Interstitial Lung Disease

Interstitial Lung Disease (ILD) consists of a variety of diseases that cause a "progressive scarring of lung tissue" that ultimately leads to difficulty breathing, low oxygen levels in the blood (hypoxemia). Regardless of the cause, lung scarring is irreversible.

Some diseases that fit under this category are:

1. Interstitial pneumonitis (UIP),
2. Bronchiolitis obliterans with organizing pneumonia (BOOP),
3. Lymphocytic interstitial pneumonitis (LIP), and
4. Desquamative interstitial pneumonitis (DIP).
5. Pulmonary Fibrosis
6. Children's Interstitial Lung Disease (chILD)
7. Asbestosis
8. Nonspecific interstitial pneumonitis
9. Respiratory bronchiolitis-associated interstitial lung disease
10. Familial pulmonary fibrosis

The Mayo Clinic ILD is caused when "the walls of the air sacs may become inflamed, and the tissue (interstitium) that lines and supports the sacs becomes increasingly thickened and scarred. Normally, the air sacs are highly elastic, expanding and contracting like small balloons with each breath. But scarring (fibrosis) causes the thin, interstitial tissue to become stiffer and thicker, making the air sacs less flexible. Instead of being soft and elastic, scarred air sacs have the texture of a stiff sponge, which makes it more difficult to breathe and harder for oxygen to enter your bloodstream through the thickened walls."

So what causes ILD. Generally, something occurs in your lungs that causes an abnormal healing response that results in this permanent scarring. Normally your body will do a good job of repairing damaged tissue, but with ILD the healing process goes "awry," according to the Mayo Clinic, "producing excess scar tissue that increasingly interferes with lung function."

Finding the exact cause can be difficult because there are so many things that can cause ILD. Usually diagnosis is made by a good question and answer session. Possible causes include:

1. Occupational Hazard: Workers who inhale certain chemicals over a long period of time, such as silica, dust, asbestos fibers, or hard metal dust.
2. Pollutants: Inhaling some pollutants over a long period of time. This may actually be very difficult to diagnose.
3. Infections: The healing process as a result of bacterial or viral infections, especially in those with weakened or underdeveloped immune responses, which would include newborn infants. Such infections include pneumonia, fungal infections, histoplasmosis, and parasitic infections.
4. Radiation: Exposure from radioactive therapy for breast or lung cancer long term can cause damage to the lungs.
5. Drugs: Chemotherapy drugs, meds used to treat heart arrhythmias, and some antibiotics.
6. Other lung disorders: Lupus, scleroderma, rheumatoid arthritis, dermatomyositis, polymyositis, Sjogren's syndrome and sarcoidosis all can result in ILD. Some researchers think that gastroesophageal reflux disease (GERD) can also cause ILD and asthma because the acid can destroy lung tissue.
7. Oxygen: Inhaling greater than 40% oxygen over for a period greater than three hours.
   
8. Idiopathic: If the source is unknown, the diagnosis is often idiopathic ILD or idiopathic pulmonary fibrosis. Another similar disease is interstitial pneumonitic, which is often called idiopathic ILD or fibrosis, where the ILD develops not throughout the lung but in patches. These patients will have some normal parts of the lung and some scarred parts of the lung.
9. Smoking: Does not directly cause ILD, but can increase progression and make the disease worse.
10. Genetics: Familial pulmonary fibrosis is one type that runs in the family. The gene has not yet been identified.
11. Age: It usually occurs in adults over 50, although there are some exceptions.

Over time inhaled oxygen is able to make it into the lungs, yet become unable to cross the membrane between the alveolar sacs and the arterioles. Thus, this causes shunting that results in a lowered saturation.

Because the lungs become stiff, this results in pulmonary hypertension as a result of the right heart having to work extra hard to pump blood through the lungs. This often results in right heart failure in later stages, and ultimately to left heart failure. Left heart failure, or an enlarged heart, is often a key finding to diagnose late stage lung disease.

The final complication is respiratory failure.

Diagnosis can be made by any of the following:

1. X-ray
2. CT
3. High resolution computerized tomography
4. Pulmonary function testing
5. Bronchoscopy
6. Bronchiolar lavage
7. Video assisted thoroscopic surgery

Generally treatment is supportive. You'll first want to make sure the person is no longer exposed to the causative agent. Second you'll want those who smoke to quit.

Treatment include:

1. Corticosteroids: These help some with ILD, although the side effects of these are generally greater than the benefits. Therefore Corticosteroids should not be used long term.
2. Mucomyst: This can help break up thick secretions and make it easier to cough up junk.
3. Anti-fibrotics: These drugs can help reduce the development of scar tissue. Penicillamine, colchicine and interferon gamma-1b are presently in the testing phase and have shown some efficacy in treating ILD.
4. Oxygen therapy: Most patients with ILD will eventually need supplemental oxygen, and usually this is required 24 hours for the duration.
5. Pulmonary Rehabilitation: This is a program to help the patient stay physically fit in order to live normal active lives. While this does not improve lung function, it is essential.
6. Lung Transplantation: May be an option for severe or end stage cases.
7. Diet: The patient will want to eat a healthy diet, and not to eat too much because this can cause the diaphragm to push up against the lungs. It's also recommended not to drink carbonated beverages for the same reason.
   
8. BiPAP: A mask worn over mouth and nose that assists with inhalation and helps to keep the alveolar sacs open and improve oxygenation. This is generally worn while sleeping and is generally reserved for those with progressive disease.
9. Anti-anxiety meds: As the disease progresses, it may cause anxiety. This can be treated with medicines like Ativan and Xanax.

Life changes are are almost forced upon these patients. They more than likely will have to stop smoking if they smoke, change careers or even quit work altogether. They will also no longer be able to participate in certain events, such as going places where people smoke, adjust to wearing oxygen all the time, and cope with progressive dyspnea (feeling of air hunger) either with exertion or ultimately at rest.

A typical complication is anxiety as being forced to change the way you live can be very daunting. Although working with your doctor, being honest about your feelings, and maintaining a good and positive relationship with God can often be very helpful in dealing with this side effect of any lung disease.

Another key to dealing with anxiety is by participating in a pulmonary rehabilitation group, finding other friends with the same disease, joining online support groups, learning as much as possible about the disease, and being honest about feelings.