What is Nonspecific Interstitial Pneumonia (NSIP)?

Nonspecific Interstitial PneumoniaNonspecific interstitial pneumonia (NSIP) is a rare condition that affects the tissue surrounding and separating the alveoli, the tiny air sacs in the lungs where the exchange of oxygen and carbon dioxide takes place between the lungs and the bloodstream. Interstitial pneumonia is a disease that causes inflammation in both the mesh-like walls of the alveoli and sometimes the pleura, a protective covering that cushions the lungs. Many patients affected with NSIP also have idiopathic NSIP,  meaning there is no known cause. The disease mainly affects Caucasians between the ages of 40 and 50 years of age and does not appear to be linked to cigarette smoking.[1]

NSIP can occur in a number of different diseases including connective tissue disorders that affect the structural tissues in the body and human immunodeficiency virus (HIV). It can also occur as a reaction to certain types of medications.1  

Types of Nonspecific Interstitial Pneumonia

There are two primary forms of NSIP:1

  • Cellular – defined predominantly by inflammation in the cells of the interstitium, the tissue between the alveoli and the bloodstream.
  • Fibrotic – defined by thickening and scarring of the lung tissue.

The characteristic scarring of lung tissue is known as fibrosis, a process that is irreversible for which there is no cure. When lung tissue thickens or becomes fibrotic, breathing is affected and there is less oxygen in the bloodstream.1

Both types of NSIP can be present at the same time, but patients with the cellular type usually have a better prognosis.1

Symptoms of Nonspecific Interstitial Pneumonia

Symptoms of NSIP include:

  • Dry cough.
  • Shortness of breath/labored breathing that worsens with activity and overtime.
  • Fatigue (tiredness).
  • Clubbing of the fingertips caused by lack of oxygen in the bloodstream.

Diagnosis of Nonspecific Interstitial Pneumonia

NSIP is not readily diagnosed because its symptoms resemble those of other diseases, especially idiopathic pulmonary fibrosis (IPF). To make an accurate diagnosis, your doctor will run a series of tests to rule out similar disorders, some of which are listed below:

  • Pulmonary function tests – to assess lung function and the rate of oxygen and carbon dioxide exchange in the lungs.1
  • Chest X-ray – may show opacities (shadiness) in some areas of the lung in the presence of disease.[2]
  • High-resolution computed tomography (HRCT) – in patients with NSIP, a CT scan will show what’s called a “ground glass” pattern that’s typical of the interstitial inflammation seen in NSIP. In the fibrotic form of the disease, a CT scan will show fibrosis, or scarring.1
  • Bronchoscopy – occasionally done to get a closer look at the inflammation or scarring of the lung tissue.1
  • Surgical lung biopsy – helps to determine the degree of fibrosis present in the lungs.2

Treatment of Nonspecific Interstitial Pneumonia

Many patients with the cellular form of NSIP respond well to oral corticosteroids (usually prednisone), medications that help reduce swelling and inflammation characteristic of the disease. Patients who don’t do well on corticosteroids may need to be treated with immunosuppressants, medications that suppress, or reduce, the strength of the immune system such as azathioprine, mycophenolate mofetil and cyclophosphamide.1 


The prognosis (how long a person will live after diagnosis) for people with the cellular form of the disease is remarkable, with a low mortality rate (how many people die from the disease in a given period of time). Prognosis is less auspicious for people with the fibrotic form of the disease, with an average survival rate of 6 to 13.5 years after diagnosis.1

For more information about nonspecific interstitial pneumonia, talk to your pulmonologist or primary care provider. 

[1] Cleveland Clinic. Nonspecific Interstitial Pneumonia. Last reviewed January 16, 2015.

[2] Lee, Joyce, MD, MAS. Nonspecific Interstitial Pneumonia. Merck Manual. Professional Version. Last review/revision April, 2016.


Inogen Call For Support View Cart
Request a FREE Info Kit