Fasting hypoglycaemia secondary to carnitine deficiency: a late consequence of gastric bypass

• Published in: BMJ case reports Vol. 14; no. 7; p. e241703
• Main Authors: Chen, Xin, Kimura, Brad, Nagelberg, Jodi, McCowen, Karen C
• Format: Journal Article
• Language: English
• Published: England BMJ Publishing Group LTD 19.07.2021; BMJ Publishing Group
• Subjects: Aged; C-Peptide; Carbohydrates; Carnitine - therapeutic use; Case Report; Case reports; Fasting; Fatty acids; Female; Gastric Bypass - adverse effects; Gastrointestinal surgery; Glucose monitoring; Hormones; Hospitals; Humans; Hypoglycemia; Hypoglycemia - etiology; Insulin; Insulin-like growth factors; Malnutrition; Oxidation; Patients; Peptides; Plasma; Regulation; Weight control; malabsorption; malnutrition; metabolic disorders; gastrointestinal surgery; vitamins and supplements
• ISSN: 1757-790X; 1757-790X
• DOI: 10.1136/bcr-2021-241703

Twelve years following gastric bypass surgery, a cachectic 69-year-old woman presented with both fasting and postprandial hypoglycaemia. Postprandial symptoms were relieved by dietary modification and acarbose, as is common in such cases. During a supervised fast, symptomatic hypoglycaemia occurred. Concurrent laboratory testing showed suppression of plasma insulin, c-peptide, proinsulin and insulin-like growth factor II. However, beta-hydroxybutyrate was also low, surprising given insulin deficiency. Elevated plasma free fatty acid (FFA) concentrations suggested that lipolysis was not impaired, making cachexia/malnutrition a less likely cause of hypoglycaemia. The apparent diagnosis was failure to counter-regulate—subsequent plasma carnitine measurements showed carnitine deficiency which presumably prevented FFA transport across mitochondrial membranes for ketogenesis. Repletion with high-dose oral carnitine supplements effected resolution of fasting hypoglycaemia.