Syndrome of inappropriate secretion of antidiuretic hormone after endoscopic submucosal dissection for early gastric cancer.

We report the first case of syndrome of inappropriate secretion of antidiuretic hormone (SIADH) after endoscopic submucosal dissection (ESD) for early gastric cancer. A 64-year-old man with early gastric cancer was admitted to our hospital for ESD. Baseline laboratory tests showed a serum sodium concentration of 132 mEq l(-1). We performed an ESD for the gastric cancer, which was 9 mm in diameter and located in the posterior wall of the mid-gastric body. The patient experienced nausea and lethargy the second day after ESD. His serum sodium level was low (118 mEq l(-1)), and he fulfilled the criteria for SIADH. Fluid restriction, infusion of normal saline, and administration of diuretics gradually increased his serum sodium level, and his symptoms disappeared. Endoscopists should recognize that SIADH is a potential complication of endoscopic procedures such as ESD, especially among patients with low baseline sodium concentrations.