MON-627 Type B Insulin Resistance Syndrome Secondary to Systemic Lupus Erythematosus

Abstract Disclosure: L.G. Delgado Castro: None. J.E. Esquivel Vargas: None. L. Ulate Oviedo: None. Background: Type B insulin resistance syndrome is a rare autoimmune disorder caused by autoantibodies against the insulin receptor, with only about 100 reported cases. It occurs mostly in Afro descendant woman, and in patients with rheumatologic diseases or as a paraneoplastic syndrome. It presents with severe insulin resistance, difficult to manage hyperglycemia or hypoglycemia, hyperandrogenism, and acanthosis nigricans. Treatment includes immunosuppression and glycemic control. Clinical case: A 25-year-old female with a chronic history of alopecia, hyperpigmented macules, joint pain, and 10 kg weight loss; and in addition, acute diarrhea, vomiting, epistaxis, febrile sensation, significant hirsutism and acanthosis nigricans. Laboratories revealed pancytopenia, systemic inflammation, acute kidney injury, hyponatremia, and hypokalemia. Despite initial improvement, she developed respiratory distress, hypertension, tachycardia, hemolytic anemia, pleural and pericardial effusions, nephrotic range proteinuria, so an autoimmune panel was performed, leading to a diagnosis of systemic lupus erythematosus (SLE). During this time, patient developed glucose levels exceeding 400 mg/dL, without acidosis or ketonemia. Insulin infusion was started, with a progressive increase in the rate, from an initial 10 units/hour to 750 units/hour, amounting to a total daily dose of 18,000 units of insulin. Given the high suspicion of severe insulin resistance, insulin receptor antibodies were tested; and four sessions of plasmapheresis were performed, that led to a progressive decrease in insulin requirements, eventually resulting in hypoglycemic episode with infusion rate of just 1 unit/hour. Patient was discharged with a diagnosis of Type B insulin resistance syndrome secondary to SLE, treated with a combination of immunosuppressive agents for her lupic nephritis and insulin resistance. Since discharge, she has remained off insulin therapy with blood glucose levels within normal ranges. Conclusion: We present an extremely rare case of Type B insulin resistance syndrome in an Afro descendant woman, whose clinical presentation led to the diagnosis of SLE as the predisposing autoimmune disease. This case highlights the importance of clinical suspicion and prompt initiation of immunosuppressive therapy, as demonstrated by the patient’s excellent clinical outcome. What sets this case apart is occurrence in a young individual, the onset and diagnosis of the syndrome were made during hospitalization, coinciding with the diagnosis of her rheumatologic disease. There are few published case reports to date in which plasmapheresis has been used as an initial therapy to control hyperglycemia and reduce circulating antibodies, as demonstrated in this patient with an excellent initial response. Presentation: Monday, July 14, 2025