O-17 A case of severe and recurrent hypoglycaemia in a healthy patient

Abstract

Abstract Introduction Hypoglycaemia is a challenging condition for the endocrinologist. Clinical Case A 75 y/o man was admitted to ER due to severe symptoms of hypoglycaemia (weakness, blurring and sweating). His symptoms improved after eating some food and blood glucose was 50 mg/dL. He was treated with oral glucose and referred to our endocrinology clinic. His personal and family history was uneventful (no endocrine, autoimmune or neoplastic disease, no drug) and he did not complain any other symptoms besides hypoglycaemic ones. When going deeply into his medical history, he reported that back pain had occurred 4 weeks before ER access. His GP had thus prescribed supplements containing alpha lipoic acid (ALA) that he had assumed for 3 weeks and then discontinued for the lack of any benefit. He regarded this information as useless as ALA was “just a supplement”. Furthermore, he reported symptoms as shaking, anxiety, dizziness, sweating, and hunger that occurred 5-7 times per day far from meals and faded after eating. A diet was prescribed with frequent eatings, high content of fibers and whole foods. He started flash glucose monitoring (FGM) with the alarm for hypoglycaemia set at 70 mg/dL and was trained for the management of hypoglycaemia. The laboratory alerted us due to the results of oral glucose tolerance test (Table 1). Hypoglycaemic episodes after the test were neither reported nor registered by FGM. The differential diagnosis was among insulinoma, insulin resistance or insulin autoimmune syndrome (Hirata disease). The calculated molar ratio of insulin to C-peptide was 2.68, thus pointing to Hirata disease (to be suspected when the ratio is >1). We opted for watchful waiting while continuing the monitoring. Two weeks later the pending results became available: TSH 1.69 mU/L, HbA1c 5.2%, serum cortisol 14.8 μg/dL, ACTH 18.2 pg/mL, anti-endogenous insulin antibodies 5.8 U/ml (nv <2.4), normal values of transaminases, lipase, and amylase. The patient reported adherence to the diet, two symptomatic hypoglycaemias (in the afternoon, when he couldn't have the snack) as well as asymptomatic FGM alarms once daily, usually early in the morning. We advised to add a snack before bedtime to shorten the fasting period. At the 3-month follow-up he had had no further hypoglycaemias, blood glucose was normal and anti-endogenous insulin antibodies were negative. Conclusion Hypoglycaemia can be a life-threatening condition and differential diagnosis is crucial. It is important to consider even rare conditions, such as Hirata syndrome that can be triggered by several factors and medications, the most common being ALA. Complete medical history is mandatory and tight follow-up essential. Most cases, as the one reported, resolve with a correct diet after the withdrawal of supplements.Table 1.Oral Glucose Tolerance Test