SAT172 Unmasking A Pediatric Disease In Adult, A Belated Diagnosis

Disclosure: H. Syed: None. P. Au: None. M.J. Gardner: None. Background: Glycogen storage diseases (GSD) are a rare group of diseases that change the way the body uses and stores glycogen. They are usually diagnosed in the pediatric population. Hypoglycemia can be a sign. Clinical Case: A 32 year old female presented with worsening and more frequent episodes of hypoglycemia. She had no history of diabetes and was not on any hypoglycemic agents. She had been having episodes of spontaneous hypoglycemia since childhood and would get symptomatic as well. No comprehensive workup had been done prior. The episodes were becoming more frequent. A blinded continuous glucose monitor was placed on the patient to monitor her glucose levels. Results indeed showed few episodes of hypoglycemia with glucose levels in the 40s. Interestingly, she also had postprandial hyperglycemia with glucose level above 180 following an episode of hypoglycemia. She underwent a 72 hour fast in the hospital and became hypoglycemic within 24 hours with a low blood glucose of 55, consistent with hypoglycemia, and she was also symptomatic as well. At the same time, her beta hydroxybutyrate increased to 3.91 mmol/L, consistent with ketosis. Her insulin level and C-peptide level at the time of hypoglycemia were 4.35 mcunit/mL and 0.239 nmol/L, respectively, and thus insulinoma was ruled out. She next underwent a mixed meal study during which her postprandial blood glucose increased to at least 198 indicating postprandial hyperglycemia. At the same time, patient's postprandial lactate also elevated to 4 mmol/L, consistent with lactic acidosis. Her symptoms of hypoglycemia resolved once her blood sugar (BG) improved. She met criteria for Whipple’s triad. She also had had an 8 am cortisol of 13.06 mcg/dL and had an appropriate response to the ACTH stimulation test with a 60 minute post cortisol above 20 mcg/dL, thus ruling out adrenal insufficiency as a cause of hypoglycemia. These findings of the 72 hour fast that resulted in hypoglycemia, followed by postprandial hyperglycemia with lactic acidosis are consistent with Glycogen Storage Disorder Type 0. Treatment involves intake of uncooked cornstarch with protein. Patient incorporated both uncooked cornstarch along with increasing amount of protein in her diet and started using a continuous glucose monitor with alarm to monitor her BGs. As a result her episodes of frequent hypoglycemia improved. Conclusion: This case illustrates a rare case of hypoglycemia in an adult that was not thoroughly investigated when she was in her childhood and adolescence. This case teaches the importance of being familiar with pediatric conditions since it is possible that pediatric conditions, especially if they are missed by providers and not appropriately diagnosed. Presentation: Saturday, June 17, 2023