Endocrine Abstracts

Insulin autoimmune syndrome is a condition characterized by production of autoantibodies against insulin. Drugs are one of the ethiological factors, especially when they contain the sulfydryl group such as methimazole and alpha lipoic acid. Herein we present a case report of insulin autoimmune syndrome due to alpha lipoic acid. A 77 year-old female patient presented to emergency department with syncope because of hypoglycemia. She was diagnosed with type 2 diabetes mellitus a year ago. Metformin and gliclazide was prescribed. During her follow-up, she had complaints of neuropathy, so alpha lipoic acid was added to her treatment. She also had autoimmune thyroid disease but didnot need for levothyroxine replacement. When she was questioned it was learned that she hadnot been taking metformin and gliclazide aproximately for 2 weeks, but she continued to take alpha lipoic acid. During a hypoglycemic episode insulin and c-peptide levels were examined and was compatible with hyperinsulinemic hypoglycemia. Anti-insulin antibody titer was high. She was considered to have insulin autoimmune syndrome due to alpha lipoic acid. Alpha lipoic acid was stopped, afterwards hypoglycemia was ceased, anti-insulin antibody titer decreased accordingly. There are several case reports of insulin autoimmune syndrome presented in literature due to intake of alpha lipoic acid. All of the cases had autoantibodies against insulin at presentation, cessation of hypoglycemia and deacrease of anti-insulin antibody titer after discontinuation of alpha lipoic acid. There are certain HLA allels which causes predisposition to this syndrome. Also these patients have higher incidance of other autoimmune diseases. If a patient who takes a drug containing sulfydryl group and has any of the autoimmune diseases presents with hyperinsulinemic hypoglycemia, insulin autoimmune syndrome must be considered.