It is critically important to distinguish IPF from other types of lung disease. There is a family of lung diseases that are termed “interstitial lung diseases” or ILD. This collection of diseases has different causes and treatments. Some are related to connective tissue diseases such as Lupus, while others may be related to viral infections.
Some doctors are “lumpers” and others are “splitters”. Being a “splitter” means that for some doctors it is important to categorize and then further sub categorize each diagnosis. Other doctors, the “lumpers”, are more comfortable with large groupings- such as diseases that are treated with one type of therapy or another. I am a “lumper” when it comes to ILD. The most important question is whether the lung process will respond to medicines that suppress the immune system (immunosuppresants such as prednisone). In the world of ILD, most respond to prednisone whereas IPF dose not. Thus it is important to separate Idiopathic Pulmonary Fibrosis from all of the other interstitial lung diseases.
Can You Distinguish Idiopathic Pulmonary Fibrosis from Interstitial Lung Disease?
You can distinguish the difference between Idiopathic Pulmonary Fibrosis and other interstitial lung diseases by examining lung tissue under a microscope. The tissue of IPF patients has a very specific pattern. This pattern is called UIP (usual interstitial pneumonia). This term is a bit confusing because there is no infection despite having the word pneumonia in the phrase. In some geographic areas UIP is used interchangeably with IPF. Fibrotic foci can be seen during microscopic evaluation of IPF lung tissue. These are small areas of active collagen deposition and are felt to be the engines of progressive fibrosis (scarring). The lesions are unevenly distributed in the lung tissue, more prominently at the bases (bottoms) and in the periphery (outside) areas. There is abnormal lung tissue adjacent to normal lung tissue. Honeycomb change is also typically seen and is felt to be an advanced stage of fibrosis.