Spurious Elevation of Glucose Concentration during Administration of High Dose of Ascorbic Acid in a Patient with Type 2 Diabetes on Hemodialysis

We describe herein a case of life-threatening hypoglycemia due to spurious elevation of glucose concentration during the administration of ascorbic acid in a type 2 diabetic patient. A 31-year-old female was admitted for proliferative diabetic retinopathy treatment and prescribed high dose ascorbic acid. During hospitalization, she suddenly lost her consciousness and her glucose concentration was 291 mg/dL, measured using self-monitoring blood glucose (SMBG) device, while venous blood glucose concentration was 12 mg/dL. After intravenous injection of 50% glucose solution, the patient became alert. We reasoned that glucose measurement by SMBG device was interfered by ascorbic acid. Physicians should be aware of this interference; high dose ascorbic acid may cause spurious elevation of glucose concentration when measuring with SMBG devices.

Delayed Surgery for Parathyroid Adenoma Misdiagnosed as a Thyroid Nodule and Treated with Radiofrequency Ablation

Primary hyperparathyroidism occurs as a result of isolated parathyroid adenoma in 80% to 85% of all cases. A 99mtechnetium (99mTc) sestamibi scan or neck ultrasonography is used to localize the neoplasm prior to surgical intervention. A 53-year-old female was referred for the exclusion of metabolic bone disease. She presented with low back pain that had persisted for the past 6 months and elevated serum alkaline phosphatase (1,253 IU/L). Four years previously, she had been diagnosed at a local hospital with a 2.3-cm thyroid nodule, which was determined to be pathologically benign. Radiofrequency ablation was performed at the same hospital because the nodule was still growing during the follow-up period 2 years before the visit to our hospital, and the procedure was unsuccessful in reducing the size of the nodule. The results of the laboratory tests in our hospital were as follows: serum calcium, 14.6 mg/dL; phosphorus, 3.5 mg/dL; and intact parathyroid hormone (iPTH), 1,911 pg/mL. Neck ultrasonography and 99mTc sestamibi scan detected a 5-cm parathyroid neoplasm in the left lower lobe of the patient's thyroid; left parathyroidectomy was performed. This case indicated that thyroid ultrasonographers and pathologists need to be experienced enough to differentiate a parathyroid neoplasm from a thyroid nodule; 99mTc sestamibi scan, serum calcium, and iPTH levels can help to establish the diagnosis of parathyroid neoplasm.