Severe hypoglycemia due to insulin autoimmune syndrome with insulin autoantibodies crossreactive to proinsulin

Summary:

We report the case of a 69-year-old woman with insulin autoimmune syndrome first misdiagnosed as insulinoma. The case demonstrates the difficulties to correctly diagnose this rare disorder as both insulin and proinsulin levels were increased by crossreactive autoantibodies. No known triggering agent could be identified. We suggest that this diagnosis should be considered more often also in caucasian patients to avoid useless operations for such patients.

Abbreviations: Ab, antibodies; IAA, insulin autoantibodies; IAS, insulin autoimmune syndrome; IRI, immune reactive insulin; PI, proinsulin; SEC, size exclusion chromatography

Key words:

Hypoglycemia - insulin autoimmune syndrome - proinsulin - insulin autoantibodies

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