Fractional excretion of urea in severely dehydrated elderly with dementia

MUSSO, CARLOS GUIDO; CACERES, J.; PERALTA, M.; LUQUE, K.; VARELA, FEDERICO; DOS RAMOS FARIAS, E.; ALGRANATI, LUIS

Electron J Biomed

MJ Coma MD, PhD. Unidad de Investigación. Hospital General Yagüe.

Año: 2005

Fractional excretion of urea (FEurea) is a useful marker to evaluate renal perfusion in people with normal renal function. The value of this marker in a well hydrated person is around 50%, in a low renal perfusion state is lower than 35%, and in an over-hydrated state is higher than 65%.A recent study reported that well-hydrated healthy old and very old people had FEurea higher than young people under the same conditions. That faced us with the fact that there is no information about FEurea values during abnormal renal perfusion states in the elderly.We present two dehydrated elderly patients with dementia that provided us with an opportunity to evaluate the FEurea.Conclusion: We observed that only during severe dehydration an old patient with dementia reached a low FEurea (20%) as a young person. When these patients were dehydrated (hypernatremic) but not hypotensive they showed FEurea higher than a young patient. It seems that new FEurea values are needed in this age group to interpret altered renal perfusion states.