(See also Overview of Idiopathic Interstitial Pneumonias Overview of Idiopathic Interstitial Pneumonias Idiopathic interstitial pneumonias are interstitial lung diseases that have no known cause that have some similarities in symptoms and how they affect the lungs. Some types of these diseases... read more and Overview of Interstitial Lung Diseases Overview of Interstitial Lung Diseases Interstitial lung disease (also called diffuse parenchymal disease) is a term used to describe a number of different disorders that affect the interstitial space. The interstitial space consists... read more .)
In idiopathic pulmonary fibrosis, the lungs develop progressive scarring for unknown reasons. There seems to be a genetic component because some families have more than one person affected by the disorder. Specific gene mutations have been identified in some people with idiopathic pulmonary fibrosis.
Symptoms depend on the extent of the lung damage, the rate at which the disease progresses, and whether complications, such as lung infections and right-sided heart failure (cor pulmonale Cor Pulmonale Cor pulmonale is enlargement and thickening of the ventricle on the right side of the heart resulting from an underlying lung disorder that causes pulmonary hypertension (high pressures in the... read more ) develop.
The main symptoms start insidiously as shortness of breath during exertion, cough, and diminished stamina. In most people, symptoms worsen over a period ranging from about 6 months to several years.
As the disease progresses, the level of oxygen in the blood decreases, and the skin may take on a bluish tinge (called cyanosis) and the ends of the fingers may become thick or club-shaped (see figure Recognizing Finger Clubbing ). Strain on the heart may cause the right ventricle to enlarge, eventually resulting in right-sided heart failure Heart Failure (HF) Heart failure is a disorder in which the heart is unable to keep up with the demands of the body, leading to reduced blood flow, back-up (congestion) of blood in the veins and lungs, and/or... read more . Through a stethoscope, doctors often hear crackling sounds in the lungs.
A chest x-ray may show lung damage, mostly in the lower parts of both lungs. Computed tomography (CT) typically shows the damage and thick scarring in more detail. Pulmonary function tests Pulmonary Function Testing (PFT) Pulmonary function tests measure the lungs' capacity to hold air, to move air in and out, and to absorb oxygen. Pulmonary function tests are better at detecting the general type and severity... read more show that the amount of air the lungs can hold is below normal. Analysis of a blood sample (see Arterial Blood Gas Analysis Arterial Blood Gas (ABG) Analysis and Pulse Oximetry Both arterial blood gas testing and pulse oximetry measure the amount of oxygen in the blood, which helps determine how well the lungs are functioning. Arterial blood gas tests are invasive... read more ) or use of an oximeter shows a low level of oxygen during minimal exercise (walking at a normal pace) and, as the disease progresses, even when the person is resting.
To confirm the diagnosis, doctors may do a lung biopsy with use of a thoracoscope Thoracoscopy Thoracoscopy is the visual examination of the lung surfaces and pleural space through a viewing tube (a thoracoscope). Thoracoscopy is used to view the lung and the space surrounding the lungs... read more .
Blood tests cannot confirm the diagnosis but are done as part of the search for other disorders that may cause a similar pattern of inflammation and scarring. For example, doctors do blood tests to screen for certain autoimmune disorders.
Most people continue to get worse. On average, people live about 3 to 5 years after diagnosis. Some people survive for more than 5 years after diagnosis. A few die within several months.
Pirfenidone and nintedanib appear to slow the decline in lung function. Other drug treatments are being studied in clinical trials.
Other treatments are aimed at relieving symptoms:
Pulmonary rehabilitation Pulmonary rehabilitation is the use of exercise, education, and behavioral intervention to improve how people with chronic lung disease function in daily life and to enhance their quality of... read more for improving ability to carry out activities of daily life
Oxygen therapy for low blood oxygen levels
Antibiotics for infection
Drugs for the heart failure that is caused by cor pulmonale
Lung transplantation Lung and Heart-Lung Transplantation Lung transplantation is the surgical removal of a healthy lung or part of a lung from a living person and then its transfer into someone whose lungs no longer function. Heart-lung transplantation... read more (in some cases with a single lung) has been successful in some people with severe idiopathic pulmonary fibrosis.