[A case of repeated severe hypoglycemia caused by accidental ingestion of sulfonylurea in an elderly patient].

An 81-year-old man was being treated with oral medication for chronic heart failure and epilepsy. He had no history of diabetes, cirrhosis, or gastric surgery. He was admitted to our hospital due to disturbance of consciousness. His blood glucose level was 6 mg/dl, with a relatively high insulin level (14.4 µU/ml). Computed tomography and a 48 h fasting test showed no signs of insulinoma. There were no signs of reactive hypoglycemia, insulin autoimmune syndrome, or adrenal insufficiency. His wife had been taking medication for diabetes, including sulfonylurea. She had dementia, and he managed her medication. Since his medication was found in his wife's medicine box, we considered the possibility that he might have taken sulfonylurea by mistake. We asked his daughter to manage their medicine. However, one month later, he was admitted to our hospital again with severe hypoglycemia. His wife's HbA1c value and estimated glomerular filtration rate were 6.9% and 30 ml/min/1.73 m2. We asked his wife's home doctor to stop sulfonylurea prescription, and the hypoglycemia did not recur, with his wife's level of HbA1c remaining stable.Elderly individuals and patients with an impaired renal function are prone to hypoglycemia from sulfonylurea. In elderly households, there is a possibility of accidental ingestion of oral hypoglycemic agents by other family members living with the patient. It is therefore necessary to understand and manage the medications of family members living together. It is also important to avoid prescribing medications with a high risk of hypoglycemia to elderly patients.

A case of a novel hemoglobin variant, Hb A2-Karatsu, discovered following a falsely elevated HbA1c value.

The patient, a man in his thirties, presented to our hospital for a secondary examination after a 2020 medical check-up found a high hemoglobin A1c (HbA1c) level on high-performance liquid chromatography (HPLC). The HbA1c level determined by HPLC (HA-8180V, fast mode) was elevated at 6.8%, but a 75-g glucose tolerance test showed normal glucose tolerance. The glycated albumin level was within the reference range at 14.6%. The continuous glucose monitoring-derived mean blood glucose and the percentage of time in range were 99 mg/dL and 98%, respectively. The HbA1c levels determined by HPLC (G9, fast mode), enzymatic assay, and immunoassay were all 5.3%. An isoelectric focusing analysis showed an abnormal band on the anode side of HbA2, and a globin gene analysis detected a heterozygous mutation at codon 144 [AAG (Lys) → TAG (stop codon)] in the δ-chain. Since this mutation is a novel δ-chain hemoglobin variant, it was given the name 'Hb A2-Karatsu'.