What happens to the lungs in cryptogenic fibrosing alveolitis?
Cryptogenic fibrosing alveolitis is also known as idiopathic pulmonary fibrosis or interstitial pulmonary fibrosis. It is useful to understand what the words mean:
- Alveolitis means inflammation of the alveoli.
- Fibrosis means thickening or scarring.
- Cryptogenic and idiopathic mean 'of unknown cause'.
- Pulmonary means 'affecting the lungs'.
In cryptogenic fibrosing alveolitis there is inflammation in the alveoli, the alveoli walls, and in the lung tissue next to the alveoli (the interstitial lung tissue). The inflammation causes thickening and damage to the walls of the alveoli, and to fibrosis (scarring). The thickening and scarring reduces the amount of oxygen that can pass into the blood vessels from affected alveoli. Therefore, as the disease progresses, less oxygen than normal is passed into the body when you breathe.
What causes cryptogenic fibrosing alveolitis?
The cause is not known. One theory is that it is an autoimmune disease. This means that the body's immune system causes disease. Antibodies and white blood cells of the immune system normally fight off germs (viruses, bacteria, etc). In cryptogenic fibrosing alveolitis, white blood cells of the immune system seem to attach to the cells of the alveoli and cause inflammation. The reason why this happens is not clear. There may be some trigger such as a virus infection or other factor that causes the immune system to 'attack' the alveoli.
Some people are more prone (genetically susceptible) to autoimmune diseases and a small number of cases seem to run in families. However, in most cases, there is no family history of the disease. The disease is more common in people who smoke, or have been smokers at some time. So, cigarette smoke may play a part to trigger the disease in some cases.
(A similar fibrotic lung condition sometimes occurs as a result of exposure at work to certain metals, wood dusts and other chemicals, and as a side-effect to certain medicines. These conditions are not 'idiopathic' as the cause can be identified. If you have suspected lung fibrosis your doctor is likely to ask you about your work history to rule out these other conditions).
How common is cryptogenic fibrosing alveolitis?
Cryptogenic fibrosing alveolitis is rare. Less than 3 in 10,000 people develop this disease. However, it seems to be getting more common. It can affect anybody at any age but it most commonly develops between the ages of 50 and 70.
What are the symptoms of cryptogenic fibrosing alveolitis?
- Breathlessness (shortness of breath) that gradually becomes worse is the main symptom. This is due to the reduced amount of oxygen that gets into the bloodstream. Shortness of breath after exertion may be noticed at first. This may be passed off as 'just getting older' for a while until the shortness of breath becomes worse.
- A dry cough often develops (a cough with little or no sputum).
- Clubbing occurs in about half of cases. Clubbing is a painless swelling at the base of the fingernails. The cause of clubbing is not clear. It occurs in people with various chest and heart diseases.
- Tiredness.
- An increased risk of developing chest infections
Heart failure develops if the condition becomes severe. This is due to the poor supply of oxygen from the lungs to the heart muscle. Heart failure can cause various symptoms including worsening breathlessness and fluid retention.
How is cryptogenic fibrosing alveolitis diagnosed?
The above symptoms combined with 'crackles' heard by a doctor listening with a stethoscope suggest cryptogenic fibrosing alveolitis. A chest X-ray may show a scarring pattern in the lungs suggestive of this disease. Breathing tests help to rule out other causes of shortness of breath.
To confirm the diagnosis and to assess the severity of the disease, a CT scan of the lung and/or a lung biopsy is usually needed. A biopsy is a small sample of lung tissue which is taken by a small operation. The sample is looked at under a microscope. Cryptogenic fibrosing alveolitis causes a typical appearance of scarring and inflammation of the alveoli and nearby lung tissue which can be seen in the biopsy sample.
What are the treatment options for cryptogenic fibrosing alveolitis?
There is no cure for cryptogenic fibrosing alveolitis. One or more of the following options may be advised to help to improve symptoms, and to slow down the progression of the disease.
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Steroid medication is commonly tried. A high dose is used at first and then reduced to a lower 'maintenance' dose. Steroids reduce inflammation and are used in a variety of inflammatory conditions. Reducing the inflammation may prevent or slow down further damage and fibrosis to the alveoli. Steroid medication improves symptoms in about 1 in 4 affected people. If there is no improvement after a few months then the steroids are stopped. Some people who take steroids develop side-effects. Another page describes possible side-effects of steroids in more detail.
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Immunosuppressant medicines such as azathioprine may also be tried. These also suppress inflammation. Like steroids, these help in just some cases.
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Combination treatment. A combination of steroids plus an immunosuppressant is an option. The chance of improvement is thought to be better than either treatment alone. It also allows the dose of steroid to be lower than if it was used alone so any side-effects from steroids are likely to be less severe.
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No treatment is an option. Steroids or immunosuppressant medication cause serious side-effects in some people. The risk of side-effects has to be balanced with the chance of improving symptoms and slowing down the progression of the disease. No treatment may be advised particularly for elderly people if their symptoms are mild or are not getting much worse. A chest specialist usually keeps the situation under review.
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Oxygen treatment - in the home may be required if symptoms become severe.
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A lung transplant may be an option. This is becoming more common in younger people who develop severe disease despite medication. It is less of an option for older people.
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Get immunised against influenza and pneumococcus. They protect against infections that can be particularly severe if you have a disease of the lung.
What is the prognosis (outlook)?
The progression of the disease can vary greatly. Some people respond well to medication which may slow the progression of the disease, but in others it makes little difference. About half of affected people die within 3-5 years of first being diagnosed. However, some people live for 10 or more years after being diagnosed, and some die within months of being diagnosed.
The variation in outlook is probably because some people have more inflammation and less fibrosis in their alveoli. In others there is more fibrosis and less inflammation. Medication tends to help most when there is a lot of inflammation (when the disease is 'active'). It works less well if there is a lot of fibrosis and little inflammation. Medication cannot undo the fibrosis (scarring) that has already occurred. Tests such as lung biopsy and CT lung scan are sometimes done to give a better idea as to how much inflammation and/or fibrosis is present. This may help to give a clearer idea of the outlook in each case.
People with cryptogenic fibrosing alveolitis have about a 10 times increased risk of developing lung cancer compared to the average risk.
Further help and information
British Lung Foundation
73-75 Goswell Road, London EC1V 7ER
Tel: 020 7688 5555 Web: www.lunguk.org
©EMIS and PIP 2005 Updated: September 2005
