Abstract
Background:
Insulin Autoimmune Syndrome (IAS) or Hirata disease is reported more in Asians. We report the case of a patient with acute onset hypoglycemia secondary to IAS.
Case Presentation:
A 64 year old ARAB male physician presented with 2 weeks history of episodic hypoglycaemia with blood glucose (BG) 40–60 mg/dl, unrelated to food and occurring throughout the day. His attacks were associated with sweating, dizziness and palpitations, relieved by intake of juice. He reported 3 kg weight gain since the beginning of his symptoms.
Past medical history revealed hypertension, past HCV infection with negative PCR and history of allergy to sulfa drugs. His medications included bisoprolol 2.5 mg daily.
Physical exam showed no acanthosis nigericans. Laboratory investigations: Normal hepatic, renal and thyroid functions. 72 Hours fasting test was performed. at hour 3, the BG was 2.27 mmol (40.86 mg/dl), insulin > 1000 mU/ml (N: 2.6–24.9), c- peptide 15 ng/ml (N: 1.1–4.4), negative beta-hydroxybutyrate, with good glycemia response to glucagon 1mg. Urine sulfonylurea (SU) screen was negative. Insulin antibodies titre was high 8.9 nmol/L (N: 0–0.02) and Proinsulin >700 pmol/L (N: 3.6–22). MRI Abdomen showed only 3 mm lesion in the pancreatic head, likely a cyst.
During hospitalization, the patient continued to have episodic hypoglycaemia and received dextrose 10% and octreotide injection. Bisoprolol was changed to amlodipine as it may mask his symptoms.
Episodes of hypoglycaemia improved with octreotide but did not resolve completely. Prednisolone 30 mg daily was started with improvement and was tapered slowly after 16 weeks after mild hyperglycemia developed. Repeat work up showed reduction in insulin 67.4 mcunit/ml, C- peptide 2.66 ng/ml and insulin antibody titres to 0.24 nmol/L and remission of hypoglycemia.
Discussion:
Autoimmune hypoglycaemia is rare resulting from insulin antibodies(IAS), or anti-insulin receptor antibodies (Type B insulin Resistance). IAS can be triggered by drugs or viruses including hepatitis C and is associated with autoimmune diseases and hematologic malignancies. the differential diagnosis of hyperinsulinemic hypoglycemia include insulinoma, the presence of extreme levels of insulin, c-peptide and proinsulin and insulin antibodies is diagnostic of AIS. Short-term treatment with steroids was effective in treating hypoglycaemia and careful follow-up is ongoing. If the patient recurs, rituximab will be employed.
References:
1-CHURCH, D., CARDOSO, L., KAY, R. G., WILLIAMS, C. L., FREUDENTHAL, B., CLARKE, C., HARRIS, J., MOORTHY, M., KARRA, E., GRIBBLE, F. M., REIMANN, F., BURLING, K., WILLIAMS, A. J. K., MUNIR, A., JONES, T. H., FUHRER, D., MOELLER, L. C., COHEN, M., KHOO, B., HALSALL, D. & SEMPLE, R. K. 2018. Assessment and Management of Anti-Insulin Autoantibodies in Varying Presentations of Insulin Autoimmune Syndrome. J Clin Endocrinol Metab, 103, 3845–3855.
Primary insulin autoimmune syndrome in an Italian woman: a case report
