Lung Fibrosis describes a condition in which the lung tissue becomes thickened, stiff, and scarred. The medical terminology used to describe this scar tissue is fibrosis. The alveoli and the blood vessels within the lungs are responsible for delivering oxygen to the body, including the brain, heart, and other organs. As lung tissue becomes scarred and thicker, it is more difficult for the lungs to transfer oxygen into the bloodstream. As a result, the brain, heart, and other organs do not get the oxygen they need to function properly. In some cases, doctors can determine the cause of the fibrosis, but in many cases the cause remains unknown. When there is no known cause for the development of pulmonary fibrosis (and certain radiographic and/or pathologic criteria are met), the disease is called idiopathic pulmonary fibrosis or IPF. More specifically, consensus treatment guidelines from international lung societies define IPF as “a specific form of chronic, progressive fibrosing interstitial pneumonia of unknown cause, occurring primarily in older adults, limited to the lungs, and associated with the histopathologic and/or radiologic pattern of UIP [usual interstitial pneumonia].
The confirmation of diagnosis of PF involves the exclusion of other IPP's and interstitial lung disease that may be caused or associated with drug use, environmental exposure, or other systematic diseases. The diagnois of this disease requires the use of a multidisciplinary team which will include pulmonologists, radiologists, and pathologists.
If there is a clear association with another illness or the lung fibrosis is the result of a side effect from a medication or an exposure to an agent known to cause PF, then the cause of the disease is no longer considered idiopathic. PF clearly associated with another disease, such as scleroderma or rheumatoid arthritis, would be referred to as pulmonary fibrosis secondary to scleroderma or secondary to rheumatoid arthritis.
Idiopathic pulmonary fibrosis portends a poor prognosis, with an estimated mean survival of 2-5 years from the time of diagnosis.Estimated mortality rates are 64.3 deaths per million in men and 58.4 deaths per million in women. The most common cause of death associated with PF is respiratory failure and will account for an estimated 80% of all fatalities associated with the disease. Other causes of death are likely to be heart failure and disease, bronchogenic carcinoma, ischemic heart disease, infections, as well as pulmonary embolism.
In order to diagnose Idiopathic Pulmonary Fibrosis, which is the most common type, the following diagnostic criteria have to be present:
Treatment courses for pulmonary fibrosis are highly variable and difficult to predict. Each therapy strategy is individualized according to the patient's history and symptoms.
The pharmacologic treatment options include Cyclophosphamide, Azathioprine, N-acetylcysteine, Pirfenidone. They medications may stabilize their disease and there may be a benefit to continuing usage. Further, some of these medications may be prescribed to manage symptoms when a patient has an acute exacerbation or period of worsening. Medications may be used alone or in combination. Also, as fibrosis inhibits an adequate transfer of oxygen into the bloodstream, some patients may require supplemental oxygen. This helps to reduce breathlessness, enabling the patient to be more active. Some patients may need oxygen therapy all the time while others may only need it during sleep and exercise.
The non-pharmacologic treatment option is pulmonary rehabilitation. Pulmonary rehabilitation programs involve aerobic conditioning, strength and flexibility training, educational lectures, nutritional interventions, and psychosocial support. Pulmonary rehabilitation has recently been studied in patients with ILD. Two controlled trials of pulmonary rehabilitation in IPF have demonstrated an improvement in walk distance and symptoms or quality of life. Other uncontrolled studies have found similar findings. The beneficial effects of pulmonary rehabilitation may be more pronounced in patients with worse baseline functional status. Pulmonary rehabilitation may not be reasonable in a minority.
Lung transplantation for Idiopathic Pulmonary Fibrosis patients confer a survival benefit over medical therapy. Due to the use of the Lung Allocation Score(LAS) IPF has now replaces COPD as the most common indication for lung transplantation in the United States.
Due to the unknown cause of idiopathic pulmonary fibrosis, prevention of the respiratory disease is difficult. Higher prevalence of the disease is attributed with certain family genetics and cigarette smokers. As such, a physiotherapist can advise patients to avoid or stop smoking in order to decrease the chance of idiopathic pulmonary fibrosis.