IDIOPATHIC INTERSTITIAL PNEUMONITIS: A MANIFESTATION OF SYSTEMIC SCLEROSIS SINE SCLERODERMA

Abstract

TOPIC: Pulmonary Manifestations of Systemic Disease TYPE: Fellow Case Reports INTRODUCTION: Systemic Sclerosis (SSc) is a multisystem disease characterized by vascular dysfunction and progressive fibrosis. Systemic sclerosis sine scleroderma (ssSSc) is a rare subtype of SSc which lacks the hallmark feature of the disease i.e., scleroderma. We present a case of systemic sclerosis sine scleroderma manifesting as interstitial pneumonitis. CASE PRESENTATION: A 76-year-old Caucasian female presented to the clinic for evaluation of dyspnea and decreased exercise tolerance since recent TAVR performed 1 month ago. She had a history of Raynaud phenomenon, renal artery stenosis, CKD 4, and HTN. She was hypoxic at rest with SpO2 87% on room air, the rest of the vitals were normal. Chest x-ray showed coarse reticular opacities. Pulmonary function tests (PFTs) showed mild restriction (FEV1/FVC 85%, TLC 74% of predicted) and severely decreased diffusing capacity for carbon monoxide (DLCO) 31% of predicted (N: 80-120%). High-resolution CT chest demonstrated bilateral middle and lower lung zone reticular opacities, and traction bronchiectasis. Pre TAVR right heart catheterization was consistent with pulmonary arterial hypertension (PAH). Her PAH was not considered as the cause of all her symptoms.Further workup showed positive serum ANA 1:1280 (N: <1:80), and weakly positive RNA polymerase III antibody at 30.2U (N: < 20U). Anti CCP, anti- dsDNA, anticentromere antibodies, rheumatoid factor, serum aldolase, CRP, complement levels, ESR, and ANCA panel were normal. Although she did not have any skin findings suggestive of scleroderma, based on serological and imaging abnormalities she was diagnosed with ssSSc presenting as interstitial pneumonitis. She was treated initially with prednisone followed by mycophenolate for 5 months. Despite stabilization of PFTs, her respiratory status continues to decline from worsening PAH. She remains on supplemental oxygen, sildenafil, and treprostinil. DISCUSSION: ssSSc is a subset of SSc affecting 5-10% of patients, with clinical and laboratory features resembling limited SSc (lcSSc) subset. Lungs are the second most common organ involved. ILD followed by PH are the most common presentations. Patients with ssSSc are reported to have a greater degree of dyspnea, and reduced DLCO (<70% of predicted normal). Other predominant features include a positive ANA, restrictive lung disease, and Raynaud's phenomenon, which were present in our patient. CONCLUSIONS: Systemic sclerosis should be considered in patients with idiopathic ILD even in the absence of skin involvement. REFERENCE #1: Poormoghim H, Lucas M, Fertig N, Medsger TA Jr. Systemic sclerosis sine scleroderma: demographic, clinical, and serologic features, and survival in forty-eight patients. Arthritis Rheum. 2000 Feb;43(2):444-51. doi: 10.1002/1529-0131(200002)43:2<444: AID-ANR27>3.0.CO;2-G. PMID: 10693887. REFERENCE #2: Diab S, Dostrovsky N, Hudson M, Tatibouet S, Fritzler MJ, Baron M, Khalidi N; Canadian Scleroderma Research Group. Systemic sclerosis sine scleroderma: a multicenter study of 1417 subjects. J Rheumatol. 2014 Nov;41(11):2179-85. doi: 10.3899/jrheum.140236. Epub 2014 Oct 1. PMID: 25274885. REFERENCE #3: Kucharz EJ, Kopeć-Mędrek M. Systemic sclerosis sine scleroderma. Adv Clin Exp Med. 2017 Aug;26(5):875-880. doi: 10.17219/acem/64334. PMID: 29068586. DISCLOSURES: No relevant relationships by Mirza Ali, source=Web Response No relevant relationships by Shujaa Faryad, source=Web Response No relevant relationships by Hasan Shoaib, source=Web Response