Daily Bolus of LR: Classic Radiographic Signs of Lobar Pneumonia

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May 27, 2011 by dailybolusoflr


Classic Radiographic Signs of Lobar Pneumonia



Lobar pneumonia, also known as segmental pneumonia, is an infection that is noted on CXR in a segmental distribution.  These pneumonias are often easier to see than interstitial pneumonias

Classic teaching has been that lobar pneumonias are more likely to be bacterial while interstitial pneumonias or “atypical” pneumonias are more likely to be viral or mycoplasmal, but this statement appears to be unreliable.




A few radiographic signs more commonly seen in lobar pneumonias are listed below:




Silhouette sign– when the interface between the heart, diaphragm or aorta and the lung is obliterated 






Spine sign– when the density of the lower spine on the lateral film increased instead of decreases






Air bronchogram-infection is present in the alveoli but the air filled bronchi are still noted








Schwartz’s Emergency Radiology





Linda Regan, MD FACEP

Program Director, Emergency Medicine Residency

Johns Hopkins Medical Institutions


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