Endocrine Abstracts

Introduction: Non-diabetic hypoglycaemia (NDH) has many causes including insulinoma, non-insulin producing cancers and gastric bypass surgery but medications like fluoxetine are rarely reported.

Case history: 55 years female, university lecturer, history of Roux-en-Y gastric bypass in 2015 and depression, referred for recurrent symptomatic hypoglycaemia 1 to 2 hours post-meal (reactive hypoglycaemia) with recorded capillary blood glucose up to 1.6 mmol/l and symptoms resolution with carbohydrate (fulfilling Whipple’s triad). No history of diabetes and medications included Lansoprazole, Fluoxetine and Multi-vitamins. After excluding other causes of NDH she was diagnosed as post gastric bypass hypoglycaemia (PGBH), treated initially with Acarbose 50 mg TDS along-with small frequent, low glycaemic index meals and later Diazoxide 100 mg BiD with no benefits. She was started on Flash glucose monitoring (FGM), which confirmed post-prandial hypoglycaemia with time below range (TBR) (<3.9 mmol/l) of 25%, of which 1 % was below 3 mmol/l. Liraglutide 1.2 mg subcutaneously OD reduced hypoglycaemic episodes but did not eliminate completely. Surprisingly, she remained euglycaemic when she accidentally missed fluoxetine and then complete discontinuation along-with other ongoing measures resulted in significant hypoglycaemia improvement with FGM showing 97% time in range and only 3% TBR.

Investigations: Full blood count, thyroid, liver, and renal function tests, pancreatic imaging and esophagogastroduodenoscopy were normal. Mixed meal test confirmed post-prandial hypoglycaemia with insulin levels 36.2 pmol/l (Normal: <18 pmol/l) and C-peptide levels 0.96 nmol/l (Normal: <0.2 nmol/l) with venous blood glucose of 2.9 mmol/l.

Results and treatment: Stopping fluoxetine besides other measures like dietary modification, Acarbose and Liraglutide resulted in reduction of hypoglycaemia frequency from 25% of the time to only 3% on FGM along-with symptom improvement and QoL.

Conclusions and points for discussion: 1. Medications like Fluoxetine/SSRI should be considered as potential contributory agents in non-diabetic hypoglycaemia.

2. Consideration of FGM can help detecting hypoglycaemic episodes, improving patient’s confidence in managing hypoglycaemia and thus QoL.