A patient presents with symptoms of Hypoglycemia. Investigations reveal decreased blood glucose and increased Insulin levels. C-peptide assay is done which shows normal levels of C- peptide. The most likely diagnosis is:
Answer is C (Accidental exogenous Insulin administration): Normal / Reduced levels of C- peptide in the presence of increased insulin suggest a diagnosis of exogenous insulin administration as the cause of hypoglycemia. Approach to a patient with Hypoglycemia and Increased Insulin levels: Role of C- peptide Assay Normally Endogemous Insulin is secreted from (3-cells of pancreas in the form of Pro-insulin This proinsulin is then broken down to Insulin and C- peptide such that for each molecule of endogenous insulin, one molecule of C-peptide is produced. C-peptide levels are thus increased whenever endogenous insulin is increased e.g. Insulinomas, Sulfonylureas, Autoimmune processes and in cases of Insulin resistance (type II DM).
Insulinoma
Accidental sulfonylurea ingestion
Accidental exogenous Insulin administration
Accidental Metformin ingestion