What is nonspecific interstitial pneumonia?
Nonspecific interstitial pneumonia (NSIP) is a rare
disorder that affects the tissue that surrounds and separates the tiny air sacs
of the lungs. These air sacs, called the alveoli, are where the exchange of
oxygen and carbon dioxide takes place between the lungs and the bloodstream.
Interstitial pneumonia is a disease in which the mesh-like walls of the alveoli
become inflamed. The pleura (a thin covering that protects and cushions the
lungs and the individual lobes of the lungs) might become inflamed as well.
NSIP can be found in a number of different diseases,
including connective tissue disorders (diseases that affect the structural
tissues in the body), reaction to certain medications, hypersensitivity
pneumonitis, and HIV. A large number of patients also have idiopathic NSIP,
which means that the specific cause of the lung disease is unknown.
There are two primary forms of NSIP, cellular and
fibrotic. The cellular form is defined mainly by inflammation of the cells of
the interstitium. The fibrotic form is defined by thickening and scarring of
lung tissue. This scarring is known as fibrosis and is irreversible. When the
lung tissue thickens or becomes scarred, it does not function as effectively.
Breathing becomes less efficient, and there are lower levels of oxygen in the
Both inflammation and fibrosis may be present at the
same time. Generally, the prognosis is better for patients with the cellular
form of NSIP.
What are the symptoms of nonspecific interstitial
A person may experience the following symptoms:
- a dry cough
- shortness of breath, which may occur after exertion or become worse over
- difficult or labored breathing
- clubbing, or enlargement of the fingertips at the base of the nails.
Clubbing may be present due to a deficiency of oxygen in the blood.
Generally, this occurs in only about 10% of people with NSIP.
How common is NSIP?
NSIP has only been defined for a relatively short
time, and less is known about how common it is versus other kinds of
interstitial pneumonia. Caucasian individuals appear to account for most of the
cases, with an average age of onset between 40 and 50 years. There does not seem
to be a correlation between cigarette smoking and the occurrence of NSIP.
What causes NSIP?
No one is really sure what causes NSIP. Many
researchers believe that it is an autoimmune disease, because of the
similarities between NSIP and certain connective tissue diseases, such as
systemic sclerosis. Some researchers suggest that genes are involved, with
heredity playing a role in its development. Inhaling chemicals or dust, use of
certain chemotherapy drugs, or radiation treatment could result in the lung
damage associated with NSIP.
How is NSIP diagnosed?
Because the symptoms of NSIP resemble those of other
diseases, especially idiopathic pulmonary fibrosis, tests must be performed to
rule out other related disorders. The diagnosis of the disease depends on a
combination of clinical, radiologic and other factors.
Pulmonary function tests may be ordered to assess how
well the lungs are working and the rate of carbon dioxide and oxygen exchange.
Generally, a high-resolution computed tomography (CT)
scan is performed to help diagnose NSIP. CT scans of patients with NSIP show a
typical "ground glass" pattern. Interstitial inflammation may also be seen.
Bronchoalveolar lavage is a test in which epithelial
lining fluid (ELF) is collected from the airways and alveoli of the respiratory
tract. A flexible tube called a bronchoscope is inserted into the bronchi (air
passages) of the lung, and a saline fluid is passed through the bronchoscope.
After coming into contact with the airways and alveoli, the fluid is aspirated
(sucked out) and collected for further analysis. Elevated levels of lymphocytes
(white blood cells) in the fluid have been detected in over half of patients
with NSIP, but this is not always specific to this disease. Biopsies may also be
taken during the bronchoscopy to get a closer look at the lung tissue for
inflammation or scarring.
How is NSIP treated?
Most patients with the cellular type of NSIP respond
well to treatment with oral corticosteroids, such as prednisone. However,
patients who do not respond to corticosteroid therapy may require additional
treatment with immunosuppressive drugs. Patients with the fibrotic type of NSIP
might benefit from the use of both types of drugs to prevent irreversible
The prognosis for patient with cellular NSIP is
excellent, with a low mortality rate. In the case of fibrotic NSIP, the
prognosis is less favorable, with a median survival period of 6 to 13.5 years
"Classification and Natural History of the Idiopathic
Interstitial Pneumonias" Dong Soon Kim, Harold R. Collard and Talmadge E. King
www.ncbi.nlm.nih.gov Accessed 7/21/2011
"Nonspecific Interstitial Pneumonia: Evolving Concepts"
www.radiology.rsna.org Accessed 7/21/2011
Idiopathic Nonspecific Interstitial Pneumonia: Lung
Manifestation of Undifferentiated Connective Tissue Disease?
"Idiopathic interstitial pneumonias: progress in
classification, diagnosis, pathogenesis and management"
© Copyright 1995-2011 The Cleveland Clinic Foundation. All rights reserved.
Can't find the health information you’re looking for?
This information is provided by the Cleveland Clinic and is not intended to replace the medical advice of your doctor or health care provider. Please consult your health care provider for advice about a specific medical condition. This document was last reviewed on: 8/5/2011…#14804