Renal reserve in the oldest old.

INTRODUCTION: Decline in glomerular filtration rate (GFR) is one of several changes in renal physiology in the elderly. Renal reserve (RR) is the kidney's capacity to increase its basal GFR by at least 20% after a protein overload. Even though it has already been reported that RR is preserved in healthy old people, there is no information whether RR is also preserved in the healthy very old one (older than 74 of age), which we decided to study and report our findings in this paper. MATERIAL AND METHOD: We studied RR in 16 healthy persons divided into three age groups: young: 20-40 years old (n: 5): 64-74 years old (n: 6) and oldest old: >74 years old (n: 5). Renal reserve test was performed by assessing creatinine clearance with cimetidine before and after an oral protein load. Statistical analysis was performed using ANOVA test. RESULTS: Even though renal reserve response was present in all age groups, its magnitude (delta GFR) was significantly higher in the healthy young group (103.6 ± 53 ml/min) compared to the old one (34.1 ± 40 ml/min) (P = 0.002), while it was significantly lower in the healthy oldest old (20.7 ± 0.7 ml/min) group compared to the other two groups (P = 0.002). CONCLUSION: Renal reserve is preserved in healthy very old people, but its magnitude decreases significantly with age.

Combination of oral activated charcoal plus low protein diet as a new alternative for handling in the old end-stage renal disease patients.

Chronic dialysis is a valid therapeutic option in very elderly ESRD patients, even though the decision to dialyze or not has little impact on survival. Additionally, very old patients usually do not agree with starting chronic dialysis. Even though, activated charcoal is a cheap treatment for working as adsorbent for nitrogenous products its utility is very limited. We studied the combination of a low protein diet and oral activated charcoal to reduce serum urea and creatinine levels in very old ESRD patients who had refused to start chronic dialysis. Nine lucid, very old > 80 years, ESRD patients who had refused to start dialysis were prescribed a treatment based on a combination of a very low protein diet and oral activated charcoal (30 gram/day). None of the patients had anuria, oliguria, edema, significant metabolic acidosis or hyperkalemia. None of them had significant gastrointestinal symptoms. After one week and ten months of charcoal use significant decrease in blood urea and creatinine levels was observed and none of them required emergency dialysis during this time. In conclusion, in patients more than 80 years of age low protein diet and oral activated charcoal may control the uremic symptoms effectively.

Renal potassium excretion: comparison between chronic renal disease patients and old people.

UNLABELLED: Senescence and chronic renal failure bring about a progressive glomerular filtration reduction. Moreover, a reduction in glomerular filtration usually modifies the potassium renal excretion. In the present study, we compared the renal potassium handling between old and chronic renal disease populations. MATERIALS AND METHODS: Fifty-five volunteers were studied, 43 of them were healthy old persons and 12 were predialysis chronic renal disease patients. Exclusion criteria were: presence of altered plasma potassium (Kp), diabetes mellitus, obstructive uropathy, drugs that could alter plasma potassium levels. All volunteers were on a diet with a potassium content around 50 mmol/day (3-day dietary register). We measured potassium, creatinine, urea in plasma and 24 hours urine. We also measured creatinine clearance (CrCl) and fractional excretion of potassium (FEK), and we studied the relationship between these parameters. Statistical analysis was made using Student's test. RESULTS: Slopes of the correlation curves between CrCl and FEK. [Table: see text]. CONCLUSION: The relationship between creatinine clearance and fractional excretion of potassium in old and chronic renal disease groups were different with the excretion of potassium being lower in the elderly.

Plasma erythropoietin levels in the oldest old.

UNLABELLED: Erythropoietin (EPO) regulates erythrocytes production and is synthesized mainly by the kidney. Its production is reduced during chronic renal failure but is not altered by the senescence process in spite of the morphological changes that occur in the kidney. However, there is no information regarding what happens to erythropoietin synthesis during advanced ageing. Thus, we carried out an investigation to determine whether there was any significant difference in plasma erythropoietin between adults, old and very old people. MATERIAL AND METHODS: We studied 74 healthy volunteers: 22 adults, 30 old, and 22 very old. None of them were smokers or were suffering from any disease that may intefere with hemoglobin (Hb) levels or with EPO production. Hematocrit, Hb, plasma creatinine and plasma erythropoietin were measured, and creatinine clearance was calculated from serum creatinine using two different formulae. Statistical analysis was performed using ANOVA and Bonferroni tests. RESULTS AND CONCLUSION: Among the three groups we found a significant difference in creatinine clearance (p < 0.001), but not in plasma erythropoietin levels; we conclude that normal senescence does not alter plasma erythropoietin levels, even during advanced ageing.

Fístula urinaria en el trasplante renal / Urinary fistula in the renal transplantation

Entre agosto de 1988 y diciembre de 1995 se realizaron 73 trasplantes renales en el Hospital Italiano de Buenos Aires. El seguimiento medio fue de 35 meses. Se evaluó la incidencia de fístula urinaria ureterovésical y la repercusión de la misma en la evolución del implante renal. Se constataron 6 casos de fístula. En todos los casos el diagnóstico fue clínico (dolor abdominal, caída del ritmo diurético, pérdida de orina por la herida) y en algunos casos se emplearon, además la cistografía y ecografía para la evaluación de esyos pacientes. El tiempo trancurrido al momento del diagnóstico fue menor de 24 hrs. en cuatro pacientes y mayor de 72 hrs. en los restantes. La resolución fue quirúgica en todos los casos (reimplante ureterovesical). La incidencia de fístula urinaria fie del 8,21 por ciento (seis pacientes). De los pacientes en los que el diagnóstico fue precoz tres conservan una función renal aceptable y el cuarto quedó con función renal alterada. Aquellos en los que el diagnóstico fue más tardío presentaron en el seguimiento estenosis ureterovesical (18 meses). Los estudios por imágenes utilizados en la evaluación de algunos de estos pacientes no fueron utilidad para llegar al diagnóstico. El seguimiento estricto en el postoperatorio inmediato y un diagnóstico precoz son cruciales para el tratamiento adecuado d esta complicación. Los estudios imagenológicos no aportaron infor mación para decidir la conducta. En los pacientes que presentaron fístula se observó una mayor incidencia de estenosis ureterovesical en el seguimiento a lar go plazo (33 por ciento)