Endocrine Abstracts

Introduction: Type B insulin resistance is an extremely rare disease with unknown incidence. It is caused by autoantibodies, mostly IgG, against the insulin receptor that in low titres act as partial agonists. This can cause symptoms that include both hypoglycemia and hyperglycemia. It mostly affects middle-aged African-American women and the proposed treatment approaches include plasmapheresis, cyclosporine or cyclophosphamide, steroids and rituximab.

Case Report: We present a case of a 30-year-old Caucasian woman who referred to our outpatient department due to amenorrhea, worsening of pre-existing hirsutism, polyurea and weight loss, 8 months after giving birth. Medical history included Raynaud Syndrome, Polycystic Ovary Syndrome (PCOS) and newly diagnosed Systemic Lupus Erythematosus (SLE) on treatment with prednisolone. Clinical examination revealed severe hirsutism (Ferryman-Gallway score 24) and profound acanthosis nigricans. Her BMI was 19,2 kg/m². The paraclinical investigation showed deranged glucose metabolism with fasting hypoglycemia (65 mg/dl) and postprandial hyperglycemia (>200 mg/dl) with concomitant hyperinsulinemia (insulin 1201 μIU/ml) during OGTT and increased HbA1C (9.3%). Also, hyperandrogenemia with increased testosterone 575 ng/dl (5-52), and Δ4α 12.3 ng/dl (0.3-3.3). DHEAS,17OHPRG, SHBG were within normal limits and low titres of triglycerides were recorded. Immune panel revealed high IgG [2069 mg/dl (700-1600)], ANA and anti-RNP titres, and low C3 [46 g/l (90-180)] and C4[5 g/l (10- 40)]. Imaging was uneventful except from polycystic ovaries. Due to her medical history including a recent diagnosis of SLE and the affected glycemic control (hypoglycemia and hyperglycemia), the diagnosis of insulin resistance type B was proposed. Positive antibodies against the insulin receptor confirmed it (immunoprecipitation assay). Therapeutic approach consisted of dietary modifications, dapagliflozin and the immunoregulatory agent rituximab, an anti-CD 20 antibody, combined with pulses of steroids. Patient responded well with remission of hirsutism and an excellent glycemic control. Menstruation was restored. She remains stable until now.

Conclusion: Type B insulin resistance is an extremely rare disease with non-standardized treatment. Its clinical course can be confusing and the mortality rates remain high. Our patient benefited greatly from treatment with rituximab and steroids, and her current health status suggests that this approach may benefit more patients that fit similar characteristics.