Causes | Symptoms | Treatment | Outcome
Pulmonary fibrosis is a chronic disease that causes swelling and scarring of the alveoli (air sacs) and interstitial tissues (tissue between cells) of the lungs. The scar tissue replaces healthy tissue and causes inflammation. This damage causes your lungs to stiffen and makes breathing more and more difficult.
Some common and some rare diseases can cause pulmonary fibrosis, but in the majority of cases the cause is not known (idiopathic pulmonary fibrosis). Pulmonary fibrosis can be a mild disease causing few symptoms or it can be a severe and possibly fatal.
This condition is known by many different names, "Interstitial pulmonary fibrosis" is perhaps the most common, but other terms frequently used include: "fibrosing alveolitis", "interstitial pneumonitis" and "Hamman-Rich syndrome".
What causes pulmonary fibrosis?
Pulmonary fibrosis is a complicated illness that can come from many different causes.
It appears that the lung is reacting to microscopic damage by developing inflammation and fibrosis (scarring). The nature of the initial damage is not always known and although doctors may say that pulmonary fibrosis is due to a given disease (for example, sarcoidosis) they often may not know the specific causes of those diseases either.
The most frequent cases of pulmonary fibrosis are related to sarcoidosis — fibrosis associated with certain occupational diseases — and pulmonary fibrosis where the causes are not known ("idiopathic").
Occupational diseases and pulmonary fibrosis
Many jobs, particularly those that involve working with asbestos, ground stone or metal dust, can cause pulmonary fibrosis. The small particles of these materials are inhaled, and they damage the alveoli and cause fibrosis.
Some organic substances, such as mouldy hay can also cause pulmonary fibrosis; this is known as farmer's lung.
Asbestosis and pulmonary fibrosis
Asbestosis is usually caused when small needle-like particles of asbestos are inhaled into the lungs. This can cause lung scarring (pulmonary fibrosis) and in addition can lead to lung cancer.
Cigarette smoking has an interactive relationship with asbestos — the asbestos worker who smokes has a much higher chance of developing lung cancer than does the non-smoker.
Silicosis and pulmonary fibrosis
Silicosis is another disease producing pulmonary fibrosis in which the cause is known. It is a disease that results from breathing in free crystalline silica dust.
All types of mining in which the ore is extracted from quartz rock can produce silicosis if precautions are not taken. This includes the mining of gold, lead, zinc, copper, iron, anthracite (hard) coal and some bituminous (soft) coal. Workers in foundries, sandstone grinding, tunneling, sandblasting, concrete breaking, granite carving and china manufacturing also encounter silica.
Large silica particles are stopped in the upper airways. But the tiniest specks of silica can be carried down to the alveoli where they lead to pulmonary fibrosis.
Silicosis can be either mild or severe, in direct proportion to the percentage and concentration of silica in the air and the duration of exposure.
Silicosis can be prevented by measures specifically designed for each industry and each job. Dust control is essential. Sometimes this is accomplished by the wetting down of mines, improved ventilation or the wearing of masks.
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Some medicines that can cause pulmonary fibrosis
Certain strong medicines may have the undesirable side effect of causing pulmonary fibrosis. Some of them are:
- nitrofurantoin (sometimes used for urinary tract infections)
- amiodarone (sometimes prescribed for an irregular heart rate)
- bleomycin, cyclophosphamide and methotrexate (sometimes prescribed to fight cancer)
Who is at risk for pulmonary fibrosis?
Patients of any age with any of the diseases listed above, or with exposure to any of the drugs listed above, may develop pulmonary fibrosis, but this is rare. Patients who develop idiopathic pulmonary fibrosis are usually middle-aged men and women, and there appears to be no sexual, racial or geographical tendency.
People who smoke or who are former smokers are more likely to develop pulmonary fibrosis than people who have never smoked."
What are the symptoms of pulmonary fibrosis?
Breathlessness is the most common symptom of pulmonary fibrosis. Many lung diseases show breathlessness as the main symptom — a fact that can complicate and confuse diagnosis.
Usually the breathlessness of idiopathic pulmonary fibrosis first appears during exercise. The condition may progress to the point where any exertion (serious physical activity) is impossible and where breathlessness occurs even at rest.
A dry cough is also a common symptom.
The fingertips may enlarge at the ends and take on a bulbous appearance, referred to as "clubbing". Cyanosis (blue lips, nail beds, skin from lack of oxygen in tissue) may also occur.
How is pulmonary fibrosis diagnosed?
A chest X-ray may give some clues. Pulmonary function test (spirometry) determines how well your lungs do their job and how much air they can hold.
Bronchoalveolar lavage (a test which allows removal and examination of cells in the lower respiratory tract) is sometimes used for diagnosis.
At some point, a lung biopsy may be performed so that cells in and around the alveoli can be examined externally.
What is the treatment for pulmonary fibrosis?
If one of the known causes of pulmonary fibrosis exists, then treatment of that underlying disease can be effective. Removal of the patient from the environment and or occupation causing the disease can also be effective.
Many times treatment is limited only to treating the inflammatory response that occurs in the lungs. This is done in the hope that stopping the inflammation will prevent the growth of scar tissue (fibrosis) in the lungs and thus stop the progression of the disease. Corticosteroids are the drugs which are usually given in an attempt to stop the inflammation. The advantage of this treatment has not been proven in every case, although it does appear that if the drugs are given early on in the course of the disease, there is a better chance of improvement. Corticosteroid medications can have various side effects and so patients taking these medications must be frequently reassessed by their doctors in order to judge the safety and benefit of this therapy.
Other medications have been tried but there is not a lot of convincing evidence of their effectiveness.
However, there is much that can be done in the way of supportive therapy that will ease the breathlessness that accompanies pulmonary fibrosis. Rehabilitation and education programs can help considerably in teaching patients how to breathe more efficiently (using as little energy as possible) and to perform their activities of daily living with less breathlessness. Find a pulmonary rehabilitation clinic near you.
Sometimes supplemental oxygen therapy is required in order to treat breathlessness. Early treatment of chest infections is required.
Smoking must be discontinued, as the effects of tobacco will aggravate the shortness of breath. Get help to quit smoking.
What is the outcome of pulmonary fibrosis?
Many times the disease is mild with few symptoms and does not progress significantly over time. In other cases, when pulmonary fibrosis is caused by some other underlying disease, such as rheumatoid arthritis, progression of the lung condition may reflect progression of the underlying diseases.
Very rarely pulmonary fibrosis progresses over a period of a few weeks from a sudden onset to death from respiratory failure. However, the usual course of pulmonary fibrosis, particularly idiopathic pulmonary fibrosis, is one of slowly progressive scarring of the lungs. The duration and speed of this process is variable. Some patients do not respond to therapy and have a slow deterioration over months to years, eventually ending in death when the lungs can no longer function adequately. In many cases, patients respond to therapy.
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