Lymphocytic interstitial pneumonitis and cryoglobulinemia as clues towards the diagnosis of Sjögren’s syndrome

Introduction: cryoglobulinemia is associated with extraglandular features in patients with sjgren's syndrome, while lymphocyte interstitial pneumonitis (Lip) is a type of interstitial lung disease relatively specific for this syndrome.Case presentation: a 61-year-old male was admitted for further workup of suspected pneumonia, presenting with a history of persistent cough and fever as well as a finding of a unilateral infiltrate on his chest X-ray.His chest ct was consistent with Lip.due to decreased serum c3 and c4 levels and the presence of cryoglobulinemia type 3, he underwent further workup that finally confirmed the diagnosis of sjgren's syndrome and Lip as its extraglandular feature. in addition to appropriate antibiotic treatment of his acute respiratory infection, he was initially treated with hydroxychloroquine and prednisone with improvement in symptoms and normalization of his erythrocyte sedimentation rate as well as complement levels.However, due to a slight aggravation of his dyspnea and decline in c3 and c4 levels in the further course, azathioprine was added with a beneficial therapeutic and glucocorticoid-sparing effect.Conclusion: although cryoglobulinemia does not seem to be a direct cause of Lip, it may serve as a clue towards recognizing extraglandular features of undiagnosed sjgren's syndrome.