MIXED CONNECTIVE TISSUE DISEASE EVOLVING FROM THE SEQUENTIAL OVERLAP OF SYSTEMIC LUPUS ERYTHEMATOSUS, SJÖGREN’S SYNDROME, RHEUMATOID ARTHRITIS AND DERMATOMYOSITIS: A FOLLOW-UP

PV297 / #642 Case Report Poster Topic: AS22 - SLE Heterogeneity Introduction Mixed Connective Tissue Disease (MCTD) is a rare autoimmune disease, generally described as having overlapping features of at least 2 connective tissue diseases. Anti-U1-RNP, in high titers, is distinctly associated with such. Observational studies have reported sequential evolution of the connective tissue diseases. We aim to present a case of MCTD, with the sequential evolution of Systemic Lupus Erythematosus, Sjögren’s Syndrome, Rheumatoid Arthritis, followed by Amyopathic Dermatomyositis. Case Presentation With Investigation She presented to the emergency room with fatigue, high-grade fever, cough, and myalgia. Physical examination revealed violaceous rash on both eyelids (heliotrope rash), erythematous rashes on her upper chest (V Sign) and back (Shawl Sign). Serial manual muscle tests were 5/5 on all extremities. Creatine kinase were normal. A diagnosis of Amyopathic Dermatomyositis was made. She concomitantly developed cough, with computed tomography scan showing features of honeycombing, consistent with usual interstitial pneumonia. Treatment armamentarium comprised of corticosteroids, conventional synthetic DMARDs, & nintedanib. We present a case of a 32-year-old Filipino female whose initial manifestations occurred 7 years prior. Fever, alopecia, arthritis, and hypocomplementemia with high-titer ANA (1:160, Speckled) and Anti-Smith seropositivity (592.5 U/mL), fulfilled the 2019 EULAR/ACR Criteria for SLE. Six years prior, she presented with dry eyes, dry mouth, with otorhinolaryngologic symptoms of lip mucocele and recurrent tonsillitis. Serologies revealed high-titer Anti-SSA 173.4 U/mL and Anti-SSB 24.6 U/mL; symptoms were consistent with Secondary Sjögren’s. Few months later, she reported morning stiffness with chronic hand joint pains. Physical examination by a rheumatologist revealed symmetric arthritis involving the hand joints; with concomitant seropositivity of Rheumatoid Factor. A diagnosis of Seropositive Rheumatoid Arthritis was made, in concordance with the 2010 ACR/EULAR Criteria. Literature Review Mixed connective tissue disease (MCTD) is a rare systemic autoimmune disease which presents with at least 2 overlapping connect tissue diseases. Among the disease included - systemic lupus erythematosus (SLE), Sjögren’s syndrome, systemic sclerosis, dermatomyositis, polymyositis and rheumatoid arthritis. Interstitial lung disease may also be involve as a result of a complication of the MCTD and is responsible for significant morbidity. Amyopathic dermatomyositis (ADM) is a clinical subtype of dermatomyositis, presents with dermatologic lesions of the dermatomyositis but lacks the myopathic. In addition to the symptoms of Raynaud syndrome, arthritis, myositis and pulmonary hypertension among others with a high anti-U1 RNP antibody titers. A hallmark of the disease is the presence of Anti-U1 ribonucleoprotein (RNP). This may have a prognostic value, titer levels may be associated with prognosis of MCTD. Since MCTD has no unique clinical features, diagnosis may be challenging. Overall goals of therapy are to control symptoms, reduce risk for future diseases. Discussion The sequential overlap of connective tissue diseases is rarely reported. Her constellation of symptoms is consistent with MCTD, SLE being the initial autoimmune disease. Despite conferring a better prognosis, manifestations such as ILD may be more common in overlap syndromes; hence, must be vigilantly monitored.