ABSTRACT
Picosulfate sodium/Magnesium citrate (PS/MC) is a common bowel cleansing agent for colonoscopy. It is equally effective and better tolerated by patients with regard to taste and volume than polyethylene glycol. However, because of its osmotically active characteristics, PS/MC can cause plasma volume depletion and electrolyte disturbances, such as hyponatremia. Here, we report a case of severe hyponatremia combined with loss of consciousness in a 59-year-old woman following ingestion of PS/MC as bowel preparation for a screening colonoscopy. Upon arrival, serum sodium level was 109 mEq/L and urine osmolality and sodium levels were 393 mOms/Kg and 99 mmol/L, respectively. She was euvolemic and showed normal kidney, thyroid, and adrenal function. Based on these findings, inappropriate anti-diuretic hormone syndrome (SIADH) was diagnosed. She was treated with 3% hypertonic saline and completely recovered without any neurologic sequelae. This case shows that SIADH can be caused by PS/MC (not accompanied by dehydration), even in patients without any underlying renal, heart, or liver diseases.