Endocrine Abstracts

Introduction: Unexplained falls are a common rationale for emergency presentations amongst older adults. Admissions are associated with significant morbidity. We present a case series of two older adults presenting following collapse, with resultant diagnosis of insulin-mediated hypoglycaemia.

Case 1: 79 year-old woman presenting following a presyncopal event. In the weeks preceding admission, described lethargy and weight loss, with associated palpitations and tremor. TSH was <0.01mu/l and fT4 60 pmol/l. Random serum glucose was 2.9 mmol/l, without associated symptoms. TSH-Receptor antibody was positive, and a diagnosis of Graves thyrotoxicosis made. Carbimazole 20 mg BD was commenced. A 72-hour fast was undertaken (Table 1), with serum glucose nadir 1.9 mmol/l. Endoscopic ultrasound identified a pancreatic head insulinoma. Diazoxide was commenced, with surgical input and successful resection.

Case 2: 87 year-old woman admitted with an intertrochanteric fracture following a nocturnal fall. Random capillary glucose was 2.7 mmol/l. Notable symptoms included recurrent episodes of diaphoresis and presyncope requiring use of dextrose tablets in the years preceding admission. Fasting serum glucose was 3.5 mmol/l, with normal serum cortisol and HbA1c of 30 mmol/mol. 72-hour fast identified serum glucose of 1.7 mmol/l at 14 hours, with hyperinsulinaemia(Table 2) and full ketone suppression. CT pancreas was unremarkable, however there was subsequent diagnosis of small-cell lung cancer. Diazoxide was commenced. Diagnosis was of presumed insulinoma, given biochemistry and symptom chronicity. IGFII:IGFI ratio was preserved. Further work-up was deferred given prognosis.

Discussion: This case series describes two unexpected diagnoses of insulin-mediated-hypoglycaemia in older adults, as a causative factor in falls presentations. This highlights an unusual underlying pathology of syncopal events, with significant associated morbidity.