Endocrine Abstracts

Somatostatin analogues (SSA) are used to treat different forms of hyperinsulinemic hypoglycemia (HH) in children and adults and therapeutic effect is achieved by suppressing insulin secretion from pancreatic β-cells by complex mechanisms. These treatments might be associated with several side effects, can even cause the worsening of severity of hypoglycemia. This is a report of the treatment of HH with SSA in patient with Activating Mutation (GCK), c.295T>C (p.Trp99Arg). We present a 58-year-old male with HH, which was diagnosed at the age of 20 years. However, symptoms of hypoglycemia were present from the postnatal period. Fasting was mainly the trigger for hypoglycemia episodes. Additionally, epilepsy was diagnosed at the age of 10 years and he is currently treated with carbamazepine. At the age of 54 years, the patient underwent genetic testing and a heterozygous variant in Glucokinase (GCK) c.295T>C was confirmed. The severity of hypoglycemia ranged from mild to serious with the lowest glucose of 1.88 mmol/l during fasting. In early adulthood, the patient did not consent to pancreatectomy. At the age of 20 years, diazoxide treatment was introduced. It resulted in decreased both the number and severity of hypoglycemic episodes, however, poor patient compliance was observed in terms of regular medical follow-ups and regular diazoxide intake. In 11.2021 SAA treatment was introduced at the age of 57. At that time, his HbA1c level was 4.1%, fasting glucose level 2.59 mmol/l with c-peptide level 2.1 ng/ml, and insulin level 7 uU/ml. Initially patient received 10 mg short-acting octreotide with a good response. He is now treated with 20 mg octreotide monthly. In self-monitoring mean fasting and after meal glycemia values increased by 20-30 mg%. His most recent 4-h oral glucose tolerance test (OGTT), performed after three months of treatment with SSA, showed fasting glucose level 3.22 mmol/l with insulin level 3.82 uU/ml and c-peptide 1.1 ng/ml. The lowest glucose level (1.58 mmol/l) was observed in 180 min in OGTT. Currently, the patient reports no symptomatic and self-monitored hypoglycemia as well as no side effects of SSA. The SSA treatment of HH with activating GCK mutation, c.295T>C improved both fasting and after meal glucose levels by 20-30 mg% with complete remission of hypoglycemia. However, hypoglycemia during OGTT suggests that glucose load is a very strong trigger of insulin oversecretion despite SSA treatment. Therefore efficient treatment with SSA analogues should be combined with the low glycemic diet.