Hazardous Substances Raise Risk of Interstitial Lung Diseases

A large group of diseases that cause progressive scarring of lung tissue – known as interstitial lung disease – can rob a person’s ability to get enough oxygen.

Interstitial lung disease can be severe, leading to disability and death. But there is hope. Early diagnosis and treatment can slow disease progression and minimize damage to the lungs, says Maroun Matta, MD, a University Hospitals pulmonary and critical care specialist.

Symptoms Are Often Misdiagnosed

The most common symptoms of interstitial lung disease – dry cough and shortness of breath – are often mistaken for more common lung diseases, Dr. Matta says. Patients with symptoms are questioned extensively about medications associated with the disease and possible exposures at home, work and other places where they spend time.

“There often is a lot of misdiagnosis and delays in diagnosing patients,” Dr Matta says. “It’s a complicated process of going through evaluation. Many people who end up with a diagnosis have had symptoms for two or three years.”

“They may have seen their doctors because of shortness of breath, but were told they have COPD (chronic obstructive pulmonary disease), or they have heart failure or asthma.”

Other symptoms of interstitial lung disease include:

• Fatigue
• Chest discomfort
• Loss of appetite
• Weight loss

Patients often have exposures with construction work or farm work, where they breath in hazardous substances, mold and dust, Dr. Matta says. Being around moldy hay and grain long-term is a risk for the disease.

Patients with suspected cases also are asked about exposure to bird feathers – even feather pillows – and whether they have hot tubs or leaky air conditioners, which can trigger production of mold spores.

“People who have birds at home is one of the most common causes. Bird feathers can have antigens that can cause inflammation,” Dr. Matta says. “If we find the causes and remove those causes, patients do much better,” he says. “They stop progressing and they will live longer.”

Diagnosis requires a number of other tests, including pulmonary function, blood work, biopsies and imaging tests. “The most important test is a high-resolution CT scan of the lungs,” Dr. Matta says. "This gives us a much clearer picture of what’s going on.”

What Causes Interstitial Lung Disease?

Most often, the exact cause is unknown. But there are a number of contributing factors:

• Long-term environmental and occupational exposures. These include asbestos fibers, grain dust, silica, mold and bird feathers.
• Autoimmune diseases such as rheumatoid arthritis, lupus, dermatomyositis and scleroderma.
• Some medications, including chemotherapy drugs, and radiation exposure.

The most serious type of interstitial lung disease is called idiopathic pulmonary fibrosis. “Idiopathic pulmonary fibrosis occurs in about 1 in 5,000 people, and up to 1 in 200 in people over 65 years of age,” Dr. Matta says. “The mortality rate associated with it is fairly high. Once somebody is diagnosed with idiopathic pulmonary fibrosis, the expected survival is about two to five years.”

But early detection, elimination of environmental triggers and treatment with medications to slow progression of the disease can improve the prognosis considerably.

Treating Interstitial Lung Disease

There is no treatment to cure or reverse interstitial lung diseases. Medications to slow progression of the disease can be prescribed. Medications to suppress the immune system and reduce lung inflammation may be prescribed for patients with an autoimmune disease.

“It’s important to be cared for in a specialty clinic, because it’s not a common disease like COPD or asthma. It takes a specialized approach, which not only involves medication, but education, pulmonary rehab, screening for co-morbidities and making sure the patient’s other medication are in line,” Dr. Matta says.

“Now that we have more awareness, hopefully people can get diagnoses earlier and we can start treatment on the right people.”

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