**8. Change cerebral salt wasting to renal salt wasting**

The 2 cases of RSW without clinical cerebral disease were the impetus to propose replacing the designation, cerebral salt wasting, to renal salt wasting. (Bitew et al, 2009; Maesaka et al, 2007, 2009) Based on these reports, cerebral salt wasting should be considered an outmoded and inappropriate designation; it should now be called RSW because RSW will be considered in any hyponatremic patient with or without cerebral disease. (Maesaka et al, 2009) Although we feel that RSW might be rare in patients without clinical cerebral disease, these cases of RSW without clinical cerebral disease support our contention that the true prevalence of RSW cannot be viewed as rare until future studies can accurately determine the prevalence of SIADH and RSW in patients with and without clinical evidence of cerebral disease. This would depend on our ability to differentiate SIADH from RSW. The volume studies indicate that RSW is much more common than SIADH in neurosurgical patients. We hope this expanded approach to hyponatremia and RSW will eliminate the inappropriate treatment of RSW by fluid restriction, which has been shown to increase morbidity and mortality when misdiagnosed as SIADH. (, Gutierrez & Lin, 2009; Maesaka et al, 1990, 2007; Wijdicks et al, 1985)
