Published Aug 2020
1 Clinical Instructor, Hospital Medicine, University of Colorado, 2 Assistant Professor of Medicine, University of Colorado, 3 Professor of Radiology, University of Washington
Objectives
- Differentiate basilar from apical emphysema to demonstrate the pathophysiologic difference from hematogenous versus inhaled lung toxicity.
Teaching Instructions
Plan to spend 5-10 minutes familiarizing yourself with the animations of the PowerPoint and the key findings of this chest X-ray.
Present the image either by expanding the window (bottom right) in a browser or downloading the PowerPoint file (recommended for optimal function). Have the image pulled up in presenter mode before learners look at the screen to avoid revealing the diagnosis. Ask a learner to provide an overall interpretation. Then advance through the animations to prompt learners with key questions and reveal the findings, diagnosis, and teaching points.
CXR interpretation: Hyperinflated lungs with flattening diaphragms. There is lucency at the bases reflecting basal-predominant emphysema. The upgoing vessels are fatter than normal reflecting redistribution because of the basal destruction. Flattening of the diaphragm is best seen on the lateral view.
Teaching: The basic concept to reinforce in this case is that inhaled substances and processes have a predominant impact on the upper lungs and hematogenous substances and processes have a predominant impact on the lower lobes. This case demonstrates that injected substances that are destructive to the lung parenchyma (e.g. crushed Ritalin) cause basilar destruction > apical.
Presentation Board
Take Home Point
- Tobacco-related emphysema is apical-predominant and centrilobular
- Basal-predominant emphysema is strongly suggestive of a hematogenous mechanism. This is most commonly alpha-1 antitrypsin disease, but may also be seen in with other destructive toxins spread hematogenously to the lungs (e.g. excipient lung disease).
References
Schmidt, Rodney A., et al. “Panlobular Emphysema in Young Intravenous Ritalin Abusers.”American Review of Respiratory Disease, vol. 143, no. 3, 1991, pp. 649–656., doi:10.1164/ajrccm/143.3.649.
