Interstitial Lung Diseases – Adult
Interstitial lung diseases (ILD) are a group of rare lung conditions that cause chronic
breathlessness. The problem usually develops over the age of 50 years, and can affect both
men and women, and also children. Generally the causes of these diseases are unknown.
Only very rarely are ILDs inherited. They are not contagious.
The lungs are responsible for the delivery of oxygen into the blood stream and the removal
of carbon dioxide. The major problem in ILD is inflammation of the lung tissue which leads
to scarring (fibrosis) of the air sacs (alveoli) that interferes with the ability of the lungs to
deliver oxygen. If the problem gets worse, the lungs become stiff, and shrink resulting in
increased breathlessness.
What are the symptoms?
People with ILD usually complain of breathlessness on exertion, and occasionally a dry
cough. It is uncommon for people to develop breathlessness at rest, chest pains or to cough
up phlegm. If these other symptoms develop then another problem needs to be considered.
The breathlessness in ILD, unlike in asthma, is generally constant from one day to the next
and if it deteriorates, does so over a period of months to years. For some, the cough can be
the most distressing feature of ILD and is often made worse by viral infections or exercise.
What causes these diseases?
There are many different types of ILD, and distinguishing them is often difficult. Frequently,
diagnosis requires a biopsy due to the similarity of symptoms and x-ray findings. The vast
majority of ILDs occur as a result of a spontaneous disorder of the body’s inflammation and
repair mechanisms.
Sometimes this disorder only affects the lung; common diseases of this variety include
the idiopathic interstitial pneumonias, such as idiopathic pulmonary fibrosis. Other forms of
ILD occur as part of a more widespread disorder that can affect other parts of the body as
well. These disorders include sarcoidosis and conditions such as rheumatoid
arthritis and scleroderma. Inherited forms may occur, and usually become apparent in
childhood or young adulthood.
Causes and types of interstitial lung disease
Common Unknown Causes
• Idiopathic pulmonary fibrosis
• Cryptogenic organizing pneumonia
• Sarcoidosis
Rheumatological Disease
• Rheumatoid arthritis
• Scleroderma
• Systemic lupus erythematosus
Drugs
Radiation
Common types of ILD include extrinsic allergic alveolitis such as bird fancier’s lung and
asbestosis. Doctors caring for patients with ILDs will need to know about a patient’s
previous employment and be made aware of all unusual exposures at home. It is rare for
the lungs to develop scarring as a result of environmental or occupational exposures.
OCCUPATIONAL EXPOSURE
Asbestos
Quartz
DOMESTIC EXPOSURE
Bird proteins
DISEASE
Asbestosis
Silicosis
DISEASE
Bird fancier's lung
A large number of prescribed drugs are known to cause ILD. This problem may first arise
after a patient has been exposed to the medication for many years and is not generally
related to dose. A website for drug associated lung diseases www.pneumotox.com is a
useful resource for doctors and patients concerned that a medication may be causing ILD.
Non prescription complementary therapies can also cause ILD and doctors should be made
aware if these are being taken.
How is interstitial lung disease investigated?
After a careful patient history is taken and an examination is carried out, a doctor will
undertake a number of investigations to confirm a suspected diagnosis of ILD.
1. Chest x-ray. This simple and cheap investigation provides very important information
to a treating doctor, particularly if there are previous x-rays available for comparison.
Every effort should be made to locate any previous chest x-rays no matter how old.
2. Lung function testing. These tests performed in a respiratory laboratory provide the
doctor with a functional assessment of the lungs. The tests allow your doctor to
assess the severity of the scarring in the lungs and monitor the progress of the
disease.
3. Blood tests. These tests are used to rule out those causes for ILD that are part of a
more widespread illness.
4. Computed Tomography (CT scan). Inevitably this investigation is required to confirm
the presence of ILD. The pattern and extent of the scarring in the lungs predicts if the
scarring will get worse or respond to therapy. Based on this investigation your doctor
may recommend a surgical biopsy.
5. Bronchoscopy. Examination of the bronchial tubes with a fibre-optic instrument that
allows samples of fluid and tissue to be taken from the lung is useful in diagnosing
some forms of ILD.
6. Lung biopsy. The removal at surgery of a specimen of lung tissue is recommended in
a small number of patients when the diagnosis of ILD is uncertain despite the other
investigations described above. This investigation requires a hospital stay and is
generally performed in a specialist centre.
Disease treatment
As in other forms of chronic lung disease, smoking cessation, maintenance of ideal body
weight and vaccination against influenza and pneumococcal infection is recommended. In
cases where inhalation of foreign material or a medication is felt to be the cause of the ILD,
removal of the offending agent is a critical step in preventing worsening of the condition.
This should be done in consultation with your doctor. Do not stop any medication without
speaking to your doctor first. Sometimes treatment of ILD may involve modification of the
work or home environment.
Depending on the type of ILD and its severity, treatment with immune suppressing
medication, such as prednisolone, may be required. Unfortunately for idiopathic
pulmonary fibrosis, the most common form of ILD, there is no conventional therapy
proven to improve the outcome. A trial of immune suppressing medication can be
considered, but should be discontinued if shown to be ineffective or side effects intolerable.
Although there is no published evidence for its effectiveness in ILD, a course of pulmonary
rehabilitation is often of benefit to patients, providing an exercise program, education and
emotional support.
Patients with low oxygen levels may also benefit from oxygen therapy.
International guidelines suggest that patients diagnosed with ILD should be managed in a
specialist centre, with access to clinical trials and the availability of lung transplantation for
suitable candidates.
Research initiatives
Current therapies for ILD suppress the immune system and are aimed at reducing lung
inflammation. Unfortunately this approach only addresses part of the process that causes
lung injury in ILD and does not prevent the scarring. New treatments are focused on
preventing the scarring process and are the product of basic research that is currently
focused in the following areas:
1. Genetics: It is likely that the presence of certain genes makes individuals more
susceptible to the effects of environmental dusts that cause scarring of the lungs.
It is hoped that identifying these genes and the proteins that they are responsible for
producing, will lead to the development of new therapies.
2. Anti-fibrotic medication: Drugs that stop scarring in the body are currently the subject of
clinical trials involving a large number of diseases, e.g. diabetic kidney and ischaemic heart
disease. It is likely that lessons learnt in these more common conditions will be applied to
ILD and offer hope for more effective therapies.
3. Novel treatments: It is hoped that novel treatment approaches available in clinical trials
that focus on preventing lung scarring rather than reducing inflammation will prove to be
more effective therapies in the future.
Patient support
The Lung Foundation Australia provides information and support to patients with all forms of
lung disease including ILD and advocates on their behalf. We encourage you to call our
Information and Support Centre toll free on 1800 654 301.
As patients, we encourage you to manage your condition by:
• Having regular medical check-ups.
• Joining a pulmonary rehabilitation program.
• Joining a patient support group.
• Exercising to your level of activity - check with your doctor first.
• Making lifestyle changes that will help to reduce physical and mental stress e.g.
quitting smoking.
A number of internet sites exist that provide useful information relating to ILD:
• www.lungusa.org
• www.nhlbi.nih.gov
• www.mayoclinic.com/health/interstitial-lung-disease
• www.lungnet.com.au
• www.bpold.co.uk
• www.pulmonaryfibrosis.org
TD1011V2ILD
Content last updated November 2011
Last Updated (Friday, 18 November 2011)