Signs and symptoms of pulmonary fibrosis include:
- Shortness of breath (dyspnea)
- A dry cough
- Unexplained weight loss
- Aching muscles and joints
The course of pulmonary fibrosis — and the severity of symptoms — can vary considerably from person to person. Some people become ill very quickly with severe disease. Others have moderate symptoms that worsen more slowly, over months or years.
Pulmonary fibrosis scars and thickens the tissue around and between the air sacs (alveoli) in your lungs. This makes it more difficult for oxygen to pass into your bloodstream. The damage can be caused by many different things — including airborne toxins in the workplace, certain lung diseases, radiation directed to cancers in the lung or breast, and even some types of medical treatments.
Occupational and environmental factors
Long-term exposure to a number of toxins and pollutants can damage your lungs. These may include:
- Silica dust
- Asbestos fibers
- Grain dust
- Bird and animal droppings
Some people who receive radiation therapy for lung or breast cancer show signs of lung damage months or sometimes years after the initial treatment. The severity of the damage depends on:
- How much of the lung was exposed to radiation
- The total amount of radiation administered
- Whether chemotherapy also was used
- The presence of underlying lung disease
Many drugs can damage your lungs, especially:
- Chemotherapy drugs. Drugs designed to kill cancer cells, such as methotrexate (Trexall) and cyclophosphamide (Cytoxan), can also damage lung tissue.
- Heart medications. Some drugs used to treat irregular heartbeats, such as amiodarone (Cordarone, Nexterone, Pacerone) or propranolol (Inderol , Innopran), may harm lung tissue.
- Some antibiotics. Nitrofurantoin (Macrobid, Macrodantin, others) and sulfasalazine (Azulfidine) can cause lung damage.
Lung damage can also result from:
- Systemic lupus erythematosus
- Rheumatoid arthritis
The list of substances and conditions that can lead to pulmonary fibrosis is long. Even so, in most cases, the cause is never found. Pulmonary fibrosis with no known cause is called idiopathic pulmonary fibrosis.
Researchers have several theories about what might trigger idiopathic pulmonary fibrosis, including viruses and exposure to tobacco smoke. And because one type of idiopathic pulmonary fibrosis runs in families, heredity also is thought to play a role.
Factors that make you more susceptible to pulmonary fibrosis include:
- Age. Although pulmonary fibrosis has been diagnosed in children and infants, the disorder is much more likely to affect middle-aged and older adults.
- Smoking. Far more smokers and former smokers develop pulmonary fibrosis than do people who have never smoked. Pulmonary fibrosis can occur in patients with emphysema.
- Your occupation. You have an increased risk of developing pulmonary fibrosis if you work in mining, farming or construction or if you're exposed to pollutants known to damage your lungs.
- Cancer treatments. Having radiation treatments to your chest or using certain chemotherapy drugs makes you more susceptible to pulmonary fibrosis.
- Genetic factors. Some types of pulmonary fibrosis appear to run in families, so a genetic component is suspected.
Complications of pulmonary fibrosis may include:
- High blood pressure in your lungs (pulmonary hypertension). Unlike systemic high blood pressure, this condition affects only the arteries in your lungs. It begins when the smallest arteries and capillaries are compressed by scar tissue, causing increased resistance to blood flow in your lungs. This in turn raises pressure within the pulmonary arteries and the right ventricle. Pulmonary hypertension is a serious illness that becomes progressively worse and may eventually prove fatal.
- Right-sided heart failure (cor pulmonale). This serious condition occurs when your heart's lower right chamber (ventricle) has to pump harder than usual to move blood through partially blocked pulmonary arteries.
- Respiratory failure. This is often the last stage of chronic lung disease. It occurs when blood oxygen levels fall dangerously low. Because your lungs are so stiff, like an old dried sponge, it is harder to breathe and that adds to your fatigue and loss of appetite.
- Lung cancer. Long-standing pulmonary fibrosis also increases your risk of developing lung cancer.