Pulmonary Edema

  • Alveolus at a Cytologic Level
    The diagram shows an alveolus (a) above, lined by a single layer of squamous cells, surrounded by a capillary with red cells which is also lined by a single layer of squamous endothelial cells . The images below show progressive magnification of the alveolar wall demonstrating the two thin layer of the alveolar membrane .
    Ashley Davidoff
    TheCommonVein.net
    lungs-0028-low res
  • Pulmonary edema is
    • caused by the
      • extravascular movement of fluid into the
        • pulmonary interstitium and
        • alveoli.
      • It is therefore not a helpful term when trying to distinguish between
        • moderate heart failure  ie interstitial edema
        • severe heart failure – alveolar edema
      • classified into four categories based on these physiologic
        • hydrostatic pressure edema,
          • left heart failure and
          • volume overload
        • permeability edema with and without diffuse alveolar damage (DAD)
          •  DAD is acute respiratory distress syndrome,
            • direct injury to the
              • capillary endothelium and
              • alveolar epithelium by
                • many  different causes including
                  • infectious processes,
                  • inhaled toxins,
                  • inflammatory mediators arising from a larger systemic insult.
            • changes in membrane permeability without severe alveolar damage.
              • “crack-lung” or
              • opioid overdose or,
              • high-altitude pulmonary edema, or
              • cytokine administration such as IL-2.
        • both an increase in hydrostatic pressure and membrane permeability.
          • severe neurologic injury
          • following abrupt lung re-expansion or
          • lung transplant.
  • Cardiogenic Pulmonary Edema
  • NORMAL, CEPHALIZATION, INTERSTIAL EDEMA, ALVEOLAR EDEMA
    Ashley Davidoff MD
    TheCommonVein.net

    PHASES OF HEART FAILURE
    The top left image is the a histological section of normal alveoli and normal wall and interstitium. Heart failure occurs when the left ventricular end diastolic pressure rises. There are 3 basic phases of heart failure. in the first phase (top right) the LVEDP rises above 12 mmHg and on an upright CXR there is equalization of the size of the vessels going to the upper lobes and lower lobes. As the LVEDP goes above about 15-18 mm Hg there is cephalization of the vessels and the upper lobe vessels are larger than the lower lobe vessels.
    The second phase of interstitial edema (bottom left) occurs when the intravascular hydrostatic pressure exceeds the intravascular oncotic pressure and this occurs when the LVEDP goes above 25 mm Hg. Fluid accumulates in the alveolar walls and interstitium and the wall becomes thicker with fluid, and the lymphatics and interlobular septa are distended.
    The last phase of alveolar edema (lower right) occurs when the pressure exceeds 35 mmHg and the fluid leaks into the alveoli .
    Ashley Davidoff MD
  • batwing alveolar edema
    Courtesy Start Radiology
    CHF – Alveolar Edema
    CT scan shows Diffuse ground glass pattern with thickening of the interlobular septa and manifesting as crazy paving pattern
    Ashley Davidoff MD

    NORMAL, CEPHALIZATION, INTERSTITIAL EDEMA, ALVEOLAR EDEMA
    Ashley Davidoff MD
  • ARDS
  • 31 yo F with MRSA bacteremia and ARDS. (a) Portable CXR demonstrating perihilar consolidative opacities. (b) Chest CT in the same patient demonstrates consolidative and groundglass opacities with air bronchograms most significantly affecting the dependent portion of the lung in keeping with ARDS.
    Barile M Pulmonary Edema: A Pictorial Review of Imaging Manifestations and Current Understanding of Mechanisms of Disease Eur J Radiol Open. 2020; 7: 100274.

     

  • Re-Expansion Pulmonary Edema
  • CXR of a patient with a large left pleural effusion before (a) and after (b) a left thoracentesis with removal of 2 L of fluid. Note that following the thoracentesis (b), the left pleural effusion has decreased in size, the mediastinum is midline, and there is a new left perihilar consolidation. (c) CT following thoracentesis demonstrating central perihilar parenchymal consolidation consistent with re-expansion pulmonary edema.
    Barile M Pulmonary Edema: A Pictorial Review of Imaging Manifestations and Current Understanding of Mechanisms of Disease Eur J Radiol Open. 2020; 7: 100274.
  • Neurogenic Pulmonary Edema
  • 54 year old female with subarachnoid hemorrhage with mild pulmonary edema
    Ashley Davidoff
    TheCommonvein.net
    54 year old female with subarachnoid hemorrhage with mild pulmonary edema
    Ashley Davidoff
    TheCommonvein.net

    54 year old female with subarachnoid hemorrhage with mild pulmonary edema
    Ashley Davidoff
    TheCommonvein.net
  • 34 M following a fall from ladder with a subarachnoid hemorrhage, causing brain dead. Portable CXR demonstrates bilateral hazy and consolidative opacities, with a perihilar predominance on the left and a small layering right pleural effusion. Findings were suggestive of neurogenic pulmonary edema.
    Barile M Pulmonary Edema: A Pictorial Review of Imaging Manifestations and Current Understanding of Mechanisms of Disease Eur J Radiol Open. 2020; 7: 100274.
  • Crack Cocaine Use – “crack lung”
  • is a pulmonary syndrome of
    • edema,
    • hemorrhage,
    • alveolitis, and
    • diffuse alveolar damage
      • following free base cocaine inhalation.
        •  mechanism of edema
        • permeability component with
            • diffuse alveolar damage
              • caused by
                • direct damage to the capillary endothelium
                • hydrostatic component, caused by vasoconstriction, myocardial ischemia, infarction, and arrhythmias.
            • Resulting in
              • hemorrhage,
              • alveolitis, and
              • diffuse alveolar damage
      • Radiographic findings
        • perihilar alveolar opacities,
        • interstitial thickening, and
        • pleural effusions
        • resolve within 24-72 hours
        • following free base cocaine inhalation.
    • 49 yo M with a history of smoking free-base crack cocaine, presenting with mental status changes and dyspnea. (a) PA CXR demonstrating faint patchy opacities in both lungs. (b) Chest CT in same patient demonstrating geographic areas of ground-glass opacity with associated interlobular septal thickening. The diagnosis of “crack lung”.
      Barile M Pulmonary Edema: A Pictorial Review of Imaging Manifestations and Current Understanding of Mechanisms of Disease Eur J Radiol Open. 2020; 7: 100274.
  • Unilateral Pulmonary Edema
  • Asymmetric edema secondary to decubitus positioning after a long surgery characterized by interstitial and alveolar opacities involving the right lung only.
    Barile M Pulmonary Edema: A Pictorial Review of Imaging Manifestations and Current Understanding of Mechanisms of Disease Eur J Radiol Open. 2020; 7: 100274.

     

  • Asymmetric and/or unilateral pulmonary edema
    • decubitus position for long periods of time
    • emphysema with bullous disease,
    • severe mitral valve regurgitation (sidedness depends on direction of the jet),
    • re-expansion pulmonary edema, and
    • pulmonary vein occlusion.

References and Links

Barile M Pulmonary Edema: A Pictorial Review of Imaging Manifestations and Current Understanding of Mechanisms of Disease Eur J Radiol Open. 2020; 7: 100274.