Usual interstitial pneumonia is a type of lung disease in which patches of inner lung tissue become inflamed and scarred. The condition tends to progress rapidly, causing irreparable lung damage in as little as one year after symptoms begin and ultimately leading to respiratory failure. Doctors may try to treat usual interstitial pneumonia with corticosteroids to ease inflammation, though the persistent disease spreads so quickly that a lung transplant is often necessary to prevent life-threatening complications.
The lungs are filled with tiny air sacs, called alveoli, which expand and contract to oxygenate the bloodstream. Alveoli are lined and protected with a membranous tissue called the interstitium. Usual interstitial pneumonia begins when alveoli become inflamed, causing the interstitium to harden. The interstitium stiffens further as the disease progresses, eventually leading to scarring and significantly reducing the lungs' ability to oxygenate the blood.
Symptoms are not typically noticeable until the disease is already past its early stages. As interstitial pneumonia progresses, an individual is likely to experience shortness of breath and a dry cough that worsens after engaging in physical activity. The disease can eventually become so severe that breathing becomes very difficult even while a person is at rest.
Most instances of usual interstitial pneumonia are idiopathic, meaning that doctors cannot determine why inflammation and scarring occur. Some cases can be tied to underlying causes, such as smoking, genetic connective tissue disorders, or long-term exposure to industrial chemicals and silica. The condition is slightly more common in men than in women, and most patients who are diagnosed with this condition are over the age of 60.
A physician can diagnose usual interstitial pneumonia by taking chest x-rays to look for signs of scarring. When signs of lung disease are present, the doctor usually collects a blood sample to check for traces of toxic chemicals, bacteria, and other abnormalities. A lung tissue biopsy may be needed to confirm the diagnosis and rule out other forms of lung disease, including cancer.
Once a diagnosis has been made, a patient who has mild symptoms is typically given an oxygen machine, prescribed corticosteroids, and instructed to limit his or her physical activity. A severe case generally requires immediate hospitalization and oxygen therapy to prevent total respiratory failure. The condition cannot be cured, and even with intensive medical treatment patients tend to get worse over time. The most effective treatment for usual interstitial pneumonia is a lung transplant when a donor is available.