ALPHA LIPOIC ACID-INDUCED INSULIN AUTOIMMUNE SYNDROME (IAS)

A REPORT OF TWO CASES

Abstract

INTRODUCTION/BACKGROUND
Insulin Autoimmune Syndrome (IAS) is a rare cause of hypoglycemia. Alpha-lipoic acid (ALA), found in Bionerv (Vitamin B supplement), induces IAS by modifying insulin structure, leading to insulin autoantibody (IAA) production in genetically susceptible individuals. Most cases are self-limiting. We present two IAS cases, emphasizing diagnostic and management challenges.

CASE
A 49-year-old man presented with recurrent hypoglycemia. During his first clinical consult, a computed tomography (CT) scan of the pancreas was done and showed normal findings. Prolonged fasting test was consistent with endogenous hyperinsulinemic hypoglycemia. He was later referred to our center. In further history, he revealed that his symptoms started 10 days after taking Bionerv. A mixed meal test showed fasting hypoglycemia with late postprandial hypoglycemia, and markedly elevated serum insulin levels. His IAA was positive, and his sulfonylurea screen was negative. A diagnosis of ALA-induced IAS was made. Despite stopping ALA and dietary modifications, his symptoms persisted, requiring diazoxide and prednisolone. The patient was monitored with continuous glucose monitoring (CGM), which revealed episodes of alternating hyper and hypoglycemia.

A 69-year-old man with a history of thyrotoxicosis presented with symptoms of hypoglycemia. Prolonged fasting confirmed endogenous hyperinsulinemia. Abdominal CT and endoscopic ultrasound (EUS) were normal, while Galium-68 DOTOTATE imaging showed mild uptake at a 10 mm pancreatic tail nodule. He was suspected of having insulinoma and was referred to us for further assessment. Further history revealed that the symptoms started after 1 week of taking Bionerv. His IAA was positive. In view of the temporal relationship with ALA, an IAS diagnosis was made. Symptoms improved after discontinuation of ALA, dietary modification and medical therapy. His CGM showed predominant hyperglycemia with late evening hypoglycemia.

CONCLUSION
Although ALA is generally safe, emerging case reports demonstrate its potential to trigger IAS. Detailed drug history and clinical suspicion is crucial to avoid the misdiagnosis of insulinoma and unnecessary interventions.