Pulmonary Edema: Pathophysiology and Radiographic Manifestations

1. Pulmonary Edema Pathophysiological Considerations Manifestations on Chest Radiography Pulmonary Edema Pathophysiological Considerations Manifestations on Chest Radiography Kathryn Glassberg MS4 Kathryn Glassberg MS4 February 2006 February 2006

2. Pulmonary Edema: Overview Pulmonary Edema: Overview Pathophysiology : Edema as an end result of a multitude of diverse insults (not just heart failure vs. ARDS!) Pathophysiology : Edema as an end result of a multitude of diverse insults (not just heart failure vs. ARDS!) Physiologic approach for radiologic evaluation of edema Physiologic approach for radiologic evaluation of edema Hydrostatic edema Hydrostatic edema Permeability edema +/- diffuse alveolar damage Permeability edema +/- diffuse alveolar damage Mixed permeability and hydrostatic edema Mixed permeability and hydrostatic edema

3. Pulmonary Edema Pulmonary Edema Edema occurs when physiologic resorption of fluid via lymphatics is overwhelmed Edema occurs when physiologic resorption of fluid via lymphatics is overwhelmed Causes usually divided into hydrostatic and increased capillary permeability, but both mechanisms can occur in the same patient! Causes usually divided into hydrostatic and increased capillary permeability, but both mechanisms can occur in the same patient! Chest radiography, when combined with clinical data, helps distinguish pathologic cause in vast majority of cases Chest radiography, when combined with clinical data, helps distinguish pathologic cause in vast majority of cases

4. Causes of Pulmonary Edema 1 Causes of Pulmonary Edema 1 Hydrostatic Cardiac : Left heart failure Noncardiac Increased transmural capillary pressure Increased intracapillary pressure : neurogenic, hyperperfusion (high altitude, postembolic, post transplant) Lowered extracapillary pressure : reexpansion edema, postglottic spasm Oncotic : nutritional, near- drowning Combined hemodynamic/oncotic : renal failure, overhydration Lymphatic block : lymphangitis, carcinomitosis, lymphangiectasia

5. Causes of Pulmonary Edema 1 Causes of Pulmonary Edema 1 Increased capillary permeability Injury Extracapillary (alveolar insult): Inhalation, aspiration, infection Intracapillary Trauma: sepsis, hypotension, Pancreatitis, DIC Embolism : fat, air, amniotic fluid Noninjury: Allergic, endocrine

6. Pathophysiology overview 2 Pathophysiology overview 2 Normally, excess hydrostatic transudate from pulmonary capillaries is filtered into peribronchovascular lymphatics and removed

7. Pathophysiology overview 2 Pathophysiology overview 2 In hydrostatic edema, transudate accumulates in the interstitum initially, only entering alveoli in severe cases In permeability edema associated with diffuse alveolar damage (DAD), exudate fills the interstitum and the alveoli

8. Hydrostatic Edema 3 Hydrostatic Edema 3 The lungs can accommodate increases in fluid: the lymphatic flow can increase 3-10x before edema develops The lungs can accommodate increases in fluid: the lymphatic flow can increase 3-10x before edema develops Higher hydrostatic pressures force fluid through endothelial cell pores, but the tighter junctions of epithelial cells prevent fluid from entering alveoli until pulmonary capillary pressures reach ~ 40 mm Hg, causing stress failure Higher hydrostatic pressures force fluid through endothelial cell pores, but the tighter junctions of epithelial cells prevent fluid from entering alveoli until pulmonary capillary pressures reach ~ 40 mm Hg, causing stress failure

9. Hydrostatic Edema: radiologic manifestations 3 Hydrostatic Edema: radiologic manifestations 3 Earliest sign: vascular indistinctness Earliest sign: vascular indistinctness Bronchial wall thickening/peribronchial cuffing Bronchial wall thickening/peribronchial cuffing Septal lines: Kerley A, B, C Septal lines: Kerley A, B, C Thickened fissures Thickened fissures Severe edema: dependent ground glass opacities reflecting alveolar involvement Severe edema: dependent ground glass opacities reflecting alveolar involvement Often associated with bilateral transudative pleural effusions Often associated with bilateral transudative pleural effusions

10. Hydrostatic Edema: radiologic manifestations 3 Hydrostatic Edema: radiologic manifestations 3 Cephalization or inversion not specific for edema Cephalization or inversion not specific for edema Reflects chronic pulmonary venous changes in patients with left-sided heart failure Reflects chronic pulmonary venous changes in patients with left-sided heart failure Vascular pedicle width Vascular pedicle width patients with volume overload often have widened vascular pedicles when compared to previous studies patients with volume overload often have widened vascular pedicles when compared to previous studies However, patients can certainly have hydrostatic edema despite a narrow pedicle, thus this sign can be misleading However, patients can certainly have hydrostatic edema despite a narrow pedicle, thus this sign can be misleading

11. Vascular indistinctness Vascular indistinctness Norma l Edema Images courtesy of Dr. Marc Gosselin

12. Vascular Indistinctness Vascular Indistinctness Norma l Edema Images courtesy of Dr. Marc Gosselin

13. Peribronchial cuffing Peribronchial cuffing Images shown are pre- and post-treatment for hydrostatic edema Images shown are pre- and post-treatment for hydrostatic edema Arrowheads point to Kerley A lines Arrowheads point to Kerley A lines

14. Septal Lines 3 Septal Lines 3 The presence of septal lines reflects fluid accumulation between the lung lobules The presence of septal lines reflects fluid accumulation between the lung lobules Kerley lines Kerley lines A: long, diagonal, central A: long, diagonal, central B: short, horizontal, extend to lateral pleural surfaces B: short, horizontal, extend to lateral pleural surfaces C: reticular pattern of ~ 1 cm polygons representing septal lines viewed on end (Ive heard Dr. Kerley is the only one who has ever really seen these) C: reticular pattern of ~ 1 cm polygons representing septal lines viewed on end (Ive heard Dr. Kerley is the only one who has ever really seen these)

15. Septal Lines Septal Lines Septal lines in a patient with cardiac failure Septal lines in a patient with cardiac failure

16. Septal Lines Septal Lines Lateral view of same patient note fluid in both fissures Lateral view of same patient note fluid in both fissures

17. Septal Lines Septal Lines All three Kerleys claim to be present; can you find them? All three Kerleys claim to be present; can you find them?

18. Septal Lines Septal Lines Even in you cant name the lines, you can see that this patient has severe hydrostatic edema in need of treatment! Even in you cant name the lines, you can see that this patient has severe hydrostatic edema in need of treatment! A B C?

19. Evolving hydrostatic edema 4 Evolving hydrostatic edema 4 33 year-old with AML admitted for renal failure and fluid overload 33 year-old with AML admitted for renal failure and fluid overload

20. Evolving hydrostatic edema 4 Evolving hydrostatic edema 4 Arrows indicate peri- bronchial cuffing Note increasing size of azygous vein

21. Evolving hydrostatic edema 4 Evolving hydrostatic edema 4 Arrowheads indicate septal lines Arrowheads indicate septal lines Note ground-glass, indicating alveolar edema Note ground-glass, indicating alveolar edema

22. Permeability Edema Permeability Edema multiple insults can cause increased pulmonary vessel permeability resulting in leakage of fluid AND protein multiple insults can cause increased pulmonary vessel permeability resulting in leakage of fluid AND protein In its most severe form, the disease is a combination of vessel permeability and DAD, leading to the acute respiratory distress syndrome (ARDS) In its most severe form, the disease is a combination of vessel permeability and DAD, leading to the acute respiratory distress syndrome (ARDS)

23. ARDS pathology 3 ARDS pathology 3 Acutely, exudative edema in the alveoli causes hyaline membrane formation Acutely, exudative edema in the alveoli causes hyaline membrane formation Type II epithelial cells then proliferate and, usually, fibrosis occurs Type II epithelial cells then proliferate and, usually, fibrosis occurs

24. ARDS: Radiologic manifestations 3 ARDS: Radiologic manifestations 3 Patchy, diffuse ground glass opacities Patchy, diffuse ground glass opacities Pattern of opacification does not change with position change, as the exudates are trapped in alveoli Pattern of opacification does not change with position change, as the exudates are trapped in alveoli Septal lines, peribronchial cuffing, and thick fissures are usually ABSENT Septal lines, peribronchial cuffing, and thick fissures are usually ABSENT In severe cases, air bronchograms can be seen In severe cases, air bronchograms can be seen Good rule of thumb: presence of ET tube! Good rule of thumb: presence of ET tube!

25. ARDS: Radiologic manifestations 3 ARDS: Radiologic manifestations 3 Caution: While a normal sized heart and narrow vascular pedicle are helpful signs, neither is specific for injury edema Caution: While a normal sized heart and narrow vascular pedicle are helpful signs, neither is specific for injury edema

26. ARDS ARDS Patchy diffuse ground glass Patchy diffuse ground glass Air bronchograms Air bronchograms ET tube ET tube

27. Permeability Edema without DAD 3 Permeability Edema without DAD 3 Seen in IL-2 therapy for metastatic disease, hantavirus pulmonary syndrome Seen in IL-2 therapy for metastatic disease, hantavirus pulmonary syndrome Severe capillary permeability without alveolar involvement Severe capillary permeability without alveolar involvement Radiographically, resembles hydrostatic edema (septal lines, peribronchial cuffing) because alveolar epithelium remains intact Radiographically, resembles hydrostatic edema (septal lines, peribronchial cuffing) because alveolar epithelium remains intact

28. Mixed hydrostatic and permeability edema Mixed hydrostatic and permeability edema High-altitude pulmonary edema High-altitude pulmonary edema Neurogenic edema Neurogenic edema Reexpansion and post-obstructive Reexpansion and post-obstructive

29. High-altitude pulmonary edema (HAPE) 3 High-altitude pulmonary edema (HAPE) 3 Hypoxia causes non-uniform pulmonary vasoconstriction, leaving other lung units over- perfused and predisposed to edema Hypoxia causes non-uniform pulmonary vasoconstriction, leaving other lung units over- perfused and predisposed to edema Higher pressures can result in some capillary damage and stress failure Higher pressures can result in some capillary damage and stress failure

30. High-altitude pulmonary edema 3 High-altitude pulmonary edema 3 Radiographs show patchy ground glass with a central distribution favoring peribronchial cuffing and vascular indistinctness over septal lines Radiographs show patchy ground glass with a central distribution favoring peribronchial cuffing and vascular indistinctness over septal lines

31. Neurogenic Edema 3 Neurogenic Edema 3 Pathophysiology similar to HAPE neural mechanisms result in non-uniform vasoconstriction Pathophysiology similar to HAPE neural mechanisms result in non-uniform vasoconstriction High protein content of fluid indicates capillary leakage involved as well High protein content of fluid indicates capillary leakage involved as well

32. Neurogenic Edema 3 Neurogenic Edema 3 Classically, neurogenic edema has an upper lobe predominance; however, it can present with any pattern Classically, neurogenic edema has an upper lobe predominance; however, it can present with any pattern Often clears rapidly, arguing for intact alveoli Often clears rapidly, arguing for intact alveoli

33. Neurogenic Edema 4 Neurogenic Edema 4 54 year-old woman with intracranial hemorrhage 54 year-old woman with intracranial hemorrhage Note upper lobe predominance Note upper lobe predominance

34. Reexpansion and Postobstructive Edema 3 Reexpansion and Postobstructive Edema 3 Both occur in setting of high negative pleural pressure Both occur in setting of high negative pleural pressure Reexpansion: usually seen as localized lung injury, with alveolar filling and exudative fluid, arguing for increased permeability as a cause Reexpansion: usually seen as localized lung injury, with alveolar filling and exudative fluid, arguing for increased permeability as a cause Postobstructive: pattern usually hydrostatic, secondary to increased central blood volume caused by the relief of obstruction Postobstructive: pattern usually hydrostatic, secondary to increased central blood volume caused by the relief of obstruction

35. Reexpansion Edema 4 Reexpansion Edema 4 Right pneumothorax One-hour post chest-tube placement

36. Postobstructive Edema 4 Postobstructive Edema 4 Postextubation Laryngospasm: note central distribution and peribronchial cuffing. Postextubation Laryngospasm: note central distribution and peribronchial cuffing.

37. Conclusions Conclusions Hydrostatic Edema is characterized by Hydrostatic Edema is characterized by Vascular indistinctness Vascular indistinctness Peribronchial cuffing Peribronchial cuffing Septal lines/fissure thickening Septal lines/fissure thickening Permeability Edema with DAD (ARDS) is characterized by Permeability Edema with DAD (ARDS) is characterized by Diffuse, patchy ground glass opacities Diffuse, patchy ground glass opacities Air bronchograms Air bronchograms Overlap is seen in pathophysiology, thus can be reflected in the radiograph Overlap is seen in pathophysiology, thus can be reflected in the radiograph

38. Summary Table 1 Summary Table 1 Hydrostatic Hydrostatic Permeability with DAD Permeability with DAD Heart size Heart size Often enlarged Often enlarged Usually not enlarged Usually not enlarged Septal Lines Septal Lines Common Common Absent Absent Peribronchial cuffs Peribronchial cuffs Common Common Not common Not common Air bronchograms Air bronchograms Not common Not common Very common Very common Regional distribution Regional distribution Even or central Even or central Patchy or peripheral Patchy or peripheral

39. Hydrostatic and Permeability Edema Hydrostatic and Permeability Edema Images courtesy of Dr. Marc Gosselin

40. The condition of the capillary endothelium and that of the alveolar epithelium are the main determinants 3 The condition of the capillary endothelium and that of the alveolar epithelium are the main determinants 3

41. References References 1 Milne ENC and Massimo P. Reading the Chest Radiograph: A Physiologic Approach. Mosby, 1993. 1 Milne ENC and Massimo P. Reading the Chest Radiograph: A Physiologic Approach. Mosby, 1993. 2 Ware LB and Matthay MA. Acute pulmonary edema. The New England Journal of Medicine. 2005; 353: 2788-96. 2 Ware LB and Matthay MA. Acute pulmonary edema. The New England Journal of Medicine. 2005; 353: 2788-96. 3 Ketai LH and Godwin JD. A new view of pulmonary edema and acute respiratory distress syndrome. Journal of Thoracic Imaging . 1998; 13: 147-171. 3 Ketai LH and Godwin JD. A new view of pulmonary edema and acute respiratory distress syndrome. Journal of Thoracic Imaging . 1998; 13: 147-171. 4 Gluecker T. Capasso P. Schnyder P. Gudinchet F. Schaller MD. Revelly JP. Chiolero R. Vock P. Wicky S. Radiographics. 19(6):1507-31; discussion 1532-3, 1999 Nov-Dec. 4 Gluecker T. Capasso P. Schnyder P. Gudinchet F. Schaller MD. Revelly JP. Chiolero R. Vock P. Wicky S. Clinical and radiologic features of pulmonary edema. Radiographics. 19(6):1507-31; discussion 1532-3, 1999 Nov-Dec.

42. References References Images taken from: Images taken from: myweb.lsbu.ac.uk/ ~ dirt/museum/p6-71.html myweb.lsbu.ac.uk/ ~ dirt/museum/p6-71.html www.bcm.edu/.../cases/ pediatric/text/7a-desc.htm www.bcm.edu/.../cases/ pediatric/text/7a-desc.htm http://www.hcoa.org/hcoacme/chf-cme/chf00030.htm http://www.hcoa.org/hcoacme/chf-cme/chf00030.htm http://www-medlib.med.utah.edu/WebPath/LUNGHTML/LUNG131.html http://www-medlib.med.utah.edu/WebPath/LUNGHTML/LUNG131.html http://www-medlib.med.utah.edu/WebPath/LUNGHTML/LUNG133.html http://www-medlib.med.utah.edu/WebPath/LUNGHTML/LUNG133.html http://www.lumen.luc.edu/lumen/MedEd/MEDICINE/PULMONAR/CXR/atlas/images/310a1.jpg http://www.lumen.luc.edu/lumen/MedEd/MEDICINE/PULMONAR/CXR/atlas/images/310a1.jpg www.high-altitude-medicine.com/ AMS-medical.html www.high-altitude-medicine.com/ AMS-medical.html Sherman SC. Reexpansion pulmonary edema: a case report and review of the current literature. Journal of Emergency Medicine. Jan 2003; 24(1): 23-7. Sherman SC. Reexpansion pulmonary edema: a case report and review of the current literature. Journal of Emergency Medicine. Jan 2003; 24(1): 23-7. Thanks to Dr. Marc Gosselin for images, insights Thanks to Dr. Marc Gosselin for images, insights