A Rare Diagnosis of Insulin Autoimmune Syndrome Causing Recurrent Hypoglycemia
https://doi.org/10.15605/jafes.041.S1
- Author:
Ju Vern Ew
1
;
Jia En Chew
1
;
Eunice Lau Yi Chwen
2
Author Information
1. Department of Internal Medicine, Hospital Sibu
2. Endocrine Unit, Department of Internal Medicine, Hospital Sibu
- Publication Type:Journal Article
- MeSH:
Hypoglycemia;
Insulins
- From:
Journal of the ASEAN Federation of Endocrine Societies
2026;41(S1):54-
- CountryPhilippines
- Language:English
-
Abstract:
Introduction:Insulin autoimmune syndrome (IAS), or Hirata syndrome,
is characterized by hyperinsulinemic hypoglycemia
resulting from the presence of high titers of insulin
autoantibodies (IAAs) in the absence of exogenous insulin.
We present a rare case of IAS.
Case:A 75-year-old female with underlying hypertension,
dyslipidemia, and osteoporosis presented with symptoms
suggestive of spontaneous hypoglycemia of 3 months
duration. She was non-diabetic with no history of
antidiabetic agents or exogenous insulin use. Notably, she
had taken traditional medications 1 month prior to onset
of symptoms.
Her fasting blood glucose was 2 mmol/L. Serum insulin
was significantly elevated at >1,000 iui/mL and serum
C peptide was 2,950 pmol/L, consistent with hyperinsulinemic hypoglycemia. Blood sulfonylurea level was
not available. Her complete blood count and renal and
liver function were normal. Thyroid function test was
normal, and a short corticotropin stimulation test showed
adequate cortisol response. Computed tomography (CT)
pancreas, endoscopic ultrasound and PET-CT scan with
Galium-68 DOTATATE showed no evidence of insulinoma.
Serum IAAs were raised at 175 IU/mL, which confirmed
a diagnosis of IAS.
The patient was managed with dietary modifications and
advised for frequent, small meals with low glycemic index,
incorporating oral raw cornstarch. She was also started on
oral diazoxide 100 mg twice daily (3 mg/kg/day) due to
persistent hypoglycemia. She responded well to diazoxide
with no more spontaneous hypoglycemia, however,
developed fluid retention which was managed with oral
diuretics. Subsequently, we managed to taper and stop the
diazoxide after 18 months of treatment. Patient remains
well with no further episodes of hypoglycemia.
Conclusion:IAS may be triggered by medications or viral infections,
occurs more frequently in people with autoimmune
conditions, and shows genetic predisposition. However,
as in our patient, IAS may be idiopathic, and the cause
remains unknown. IAS is frequently self-limiting, and our
patient experienced spontaneous remission with no further
hypoglycemic episodes after discontinuation of treatment.
- Full text:2026073016184532170EP_A064.pdf
