Renal function following acute renal failure in childhood: a long term follow-up study

Acute Kidney Injury and Renal Tubular Damage in Children With Type 1 Diabetes Mellitus Onset

CONTEXT

Acute kidney injury (AKI) and renal tubular damage (RTD), especially if complicated by acute tubular necrosis (ATN), could increase the risk of later chronic kidney disease. No prospective studies on AKI and RTD in children with type1diabetes mellitus (T1DM) onset are available.

OBJECTIVES

To evaluate the AKI and RTD prevalence and their rate and timing of recovery in children with T1DM onset.

DESIGN

Prospective study.

SETTINGS AND PATIENTS

185 children were followed up after 14 days from T1DM onset. The patients who did not recover from AKI/RTD were followed-up 30 and 60 days later.

MAIN OUTCOME MEASURES

AKI was defined according to the KDIGO criteria. RTD was defined by abnormal urinary beta-2-microglobulin and/or neutrophil gelatinase-associated lipocalin and/or tubular reabsorption of phosphate < 85% and/or fractional excretion of Na (FENa) > 2%. ATN was defined by RTD+AKI, prerenal (P)-AKI by AKI+FENa < 1%, and acute tubular damage (ATD) by RTD without AKI.

RESULTS

Prevalence of diabetic ketoacidosis (DKA) and AKI were 51.4% and 43.8%, respectively. Prevalence of AKI in T1DM patients with and without DKA was 65.2% and 21.1%, respectively; 33.3% reached AKI stage 2, and 66.7% of patients reached AKI stage 1. RTD was evident in 136/185 (73.5%) patients (32.4% showed ATN; 11.4%, P-AKI; 29.7%, ATD). All patients with DKA or AKI presented with RTD. The physiological and biochemical parameters of AKI and RTD were normal again in all patients. The former within 14 days and the latter within 2months.

CONCLUSIONS

Most patients with T1DM onset may develop AKI and/or RTD, especially if presenting with DKA. Over time the physiological and biochemical parameters of AKI/RTD normalize in all patients.

Pediatric acute kidney injury and the subsequent risk for chronic kidney disease: is there cause for alarm?

Acute kidney injury (AKI) is characterized clinically as an abrupt decline in renal function marked by reduced excretion of waste products, disordered electrolytes, and disrupted fluid homeostasis. The recent development of a standardized AKI definition has transformed our understanding of AKI epidemiology and outcomes. We now know that in the short term, children with AKI experience greater morbidity and mortality; additionally, observational studies have established that chronic renal sequelae are far more common after AKI events than previously realized. Many of these studies suggest that patients who develop AKI are at greater risk for the subsequent development of chronic kidney disease (CKD). The goal of this review is to critically evaluate the data regarding the association between AKI and CKD in children. Additionally, we describe best practice approaches for future studies, including the use of consensus AKI criteria, the application of rigorous definitions for CKD and renal sequelae, and the inclusion of non-AKI comparator groups. Finally, based upon existing data, we suggest an archetypal approach to follow-up care for the AKI survivors who may be at greater CKD risk, including children with more severe AKI, those who endure repeated AKI episodes, patients who do not experience full recovery, and those with pre-existing CKD.

High incidence of acute kidney injury during chemotherapy for childhood acute myeloid leukemia

BACKGROUND/OBJECTIVES

Childhood acute myeloid leukemia (AML) is a rare and heterogeneous disease. Pediatric data on the epidemiology of acute kidney injury (AKI) in AML are limited. We report on the incidence of AKI in childhood AML and the risk factors associated with AKI episodes.

METHODS

A retrospective cohort of 53 patients (≤18 years), with de novo AML, receiving chemotherapy over a 10-year period. All serum creatinine (SCr) levels during therapy-related hospitalizations were assessed to stage AKI episodes as per Kidney Disease: Improving Global Outcomes criteria. Severe AKI was defined as AKI stages 2 or 3 and urine output criteria were not used. AKI risk factors were assessed independently in both cycle 1 alone and combining all chemotherapy cycles.

RESULTS

AKI developed in 34 patients (64%) with multiple AKI episodes in 10 patients (46 total episodes). Twenty-four severe AKI episodes occurred in 23 patients (43.4%) with a mean duration of 26.1 days (SD 7.3). In cycle 1, hyperleukocytosis was not predictive of AKI, but severe sepsis was an independent risk factor of severe AKI (odds ratio [OR]: 13.4; 95% CI 1.9-94.9). With cycles combined, all subjects with AKI had severe sepsis and older age (≥10 years) was associated with severe AKI (OR: 20.8; 95% CI 3.8-112.2).

CONCLUSION

There was a high incidence of AKI in our AML cohort with a strong association with older age (≥10 years) and severe sepsis. Larger prospective studies are needed to confirm the high burden of AKI and risk factors in this susceptible population.

Acute kidney injury in children with sickle cell disease-compounding a chronic problem

In an article recently published in Pediatric Nephrology, Baddam and colleagues discuss the relatively underreported clinical problem of repeated episodes of acute kidney injury (AKI) in children with sickle cell disease (SCD). Their report is a cautionary note about the importance of repeated kidney injury on the background of underlying chronic kidney injury and its potential implications on long-term kidney outcome. In children and adults with SCD, this includes the effects of repeated vaso-occlusive crises and the management of these painful episodes with non-steroidal anti-inflammatory drugs. Here we review the scope of kidney involvement in SCD in children and discuss the potential short- and long-term consequences of AKI in children with SCD.

The path to chronic kidney disease following acute kidney injury: a neonatal perspective

The risk of acute kidney injury (AKI) in hospitalized critically ill neonatal populations without primary renal disease continues to be high, in both term and premature infants. Observational studies have revealed high rates of chronic kidney disease (CKD) in survivors of neonatal AKI. Proposed mechanisms underlying the progression of CKD following AKI include nephron loss and hyperfiltration, vascular insufficiency and maladaptive repair mechanisms. Other factors, including prematurity and low birth weight, have an independent relationship with the development of CKD, but they may also be positive effect modifiers in the relationship of AKI and CKD. The large degree of heterogeneity in the literature on AKI in the neonatal population, including the use of various AKI definitions and CKD outcomes, has hampered the medical community's ability to properly assess the relationship of AKI and CKD in this vulnerable population. Larger prospective cohort studies with control groups which utilize recently proposed neonatal AKI definitions and standardized CKD definitions are much needed to properly quantify the risk of CKD following an episode of AKI. Until there is further evidence to guide us, we recommend that all neonates with an identified episode of AKI should have an appropriate longitudinal follow-up in order to identify CKD at its earliest stages.

PROGRESSION OF CHRONIC KIDNEY DISEASE AFTER ACUTE KIDNEY INJURY

The incidence of chronic kidney disease (CKD) in children and adults is increasing. Cardiologists have become indispensable members of the care provider team for children with CKD. This is partly due to the high incidence of CKD in children and adults with congenital heart disease, with current estimates of 30-50%. In addition, the high incidence of acute kidney injury (AKI) due to cardiac dysfunction or following pediatric cardiac surgery that may progress to CKD is also well documented. It is now apparent that AKI and CKD are uniquely intertwined as interconnected syndromes. Furthermore, the well-known long-term cardiovascular morbidity and mortality associated with CKD require the joint attention of both nephrologists and cardiologists. Children with both congenital heart disease and CKD are increasingly surviving to adulthood, with synergistically negative medical, financial, and quality of life impact. An improved understanding of the epidemiology, mechanisms, early diagnosis, and preventive measures is of importance to cardiologists, nephrologists, scientists, economists, and policy makers alike. Herein, we report the current definitions, epidemiology, and complications of CKD in children, with an emphasis on children with congenital heart disease. We then focus on the clinical and experimental evidence for the progression of CKD after episodes of AKI commonly encountered in children with heart disease, and explore the role of novel biomarkers for the prediction of CKD progression.

Long-term risk of chronic kidney disease and mortality in children after acute kidney injury: a systematic review

BACKGROUND

Acute kidney injury (AKI) is associated with significant short-term morbidity and mortality in children. However, the risk for long-term outcomes after AKI is largely unknown.

METHODS

We performed a systematic review and meta-analysis to determine the cumulative incidence rate of proteinuria, hypertension, decline in glomerular filtration rate (GFR), and mortality after an episode of AKI. After screening 1934 published articles from 1985-2013, we included 10 cohort studies that reported long-term outcomes after AKI in children.

RESULTS

A total of 346 patients were included in these studies with a mean follow-up of 6.5 years (range 2-16) after AKI. The studies were of variable quality and had differing definitions of AKI with five studies only including patients who required dialysis during an AKI episode. There was a substantial discrepancy in the outcomes across these studies, most likely due to study size, disparate outcome definitions, and methodological differences. In addition, there was no non-AKI comparator group in any of the published studies. The cumulative incidence rates for proteinuria, hypertension, abnormal GFR (<90 ml/min/1.73 m2), GFR < 60 ml/min/1.73 m2, end stage renal disease, and mortality per 100 patient-years were 3.1 (95% CI 2.1-4.1), 1.4 (0.9-2.1), 6.3 (5.1-7.5), 0.8 (0.4 -1.4), 0.9 (0.6-1.4), and 3.7 (2.8-4.5) respectively.

CONCLUSIONS

AKI appears to be associated with a high risk of long-term renal outcomes in children. These findings may have implications for care after an episode of AKI in children. Future prospective studies with appropriate non-AKI comparator groups will be required to confirm these results.

Recognition and reporting of AKI in very low birth weight infants

BACKGROUND AND OBJECTIVES

AKI is associated with both increased short-term morbidity and mortality and greater long-term risk for CKD. This study determined the prevalence of AKI among very low birth weight infants using a modern study definition, evaluated the frequency of AKI diagnosis reporting in the discharge summary, and determined whether infants were referred to a pediatric nephrologist for AKI follow-up.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Records of very low birth weight infants admitted to a level IV neonatal intensive care unit from 2008 to 2011 were reviewed. AKI was classified using the Kidney Disease: Improving Global Outcomes definition modified to include only serum creatinine.

RESULTS

AKI occurred in 39.8% of 455 infants; 75 (16.5%) infants experienced multiple episodes of AKI, and 8 (2%) infants were discharged with an abnormal last creatinine. Updated clinical risk index for babies score >10 (odds ratio, 12.9; 95% confidence interval, 7.8 to 21.4) and gestational age <28 weeks (odds ratio, 10.6; 95% confidence interval, 6.8 to 16.7) were strongly associated with AKI in univariate analyses. AKI was associated with increased mortality (odds ratio, 4.0; 95% confidence interval, 1.4 to 11.5) and length of stay (11.7 hospital days; 95% confidence interval, 5.1 to 18.4), even after accounting for gestational age, birth weight, and updated clinical risk index for babies score. AKI was recorded in the discharge summary for only 13.5% of AKI survivors. No infants were referred to a nephrologist for AKI follow-up.

CONCLUSIONS

AKI occurred in 40% of very low birth weight infants and was concentrated in the most premature and severely ill infants. One in six infants experienced multiple episodes of AKI, and a small number of infants was discharged with an elevated serum creatinine. Reporting a history of AKI in the discharge summary occurred infrequently, and referral to a nephrologist for AKI follow-up did not occur, highlighting areas for quality improvement.

Delayed administration of pyroglutamate helix B surface peptide (pHBSP), a novel nonerythropoietic analog of erythropoietin, attenuates acute kidney injury

In preclinical studies, erythropoietin (EPO) reduces ischemia-reperfusion-associated tissue injury (for example, stroke, myocardial infarction, acute kidney injury, hemorrhagic shock and liver ischemia). It has been proposed that the erythropoietic effects of EPO are mediated by the classic EPO receptor homodimer, whereas the tissue-protective effects are mediated by a hetero-complex between the EPO receptor monomer and the β-common receptor (termed "tissue-protective receptor"). Here, we investigate the effects of a novel, selective-ligand of the tissue-protective receptor (pyroglutamate helix B surface peptide [pHBSP]) in a rodent model of acute kidney injury/dysfunction. Administration of pHBSP (10 μg/kg intraperitoneally [i.p.] 6 h into reperfusion) or EPO (1,000 IU/kg i.p. 4 h into reperfusion) to rats subjected to 30 min ischemia and 48 h reperfusion resulted in significant attenuation of renal and tubular dysfunction. Both pHBSP and EPO enhanced the phosphorylation of Akt (activation) and glycogen synthase kinase 3β (inhibition) in the rat kidney after ischemia-reperfusion, resulting in prevention of the activation of nuclear factor-κB (reduction in nuclear translocation of p65). Interestingly, the phosphorylation of endothelial nitric oxide synthase was enhanced by EPO and, to a much lesser extent, by pHBSP, suggesting that the signaling pathways activated by EPO and pHBSP may not be identical.

Long-term risk of CKD in children surviving episodes of acute kidney injury in the intensive care unit: a prospective cohort study

BACKGROUND

The development of standardized acute kidney injury (AKI) definitions has allowed for a better understanding of AKI epidemiology, but the long-term renal outcomes of AKI in the pediatric critical care setting have not been well established. This study was designed to: (1) determine the incidence of chronic kidney disease (CKD) in children 1-3 years after an episode of AKI at a tertiary-care pediatric intensive care unit (ICU), (2) identify the proportion of patients at risk of CKD, and (3) compare ICU admission characteristics in those with and without CKD.

DESIGN

Prospective cohort study.

SETTING & PARTICIPANTS

Patients admitted to the British Columbia Children's Hospital pediatric ICU from 2006-2008 with AKI, as defined by AKI Network (AKIN) criteria. Surviving patients, most with short-term recovery from their AKI, were assessed at 1, 2, or 3 years after AKI.

PREDICTORS

Severity of AKI as defined by AKIN and several ICU admission characteristics, including demographics, diagnosis, severity of illness, and ventilation data.

OUTCOMES & MEASUREMENTS

CKD was defined as the presence of albuminuria and/or glomerular filtration rate (GFR) < 60 mL/min/1.73 m2. Being at risk of CKD was defined as having a mildly decreased GFR (60-90 mL/min/1.73 m2), hypertension, and/or hyperfiltration (GFR ≥ 150 mL/min/1.73 m2).

RESULTS

The proportion of patients with AKI stages 1, 2, and 3 were 44 of 126 (35%), 47 of 126 (37%), and 35 of 126 (28%), respectively. The number of patients with CKD 1-3 years after AKI was 13 of 126 (10.3% overall; 2 of 44 [4.5%] with stage 1, 5 of 47 [10.6%] with stage 2, and 6 of 35 [17.1%] with stage 3; P = 0.2). In addition, 59 of 126 (46.8%) patients were identified as being at risk of CKD.

LIMITATIONS

Several patients identified with AKI were lost to follow-up, with the potential of underestimating the incidence of CKD.

CONCLUSIONS

In tertiary-care pediatric ICU patients, ∼10% develop CKD 1-3 years after AKI. The burden of CKD in this population may be higher with further follow-up because several patients were identified as being at risk of CKD. Regardless of the severity of AKI, all pediatric ICU patients should be monitored regularly for long-term kidney damage.

Hemolytic-Uremic Syndrome in Uberlândia, MG, Brazil

Purpose. To analyze the epidemiological, clinical, and laboratory characteristics of hemolytic-uremic syndrome (HUS) in Uberlandia, MG, Brazil. Methods. A historical cohort study was performed encompassing a ten-year period from January 1994 to January 2004 in the Department of Pediatric Nephrology at a full-service hospital; demographic factors, triggering factors, time of hospitalization, supportive therapy, and disease progression were analyzed. Results. Twenty-seven children aged 5 to 99 months (median age of 14 months) were studied; 70.4% were male. Of the 27 patients, 77.8% were from urban areas and 18.5% were from rural areas. Eight of the patients (29.6%) were reported to drink raw milk, and clinical diarrhea was reported in 81.5% of cases. The most common signs and symptoms were fever and vomiting (85.1%), anuria (63.0%), seizure (33.0%), cardiac involvement (11.0%), and acute pulmonary edema (7.4%). Dialysis was performed on 20 patients (74%). The mean hospital stay was 24 days (range: 13 to 36 days). While monitoring the patients, 2 died (7.4%), 3 developed chronic kidney disease (11.0%), and 21 (77.8%) developed hypertension. Conclusion. Our results emphasize the possibility of diagnosing HUS as a cause of renal failure in childhood in both typical (postdiarrheal) and atypical forms and suggest that an investigation of the etiological agent should be made whenever possible.

Haemolytic uraemic syndrome: an overview

Haemolytic uraemic syndrome (HUS) is the most common cause of acute renal failure in children. The syndrome is defined by triad of microangiopathic haemolytic anaemia, thrombocytopenia and acute renal failure (ARF). Incomplete HUS is ARF with either haemolytic anaemia or thrombocytopenia. HUS is classified into two subgroups. Typical HUS usually occurs after a prodrome of diarrhoea (D+HUS), and atypical (sporadic) HUS (aHUS), which is not associated with diarrhoea (D-HUS). The majority of D+HUS worldwide is caused by Shiga toxin-producing Esherichia coli (STEC), type O157:H7, transmitted to humans via different vehicles. Currently there are no specific therapies preventing or ameliorating the disease course. Although there are new therapeutic modalities in the horizon for D+HUS, present recommended therapy is merely symptomatic. Parenteral volume expansion may counteract the effect of thrombotic process before development of HUS and attenuate renal injury. Use of antibiotics, antimotility agents, narcotics and non-steroidal anti-inflammatory drugs should be avoided during the acute phase. Prevention is best done by preventing primary STEC infection. Underlying aetiology in many cases of aHUS is unknown. A significant number may result from underlying infectious diseases, namely Streptococcus pneumoniae and human immunedeficiency virus. Variety of genetic forms include HUS due to deficiencies of factor H, membrane cofactor protein, Von Willebrand factor-cleaving protease (ADAMTS 13) and intracellular defect in vitamin B12 metabolism. There are cases of aHUS with autosomal recessive and dominant modes of inheritance. Drug-induced aHUS in post-transplantation is due to calcineurin-inhibitors. Systemic lupus erythematosus and catastrophic antiphospholipid syndrome may also present with aHUS. Therapy is directed mainly towards underlying cause.

Malignancy and renal disease

A variety of renal diseases and electrolyte disorders may be associated with various malignancies or with treatment of malignancy with chemotherapeutic drugs or radiation. This article reviews renal disease in cancer patients, which constitutes a major source of morbidity and mortality.

Late evaluation of glomerular filtration rate, proteinuria, and urinary acidification after acute tubular necrosis

Fourteen patients were studied 2 to 36 months after acute tubular necrosis. It was observed that 43% of the patients had decreased glomerular filtration rate. These patients were older and had lower urinary excretion of ammonium and titratable acidity. Proteinuria greater than 150 mg/day, without reaching a nephrotic level, was found in 92% of the patients. The presence of oliguria, the demand of dialysis, and the acute tubular necrosis etiology were not statistically different among the patients who recovered their glomerular filtration rate either totally or partially.

Long-term outcome for children with acute renal failure following cardiac surgery

Acute renal failure requiring dialysis occurred in 34 children (2.9%) following cardiac surgery over a five year period. 17 children (50%) recovered renal function with 11 (32%) long-term survivors. The long-term outcome for the survivors, in terms of renal function, was studied from 1 to 5 years after their episodes of acute renal failure. Three children had significant abnormalities of renal function despite normal urinalysis. Detailed assessment of renal function is advocated for children who survive acute renal failure following cardiac surgery.

Oral acetazolamide in the assessment of (urine-blood) PCO2

Urine-blood (U-B)Pco2 difference in children is usually assessed following urine alkalinization with oral sodium bicarbonate (NaHCO3). Since oral NaHCO3 is often poorly tolerated by children, we compared oral acetazolamide with oral NaHCO3 in a study of (U-B)Pco2. In the first phase of the study 14 children and adolescents aged 11.1 +/- 3.7 years (mean +/- SD) were studied. Eight participants had normal kidney function and 6 had disturbed distal acidification capacity. Each child was studied twice, once with oral NaHCO3 (2.5 mEq/kg) and once with acetazolamide (17 +/- 2 mg/kg). All studies were performed according to the standard protocol. Acetazolamide administration resulted in a lower blood pH than NaHCO3 (7.30 +/- 0.03 vs 7.38 +/- 0.06, P less than 0.001) and a lower serum bicarbonate (HCO3-) concentration (25.1 +/- 2.2 mEq/l vs 27.5 +/- 2.1 mEq/l, P less than 0.025). Acetazolamide also resulted in a higher urine Pco2 (81.9 +/- 26.2 mm Hg vs 71.6 +/- 18.2 mm Hg) than NaHCO3 (P less than 0.025). No significant differences between acetazolamide and NaHCO3 were observed with respect to their effects on urinary pH and HCO3- concentration, plasma Pco2 and (U-B)Pco2. Good linear correlations were found between the effects of acetazolamide and NaHCO3 on urine Pco2 (r = 0.878, P less than 0.001), and on (U-B)Pco2 (r = 0.795, P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)