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 option 3- accidental exogenous insulin administration. Normal /reduced levels of C-peptide in the presence of increased insulin suggests a diagnosis of exogenous insulin administration as the cause of hypoglycemia. In patients with hypoglycemia and increased insulin, measure C-peptide - - - - - - increased C- peptide indicates increased endogenous insulin as in insulinoma, auto immune process, sulphonylurea ingestion. Normal or reduced C-peptide shows exogenous insulin administration. Ref Harrison 19 /2434