Renal Functional Reserve Evolution in Children with a Previous Episode of Hemolytic Uremic Syndrome

Abstract

Introduction: Glomerular filtration rate (GFR) is the most widely used indicator of kidney function in patients with renal disease, although it does not invariably reflect functional status after renal injury. The concept of renal functional reserve (RFR) as the ability of the kidney to increase GFR following a protein load was introduced in the 1980s. In this study we evaluated the RFR test in 26 children who had developed hemolytic-uremic syndrome (HUS) at least 2 years before the first evaluation, then 8 years later. At the beginning of the study they had no signs of proteinuria, hypertension or renal insufficiency. RFR was also evaluated in 15 healthy control children. Methods: Proteinuria and creatinine in serum and urine were tested. Functional reserve index (FRI) was defined in order to evaluate RFR. Patients with FRI level >1.36 were considered as responders (R) and with FRI <1.36 as non-responders (NR). Results: R and NR groups failed to show any significant differences when basal creatinine clearance (C_Cr) was evaluated. The NR group presented a significant low initial FRI that persisted unchanged at the end of the study. These patients developed proteinuria and a renal protector treatment with protein restriction was indicated. Although the proteinuria diminished, it remained within pathological range. The lack of RFR response in the NR group was significantly related to the presence of oliguria lasting longer than 8 days during the acute phase of disease. Conclusions: Those patients with a previous history of HUS with normal basal C_Cr should be evaluated by the RFR test to detect those at risk of developing glomerular hyperfiltration.

Reserva funcional renal mediante la depuración de ácido dietilen-triamino-pentaacético marcado con tecnecio-99m en niños que padecieron síndrome urémico-hemolítico

“…9 Este estudio mostró un mayor porcentaje de pacientes sin RFR, con respecto a estudios anteriores. 14,15 Esto podría deberse a la inclusión de pacientes con menos de dos años de evolución después de haber padecido el episodio agudo de SUH.…”

Effect of Chronic Inhibition of Converting Enzyme on Renal Handling of Salt and Water: A Study on a Pediatric Population

“…The patients selected were eutrophic with adequate diuresis and euhydration; they were normotensive according to the tables for children in a normal population of the same age and sex [9]. The children had normal renal function and a creatinine clearance, with cimetidine premedication [10,11], greater than 90 ml/min/1.73 m 2 . The concentration capacity was normal with urinary osmolality greater or equal than 850 mosm/kg H 2 O which is the lower level observed in our population of healthy children [12].…”

What’s new in haemolytic uraemic syndrome?

“…It is important to note that although the glomerular filtration rate returns to normal in most patients, there may be permanent nephron loss, which may have longer term sequelae [9,32]. A recent systematic review and meta-analysis of the intermediate outcome of Stx-HUS described permanent and serious renal sequelae (hypertension, proteinuria, declining GFR) in 5-25% of patients [18].…”