c-peptide and Syncope

Topics: Blood Glucose; C-Peptide; Choristoma; Confusion; Diagnosis, Differential; Fasting; Female; Humans; Hyperinsulinism; Hypoglycemia; Insulin; Insulin Secretion; Insulinoma; Middle Aged; Nesidioblastosis; Pancreatectomy; Pancreatic Diseases; Postprandial Period; Spleen; Syncope

The type B insulin-resistance syndrome is characterized by the presence of anti-insulin receptor antibodies that cause severe insulin resistance. Treatments including steroids, cyclophosphamide, plasmapheresis, or insulin-like growth factor-1 (IGF-1) are chosen according to severity of insulin resistance. We describe a patient with type B insulin resistance syndrome who was treated successfully with human recombinant (hr) IGF-1, although this treatment provoked a severe allergic reaction. An elderly man with impaired glucose tolerance and unpredictable hypoglycemic episodes which were gradually worsening increased in hemoglobin (Hb)A1c concentration from 6.5 to 13.4%. His fasting and postprandial hyperglycemia were associated with severe hyperinsulinemia. The patient was diagnosed with type B insulin-resistance syndrome by the presence of anti-insulin receptor antibodies. Double-filtration plasmapheresis, plasma exchange, and immunosuppressive therapy with cyclophosphamide and cyclosporin all failed to suppress anti-insulin receptor antibodies more than transiently. When we attempted the treatment by daily administration of hrIGF-1, fasting and postprandial plasma glucose concentrations became normal and HbA1c levels decreased to 7.1% over 2 months, until on one occasion administration resulted in anaphylaxis. After the patient became stable, desensitization therapy was performed successfully, and hrIGF-1 could be administered again with the plasma glucose returning. We concluded that IGF-1 therapy was an effective treatment choice for type B insulin-resistance syndrome in cases whose plasma exchange and immunosuppressive therapy have failed.

Topics: Aged; Autoantibodies; Blood Glucose; C-Peptide; Cyclophosphamide; Cyclosporine; Desensitization, Immunologic; Glucose Tolerance Test; Glycated Hemoglobin; Humans; Hyperglycemia; Immunosuppressive Agents; Insulin Resistance; Insulin-Like Growth Factor I; Male; Plasma Exchange; Plasmapheresis; Receptor, Insulin; Syncope

Topics: Adult; Angiography; Blood Glucose; C-Peptide; Cognition Disorders; Diagnosis, Differential; Female; Glucose Tolerance Test; Humans; Hyperinsulinism; Hypoglycemia; Insulinoma; Male; Middle Aged; Pancreatectomy; Pancreatic Neoplasms; Splenectomy; Syncope; Tomography, X-Ray Computed