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Interstitial Lung Disease

Interstitial lung disease refers to many disorders (over 100) that cause scarring and destruction of healthy lung tissue over time, leading to irreversible damage and progressive breathing problems.

The healthy interstitium (delicate lace-like tissue found throughout the lungs) supports tiny air sacs within the lungs so gas can move between the blood stream and the air in the lungs. But, interstitial lung disease causes the interstitium tissue to thicken, due to inflammation, scarring, or excess fluids. When the tissue thickens, patients develop breathing problems – usually slowly, over a period of months.


Long-term exposure to toxic materials or pollutants is a common cause of interstitial lung disease. These materials include the following:

  • Crystalline silica dust;
  • Asbestos;
  • Grain dust;
  • Coal or metal dust;
  • Bird and animal droppings.

Medications can sometimes damage lung tissue, including certain types of:

  • Chemotherapy drugs;
  • Heart medication;
  • Antibiotics.
In some cases, interstitial lung disease is caused by autoimmune diseases (e.g. rheumatoid arthritis) or when infections (e.g. pneumonia or tuberculosis) do not heal properly.

In many cases the exact cause of interstitial lung disease is not known.


The most common symptoms of interstitial lung disease are shortness of breath and dry cough. Other symptoms can occur, including weakness, unexplained weight loss, and bleeding in the lungs.

When the symptoms of interstitial lung disease become apparent, the lung tissue is already damaged. The scarring cannot be reversed. Make an appointment with a pulmonologist at the first signs of breathing difficulty. Certain treatments can help slow further scarring and make the patient’s breathing easier.


The pulmonologist will use several tests to determine the exact diagnosis. These tests include:

Imaging tests

  • Chest x-ray: while healthy interstitium tissue cannot be seen on x-rays, the damaged lung tissue will show;
  • CT scan;
  • Echocardiogram: a sonogram of the heart can determine if damage to the lungs is causing pressure to build up in the right side of the heart.

Pulmonary function tests

  • Spirometry: a machine measures how quickly the lungs can exhale air;
  • Oximetry: a device on your finger measures the saturation of oxygen in the blood;
  • Exercise stress test: running on a treadmill or using a stationary bike can show how the lungs function under stress.

Lung tissue analysis

  • Bronchoscopy: tiny tissue samples are taken from the lungs using a thin, flexible tube (bronchoscope) inserted into the lungs via the mouth;
  • Bronchoalveloar lavage: saline is inserted into the lungs via a bronchoscope and then suctioned out, the water now containing cells from the lung tissue as well;
  • Surgical biopsy: tissue samples are taken from the lungs after a surgeon makes a small incision between the ribs.


Because many different disorders are interstitial lung diseases, treatments will vary depending on individual patients’ needs. Medications can help slow the tissue damage but they cannot reverse existing damage.

Breathing pure oxygen during oxygen therapy can help make breathing easier, prevent low blood oxygen levels, and reduce blood pressure that has increased in the right side of the heart. Certain patients may only need oxygen during exercise, while some may need oxygen most of the day and night.

Lung transplantation
is sometimes an option for selected patients with severe cases of extensive tissue damage.

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