Workshop 17

Investigation of adult spontaneous hypoglycaemia: real, imaginary and pseudohypoglycaemia

Dr Rousseau Gama

Have you ever been asked to investigate a patient with hypoglycaemic symptoms, received requests for prolonged GTTs to investigate reactive hypoglycaemia or been sent samples for insulin and C-peptide measurement in patients with ‘low BMs’?

This workshop intends to use case presentations to illustrate the clinical and laboratory investigation of spontaneous hypoglycaemia in adults, which may be uncommon but important nevertheless because often preventative or curative therapy may be available.

There are many traps awaiting the unwary. In hospitalised patients the commonest pitfall is failure to recognise hypoglycaemia as an epiphenomenon in many serious disease, and this needs no further investigation but requires prompt and appropriate action. Common pitfalls to avoid when investigating apparently healthy individuals for hypoglycaemia are: failure to clinically recognise subacute neuroglycopaenia; failure to adequately document hypoglycaemia during symptoms; failure to measure pancreatic hormones, counter-regulatory hormones and ketones in hypoglycaemic samples; failure to recognise pre-analytical and analytical limitations of laboratory assays; and failure to abandon obsolete and inappropriate investigations. Providing these caveats are met, appropriate laboratory and radiological investigations will usually uncover the cause of spontaneous hypoglycaemia.