Friday, July 3, 2015
Air Way Disease
After being treated with different antibiotics for what I thought was walking pneumonia, I had a CT of the lung. Impression was of left lower lobe airspace disease compatible with volume loss with/without inflammatory component. Extensive calcification involving left hilium ... What is "airspace disease" and what is meant by "calcification"? Does this reflect something acute which has become chronic? Thanks.
When a radiologist uses the words “airspace disease,” he/she usually means that there is pneumonia in this part of the lung. However, a CT, like a chest X-ray, works by showing differences between the way X-rays pass through or are absorbed by different tissues. Normally, the air sacs that make up your lungs are filled with air and X-rays basically pass through them. On a CT scan, air shows up as black. However, when these sacs are filled with fluid, they show up as white because the X-rays are reflected off the fluid. In pneumonia, the lungs are filled with pus and blood. Strictly speaking, if your lung sacs (called alveoli) are filled with any fluid they will show up as white but when it is in a single area, the radiologists often use this term.
If this is not resolving over time (2-3 months), there may be something else there other than pneumonia causing the changes on CT scan. Calcifications are bright white areas that show up similar to your bones (which are made of calcium). The extensive calcification involving the left hilum refers to calcification in the lymph nodes located where your left lung hangs from the middle of your chest. Most often, this is due to scarring from an old, often asymptomatic infection and likely had nothing to do with your pneumonia. If you live in the Ohio or Mississippi River valleys, this is likely a sign of old infection from a fungus that lives in the soil, called Histoplasmosis. Changes like this are seen on as many as 80% of the CT scans done on people living in these areas.
James M O'Brien, Jr, MD
Former Associate Professor
Pulmonary and Critical Care Medicine
College of Medicine
The Ohio State University