Pneumonitis (noo-moe-NIE-tis) is a general term that refers to inflammation of lung tissue. Technically, pneumonia is a type of pneumonitis because the infection causes inflammation. Pneumonitis, however, is usually used by doctors to refer to noninfectious causes of lung inflammation.
Common causes of pneumonitis include airborne irritants at your job or from your hobbies. In addition, some types of cancer treatments and dozens of drugs can cause pneumonitis.
Difficulty breathing — often accompanied by a dry (nonproductive) cough — is the most common symptom of pneumonitis. Specialized tests are necessary to make a diagnosis. Treatment focuses on avoiding irritants and reducing inflammation.
The most common symptom of pneumonitis is shortness of breath, which may be accompanied by a dry cough. If pneumonitis is undetected or left untreated, you may gradually develop chronic pneumonitis, which can result in scarring (fibrosis) in the lungs.
Signs and symptoms of chronic pneumonitis include:
Call your doctor anytime you have difficulty breathing, no matter what might be the cause.
Pneumonitis occurs when an irritating substance causes the tiny air sacs (alveoli) in your lungs to become inflamed. This inflammation makes it difficult for oxygen to pass through the alveoli into the bloodstream.
Many irritants, ranging from airborne molds to chemotherapy drugs, have been linked to pneumonitis. But for most people, the specific substance causing the inflammation is never identified.
Pneumonitis causes may include:
Some occupations and hobbies carry higher risks of pneumonitis, including:
Some chemotherapy drugs can cause pneumonitis, as can radiation therapy to the lungs. The combination of the two increases the risk of irreversible lung disease.
Pneumonitis that goes unnoticed or untreated can cause irreversible lung damage.
In normal lungs, the air sacs stretch and relax with each breath. Chronic inflammation of the thin tissue lining each air sac causes scarring and makes the sacs less flexible. They become stiff like a dried sponge. This is called pulmonary fibrosis. In severe cases, pulmonary fibrosis can cause right heart failure, respiratory failure and death.
During the physical exam, your doctor will use a stethoscope to listen carefully to your lungs while you breathe. To distinguish pneumonitis from other lung disorders, you'll likely have one or more of the following tests.
Certain blood tests can be useful for pinpointing a diagnosis.
Imaging tests are useful because in most cases, pneumonia affects only a small, localized portion of your lungs, while the effects of noninfectious pneumonitis are often spread throughout all five lobes of your lungs.
A test called spirometry measures the amount of air that you're able to inhale and exhale in a specific period of time. Your doctor may also measure how efficiently your lungs transfer gases from the air into the bloodstream during exercise.
Another way to assess how well your lungs are working is to measure the oxygen in your blood with an oximeter — a device that painlessly clamps on your finger.
A bronchoscopy is a procedure that uses a flexible tube threaded down your throat to view your airways and collect samples from your lungs.
During bronchoscopy, your doctor may flush a section of your lung with a saltwater solution to collect lung cells and other materials. This flushing procedure is known as a lavage. Your doctor may also insert a tiny tool through the scope to remove a small sample of cells from the lung tissue for testing.
In some cases, your doctor may want to examine larger samples of tissue from several locations in your lungs that cannot be reached via bronchoscopy. A surgical procedure to obtain these samples may be necessary.
If you have hypersensitivity or chemical pneumonitis, your doctor will recommend eliminating exposure to the allergen or chemical irritating your lungs. This step should help lessen your symptoms.
In severe cases of pneumonitis, treatment may also include:
A diagnosis of pneumonitis may mean that you'll have to make changes to your lifestyle to protect your health. You'll need to avoid known triggers as much as possible.
For example, if your job duties expose you to substances that irritate your lungs, talk to your doctor and supervisor at work about ways to protect yourself, such as wearing a pollen mask or personal dust respirator. If a hobby is causing the problem, you may have to find a different hobby.
While you may initially consult your family doctor, he or she may refer you to a pulmonologist — a doctor who specializes in lung disorders.
You may want to write a list that includes:
A thorough medical history and physical exam can provide important clues about what might be causing your symptoms. Your doctor may ask some of the following questions:
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