A 73 year old female presented with collapse secondary to hypoglycaemia. Investigations are summarised in the table attached. In the presence of raised tumour markers and a raised IGF2/IGF1 ratio, carcinomatosis was considered as the most likely underlying diagnosis. Nutritional support was arranged with additional carbohydrate dietary intake advised. She responded well with reduced hypoglycaemic frequency of hypoglycaemia. Investigations for underlying carcinoma were unable to delineate a source. This included cross-sectional imaging. Three months later, a repeat CT scan of chest, abdomen and pelvis revealed extensive bony metastasis. No primary was identified. Hypoglycaemia most frequently results as a complication of therapy in diabetes mellitus. Less frequently, hypoglycaemia can be a manifestation of an underlying neoplastic disease. In the setting of carcinogenesis, it is mostly due to production of excess insulin/insulin related peptides or destruction of the liver and adrenal glands by tumour infiltration and/or reduction in glycogen reserves. Rarely, hypoglycaemia can be induced by the production of various different substances including antibodies, cytokines, catecholamines and different growth factors such as IGF-II. The latter condition is also known as non-islet cell tumour-induced hypoglycaemia (NICTH). Uncommonly, NICTH can be the presenting symptom of a tumour and can pose a diagnostic challenge. In our case, hypoglycaemia occurred many months before any radiological evidence of an ongoing neoplastic process. A suppressed IGF-I, insulin and c-peptide during a hypoglycaemic episode should point towards this rare cause of hypoglycaemia. Unexpected hypoglycaemia presenting in non-diabetic patients should raise alertness in physicians as it may indicate serious underlying pathology which has yet to identify itself.
Declaration of interest: There is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported.
Funding: No specific grant from any funding agency in the public, commercial or not-for-profit sector.