Refractory Hypoglycemia Related to Gastric Bypass Complicated by Hypothyroidism

Abstract

A 29-year-old African-American female was brought to the emergency department for sudden onset nausea, dizziness, and loss of consciousness at work. She was found to have low blood sugar and was fed with juice and crackers. She had history of similar episodes in the past, migraine headache, post-thyroidectomy hypothyroidism, seizures, generalized anxiety disorder, gastroesophageal reflux disease, and Roux-en-Y gastric bypass 9 months ago for morbid obesity related refractory Pseudotumor Cerebri (failed VP Shunting). She lost 41 kg, and had intolerance to foods from dumping syndrome. Her vital signs were within normal limits upon arrival to the ER. Laboratory parameters were remarkable for hypoglycemia of 52 mg/dL. She was immediately given dextrose intravenously. ECG showed sinus bradycardia. Though she regained consciousness, her blood sugar levels were persistently low, the lowest recording being 43 mg/dL. She was placed on a continuous D10 infusion. Further investigations revealed negative toxicology screens for 1st and 2nd generation sulfonylureas, and normal insulin levels at the time of the hypoglycemic event. Her TSH was found to be very high (99 nIU/mL). Her thyroglobulin (2.8 ng/mL), free T4 (0.25ng/dL), thyroglobulin antibody (99.18 uIU/mL), cortisol levels in morning (14.2 ug/mL), and evening (4.6 ug/dL) were found to be within normal range. Abdominal MRI did not reveal Insulinoma or any other pathology. Repeat ECG showed normal sinus rhythm with occasional PVCs. She was treated for nausea with ondansetron, promethazine, scopolamine, and dronabinol. Dextrose infusion was titrated down with rise in blood sugar levels. She confessed non-compliance to thyroid replacement. Therefore, she was initially treated with intravenous thyroxine replacement, which was later switched to oral therapy. Psychiatry evaluation ruled out any eating disorder. She was counselled to eat small frequent meals, increase dietary proteins, and restrict high glycemic index sugars. Educational value: National data indicates an increasing trend for admissions related to morbid obesity and bariatric procedures, especially laparoscopic (vertical) sleeve gastrectomy (see Fig 1). (1) Complex alteration in the signaling pathway to pancreas owing to changing metabolism causes hypoglycemia after bariatric surgery. When compounded by severe untreated hypothyroidism, as in our case, causes severe hypoglycemia needing hospitalization. Patient education for adjustment in dietary habits would have played a key role in preventing episodes of severe hypoglycemia.Reference:1.HCUPnet, Healthcare Cost and Utilization Project. Agency for Healthcare Research and Quality, Rockville, MD. https://hcupnet.ahrq.gov/.Fig 1: Trends for admissions for Morbid Obesity and Sleeve Gastrectomy