Tumour-induced hypoglycaemia: A narrative review

Objective: To provide an overview of the pathogenesis and clinical features of tumour-induced hypoglycaemia (TIH), its effective diagnostic work-up and management strategies and the challenges involved. Background: Hypoglycaemia, defined by a plasma blood glucose level <3.0 mmol/L (<54 mg/dL), results from failure of glucose homeostasis. Although multiple scenarios contribute to the onset of hypoglycaemia, certain tumours represent an important, although relatively uncommon group of causative factors. In patients with unexplained hypoglycaemia, it is important to conduct a careful clinical assessment, with detailed investigations to ascertain the underlying cause(s), and initiate appropriate and effective therapies. TIH often presents a clinical challenge for both accurate and timely diagnosis and effective management. Methods: We performed a narrative literature review using PubMed and search-term "Tumour-Induced Hypoglycaemia", with articles written in English. Conclusions: There are two main groups of TIH: insulinoma and non-islet cell tumours (NICTs). Insulinomas are the commonest form of pancreatic neuroendocrine tumour, and a well-recognised cause of hyperinsulinaemia associated with recurrent hypoglycaemia. Conversely, NICTs mediate hypoglycaemia through the excessive production of big insulin-like growth factor 2 (IGF2), that cross-reacts with the insulin receptor. Through careful biochemical assessment, accurate diagnosis of Insulinoma versus NICTs provides a rationale for effective and individually tailored management.