2023 Volume 66 Issue 6 Pages 476-481
The patient was a 60-year-old man who was found to have a high HbA1c level (10.0 %) during a visit to his primary care physician due to weight loss of 7 kg/year, and was then referred to our department. He showed a casual blood glucose level of 319 mg/dL and was diagnosed with type 2 diabetes, while his serum triglyceride level was ≥10000 mg/dL (reference value) and his serum sodium level was low (114 mEq/L), as measured by indirect ion selective electrodes (ISE) using an automatic biochemical analyzer. Since he was asymptomatic and his serum sodium level (as measured by a blood gas analysis [direct ISE]), was within the normal range, we concluded that severe hypertriglyceridemia caused pseudohyponatremia. With diet, glycemic control, and antihyperlipidemic drugs, the discrepancy between his serum sodium level, as measured by indirect ISE, and his serum sodium level, as measured by direct ISE, gradually decreased and eventually disappeared with a decrease in the serum triglyceride level. Although it is generally known that hypertriglyceridemia induces pseudohyponatremia, very few studies have been reported on pseudohyponatremia with serum triglyceride levels exceeding 10,000 mg/dL, which makes the present case valuable. In conditions in which the ratio of solid to water in plasma is altered (hyperlipidemia, hyperproteinemia, etc.), it is desirable to evaluate electrolytes by direct ISE.
