[Hyponatremia-workflow for intensive care physicians].

Hyponatremia (sodium <135 mmol/l) is the most common electrolyte disorder. Despite identical serum concentrations, clinical symptomatology can vary greatly from mild to life-threatening. Accordingly, individual patients require immediate active treatment, while the majority of (mostly oligosymptomatic) patients should first undergo differentiated diagnosis. The most important element is the assessment of the clinical situation of the patient and never isolated laboratory chemical constellations: "Treat the patient, not the numbers".