INTERSTITIAL LUNG DISEASE
Dr. Vinod K. Jangid
What is interstitial lung disease?
Interstitial lung disease is a large group of disorders, in which there is inflammation of interstitium of lung that is progressive in nature and can further leads to scarring. Interstitium is lung tissue between the airsacs (alveoli) and involved in oxygen and carbon dioxide exchange during respiration.
How can I acquire the disease?
Although most of the interstitial lung disease is caused by unknown factors but in some type we can identify the causing factors. Some virus, fungus & other infective agents can cause short term (acute) ILD.
There are following agents which are frequently associated with development of ILDs.
- Silica dust exposure: Silicosis
- Asbestos exposure: Asbestosis
- Grain dust exposure: Hypersensitive Pneumonitis
- Coal dust exposure: Coal worker pneumoconiosis.
- Bird protein exposure: Hyper sensitive pneumonitis
- Certain drugs like anticancer drugs (methotrexate, Bleomycin, Nitrofurantoin.
- Some systemic disorders like systemic sclerosis, rheumatoid arthritis and other collagen vascular illness may affect lung interstitium and can cause ILD.
Who Are at the risk of developing Interstitial lung disease?
- Older Age: Interstitial lung disease is much more common in adults and old age, although children sometimes may suffer from this disorder.
- Smoker: Smoking is directly associated with development of certain ILDs.
- Occupational and environmental toxins exposure: Long term exposure to dust, pollutents and chemicals may increase risk of interstitial lung disease.
- Gastroesophageal reflux disease. There are certain evidence of increased risk of interstitial lung disease in patients of GERD or acidity.
- Radiation and chemotherapy: Those patients who are on the anticancer drugs may devlop ILDs.
What happens to my lungs in interstitial lung disease?
Various known and unknown factors initate a pathogenic process in interstitium of lungs.there is inflammation and scarring of various degree depending upon the duration of illness. Scarring is generally irreversible. It makes the oxygen transport difficult .As the disease progresses the lung tissue is replaced by fibrosis or scarring.
What are the common types of ILDs?
Some types of interstitial lung disease include:
- Interstitial pneumonia . Infection of interstitium of lung with Bacteria, viruses, or fungi.
- Idiopathic pulmonary fibrosis – Cause is unknown but progressive disease, leads to fibrosis of lung. Prognosis is very poor.
- Nonspecific interstitial pneumonitis. This is an interstitial lung disease that commonly present in patients with autoimmune conditions such as rheumatoid arthritis or scleroderma.
- Hypersensitivity pneumonitis – This happens when dust, mold, or other things that you breathe irritate your lungs over a long time.
- Cryptogenic organizing pneumonia (COP)- COP is a pneumonia-like interstitial lung disease without an infection.
- Acute interstitial pneumonitis –This is a sudden, severe interstitial lung disease.
- Desquamative interstitial pneumonitis – This is an interstitial lung disease associated with smoking.
- Sarcoidosis – This causes interstitial lung disease with involvement of multiple organs like skin, heart, skin, nerves eyes etc.
What are the major symptoms ofinterstitial lung disease?
Dry cough: Long term cough which is generally non productive and does not responds to usual remedies.
Shortness of breath at rest or aggravated by exertion, progressive by the time.
How my disease is diagnosed?
Clinical features and patients history is can make the high index of suspicion. It can be confirmed by various following investigations
- Laboratory tests:
- Blood tests- Some blood marker tests are available to detect any autoimmune diseases or inflammatory responses to environmental exposures, such as those caused by molds or bird protein.
- Imaging tests:
- Xray chest: not a very sensitive tool in initial stage of disease process.
- High-resolution CT scan(HRCT) – is very helpful in the diagnosis, pattern of disease and extent of the lung tissue involvement.So it guide us to decide the treatment strategies to curb the progression of disease.
- In advance stages of the disease there is some strain on heart or may devlop pulmonary hypertension, so to find out the heart involvement echocardiography must be done.
- Pulmonary function tests
- Pulse Oximetry and six minute walk test – A small device called pulse oximeter is placed on one finger to measure the oxygen saturation in There is a fall in oxygen saturation level after walking for six or more minutes in the patients of interstitial lung disease.
- Spirometry and diffusion capacity– This test detect how much is the various capacities of the lungs, like inspiration, expiration and various volumes.
- DLCO or diffusion capacity test – we measures the exchange of oxygen across the membranes of lungs, which are the diseased part in case of interstitial lung disease.
- Lung tissue analysis (lung biopsy)
- Sometimes it is necessary to diagnose definitively for making a treatment plan and prognosis. For this we have to obtain the tissue sample of lung( Lung Biopsy).
- Tissue sample can be obtained by:
- A small tissue sample (lung biopsy) is taken through a flexible bronchoscope.it is relatively safe procedure. Another procedure for diagnosis is bronchoalveolar lavage. In this suction is done into effected part of lung, after rinsing the part. This suctioned material contains various cellular information regarding diagnosis.
- Surgical biopsy
- In this procedure surgeon get the tissue sample by doing a small surgery in thorax. This procedure has surgical complications.
What are the treatment options available for ILDs and are they curative?
Although no therapy is proved to be curative in ILDs, there are treatment modalities which slows the disease progress.Once the fibrosis or scarring occurs in a part of lung it can be reversed.
Although research is continuously going on to find out specific treatment. Current strategy is to improve the quality of life through medications, pulmonary rehabilitation.
- Immunosuppresive medications.There are many options to suppress immunological cascade of the body like corticosteroids, anticancer drugs etc.Corticosteroids are the preferred agent for treatment of ILDs, either alone or in combination with other drugs.
- Antifibrotic agents: pirfenidone and nintedanibare proved to slow the rate of disease progression. But side effects and cost of the treatment is constraints to the use of these drugs.
In the advance stage of the disease there is continuous deficiency of oxygen in the blood of the patient. This continuous deficiency may lead to serious adverse effect on heart and other vital organs.to overcome this and to make breathing easier continuous long term oxygen therapy is given to the patient. It can be delivered at home either by a cylinder or oxygen concentrator.
pulmonary rehabilitation is programmed to improve quality of life so patient can live full, satisfying life and can perform his or her daily activities. It includes physical exercise, breathing techniques that improve lung efficiency, psychological support and Nutritional counseling.
Lung transplantation may be last resort as a treatment specially in idiopathic pulmonary fibrosis patients.It is a costly procedure and donor lungs are not readily available.
Diseased lungs are very prone to the usual viral and bacterial infections and may be life threatening sometimes. So vaccination for the usual virus and bacterial infections are very helpful.
What should I take the Precautions and lifestyle modifications?
- Be active and do light exercise
- Eat nutritious food
- Quit smoking
- Keep positive attitude
- Take regular medications as advised by treating physician
Dr. Vinod K. Jangid
Associate Professor & consultant Pulmonologist
Govt. Medical College, Kota ( Rajasthan)