II. Definitions

  1. Pulmonary Edema
    1. Abnormal fluid accumulation in the extravascular lung compartments (lung parenchyma)

III. Pathophysiology

  1. See Generalized Edema
  2. Mechanisms
    1. Hydrostatic pressure gradient increased from intravascular to extravascular
      1. Cardiogenic Pulmonary Edema (increased left atrial pressure and pulmonary venous pressure)
    2. Osmotic pressure gradient decreased
      1. Malnutrition and Protein-losing conditions
    3. Capillary permeability increased
      1. Non-Cardiogenic Pulmonary Edema (lung parenchymal injury)
  3. Effects
    1. Decreased alveolar gas exchange
    2. Progressive Respiratory Failure

IV. Causes: Cardiogenic Pulmonary Edema (increased left atrial pressure)

  1. Atrial Outflow Obstruction (e.g. Mitral Stenosis, atrial Myxoma)
  2. Left ventricular outflow obstruction (Subaortic Stenosis, Aortic Stenosis, Aortic Coarctation)
  3. Cardiomyopathy (e.g. acute Myocarditis)
  4. Dysrhythmia (e.g. Atrial Fibrillation with Rapid Ventricular Rate, third degree AV Block)
  5. Acute Myocardial Infarction
  6. Acute Decompensated Congestive Heart Failure
    1. Systolic Dysfunction
    2. Diastolic Dysfunction
    3. Left ventricular volume overload

VI. Findings

  1. General Findings
    1. Dyspnea
    2. Tachypnea
    3. Hypoxia
  2. Cardiogenic Pulmonary Edema Findings
    1. See Systolic Dysfunction
    2. Cough productive of pink frothy Sputum
    3. S3 Gallup
    4. Fine rales (small airway opening on inspiration)
    5. Jugular Venous Distention
    6. Peripheral Pitting Edema
  3. Non-Cardiogenic Pulmonary Edema Findings
    1. Evaluate for signs of underlying cause (e.g. infection source including Pneumonia)

VII. Differential Diagnosis

  1. Diffuse Pulmonary Hemorrhage
  2. Diffuse pulmonary infection

X. Imaging: Chest XRay

  1. See Chest XRay in Congestive Heart Failure
  2. Cardiogenic Pulmonary Edema Findings
    1. Mediastinal Widening
      1. Vascular pedicle measurement >53 mm
    2. Pleural Effusion
    3. Cardiomegaly
    4. Peribronchial cuffing
    5. Bronchovascular markings (Kerley B Lines)
  3. Non-Cardiogenic Pulmonary Edema Findings
    1. Batwing appearance of central lung vasculature at hilum
    2. Air Bronchograms
    3. Typically absent are cardiomegaly, Mediastinal Widening, Pleural Effusion

XII. References

  1. Malek (2020) Pulmonary Edema, StatPearls, accessed 12/29/2020
  2. Sureka (2015) J Family Med Prim Care 4(2):290 +PMID:25949989 [PubMed]

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