Endocrine Abstracts

Background: Late dumping syndrome (LDS) is characterized by episodes of hypoglycaemia occurring 1 to 3 hours after carbohydrate ingestion due to excessive insulin secretion (hyperinsulinemia), commonly seen in individuals post-gastric surgery1. Hypoglycaemia diagnosis typically follows Whipple’s triad2 but can be challenging in patients with hypoglycaemia unawareness, who lack classic symptoms. In such cases, continuous glucose monitoring (CGM) technology, like Freestyle Libre, offers valuable insights into glycaemic trends.

Case Presentation: We report a 75-year-old male who underwent oesophagostomy 15 years ago for cancer. After an uneventful recovery, he presented with severe hypoglycaemia (1.5 mmol/L) and no awareness of symptoms, detected by emergency responders after a collapse. To evaluate recurrent hypoglycaemia, Freestyle Libre was employed to monitor glucose levels over 14 days. Despite not being validated for reactive hypoglycaemia, CGM identified consistent postprandial hypoglycaemia occurring 3 hours after meals, consistent with LDS. Investigations, including fasting glucose, insulin, C-peptide, cortisol, thyroid function, and IGF2, were normal, ruling out other causes. The lack of hypoglycaemia awareness in patients following upper gastrointestinal surgery remains a not understood area3. A prolonged oral glucose tolerance test4 confirmed the diagnosis. Dietary modifications were recommended, and follow-up CGM revealed improved glycaemic control, suggesting successful intervention.

Conclusion: This case highlights the utility of CGM technology in diagnosing hypoglycaemia unawareness in complex scenarios, especially when conventional methods fall short. The uniqueness of this case lies in the onset of late dumping syndrome and hypoglycaemia unawareness 15 years after oesophagostomy, an uncommon occurrence. CGM played a critical role in confirming the diagnosis and guiding management, underscoring its potential in addressing similar cases presenting with late-onset, atypical symptoms.

References: 1. Grover, A 2024. doi.org/10.1111/cen.15169.2. Mohamed, F 2024. doi: 10.1210/jcemcr/luae006.3. Ostrovsky, V 2023. doi: 10.1016/j.numecd.2023.02.012.4. Tack, J, 2024. doi.org/10.1111/nmo.14962