ECE2017 Eposter Presentations: Diabetes, Obesity and Metabolism Diabetes (to include epidemiology, pathophysiology) (95 abstracts)
1Endocrinology Department Hospital Garcia de Orta, Almada, Portugal; 2Clinical Chemistry Department Hospital Garcia de Orta, Almada, Portugal; 3Endocrinology Laboratory IPO Francisco Gentil, Lisboa, Portugal.
Insulin autoimmune syndrome (IAS) is a very rare cause of hypoglycaemia in western countries. One proposed mechanism is anti-insulin antibody capture of prandial insulin followed by the dissociation of insulin from anti-insulin antibody. The first objective was to study the relationship between glucose, insulin and C-peptide during a prolonged glucose load in two patients with active IAS. The second was to study the variation of these parameters between the active and the recovery disease states.
Methods: Two patients with IAS and frequent hypoglycaemic episodes at the time of the first study underwent an extended oral glucose tolerance test with 75 g of glucose (4 h). After apparent clinical and biochemical recovery, the procedure was repeated.
Results: The data observed during the active and recovery states are shown in Table 1.
Hyperglycaemia phase | Hypoglycaemia phase | |||
State | Glucose Mean peak at 1 h (mg/dl) | Ins/c-pep ratio (uU/ng) | Glucose Mean peak at 34 h (mg/dL) | (uU/ng) |
Active disease | 199 (range 187210) | 7.0 | 52 (range 4559) | 13.6 |
Recovery disease | 166 | 11.2 | 4.9 |
Active disease state: The insulin/c-peptide ratio increased significantly from hyperglycaemia to hypoglycaemia (P=0.023) even after adjusting for the glucose levels (glycaemia to insulin/c-peptide ratio) (P=0.027).
Recovery disease state: Patient showed a decrease in hyperglycaemia peak with a corresponding increase in the insulin/c-peptide ratio and a decreased insulin/c-peptide ratio during hypoglycaemia phase.
Discussion: During active disease, a lower insulin/c-peptide ratio during hyperglycaemia and the paradoxical increase during hypoglycaemia seem to support the role of insulin antibodies in the disease. During the recovery state, there is a reversal of these ratios supporting an increase in bioavailable insulin with lower antibody titters.