SUN-551 Massive Pericardial Effusion Complicating Systemic Lupus Erythematosus and Autoimmune Hypothyroidism: A Case Report

Background: The presence of autoantibodies is a mutual ground for Systemic Lupus Erythematosus (SLE) and Autoimmune Hypothyroidism (AH). Pericardial effusion (PEEF) is a common manifestation for each disease condition however massive PEEF especially with tamponade is a rare occurrence. The coexistence of SLE and AH causing massive PEEF is even rarer and only few cases have been reported. This presents as a diagnostic dilemma whether the massive PEEF is primarily driven by SLE, AH or is it a synergistic effect of both. Clinical Case: A case of a 54-year-old female, hypertensive, non-diabetic diagnosed previously with primary hypothyroidism came in with progressive dyspnea. She has been non-compliant to levothyroxine therapy for 1 year. Upon presentation at the Emergency Department, she was noted to be overtly hypothyroid. Thyroid panel was consistent with primary AH: elevated TSH = 95.66 uIU/mL (NV=0.35-4.94), low FT3 = <1 pg/mL (NV=1.71-3.71), low FT4 = <0.4 ng/dL (NV=0.7-1.48) and elevated anti-TPO = 770.9 IU/mL (NV=<9.0). Ultrasound of the thyroid showed non-uniform echopattern. Pertinent physical findings were an elevated JVP and muffled heart sounds but with stable blood pressure. A 2-dimensional echocardiogram (2D-Echo) confirmed the presence of massive PEEF with doppler evidence of beginning tamponade. Other laboratory findings were anemia, leukopenia, albuminuria and high creatinine level. With this unusual clinical presentation, SLE as a secondary cause of PEEF was entertained. ANA at 1:320 with speckled pattern as well as anti-dsDNA at 516.25 IU/ml (NV=<0-200) were both positive with low complement factor 3 level (C3) = 0.89 g/L (NV=0.9-1.8) fulfilling the Systemic Lupus International Collaborating Clinics (SLICC) criteria for SLE. The patient was given levothyroxine and prednisone for primary hypothyroidism and SLE, respectively. There was then gradual improvement of symptoms with a decrease in the PEEF on repeat 2D-Echo. She was noted to be clinically stable on subsequent follow-ups with further resolution of the massive PEEF. Conclusion: This was a rare case of SLE and AH causing massive PEEF with beginning tamponade which was successfully managed medically. This gave us valuable insight that massive PEEF occurring in hypothyroidism may be secondarily caused by other co-existing disease entities. Although it remained to be a diagnostic dilemma whether the massive PEEF was primarily because of SLE or AH or an effect of both, this case offered another opportunity to further explore the relationship of AH and connective tissue diseases such as SLE.