INTRODUCTION :

Interstitial lung diseases (ILDs) are a heterogeneous group of disorders characterized by inflammation and fibrosis of the lungs. Most of the patients with idiopathic interstitial pneumonia have clinical features that suggest an etiology of underlying autoimmune process but do not meet established criteria for a connective tissue disease . These patients occupy a gray zone between the Idiopathic interstitial pneumonia and  connective tissue disease related ILD. European Respiratory Society/American Thoracic Society proposed  the term “Interstitial pneumonia with autoimmune features” (IPAF) to describe these subset of patients who have underlying autoimmune basis for etiology but do not meet the diagnostic criteria of connective tissue diseases. . The present study describes the varied imaging manifestations of Interstitial pneumonia with autoimmune features with  their clinical and serological correlation.

MATERIALS AND METHODS :

The present study  was a prospective observational study conducted in  the Department of Radiology & Imageology at the Nizam’s Institute of Medical Sciences, Hyderabad between May 2017 and October  2017. Patients referred  to our department with clinical suspicion of ILD were evaluated using HRCT chest and the various patterns of ILD were analyzed in these patients. HRCT results were correlated with clinical and serological studies.

RESULTS :

Our  study group included a total of 14 patients with age range from 20–78 years (mean,49.5 years).The overall incidence of IPAF was noted to be higher in females with female : male ratio of  6:1.Most common clinical domain in our study was inflammatory polyarthritis. ANA positivity (1:320) was the most common serological finding observed in our study group. The most common radiological pattern of interstitial lung disease encountered in our study was NSIP (57.2%), followed by typical UIP (28.6%), Organizing pneumonia (7.1%) and  Combined pulmonary  fibrosis and emphysema (7.1%). Our associated findings included were  pulmonary  arterial hypertension  in 35.8% cases, significant mediastinal  lymphadenopathy in 14% of cases and  dilated esophagus in 50%  cases.

CONCLUSION :  

This study demonstrates that the recently defined criteria for IPAF are fulfilled by a significant proportion of patients referred for imaging evaluation of  ILD. Radiologist may be the first person to identify this subset of patients as all of them present with ILD at the time of diagnosis and based on the HRCT patterns an autoimmune basis for underlying etiology can be suggested. HRCT plays an important role in establishing the diagnosis in these patients as it is one of the major domain in the classification criteria of IPAF as proposed by European Respiratory Society/American Thoracic Society.