Nonspecific Interstitial Pneumonia (NIP)

NIP has been described as a distinct respiratory illness by Katzenstein and colleagues in 1994, and has emerged as the second most common type of chronic interstitial pneumonia second to Usual Interstitial Pneumonia (UIP). The abbreviation "NSIP" is sometimes used.

The microscopic findings of the lung tissue in NIP are characterized by interstitial infiltrate and three patterns of fibrosis (scar). In one-half of patients, there is little or no fibrosis. In one-third of patients there is moderate fibrosis. In about 15%, the fibrosis is dense. There is a favorable response to corticosteroid therapy for individuals with the first and second pattern.

The cause of NIP is usually not known. The lesion has been associated with the connective tissue disorders, inhalation of toxic agents, and sometimes associated with acute lung injury from a recent surgery, and severe pneumonia or ARDS (adult respiratory distress syndrome).

NIP occurs equally in men and women and at all ages, usually 40 to 70 years. Shortness of breath is the most common symptom and may be associated with cough. Crackles are common. The average duration of the illness is 8 months.

The chest x-ray in NIP shows patchy infiltrates in both lungs and sometimes small linear opacities at the lung bases. The CT scan confirms these fluffy infiltrates and does not show honeycombing.

A lung biopsy for tissue is required for the diagnosis. Tissue is obtained from a video-assisted thoracoscopy (VAT) or from a small lung operation. This may be performed on a day-surgical basis if the individual is stable or in the hospital if the individual is severely ill.

Corticosteroid therapy is the best treatment option for NIP. The outcome is fairly good, 50% of patients are cured and a higher percentage of patients are stabilized. Slightly less that 15% of patients die from this disorder.

A favorable response is directly related to the amount of fibrosis and scar seen in the lung biopsy. Individuals with no scar have an excellent chance for cure, while individuals with dense scar have a less favorable course. Lung transplantation offers an alternative treatment for individuals with the dense scarring.

NIP References:

1. Katzenstein AL, Fiorelli RF. Nonspecific interstitial pneumonia/fibrosis (NIP). Histologic features and clinical significance. Am J Surg Pathol. 1994 Feb; 18(2): 136-147.
PMID: 8291652.

2. Katzenstein AL, Myers JL. Nonspecific interstitial pneumonia (NIP) and the other idiopathic interstitial pneumonias: classification and diagnostic criteria. Am J Surg Pathol. 2000 Jan; 24(1): 1-3. PMID: 10632482.

3. Flaherty KR, Travis WD, Colby TV, Toews GB, Kazerooni EA, Gross BH, Jain A, Strawderman RL, Flint A, Lynch JP, Martinez FJ. Flaherty KR, Travis WD, Colby TV, Toews GB, Kazerooni EA, Gross BH, Jain A, Strawderman RL, Flint A, Lynch JP, Martinez FJ. Histopathologic variability in usual (UIP) and nonspecific interstitial pneumonias (NIP). Am J Respir Crit Care Med. 2001 Nov 1; 164(9): 1722-1727. PMID: 11719316.

4. Kim DS, Yoo B, Lee JS, Kim EK, Lim CM, Lee SD, Koh Y, Kim WS, Kim WD, Colby TV, Kitiaichi M. The major histopathologic pattern of pulmonary fibrosis in scleroderma is nonspecific interstitial pneumonia (NIP). Sarcoidosis Vasc Diffuse Lung Dis. 2002 Jun; 19(2): 121-127. PMID: 12108451.

X-ray Findings:

1. Kim EY, Lee KS, Chung MP, Kwon OJ, Kim TS, Hwang JH. Nonspecific interstitial pneumonia with fibrosis (NIP): serial high-resolution CT findings with functional correlation. AJR Am J Roentgenol. 1999 Oct; 173(4): 949-953.

2. MacDonald SL, Rubens MB, Hansell DM, Copley SJ, Desai SR, du Bois RM, Nicholson AG, Colby TV, Wells AU. Nonspecific interstitial pneumonia (NIP) and usual interstitial pneumonia (UIP): comparative appearances at and diagnostic accuracy of thin-section CT. Radiology. 2001 Dec; 221(3): 600-605. PMID: 11719652.

3. Johkoh T, Muller NL, Colby TV, Ichikado K, Taniguchi H, Kondoh Y, Fujimoto K, Kinoshita M, Arakawa H, Yamada H, Suga M, Ando M, Koyama M, Nakamura H. Nonspecific interstitial pneumonia (NIP): correlation between thin-section CT findings and pathologic subgroups in 55 patients. Radiology. 2002 Oct; 225(1): 199-204. PMID: 12355005.

Treatment:

1. Nanki N, Fujita J, Yamaji Y, Maeda H, Kurose T, Kaji M, Satoh K, Miyatani K, Yamadori I, Ohtsuki Y, Ishida T. Nonspecific interstitial pneumonia/fibrosis (NIP) completely recovered by adding cyclophosphamide to corticosteroids. Intern Med. 2002 Oct; 41(10): 867-870. PMID: 12413012.

Outcome:

1. Nagai S, Kitaichi M, Itoh H, Nishimura K, Izumi T, Colby TV. Idiopathic nonspecific interstitial pneumonia/fibrosis (NIP): comparison with idiopathic pulmonary fibrosis and BOOP.
Eur Respir J. 1998 Nov; 12(5): 1010-1019. PMID: 9863989.

2. Cottin V, Donsbeck AV, Revel D, Loire R, Cordier JF. Nonspecific interstitial pneumonia (NIP). Individualization of a clinicopathologic entity in a series of 12 patients. Am J Respir Crit Care Med. 1998 Oct; 158(4): 1286-1293. PMID: 9769293.

3. Daniil ZD, Gilchrist FC, Nicholson AG, Hansell DM, Harris J, Colby TV, du Bois RM. A histologic pattern of nonspecific interstitial pneumonia (NIP) is associated with a better prognosis than usual interstitial pneumonia (UIP) in patients with cryptogenic fibrosing alveolitis. Am J Respir Crit Care Med. 1999 Sep; 160(3): 899-905. PMID: 10471616.

4. Travis WD, Matsui K, Moss J, Ferrans VJ. Idiopathic nonspecific interstitial pneumonia (NIP): prognostic significance of cellular and fibrosing patterns: survival comparison with usual interstitial pneumonia (UIP) and desquamative interstitial pneumonia (DIP). Am J Surg Pathol. 2000 Jan; 24(1): 19-33.
PMID: 10632484.

5. Riha RL, Duhig EE, Clarke BE, Steele RH, Slaughter RE, Zimmerman PV. Survival of patients with biopsy-proven usual interstitial pneumonia (UIP) and nonspecific interstitial pneumonia (NIP). Eur Respir J. 2002 Jun; 19(6): 1114-1118.
PMID: 12108865.

6. Bouros D, Wells AU, Nicholson AG, Colby TV, Polychronopoulos V, Pantelidis P, Haslam PL, Vassilakis DA, Black CM, du Bois RM. Histopathologic subsets of fibrosing alveolitis in patients with systemic sclerosis and their relationship to outcome. Am J Respir Crit Care Med. 2002 Jun 15; 165(12): 1581-1586. PMID: 12070056.