Reset osmostat: Facts and controversies

Reset osmostat (RO) consists of a change in the normal plasma osmolality threshold (reduction or increase), which consequently induces chronic dysnatremia (hyponatremia or hypernatremia). Although the early papers on RO state that hyponatremic patients with this condition are usually not symptomatic, the current view is that most patients with hyponatremia are symptomatic and should be treated. RO has been associated with a myriad of clinical conditions and has clear diagnostic criteria which are crucial to arrive at the correct diagnosis and treatment.