Postoperative hyponatremia as a complication of knee arthroscopy

We report the case of a 4 year old boy who developed a massive water intoxi cation as a complication during knee arthroscopy. The sodium plasma concent ration dropped to 100 mmol/l postoperatively. This complication may be trig gered by prolonged surgery time, excessive intra-articular pressure, capsul ar tears and low body weight. To prevent massive incorporation of hypoosmol ar fluid, the inflation of a tourniquet as well as the use of NaCl 0,9% as irrigation fluid seems to be of advantage. The guidelines for replacing sod ium in hyponatremia are discussed according to literature. In general, hypo natremia should be corrected in the same amount of time as it took for it t o develop.