A difficult and often fatal disease in older adults, idiopathic pulmonary fibrosis (IPF) is one of a spectrum of diseases called interstitial lung disease. The title accurately describes the process: Idiopathic (cause is unknown), pulmonary (affecting the lungs) and fibrosis (the normally expansive tissue in the lungs becomes hardened and fibrous). The disease can be localized or generalized, with generalized findings having a particularly poor prognosis. Usually not found until its later stages, CT scanning (particularly for lung cancer screening) has shown IPF to be more prevalent than previously thought.
IPF is a progressive disease, and generally only affects the lung as opposed to involving other organs as well. It is characterized by inflammation, thickening, and scarring of lung tissue. While the idiopathic part of the name infers the exact cause is unknown, there appears to be a process of abnormal and persistent wound repair, resulting in chronic scarring. Eventually the normal lung tissue is replaced by non-functioning scar tissue and symptoms then become evident.
The most common presentation of idiopathic pulmonary fibrosis is progressive shortness of breath, generally without a cough. Risk factors appear to be male sex, older age, and a history of smoking. Many initial cases present to a doctor (particularly in those with a smoking history or past exposure to chemicals or asbestos) for a decreased ability to breathe comfortably or to exert oneself and are treated empirically as chronic obstructive pulmonary disease. However further testing differentiates IPF.
Breathing tests show distinctive abnormalities, most coinciding with a restrictive lung disease pattern. Because the fibrosis prevents the lung from expanding optimally, the FEV1 (ability to get as much air out of the lungs in a one second period) is low. Likewise, the FVC measurement of capacity is also lowered. Gas exchange testing also shows a decrease in the effectivity of exchanging air. This results in the symptoms described.
Chest X-rays and CT scanning then help to make the definitive diagnosis. The chest x-ray will show patches of fibrosis discernable from normal lung tissue. CT scanning shows a more detailed picture with coarse reticulation and a pattern called honeycombing, with rows of cysts stacked over one another whose appearance worsens as the scanner moves toward the interior of the lungs. A lung biopsy at that point is quite definitive for the pathologic changes of fibrotic lung tissue and the honeycomb-like picture.
Lab testing is important to rule out other diseases that may mimic IPF, especially as the treatments may be quite different. Scleroderma, mixed connective tissue disease and Sjogren’s syndrome may show similar lung findings early in the disease. Rheumatoid arthritis that affects the lungs, chronic active hepatitis, and inflammatory bowel disease may result in similar early findings. Blood testing, other physical findings (such as in rheumatoid arthritis for example), and eventually the biopsy results will make a more definitive diagnosis of IPF.
Idiopathic pulmonary fibrosis progresses in several ways. Some cases are rapidly progressive and the prognosis is dire, with death in a few short months to years. Others have a slower progression, with periods of acute worsening followed by periods of relative stability. Some have a slow enough stepwise progression of symptoms that the affected individual may die of another condition. Lung function testing becomes the usual way to follow the progression of the disease along with CT scanning when there is an abrupt change in condition.
Most drug therapy is able to slow the progression of IPF or improve symptoms but is not curative. Two medicines, pirfenidone and nintedanib, slow the growth factor that is continually repairing and replacing normal tissue with fibrotic one. Steroids were a treatment of choice but are no longer used routinely because of the possibility of immunosuppression out of proportion to their benefit. Lung transplantation is considered in selected patients.
When small areas of fibrosis on CXR with a question of IPF are found, but the insured is asymptomatic and the condition is stable, coverage can be considered, and the longer the period of time of non-progressive findings then the closer to a standard issue the case becomes. In cases of confirmed and more generalized idiopathic pulmonary fibrosis cases are usually declined.
Robert Goldstone, MD, FACE, FLMI
MD, FACE, FLMI, board certified internist and endocrinologist, was most recently vice president and chief medical officer for Pacific Life and Pacific Life and Annuity. He has extensive brokerage and life insurance experience, having been medical director at both MetLife Brokerage and Transamerica Occidental Life. Goldstone is board certified in insurance medicine and the inaugural recipient of the W. John Elder Award for Insurance Medicine Journalism Excellence. He was also honored as a fellow of the prestigious American College of Endocrinology and has written monthly for Broker World since 1991. Goldstone does consulting full or part-time as well as on a fill-in basis for companies who need a medical director/physician. He can be reached by telephone at 949-943-2310. Emaill: [email protected]