Imaging Sciences Interesting Cases
Case 163
Daniel T. O'Connor, MD
Clinical Presentation: Patient is a 35-year-old male with sudden onset of shortness of breath/respiratory distress; no other significant past medical history. Decreased left-sided breath sounds.
Imaging Findings: Initial AP portable view of the chest with no prior study for comparison demonstrated tension pneumothorax of the left hemithorax with classic mediastinal shift to the right and hypoexpanded/compressed appearance of the right lung (Fig. 1). Subsequent radiograph demonstrated near complete re-expansion of the left upper and lower lobes with small residual pneumothorax in the left apex after placement of left-sided chest tube, and patchy opacification with diffuse, hazy interstitial markings of the perihilar region and left lower lobe, consistent with re-expansion pulmonary edema with residual atelectasis (Fig. 2). These findings resolved rapidly, however, with near complete resolution of re-expansion edema by the following morning (Fig. 3).
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| Figure 1: AP radiograph shows classic appearance of left tension pneumothorax with loss of left-sided lung markings, mediastinal shift to the contralateral side, and compressed appearance of right lung. |
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| Figure 2: Following placement of left-sided chest tube, near complete re-expansion of left lung with secondary re-expansion pulmonary edema of the left perihilar region and lower lobe. Note small apical pneumothorax, likely left lower lobe residual atelectasis. |
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| Figure 3: Rapid resolution of radiographic findings by the following morning, with no significant pneumothorax and near-normal appearance of left lung. |
Diagnosis: Spontaneous tension pneumothorax with re-expansion pulmonary edema
Discussion: Re-expansion pulmonary edema is an acute pulmonary process of controversial etiology that is most commonly encountered following chest tube placement for tension pneumothorax. Other common situations include re-expansion of lung parenchyma following removal of an obstructing mass and following the removal of a large volume of pleural fluid (at least 1L). Radiographic changes may be near-immediate, as in the above case, but may be delayed up to 24 hours. Usually self-limiting, this condition has been historically associated with significant morbidity and mortality, with up to 20% mortality reported in some series.
Radiographic findings are typical of pulmonary edema, with distribution determined by location/extent of lung collapse, as well as clinical variables such as the rate of re-expansion and duration of collapse. Distinct from other causes of noncardiogenic pulmonary edema both by virtue of clinical history and focal appearance; contusion of lung parenchyma and reperfusion pulmonary edema following pulmonary embolism thrombolysis are important differential considerations.
References:
- Mahfood S, Hix WR, Aaron BL, Blaes P, Watson DC. Reexpansion pulmonary edema. Ann Thorac Surg. 1988 Mar;45(3):340-5. [PubMed]