ODP213 Insulin Autoimmune Syndrome a rare case report

Abstract

Abstract Background Insulin autoimmune syndrome IAS is cause of endogenous hyperinsulinemic hypoglycemia. Insulin autoimmune syndrome has been described with various drugs. Here we describe a case of IAS with use of Proton pump inhibitors, PPIs. Case report 49year old man came with complaints of recurrent documented hypoglycemia for the past 3months. He was a diagnosed as having Gastroesophageal reflux GERD 6 months back and has been on treatment with Pantoprazole with which his symptoms have subsided. Since past 3 months he started having episodes of excess sweating, tremulousness and palpitations. He was diagnosed as having hypoglycemia during one such episode using a glucometer value <60 mg/dl. After this he started monitoring his blood glucose values on glucometer and had recorded values as low as 50mg/dl, 55mg/dl, 47mg/dl. There was no specific association with meal intake. Every time his symptoms subsided with intake of diet. He was not a diabetic nor did he have any access to anti diabetic agents. With these complaints he was admitted and put on prolonged fasting, after 6 hours of fasting his blood glucose levels dropped to 42mg/dl. His critical sample revealed RBS- 42mg/dl, C peptide -15.7ng/ml (reference range 0.9-7.1ng/ml), serum insulin >300 µIU/ml (1.9-23µIU/ml fasting state) and serum cortisol 20.65 ug/dl(5-25ug/dl). His Sulphonyl urea screen was negative. Biochemically Endogenous hyperinsulinemia was thus proved but on imaging ultrasound examination was normal, CT scan abdomen did not reveal any pancreatic lesions. His endoscopic ultrasound also did not reveal any lesion in the pancreas. Insulin antibodies test showed positive antibodies >300 U/ml (reference range - <12U/ml). He is a known case of hypothyroidism on regular treatment. His thyroid profile was normal. There was no history of usage of methimazole, carbimazole, ALA, captopril, diltiazem, procainamide, Isoniazid, Imipenem, penicillin, Interferon, clopidogrel, gliclazide etc. He was treated with Diazoxide, Prednisolone and Acarbose. His blood glucose levels stabilized and he did not have a recurrence of hypoglycemia. Gradually he was tapered off diazoxide and prednisolone over a period of 6 months. His repeat insulin antibodies after 6 months showed 43.23U/ml (reference range<12). He is asymptomatic and is on follow up. IAS with PPI's is described 1 . Detailed history and physical examination did not reveal any other cause for IAS. Conclusion PPIs are commonly prescribed agents used ubiquitously. Here we wanted to highlight the importance of IAS with PPIs. There is no specific regimen used to treat IAS. Our patient showed good response to a combination of prednisolone, diazoxide and acarbose. This triple combination addresses the multiple mechanisms of hypoglycemia in IAS.