid analysis
      • Cell-rich exudative effusion
      • Cloudy or straw-colored appearance
      • Abnormal cytology
        • Pronounced nucleoli
        • Cells with multiple nuclei
        • Numerous figures of mitosis
      • pH < 7.2
      • Glucose < 60 mg/dL
      • Amylase > 200 mcg/dL
      • LDH usually high (> 0.45 x normal serum LDH)
      • If hemorrhagic: bloody appearance, RBC count > 5,000 cells/μL
    • Laboratory studies: positive tumor markers

Treatment [46]

Chylothorax

Definition [8]

Etiology [8]

Distinguishing features [8]

Treatment of chylothorax [47]

Pseudochylothorax

Definition [8][48]

Etiology [8][48]

Distinguishing features [8][48]

In contrast to chylothorax, a pseudochylothorax is characterized by high cholesterol and low triglyceride levels in the pleural fluid. The presence of cholesterol crystals may also help to differentiate a pseudochylothorax from a chylothorax.

Treatment

  • 1. McGrath EE, Blades Z, Anderson PB. Chylothorax: Aetiology, diagnosis and therapeutic options. Respir Med. 2010; 104(1): pp. 1–8. doi: 10.1016/j.rmed.2009.08.010.
  • 2. Saguil A, Wyrick K, Hallgren J. Diagnostic approach to pleural effusion. Am Fam Physician. 2014; 90(2): pp. 99–104. pmid: 25077579.
  • 3. Kasper DL, Fauci AS, Hauser SL, Longo DL, Lameson JL, Loscalzo J. Harrison's Principles of Internal Medicine. New York, NY: McGraw-Hill Education; 2015.
  • 4. Le T, Bhushan V, Chen V, King M. First Aid for the USMLE Step 2 CK. McGraw-Hill Education; 2015.
  • 5. Jenkins B, McInnis M, Lewis C. Step-Up to USMLE Step 2 CK. Lippincott Williams & Wilkins; 2015.
  • 6. Walls R, Hockberger R, Gausche-Hill M. Rosen's Emergency Medicine. Philadelphia, PA: Elsevier Health Sciences; 2018.
  • 7. Rahman, NM, Chapman SJ, Davies RJO. Pleural effusion: a structured approach to care†. Br Med Bull. 2004; 72(1): pp. 31–47. doi: 10.1093/bmb/ldh040.
  • 8. Hooper et al. Investigation of a unilateral pleural effusion in adults: British Thoracic Society pleural disease guideline 2010. Thorax. ; 65: pp. ii4–ii17. doi: 10.1136/thx.2010.136978.
  • 9. Kraus GJ. The Split Pleura Sign. Radiology. 2007; 243(1): pp. 297–298. doi: 10.1148/radiol.2431041658.
  • 10. Roberts JR. Roberts and Hedges' Clinical Procedures in Emergency Medicine and Acute Care. Philadelphia, PA: Elsevier; 2018.
  • 11. Chubb SP, Williams RA. Biochemical Analysis of Pleural Fluid and Ascites. The Clinical biochemist. Reviews. 2018; 39(2): pp. 39–50. pmid: 30473591.
  • 12. Karkhanis V, Joshi J. Pleural effusion: diagnosis, treatment, and management. Open Access Emergency Medicine. 2012: p. 31. doi: 10.2147/oaem.s29942.
  • 13. Wilcox ME, Chong CAKY, Stanbrook MB, Tricco AC, Wong C, Straus SE. Does This Patient Have an Exudative Pleural Effusion?. JAMA. 2014; 311(23): p. 2422. doi: 10.1001/jama.2014.5552.
  • 14. Goldman L, Schafer AI. Goldman-Cecil Medicine, 2-Volume Set. Elsevier; 2019.
  • 15. Machado NO. Pancreaticopleural Fistula: Revisited. Diagnostic and Therapeutic Endoscopy. 2012; 2012: pp. 1–5. doi: 10.1155/2012/815476.
  • 16. Yashant Aswani, Priya Hira. Pancreaticopleural Fistula: A Review. JOP. Journal of the Pancreas. 2015; Vol 16: pp. No 1 (2015): January–p. 1. doi: 10.6092/1590-8577/2915.
  • 17. Schweigert M, Solymosi N, Dubecz A, Ofner D, Stein HJ. Length of nonoperative treatment and risk of pleural empyema in the management of pancreatitis-induced pancreaticopleural fistula. Am Surg. 2013; 79(6): pp. 614–9. pmid: 23711272.
  • 18. Kasmani R, Irani F, Okoli K, Mahajan V. Re-expansion pulmonary edema following thoracentesis. Can Med Assoc J. 2010; 182(18): pp. 2000–2002. doi: 10.1503/cmaj.090672.
  • 19. Meeker JW, Jaeger AL, Tillis WP. An uncommon complication of a common clinical scenario: exploring reexpansion pulmonary edema with a case report and literature review. Journal of Community Hospital Internal Medicine Perspectives. 2016; 6(3): p. 32257. doi: 10.3402/jchimp.v6.32257.
  • 20. Verhagen M, van Buijtenen JM, Geeraedts LMG. Reexpansion pulmonary edema after chest drainage for pneumothorax: A case report and literature overview. Respiratory Medicine Case Reports. 2015; 14: pp. 10–12. doi: 10.1016/j.rmcr.2014.10.002.
  • 21. Zarogoulidis K, Zarogoulidis P, Darwiche K, et al. Malignant pleural effusion and algorithm management. Journal of thoracic disease. 2013; 5 Suppl 4: pp. S413–9. doi: 10.3978/j.issn.2072-1439.2013.09.04.
  • 22. Detterbeck FC, Lewis SZ, Diekemper R, Addrizzo-Harris D, Alberts WM. Diagnosis and Management of Lung Cancer, 3rd ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines. Chest. 2013; 143(5): pp. 7S–37S. doi: 10.1378/chest.12-2377.
  • 23. Simoff MJ, Lally B, Slade MG, et al. Symptom Management in Patients With Lung Cancer. Chest. 2013; 143(5): pp. e455S–e497S. doi: 10.1378/chest.12-2366.
  • 24. Puri V, Pyrdeck TL, Crabtree TD, et al. Treatment of Malignant Pleural Effusion: A Cost-Effectiveness Analysis. Ann Thorac Surg. 2012; 94(2): pp. 374–380. doi: 10.1016/j.athoracsur.2012.02.100.
  • 25. Lui MMS, Thomas R, Lee YCG. Complications of indwelling pleural catheter use and their management. BMJ Open Respiratory Research. 2016; 3(1): p. e000123. doi: 10.1136/bmjresp-2015-000123.
  • 26. Chalhoub M, Saqib A, Castellano M. Indwelling pleural catheters: complications and management strategies. Journal of Thoracic Disease. 2018; 10(7): pp. 4659–4666. doi: 10.21037/jtd.2018.04.160.
  • 27. Cafarotti S, Dall’Armi V, Cusumano G, et al. Small-bore wire-guided chest drains: Safety, tolerability, and effectiveness in pneumothorax, malignant effusions, and pleural empyema. J Thorac Cardiovasc Surg. 2011; 141(3): pp. 683–687. doi: 10.1016/j.jtcvs.2010.08.044.
  • 28. Davies HE, Davies RJO, Davies CWH. Management of pleural infection in adults: British Thoracic Society pleural disease guideline 2010. Thorax. 2010; 65(Suppl 2): pp. ii41–ii53. doi: 10.1136/thx.2010.137000.
  • 29. Porcel JM. Chest Tube Drainage of the Pleural Space: A Concise Review for Pulmonologists. Tuberculosis and Respiratory Diseases. 2018; 81(2): p. 106. doi: 10.4046/trd.2017.0107.
  • 30. Cooke DT, David EA. Large-Bore and Small-Bore Chest Tubes. Thorac Surg Clin. 2013; 23(1): pp. 17–24. doi: 10.1016/j.thorsurg.2012.10.006.
  • 31. Rahman NM, Maskell NA, Davies CWH, et al. The Relationship Between Chest Tube Size and Clinical Outcome in Pleural Infection. Chest. 2010; 137(3): pp. 536–543. doi: 10.1378/chest.09-1044.
  • 32. Hallifax RJ, Psallidas I, Rahman NM. Chest Drain Size: the Debate Continues. Current Pulmonology Reports. 2017; 6(1): pp. 26–29. doi: 10.1007/s13665-017-0162-3.
  • 33. American College of Surgeons and the Committee on Trauma. ATLS Advanced Trauma Life Support. Chicago: American College of Surgeons; 2018.
  • 34. Patrini D, Panagiotopoulos N, Pararajasingham J, Gvinianidze L, Iqbal Y, Lawrence DR. Etiology and management of spontaneous haemothorax. Journal of thoracic disease. 2015; 7(3): pp. 520–6. doi: 10.3978/j.issn.2072-1439.2014.12.50.
  • 35. Inaba K, Lustenberger T, Recinos G, et al. Does size matter? A prospective analysis of 28–32 versus 36–40 French chest tube size in trauma. The Journal of Trauma and Acute Care Surgery. 2012; 72(2): pp. 422–427. doi: 10.1097/ta.0b013e3182452444.
  • 36. Kasper DL, Fauci AS, Hauser S, Longo D, Jameson LJ, Loscalzo J . Harrisons Principles of Internal Medicine . New York, NY: McGraw-Hill Medical Publishing Division; 2016.
  • 37. Mandell LA, Wunderink RG, Anzueto A, et al. Infectious Diseases Society of America/American Thoracic Society Consensus Guidelines on the Management of Community-Acquired Pneumonia in Adults. Clinical Infectious Diseases. 2007; 44(Supplement_2): pp. S27–S72. doi: 10.1086/511159.
  • 38. Metlay JP, Waterer GW, Long AC, et al. Diagnosis and Treatment of Adults with Community-acquired Pneumonia. An Official Clinical Practice Guideline of the American Thoracic Society and Infectious Diseases Society of America. Am J Respir Crit Care Med. 2019; 200(7): pp. e45–e67. doi: 10.1164/rccm.201908-1581st.
  • 39. Sahn SA. Diagnosis and Management of Parapneumonic Effusions and Empyema. Clinical Infectious Diseases. 2007; 45(11): pp. 1480–1486. doi: 10.1086/522996.
  • 40. Shen KR, Bribriesco A, Crabtree T, et al. The American Association for Thoracic Surgery consensus guidelines for the management of empyema. J Thorac Cardiovasc Surg. 2017; 153(6): pp. e129–e146. doi: 10.1016/j.jtcvs.2017.01.030.
  • 41. Kwon YS. Pleural Infection and Empyema. Tuberculosis and Respiratory Diseases. 2014; 76(4): p. 160. doi: 10.4046/trd.2014.76.4.160.
  • 42. Hallifax RJ, Talwar A, Wrightson JM, Edey A, Gleeson FV. State-of-the-art: Radiological investigation of pleural disease. Respir Med. 2017; 124: pp. 88–99. doi: 10.1016/j.rmed.2017.02.013.
  • 43. Boersma et al. Treatment of haemothorax. Respiratory Medicine. 2010. doi: 10.1016/j.rmed.2010.08.006.
  • 44. Morgan CK, Bashoura L, Balachandran D, Faiz SA. Spontaneous Hemothorax. Annals of the American Thoracic Society. 2015; 12(10): pp. 1578–1582. doi: 10.1513/annalsats.201505-305cc.
  • 45. Psallidas et al. Malignant pleural effusion: from bench to bedside. European Respiratory Review. 2016; 25(140): pp. 189–198. doi: 10.1183/16000617.0019-2016.
  • 46. Feller-Kopman et al. Management of Malignant Pleural Effusions. An Official ATS/STS/STR Clinical Practice Guideline. American Journal of Respiratory and Critical Care Medicine. 2018; 197(7). doi: 10.1164/rccm.201807-1415ST.
  • 47. Hans H. Schild, Christian P. Strassburg, Armin Welz, Jörg Kalff. Treatment Options in Patients With Chylothorax. Deutsches Aerzteblatt Online. 2013; 110(48): pp. 819–826. doi: 10.3238/arztebl.2013.0819.
  • 48. Lama et al. Characteristics of patients with pseudochylothorax—a systematic review. Journal of Thoracic Disease. 2016; 8(8): pp. 2093–2101. doi: 10.21037/jtd.2016.07.84.
  • Romero-Candeira S, Fernández C, Martı́n C, Sánchez-Paya J, Hernández L. Influence of diuretics on the concentration of proteins and other components of pleural transudates in patients with heart failure. Am J Med. 2001; 110(9): pp. 681–686. doi: 10.1016/s0002-9343(01)00726-4.
  • Dweik RA. Pleural Disease. http://www.clevelandclinicmeded.com/medicalpubs/diseasemanagement/pulmonary/pleural-disease/. Updated August 1, 2010. Accessed February 19, 2017.
  • Rubins J. Pleural Effusion. In: Pleural Effusion. New York, NY: WebMD. http://emedicine.medscape.com/article/299959-workup. Updated June 30, 2016. Accessed February 14, 2017.
  • Socransky S, Wiss R, Hall G, Ho B, Skinner A, Turner J, Woo M, Chen R. Point-of-Care Ultrasound for Emergency Physicians. The EDE 2 Course Inc.; 2013.
  • Ward MA. Empyema and Abscess. In: Empyema and Abscess. New York, NY: WebMD. http://emedicine.medscape.com/article/807499-clinical#showall. Updated March 18, 2015. Accessed February 13, 2017.
  • Strange C. Parapneumonic effusion and empyema in adults. In: Post TW, ed. UpToDate. Waltham, MA: UpToDate. https://www.uptodate.com/contents/parapneumonic-effusion-and-empyema-in-adults?source=search_result&search=pleural%20empyema&selectedTitle=1~150. Last updated December 20, 2016. Accessed February 13, 2017.
  • Jones J, et al. Pleural effusion. https://radiopaedia.org/articles/pleural-effusion. Updated February 19, 2017. Accessed February 19, 2017.
  • Northwestern Health Sciences University. Radiology of the Chest: Chapter Four: Diagnostic Radiographic Signs. url: http://www.nwhealth.edu/resource/radca/chest4.html Accessed February 19, 2017.
  • Bien MY, Wu MP, Chen WL, Chung CL. VEGF correlates with inflammation and fibrosis in tuberculous pleural effusion. ScientificWorldJournal. 2015; 2015. doi: 10.1155/2015/417124.
  • van Zuuren EJ, Trow T. Pleural Effusion. https://www.dynamed.com/topics/dmp~AN~T474331/Pleural-effusion. Updated August 24, 2017. Accessed November 26, 2017.
  • Le T, Bhushan V, Chen V, King M. First Aid for the USMLE Step 2 CK. New York, NY: McGraw-Hill Education; 2015.
  • Heffner JE. Diagnostic Thoracentesis. In: Post TW, ed. UpToDate. Waltham, MA: UpToDate. https://www.uptodate.com/contents/diagnostic-thoracentesis. Last updated March 16, 2017. Accessed November 26, 2017.
  • Saguil A, Wyrick K, Hallgren J. Diagnostic approach to pleural effusion. Am Fam Physician. 2014; 90(2): pp. 99–104. url: http://www.aafp.org/afp/2014/0715/p99.html.
  • Gaillard F. Empyema vs pulmonary abscess. https://radiopaedia.org/articles/empyema-vs-pulmonary-abscess-2. Accessed April 18, 2018.
  • Tao Le, Vikas Bhushan, Deol M, Reyes G. First Aid for the USMLE Step 2 CK, Tenth Edition. New York: McGraw-Hill Education; 2018.
  • Heffner J; Broaddus V. Diagnostic evaluation of a pleural effusion in adults. In: Post TW, ed. UpToDate. Waltham, MA: UpToDate. https://www.uptodate.com/contents/diagnostic-evaluation-of-a-pleural-effusion-in-adults-initial-testing?search=pleural%20effusion&source=search_result&selectedTitle=1~150&usage_type=default&display_rank=1#H14. Last updated April 2, 2018. Accessed May 9, 2019.
  • King, Thompson. Radiological perspectives in empyema: Childhood respiratory infections. British Medical Bulletin. 2002; 61(1): pp. 203–214. doi: 10.1093/bmb/61.1.203.
  • Weerakkody. Thoracic empyema. https://radiopaedia.org/articles/thoracic-empyema-1. Accessed May 13, 2019.
  • Herold G. Internal Medicine. Cologne, Germany: Herold G; 2014.
last updated 08/12/2020
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