[Hypoglycemia and transient diabetes mellitus in an insulin autoimmune syndrome].
METHODS
A 53-year-old Caucasian woman presented with repeated episodes of hypoglycemia. Self-monitored blood glucose levels during the attacks were between 40 and 60 mg/dl (2.2-3.3 mmol/l).


METHODS
An oral glucose tolerance test performed over 210 minutes showed normal baseline glucose levels, markedly elevated levels of serum insulin and slightly elevated C-peptide concentrations. During the test, a marked increase of insulin and a normal increment of C-peptide were observed. The tentative diagnosis of an insulinoma was raised and a 72 h fasting test performed, throughout which the insulin-glucose-ratio was pathologically elevated, whereas C-peptide levels were only slightly elevated.


METHODS
Strongly positive levels of insulin antibodies led to the diagnosis of an insulin autoimmune syndrome.


METHODS
This syndrome is caused by IgG-insulin-complexes with prolonged plasma half-life in the presence of reduced insulin action. The therapy consisted of fractionated meals to avoid hyperinsulinism and following hypoglycemic episodes. After four months a spontaneous clinical remission was observed.


CONCLUSIONS
The autoimmune insulin syndrome is a rare cause of recurrent, spontaneous hypoglycemia in Europe in non diabetic patients. Its prognosis is good as there is a high rate of spontaneous clinical remission in up to 80 % of patients.
Reisch
N
N
Abteilung Endokrinologie/Diabetologie, Medizinische Klinik Innenstadt, Klinikum der Universität München. nicole.reisch@medizin.uni-muenchen.de
Zwermann
O
O
Reincke
M
M
D001327:Autoimmune Diseases / Q000209:etiology / Q000276:immunology*; D001786:Blood Glucose / Q000032:analysis; D002096:C-Peptide / Q000097:blood; D003924:Diabetes Mellitus, Type 2 / Q000178:diet therapy / Q000209:etiology* / Q000276:immunology; D005260:Female; D005951:Glucose Tolerance Test; D006801:Humans; D007003:Hypoglycemia / Q000178:diet therapy / Q000209:etiology* / Q000276:immunology; D007074:Immunoglobulin G / Q000097:blood; D007328:Insulin / Q000097:blood / Q000276:immunology*; D007330:Insulin Antibodies / Q000097:blood*; D008875:Middle Aged; D011379:Prognosis; D012075:Remission, Spontaneous; D013577:Syndrome
D001786:Blood Glucose; D002096:C-Peptide; D007074:Immunoglobulin G; D007328:Insulin; D007330:Insulin Antibodies