20th February 2025

Non-specific interstitial pneumonia (NSIP)

Non-specific interstitial pneumonia refers to a histological pattern which is poorly understood and can be observed in a wide variety of clinical settings. It typically affects younger patients and has a better prognosis than IPF. It can be idiopathic or associated with connective tissue disease, infection, drugs or immunodeficiency.

HRCT shows basal ground-glass opacification, often without honeycombing. Relative subpleural sparing may be a helpful sign to differentiate NSIP from other IIPs. Histology is often necessary for diagnosis. Findings are variable and range from an inflammatory, cellular pattern with no fibrosis to a more fibrotic pattern.

NSIP responds better to steroids than IPF and these are the mainstay of treatment, followed by other immunosuppressants if steroids fail.