Aetiology and outcome of acute and chronic renal failure in infants

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1 Nephrol Dial Transplant (2008) 23: doi: /ndt/gfm863 Advanced Access publication 8 January 2008 Original Article Aetiology and outcome of acute and chronic renal failure in infants Mirja Wedekin, Jochen HH Ehrich, Gisela Offner and Lars Pape Department of Pediatric Kidney-, Liver- and Metabolic Diseases, Children s Hospital, Hannover Medical School, Hannover, Germany Abstract Background. The aetiology and outcome of acute (ARF) and chronic renal failure (CRF) in infants were analysed in a retrospective study. Methods. Between January 1997 and April 2004 all children <1 year of age with a serum creatinine >100 µmol/l at Hannover Medical School were followed up for up to 6 years. One hundred and nineteen children with a serum creatinine >100 µmol/l were identified, 70 infants suffering from ARF and 49 from chronic kidney disease (CKD), stages 3 5. Results. Renal failure was caused in 49/119 (41%) by congenital and in 70/119 (59%) by acquired diseases. The aetiology of ARF (n = 70) included cardiac (27%), prematurity (27%), septic (10%), hepatic (9%), renal (9%) and other (18%) causes. Twelve infants needed transient dialysis treatment. Renal function recovered in all surviving children. The mortality rate was 37%. Causes of death were unrelated to kidney function. Twenty-one of 49 infants with CKD were dialyzed with a median age of 65 days at the start of dialysis, and 23/49 children received a kidney transplant (RTx). The 5-year patient and graft survival for RTx-children of 95.5% was not different from older children. The 5-year patient survival rate of 26 children with CKD without RTx was 63%. The causes of death were parental refusal of therapy in neonates (n = 4) and life-threatening extra-renal comorbidity (n = 3). Conclusion. Renal replacement therapy offers good chances of survival in infants without life-threatening comorbidity. Patient survival of infants treated for CKD in the first year of life was comparable to that of older children. Keywords: dialysis; infants; kidney transplantation; terminal renal failure Introduction Thirty years ago, many infants suffering from severe acute (ARF) or chronic renal failure (CRF) died because of the Correspondence and offprint requests to: Lars Pape, Department of Pediatric Nephrology, Hannover Medical School, Carl-Neuberg-Strasse 1, D Hannover, Germany. Tel: ; Fax: ; larspape@t-online.de technical limitations of renal replacement therapy (RRT), or because of the limited availability of dialysis or transplantation in many countries. Early reports on RRT for end-stage renal failure in infants were discouraging [1]. During a European conference on RRT in infants held in Berlin in 1998 there was controversy as to whether all infants with end-stage renal disease should be treated by RRT. In the past, paediatric nephrologists offered RRT preferably to children older than 1 year, and the parents decision to refuse RRT was more often accepted by nephrologists if the patients were <1 month old [2]. The age group <2 years was described as a risk factor for transplantation, because mortality and graft failure were high [3,4]. In recent years, RRT has also become a routine procedure in infants. Transplantation is regarded as the treatment of choice for all children with end-stage renal disease, regardless of age, offering the best potential for catch-up growth and development [5 9]. ARF is a significant factor of morbidity in critically ill children. Nearly half of the cases of ARF in children were reported to have occurred in the first year of life [10]. The most common causes were renal ischaemia, nephrotoxic medications and sepsis [11]. As data on the aetiology and outcome of infants with ARF and CRF is scarce, we report our experience of the treatment of 119 infants. Patient and methods Between January 1997 and April 2003, all 119 infants with a serum creatinine >100 µmol/l in the first year of life were recorded in a retrospective study at the Children s Hospital of Hannover Medical School (119 identified patients, 119 cases with adequate data). We chose creatinine >100 µmol/l as a marker for renal insufficiency because it allowed a simple database research, assuring that all infants with decreased renal function were included in our analysis. Neonates with a short-term postnatal increase of creatinine due to maternal creatinine >110 µmol/l were excluded. The median follow-up of patients was 2.9 years (0.2 6). Data collection In the first year of life data were collected monthly, thereafter every 6 months. Glomerular filtration rate (GFR), start of dialysis, age at transplantation and age and cause of death C The Author [2008]. Published by Oxford University Press on behalf of ERA-EDTA. All rights reserved. For Permissions, please journals.permissions@oxfordjournals.org

2 1576 M. Wedekin et al. Table 1. Causes of renal failure leading to a serum creatinine >100 µmol/l in the first year of life Aetiology Number of patients Table 2. Dialysis treatment for acute renal failure in the first year of life Aetiology Number of infants Median time of with dialysis dialysis (days) Acute renal failure 70/119 (59%) Structural anomaly of the heart 19/70 (27%) Prematurity 19/70 (27%) Other diseases 13/70 (18%) Sepsis/multiorgan failure 7/70 (10%) Liver disease 6/70 (9%) Acquired renal disease 6/70 (9%) Chronic renal failure 49/119 (41%) Prematurity 3/19 22 Structural anomaly 2/19 25 of the heart Other diseases 0/13 n.a. Sepsis/multiorgan failure 0/7 n.a. Acquired renal disease 5/6 171 Liver disease 2/6 40 were recorded. A mini-questionnaire was sent to parents to collect information concerning prenatal diagnosis, the course of this and previous pregnancies and psychosocial aspects during follow-up (55/119 with adequate data, 33/49 in the group of CRF). Statistical analysis The Kaplan Meier analysis was used for patient survival. A t-test was applied to show significant difference in growth at different points in time. Results are given as mean or median plus/minus range depending on whether normal distribution was given (Kolmogorov Smirnov test). A P- value of <0.05 was considered as significant. The Schwartz formula was used to calculate GFR [12]. Results Incidence Between January 1997 and April 2003, 119 infants (81 males and 38 females) with a serum creatinine >100 µmol/l were treated for ARF and CRF. Forty-one percent of infants (49/119) suffered from congenital renal disease and 59% (70/119) from acquired diseases (Table 1). Eight infants per year were registered with chronic kidney disease (CKD) stages 3 5 [13], suggesting an estimated incidence of CKD in Lower Saxony of 1: live births. Twelve infants per year were recorded as suffering from ARF. Acute renal failure Aetiology Seventy infants suffered from ARF, 64 following structural or functional anomalies of the heart, liver disease, sepsis or prematurity and 6 infants suffered from acquired renal disease (Table 1). Treatment Twelve infants underwent dialysis therapy (Table 2). All 44 surviving infants attained complete recovery of renal function (Table 3). One infant was unavailable for follow-up. Causes of death in 26 children were related to the underlying extrarenal disorders and no child died from ARF. Table 3. Outcome of acute renal failure in infants Aetiology Complete recovery Death of renal function Prematurity 13/19 7/19 Structural anomaly of the heart 13/19 8/19 Other diseases 11/13 4/13 Sepsis/multiorgan failure 4/7 3/7 Acquired renal disease 5/6 1/6 Liver disease 4/6 3/6 Fig. 1. Cumulative patient survival of 119 infants with renal failure in the first year of life (ARF n = 70, CKD stages 3 5, n = 49). Survival Patient survival of infants with ARF after 1, 2 and 5 years was 62%, 60% and 53%, respectively. Most infants died of their underlying cardiac or hepatic diseases (11/70), sepsis or multiorgan failure (6/70), prematurity (6/70), unknown causes (1/70), accident (1/70) and post-liver transplant lymphoproliferative disease (1/70).

3 Aetiology and outcome of acute and chronic renal failure in infants 1577 Table 4. Causes of CKD in the first year of life CKD Number of patients Renal dysplasia 18 (37%) Obstructive uropathy 16 (33%) Polycystic renal disease 5 (10%) Connatal nephrotic syndrome 5 (10%) VACTERL-association 3 (6%) Renal failure of unknown origin 1 (2%) Denys Drash syndrome 1 (2%) Fig. 2. Cumulative patient and graft survival of 23 transplanted children developing CNI during infancy. Chronic kidney disease Aetiology Renal dysplasia and obstructive uropathy were the main causes of CKD with a male/female ratio of 2.8:1 (Table 4). Treatment Twenty-one of 49 infants with CRF were dialyzed, beginning at a median age of 65 days range (5 531) for a median period of 313 days (27 897). All infants were treated with peritoneal dialysis. Twenty-three of 49 children received a kidney transplant. Sixteen of 23 children were successfully transplanted after a median period of 349 days on dialysis treatment, and 7 patients underwent pre-emptive renal transplantation. At transplantation, the median age of recipients was 1.9 years ( ), mean weight was 11.2 kg ( ) and mean height was 81.2 cm ( ). The median age of donors was 33 years (range 7 47). Survival Thirty-six of 49 (74%) infants with CKD survived for a mean follow-up of 2.9 years. The estimated 1-, 2- and 5-year patient survival of all 49 infants with CRF was 78%, 68% and 63%, respectively (Figure 1). Excluding the four babies with CRF who were not offered RRT, the estimated patient survival of the remaining 45 children was 90.6% after 1 year, and 82.6% after 2 and 5 years. The estimated patient survival of 23 transplanted children was 95.5% at the age of 1, 2 and 5 years (Figure 2). Seven of 49 infants with congenital CRF died after 5 to 106 days. Four of seven newborns were not offered RRT because of severe extrarenal comorbidity. The parents wish to withhold RRT was discussed and accepted during a conference with the local ethical committee. Three boys and one girl suffered from autosomal recessive polycystic kidney Table 5. Outcome of infants suffering from CKD in the first year of life Total Death NTx Renal dysplasia Obstructive uropathy Polycystic renal disease Connatal nephrotic syndrome VACTERL-association 3 Renal failure of unknown origin 1 1 Denys Drash syndrome 1 1 Total disease (ARPKD) and pulmonary hypoplasia. The infants died after 5 to 43 days. Three infants died while on dialysis treatment. One boy, having multicystic kidney disease on one side and ureteral agenesis on the other side, died of uraemia and respiratory insufficiency aged 93 days. One girl with Denys Drash syndrome died of cerebral insult on Day 167. One boy with CKD of unknown origin died of respiratory complications on Day 106. Two of 23 transplanted children died after a successful transplantation. One child had ARPKD and died from liver failure while on the waiting list for liver transplantation. The other child developed a lung oedema of unknown origin 2 months after the renal transplantation. Four children died while on conservative or dialysis treatment of CKD. One girl died due to a traffic accident. The other three infants on dialysis treatment died of myocardial dysfunction, and liver failure of unknown origin (figure 3, Table 5). Glomerular filtration rate The mean creatinine peak was 159 µmol/l for infants who underwent conservative treatment only, 426 µmol/l for infants receiving dialysis treatment only and 486 µmol/l for those children prior to transplantation. The mean GFR at the last follow-up of patients who underwent conservative treatment was 53 ml/min/1.73 m 2 and 9 ml/min/1.73 m 2 for patients who needed dialysis treatment. The mean GFR at the last follow-up of transplanted patients (mean time after RTx = 2.03 years) was 75 ml/min/1.73 m 2 (range ) (Table 6). Comorbidity Eleven of 13 deaths were associated with extrarenal malformations. Comorbidities were congenital heart defect,

4 1578 M. Wedekin et al. Fig. 3. The outcome of 49 infants with chronic renal failure diagnosed in the first year of life. Table 6. GFR of transplanted infants at the end of observation time (values in bold: death). No transplant failure Age at transplantation (years) GFR (ml/min/1.73 m 2 ) at last point of observation ml/min/m years after NTx ml/min/m years after NTx ml/min/m years after NTx ml/min/m years after NTx ml/min/m years after NTx ml/min/m years after NTx ml/min/m years after NTx ml/min/m years after NTx ml/min/m years after NTx ml/min/m years after NTx ml/min/m years after NTx ml/min/m years after NTx ml/min/m years after NTx ml/min/m years after NTx ml/min/m years after NTx ml/min/m years after NTx ml/min/m years after NTx ml/min/m years after NTx ml/min/m years after NTx ml/min/m years after NTx ml/min/m years after NTx ml/min/m years after NTx ml/min/m years after NTx liver cirrhosis, lung hypoplasia, hypothyroidism, apoplexia, analatresia and urogenital sinus. of the newborns at birth was 36.3 weeks (range 30 42). Median maternal age at birth was 28.4 years (range 18 39) for mothers and 31.3 years for fathers (21 50). Course of pregnancies The evaluation of the mini-questionnaire showed that renal abnormalities were diagnosed antenatally in nearly half of the infants with congenital CKD. Oligohydramnia was found in 29/49 foetuses and ultrasonography revealed pathological findings of the foetal renal tract in one-third of the pregnancies. The median gestational age at the time of ultrasonographic diagnosis of renal malformations was 26.8 weeks varying between the 17th and 35th weeks of pregnancy. Karyotyping was performed in 11/49 of the cases; no child showed karyotype abnormalities. One child with ARPKD was diagnosed prenatally. Median gestational age Parental coping The majority of the parents with surviving children felt profoundly restricted in their job and moderately in the categories family, time for other children and spare time. The social acceptance and the acceptance within their circle of friends were not ranked as a burden (Figure 4). Infants reached the following milestones of statomotor development: sitting independently at a mean age of 10.7 months (6 24) and walking 19.8 (12 48). Further details of psychomotor development were not included in the questionnaire.

5 Aetiology and outcome of acute and chronic renal failure in infants 1579 Fig. 4. Influence of the children s disease on their parents life. The size of the circle represents the mean influence of the child s disease on each item for their parents. Discussion The incidence of CKD, stages 3 5 in children below 1 year in Lower Saxony, Germany, between January 1997 and April 2003 ranged between 7 and 9 infants per newborns per year. This is confirmed by other research papers [14,15]. The proportion of children with prematurity in the group of infants with CKD was 53% (26/49) and thus significantly higher than the total infant population of Germany (6%). The incidence of severe infantile ARF in Lower Saxony cannot be estimated because of the definition of ARF (>100 µmol/l) and because it cannot be ruled out that some infants with a serum creatinine >100 µmol/l were treated in one of the other five major regional children s hospitals in Lower Saxony. We showed that severe renal dysfunction was acute in 59% and chronic in 41% of infants. Acute renal failure: Mortality is dominated by this underlying disease. No deaths occurred from ARF. No patients with ARF developed CKD. In the group of infants with CKD, our data confirm the findings of others reporting the dominance of renal dysplasia and obstructive uropathy [14,16] and also confirm the predominance of chronic infantile renal failure in males [4,14,17,18]. Infants with obstructive uropathy had a better prognosis than those with other congenital renal diseases [19]. Lung hypoplasia had an adverse effect on survival. Peritoneal dialysis was the most common treatment in infants requiring dialysis [17,20]. Nevertheless, dialysis treatment was a risk factor concerning the survival of young children [21]. In the early years, renal transplantation in very young children was also followed by increased mortality; however, recent data show good patient survival in young children, too. Graft survival was superior in young children undergoing pre-emptive renal transplantation. This may be associated with the fact that pre-emptive RTx is mostly performed with living donors [22]. Therefore, we conclude that the treatment of choice for infants with end-stage renal failure should be early renal transplantation. A younger age at the start of RRT was a risk factor for mortality [21,23,24] but early transplantation, especially pre-emptive transplantation, has been shown to improve survival and reduce mortality in children <5 years of age with CRF [25]. Survival of transplanted infants was comparable to that of older children. Elshiabi et al. [26] and McDonald et al. [27] reported patient survival at 1, 2 and 5 years for CAD 96.3%, 95.2% and 91.4% for LRD 97%, 96.5% and 94.5%. Furthermore, Najarian et al. found no difference in patient survival or graft survival between children aged <1 year, 1 2 years and 2 5 years [28]. The social acceptance of CKD and the acceptance of this illness within the circle of friends were complicated by a number of factors. Primarily parents felt restricted in their job. Although there was a considerable burden in their every day life, most families reported having developed positive coping strategies. Astonishingly, the groups no affect on life was most often chosen in all items. In conclusion, RRT in children without severe comorbidity starting CKD under 1 year of age is encouraging. Patient survival has increased in recent years and is similar to that of older children. ARF in infants has an excellent short-term prognosis for the recovery of normal renal function. Conflict of interest statement. None declared. References 1. Moel DI, Butt KM. Renal transplantation in children less than 2 years of age. J Pediatr 1981; 99: Geary DF. Attitudes of pediatric nephrologists to management of end-stage renal disease in infants. J Pediatr 1998; 133: Warady BA, Hebert D, Sullivan EK et al. Renal transplantation, chronic dialysis, and chronic renal insufficiency in children and adolescents. The 1995 Annual Report of the North American Pediatric Renal Transplant Cooperative Study. Pediatr Nephrol 1997; 11: Ehrich JH, Rizzoni G, Brunner FP et al. Renal replacement therapy for end-stage renal failure before 2 years of age. Nephrol Dial Transplant 1992; 7:

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