5175 A Rare Case of Type B Insulin Resistance Syndrome

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Abstract Disclosure: S. Fatima: None. A. Champion: None. S. Ward: None. Q. Aziz: None. K.E. Izuora: None. Introduction: Severe insulin resistance may be defined as a severely diminished response to insulin’s biological effects and is characterized by substantial hyperinsulinemia and impaired glucose response to endogenous and exogenous insulin. We hereby present a rare case of Type B Insulin Resistance Syndrome (TBIRS). Case:40-years old female with history of systemic lupus erythematosus (SLE), diabetes mellitus was admitted with multiple rheumatologic complaints, including arthralgias, oral ulcers, skin rash, and hair loss secondary to SLE flare. Endocrinology was consulted for diabetes management. Her HbA1c had increased from 7.3% to 11.6% in 3 months despite taking Glargine 45 units daily, Lispro 15 units pre-meals and metformin. She noticed 80 lbs weight loss for past 6 months. Her BMI was 26 and exam showed acanthosis of neck, armpits, groin, hair loss on scalp, multiple genital ulcers, and facial rash. She was noted to have refractory hyperglycemia despite high insulin doses. By 14th day of hospitalization, she was on 287 units of insulin (3.4units/kg) daily. We suspected TBIRS in the setting of SLE. Metformin and pioglitazone were started. Further testing showed insulin level 152mIU/ml (2.6-14.9mIU/ml), C-peptide 1.7 ng/ml (1.1-4.4 ng/ml), islet-cell antibody negative, GAD-65 antibody <5 u/ml, insulin antibody 6.5 uU/ml, IGF-1 14 (79-259 ng/ml), adiponectin 13.3 (2.4-17.9 ug/ml), testosterone 7 (8-60 ng/dl), free testosterone <0.2 (0-4.2 pg/ml), total cholesterol 200 mg/dl (<200 mg/dl), triglycerides 85 mg/dl (<150 mg/dl), LDL 154 mg/dl (<100 mg/dl), HDL 29 mg/dl (>60 mg/dl). She was transferred to National Institute of Health for further care. She was confirmed to have TBIRS by insulin receptor antibody testing, started on regular insulin U500 initially, and then switched to IV insulin drip requiring up to 1700 units of insulin per hour. She received methylprednisolone, cyclophosphamide (2 doses), rituximab (2 doses), hydroxychloroquine and IV immunoglobulin. Her stay was complicated by hemophagocytic lymphohistiocytosis. She was discharged on U-500 Regular insulin, 1000 units with breakfast and 500 units with lunch, Prednisone 60 mg daily and Hydroxychloroquine. Two months later she was found unresponsive at home secondary to hypoglycemic seizures. She required dextrose drip and was discharged on Glargine 16 units and Lispro 6 units with meals. Conclusion: TBIRS is caused by a highly specific polyclonal autoantibody against the cell surface insulin receptor that decreases the cellular insulin response and causes refractory hyperglycemia. About 100 cases have been reported in literature. 60% of the cases are associated with SLE. The goal of therapy is to reverse the hypercatabolic state with high doses of insulin and to eliminate the autoantibodies with immunosuppressive therapy. The most common cause of mortality is hypoglycemia. Presentation: 6/3/2024