COMBING IMAGING TO DIFFERENTIATE CONNECTIVE TISSUE DISEASE-ASSOCIATED INTERSTITIAL LUNG DISEASE FROM IDIOPATHIC PULMONARY FIBROSIS

Abstract

SESSION TITLE: Medical Student/Resident Pulmonary Manifestations of Systemic Disease Posters SESSION TYPE: Med Student/Res Case Rep Postr PRESENTED ON: October 18-21, 2020 Introduction: Parenchymal lung involvement in Sjogren's syndrome has generally been associated with a nonspecific interstitial pneumonia pattern (NSIP)1,2. We present a patient with chest CT findings compatible with usual interstitial pneumonia (UIP) pattern including exuberant honeycombing, straight edge sign, and the upper lobe sign. After thorough evaluation, the patient was diagnosed with Sjogren's syndrome with exuberant honeycombing, a rare finding in this specific connective tissue disease. Case Presentation: A 36-year-old non-Spanish speaking Guatemalan female presented with progressive chest pain, subacute on chronic dyspnea, and a dry cough. On admission, she had hypoxemic respiratory failure which responded to supplemental oxygen. CT angiogram was negative for pulmonary emboli but showed extensive bibasilar “exuberant” honeycombing. She immigrated to the US 2 years before and had no significant past medical conditions or medication use - prescription or herbal. Exposure history was notable for exposure to indoor smoke from firewood burning stove 10 years ago and she is currently employed on a food production line. Otherwise, infectious and social histories were negative. On examination, she had poor dentition with several capped teeth, cracked lips, and dry Velcro crackles on lung auscultation. Autoimmune serology was significant for positive SSA/SSB and ANA. Her QuantiFERON gold test was likewise positive. Echocardiogram and right heart catheterization showed severe pulmonary hypertension with normal PCWP with a positive vasodilator response. In the context of the UIP pattern on CT chest, examination, and autoimmune serology, she was diagnosed with Sjogren's related interstitial lung disease (ILD). She gradually improved in the hospital with conservative management including supplemental oxygen. A twelve-week course of isoniazid and rifapentine was initiated for LTBI. Sjogren's related ILD therapy is planned after completion of LTBI treatment. She is undergoing evaluation in the Pulmonary Hypertension Clinic and the Transplant Clinic. Discussion: Although mild basilar and reticular honeycombing is a well-described pattern in Sjogren's related ILD, extensive honeycombing is extremely rare1,2. Connective Tissue Disease-related-UIP (CTD-UIP) is differentiated from Idiopathic Pulmonary Fibrosis-associated-UIP (IPF-UIP) in this patient by the presence of the anterior upper lobe sign, straight-edge sign, and exuberant honeycombing sign. (See figure 1) Individually, these signs have low sensitivity (<25%) albeit high specificity (87-94%) for CTD-IPF3. When present together, the sensitivity increases to 95.5% with a likelihood ratio LR(+) of 5.28 for CTD-UIP3. Conclusions: We report an unusual case with extensive “exuberant” honeycombing due to Sjogren's disease. When present, these radiographic signs are valuable aids in differentiating CTD-related-UIP from IPF UIP. Reference #1: Kim, E. J., Collard, H. R. & King, T. E. Rheumatoid arthritis-associated interstitial lung disease: the relevance of histopathologic and radiographic pattern. Chest 136, 1397 -1405 (2009). Reference #2: Mueller-Mang, C., Grosse, C., Schmid, K., Stiebellehner, L. & Bankier, A. A. What Every Radiologist Should Know about Idiopathic Interstitial Pneumonias. RadioGraphics 27, 595 -615 (2007) Reference #3: Chung, J. H. et al. CT Features of the Usual Interstitial Pneumonia Pattern: Differentiating Connective Tissue Disease -Associated Interstitial Lung Disease From Idiopathic Pulmonary Fibrosis. Am. J. Roentgenol. 210, 307 -313 (2017) Disclosures: No relevant relationships by Timothy Dempsey, source=Web Response No relevant relationships by Samuel Falde, source=Web Response No relevant relationships by Kaiser Lim, source=Web Response