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

Paracetamol in Patent Ductus Arteriosus Treatment: Efficacious and Safe?

In preterm infants, failure or delay in spontaneous closure of Ductus Arteriosus (DA), resulting in the condition of Patent Ductus Arteriosus (PDA), represents a significant issue. A prolonged situation of PDA can be associated with several short- and long-term complications. Despite years of researches and clinical experience on PDA management, unresolved questions about the treatment and heterogeneity of clinical practices in different centers still remain, in particular regarding timing and modality of intervention. Nowadays, the most reasonable strategy seems to be reserving the treatment only to hemodynamically significant PDA. The first-line therapy is medical, and ibuprofen, related to several side effects especially in terms of nephrotoxicity, is the drug of choice. Administration of oral or intravenous paracetamol (acetaminophen) recently gained attention, appearing effective as traditional nonsteroidal anti-inflammatory drugs (NSAIDs) in PDA closure, with lower toxicity. The results of the studies analyzed in this review mostly support paracetamol efficacy in ductal closure, with inconstant low and transient elevation of liver enzymes as reported side effect. However, more studies are needed to confirm if this therapy shows a real safety profile and to evaluate its long-term outcomes, before considering paracetamol as first-choice drug in PDA treatment.

Strategies to Enhance Rehabilitation After Acute Kidney Injury in the Developing World

Acute kidney injury (AKI) is independently associated with new-onset chronic kidney disease (CKD), end-stage kidney disease, cardiovascular disease, and all-cause mortality. However, only a minority of patients receive follow-up care after an episode of AKI in the developing world, and the optimal strategies to promote rehabilitation after AKI are ill-defined. On this background, a working group of the 18th Acute Dialysis Quality Initiative applied the consensus-building process informed by a PubMed review of English-language articles to address questions related to rehabilitation after AKI. The consensus statements propose that all patients should be offered follow-up within 3 months of an AKI episode, with more intense follow-up (e.g., <1 month) considered based on patient risk factors, characteristics of the AKI event, and the degree of kidney recovery. Patients should be monitored for renal and nonrenal events post-AKI, and we suggest that the minimum level of monitoring consist of an assessment of kidney function and proteinuria within 3 months of the AKI episode. Care should be individualized for higher risk patients, particularly patients who are still dialysis dependent, to promote renal recovery. Although evidence-based treatments for survivors of AKI are lacking and some outcomes may not be modifiable, we recommend simple interventions such as lifestyle changes, medication reconciliation, blood pressure control, and education, including the documentation of AKI in the patient’s medical record. In conclusion, survivors of AKI represent a high-risk population, and these consensus statements should provide clinicians with guidance on the care of patients after an episode of AKI.

Outcome of extremely low birth weight infants with a history of neonatal acute kidney injury

OBJECTIVE

To study the outcome of extremely low birth weight (ELBW) infants with a history of acute kidney injury (AKI).

METHOD

In a retrospective, case control study, medical records of all ELBW infants admitted to the neonatal intensive care unit (NICU) between Jan 2002 and Dec 2011 were reviewed. Medical records were reviewed for infants' demographics, blood pressure (BP) at NICU discharge and at ≥3 years, and estimated glomerular filtration rate (eGFR) at ≥2 years.

RESULTS

During the study period, 222 patients met the inclusion criteria, of whom 10% (23 out of 222) had AKI stage 2 and 3, 39% (87 out of 222) had AKI stage 1, and the rest did not have AKI. At NICU discharge, there was a difference in diastolic BP (DBP) among infants who had AKI stages 2 and 3, those who had stage 1, and those who did not have AKI (53 ± 12 vs 46 ± 9 vs 46 ± 11 mmHg respectively; p = 0.007), and 11% (23 out of 209) had hypertension (HTN). Although there was a significant correlation between the rise in SCr and DBP at NICU discharge in infants with AKI (R = 0.304; p = 0.004), there was no difference in HTN between infants with and those without AKI. At ≥2 years of age, 4% (5 out of 120) across all groups had an eGFR < 90 ml/min/1.73m² or chronic kidney disease (CKD). At ≥3 years of age, 5% (11 out of 222) had HTN.

CONCLUSION

At NICU discharge, infants with AKI stages 2 and 3 have a higher DBP than infants with stage 1 AKI and those who did not have AKI. However, there is no difference in the rate of HTN between the two groups. At ≥2 years ELBW infants are at risk for CKD independently of whether or not they develop neonatal AKI.

Follow-up of Acute kidney injury in Neonates during Childhood Years (FANCY): a prospective cohort study

BACKGROUND

Very low birth weight (VLBW) neonates commonly experience acute kidney injury (AKI) in the neonatal intensive care unit (NICU). We hypothesize that VLBW neonates exposed to AKI in the NICU might be at a higher risk of renal dysfunction during childhood.

METHODS

In this cohort study, VLBW children (aged 3-7 years) completed a kidney health evaluation and were stratified according to AKI status in the NICU. The primary outcome was renal dysfunction defined as any of the following: estimated glomerular filtration rate (eGFR) <90 mL/min/1.73 m², urine protein/creatinine >0.2 or blood pressure ≥95th percentile.

RESULTS

Thirty-four subjects completed the study. Twenty subjects had a history of neonatal AKI (stage 1, n = 8; stage 2, n = 9; and stage 3, n = 3). At a median age of 5 years, the AKI group had a higher risk of renal dysfunction compared with the group without AKI (65% vs 14%, relative risk 4.5 (1.2-17.1), p = 0.01). Overall, 26% of the total cohort had an eGFR <90 mL/min/1.73 m² using serum cystatin C (35% of AKI subjects, 14% of no AKI subjects, p = 0.25).

CONCLUSIONS

Evidence of renal dysfunction in neonates born VLBW can be found early in childhood. Further work is necessary to determine how to reduce renal disease in this vulnerable population.

Acute Kidney Injury in Pediatric Severe Sepsis: An Independent Risk Factor for Death and New Disability

OBJECTIVES

The prevalence of septic acute kidney injury and impact on functional status of PICU survivors are unknown. We used data from an international prospective severe sepsis study to elucidate functional outcomes of children suffering septic acute kidney injury.

DESIGN

Secondary analysis of patients in the Sepsis PRevalence, OUtcomes, and Therapies point prevalence study: acute kidney injury was defined on the study day using Kidney Disease Improving Global Outcomes definitions. Patients with no acute kidney injury or stage 1 acute kidney injury ("no/mild acute kidney injury") were compared with those with stage 2 or 3 acute kidney injury ("severe acute kidney injury"). The primary outcome was a composite of death or new moderate disability at discharge defined as a Pediatric Overall Performance Category score of 3 or higher and increased by 1 from baseline.

SETTING

One hundred twenty-eight PICUs in 26 countries.

PATIENTS

Children with severe sepsis in the Sepsis PRevalence, OUtcomes, and Therapies study.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

One hundred two (21%) of 493 patients had severe acute kidney injury. More than twice as many patients with severe acute kidney injury died or developed new moderate disability compared with those with no/mild acute kidney injury (64% vs 30%; p < 0.001). Severe acute kidney injury was independently associated with death or new moderate disability (adjusted odds ratio, 2.5; 95% CI, 1.5-4.2; p = 0.001) after adjustment for age, region, baseline disability, malignancy, invasive mechanical ventilation, albumin administration, and the pediatric logistic organ dysfunction score.

CONCLUSIONS

In a multinational cohort of critically ill children with severe sepsis and high mortality rates, septic acute kidney injury is independently associated with further increased death or new disability.

Pregnancy Outcomes after Clinical Recovery from AKI

The effect of clinically recovered AKI (r-AKI) on future pregnancy outcomes is unknown. We retrospectively studied all women who delivered infants between 1998 and 2007 at Massachusetts General Hospital to assess whether a previous episode of r-AKI associated with subsequent adverse maternal and fetal outcomes, including preeclampsia. AKI was defined as rise in serum creatinine concentration to 1.5-fold above baseline. We compared pregnancy outcomes in women with r-AKI without history of CKD (eGFR>90 ml/min per 1.73 m2 before conception; n=105) with outcomes in women without kidney disease (controls; n=24,640). The r-AKI and control groups had similar prepregnancy serum creatinine measurements (0.70±0.20 versus 0.69±0.10 mg/dl; P=0.36). However, women with r-AKI had increased rates of preeclampsia compared with controls (23% versus 4%; P<0.001). Infants of women with r-AKI were born earlier than infants of controls (37.6±3.6 versus 39.2±2.2 weeks; P<0.001), with increased rates of small for gestational age births (15% versus 8%; P=0.03). After multivariate adjustment, r-AKI associated with increased risk for preeclampsia (adjusted odds ratio [aOR], 5.9; 95% confidence interval [95% CI], 3.6 to 9.7) and adverse fetal outcomes (aOR, 2.4; 95% CI, 1.6 to 3.7). When women with r-AKI and controls were matched 1:2 by age, race, body mass index, diastolic BP, parity, and diabetes status, r-AKI remained associated with preeclampsia (OR, 4.7; 95% CI, 2.1 to 10.1) and adverse fetal outcomes (OR, 2.1; 95% CI, 1.2 to 3.7). Thus, a past episode of AKI, despite return to normal renal function before pregnancy, associated with adverse outcomes in pregnancy.

Renal dysfunction in early adulthood following birth asphyxia in male spiny mice, and its amelioration by maternal creatine supplementation during pregnancy

BACKGROUND

Acute kidney injury affects ~70% of asphyxiated newborns, and increases their risk of developing chronic kidney disease later in life. Acute kidney injury is driven by renal oxygen deprivation during asphyxia, thus we hypothesized that creatine administered antenatally would protect the kidney from the long-term effects of birth asphyxia.

METHODS

Pregnant spiny mice were fed standard chow or chow supplemented with 5% creatine from 20-d gestation (midgestation). One day prior to term (37-d gestation), pups were delivered by caesarean or subjected to intrauterine asphyxia. Litters were allocated to one of two time-points. Kidneys were collected at 1 mo of age to estimate nephron number (stereology). Renal function (excretory profile and glomerular filtration rate) was measured at 3 mo of age, and kidneys then collected for assessment of glomerulosclerosis.

RESULTS

Compared with controls, at 1 mo of age male (but not female) birth-asphyxia offspring had 20% fewer nephrons (P < 0.05). At 3 mo of age male birth-asphyxia offspring had 31% lower glomerular filtration rate (P < 0.05) and greater glomerular collagen IV content (P < 0.01). Antenatal creatine prevented these renal injuries arising from birth asphyxia.

CONCLUSION

Maternal creatine supplementation during pregnancy may be an effective prophylactic to prevent birth asphyxia induced acute kidney injury and the emergence of chronic kidney disease.

Acute kidney injury in the fetus and neonate

Acute kidney injury (AKI) is an under-recognized morbidity of neonates; the incidence remains unclear due to the absence of a unified definition of AKI in this population and because previous studies have varied greatly in screening for AKI with serum creatinine and urine output assessments. Premature infants may be born with less than half of the nephrons compared with term neonates, predisposing them to chronic kidney disease (CKD) early on in life and as they age. AKI can also lead to CKD, and premature infants with AKI may be at very high risk for long-term kidney problems. AKI in neonates is often multifactorial and may result from prenatal, perinatal, or postnatal insults as well as any combination thereof. This review focuses on the causes of AKI, the importance of early detection, the management of AKI in neonates, and long-term sequela of AKI in neonates.

Three-year outcomes after acute kidney injury: results of a prospective parallel group cohort study

OBJECTIVES

Using a prospective study design, we aimed to characterise the effect of acute kidney injury (AKI) on long-term changes in renal function in a general hospital population.

PARTICIPANTS

Hospitalised patients with AKI (exposed) and hospitalised patients without AKI (non-exposed), recruited at 3 months after hospital admission.

DESIGN

Prospective, matched parallel group cohort study, in which renal function and proteinuria were measured at 3 months, 1 year and 3 years.

SETTING

Single UK centre.

CLINICAL END POINTS

Clinical end points at 3 years were comparison of the following variables between exposed and non-exposed groups: renal function, prevalence of proteinuria and albuminuria and chronic kidney disease (CKD) progression/development at each time point. CKD progression was defined as a decrease in the estimated glomerular filtration rate (eGFR) of ≥25% associated with a decline in eGFR stage.

RESULTS

300 exposed and non-exposed patients were successfully matched 1:1 for age and baseline renal function; 70% of the exposed group had AKI stage 1. During follow-up, the AKI group had lower eGFR than non-exposed patients at each time point. At 3 years, the mean eGFR was 60.7±21 mL/min/1.73 m² in the AKI group compared with 68.4±21 mL/min/1.73 m² in the non-exposed group, p=0.003. CKD development or progression at 3 years occurred in 30 (24.6%) of the AKI group compared with 10 (7.5%) of the non-exposed group, p<0.001. Albuminuria was more common in the AKI group, and increased with AKI severity. Factors independently associated with CKD development/progression after AKI were non-recovery at 90 days, male gender, diabetes and recurrent AKI.

CONCLUSIONS

AKI is associated with deterioration in renal function to 3 years, even in an unselected population with predominantly AKI stage 1. Non-recovery from AKI is an important factor determining long-term outcome.

The Impact of Kidney Development on the Life Course: A Consensus Document for Action

Hypertension and chronic kidney disease (CKD) have a significant impact on global morbidity and mortality. The Low Birth Weight and Nephron Number Working Group has prepared a consensus document aimed to address the relatively neglected issue for the developmental programming of hypertension and CKD. It emerged from a workshop held on April 2, 2016, including eminent internationally recognized experts in the field of obstetrics, neonatology, and nephrology. Through multidisciplinary engagement, the goal of the workshop was to highlight the association between fetal and childhood development and an increased risk of adult diseases, focusing on hypertension and CKD, and to suggest possible practical solutions for the future. The recommendations for action of the consensus workshop are the results of combined clinical experience, shared research expertise, and a review of the literature. They highlight the need to act early to prevent CKD and other related noncommunicable diseases later in life by reducing low birth weight, small for gestational age, prematurity, and low nephron numbers at birth through coordinated interventions. Meeting the current unmet needs would help to define the most cost-effective strategies and to optimize interventions to limit or interrupt the developmental programming cycle of CKD later in life, especially in the poorest part of the world.

Leveraging Big Data and Electronic Health Records to Enhance Novel Approaches to Acute Kidney Injury Research and Care

While acute kidney injury (AKI) has been poorly defined historically, a decade of effort has culminated in a standardized, consensus definition. In parallel, electronic health records (EHRs) have been adopted with greater regularity, clinical informatics approaches have been refined, and the field of EHR-enabled care improvement and research has burgeoned. Although both fields have matured in isolation, uniting the 2 has the capacity to redefine AKI-related care and research. This article describes how the application of a consistent AKI definition to the EHR dataset can accurately and rapidly diagnose and identify AKI events. Furthermore, this electronic, automated diagnostic strategy creates the opportunity to develop predictive approaches, optimize AKI alerts, and trace AKI events across institutions, care platforms, and administrative datasets.

Acute kidney injury following spinal instrumentation surgery in children

AIM

To determine acute kidney in jury (AKI) incidence and potential risk factors of AKI in children undergoing spinal instrumentation surgery.

METHODS

AKI incidence in children undergoing spinal instrumentation surgery at British Columbia Children’s Hospital between January 2006 and December 2008 was determined by the Acute Kidney Injury Networ classification using serum creatinine and urine output criteria. During this specific time period, all patients following spinal surgery were monitored in the pediatric intensive care unit and had an indwelling Foley catheter permitting hourly urine output recording. Cases of AKI were identified from our database. From the remaining cohort, we selected group-matched controls that did not satisfy criteria for AKI. The controls were matched for sex, age and underlying diagnosis (idiopathic vs non-idiopathic scoliosis).

RESULTS

Thirty five of 208 patients met criteria for AKI with an incidence of 17% (95%CI: 12%-23%). Of all children who developed AKI, 17 (49%) developed mild AKI (AKI Stage 1), 17 (49%) developed moderate AKI (Stage 2) and 1 patient (3%) met criteria for severe AKI (Stage 3). An inverse relationship was observed with AKI incidence and the amount of fluids received intra-operatively. An inverse relationship was observed with AKI incidence and the amount of fluids received intra-operatively classified by fluid tertiles: 70% incidence in those that received the least amount of fluids vs 29% that received the most fluids (> 7.9, P = 0.02). Patients who developed AKI were more frequently exposed to nephrotoxins (non steroidal anti inflammatory drugs or aminoglycosides) than control patients during their peri-operative course (60% vs 22%, P < 0.001).

CONCLUSION

We observed a high incidence of AKI following spinal instrumentation surgery in children that is potentially related to the frequent use of nephrotoxins and the amount of fluid administered peri-operatively.

Reference ranges and impact of selected confounders on classic serum and urinary renal markers in neonatal period

PURPOSE

Renal injury in term and pre-term neonates may be an antecedent to chronic kidney disease in the child's further life. The aim of the paper was to compile a reference range for selected serum and urinary renal markers in the neonatal period for full-term (FT) and pre-term (PT) newborns.

MATERIAL AND METHODS

The prospective study included 23 FT infants (birth weight - BW≥2500g and gestational age - GA≥37Hbd) and 32 PT children (BW<2500g and GA<37Hbd) in good general condition, without acute kidney injury (AKI) or sepsis. Between the 4th and 28th DOL, urinary concentrations of the studied renal markers (uCr, uNa, uOsm) were determined on a daily basis, while serum creatinine (SCr) was assessed minimum every 48-72h.

RESULTS

The mean GA and BW of the FT and PT infants were respectively as follows: 38.5±1.7Hbd; 3433±495.2g and 32.7±2.6Hbd; 1836.7±419.8g. For serum glomerular (SCr, eGFR) and tubular markers (FENa, RFI), the median values with normal ranges were compiled. For urinary renal markers (uCr, uNa, uOsm) and those values standardized for kg of body weight, percentile tables for 4-28DOL were elaborated.

CONCLUSIONS

The study has resulted in determining the normal ranges of serum glomerular and tubular renal markers, as well as percentile tables of selected urinary renal parameters during the neonatal period. The percentile tables may prove to be helpful for further standardization of other urinary parameters per urinary creatinine in neonatal population.

Design and Methods of the Pan-Canadian Applying Biomarkers to Minimize Long-Term Effects of Childhood/Adolescent Cancer Treatment (ABLE) Nephrotoxicity Study: A Prospective Observational Cohort Study

BACKGROUND

Childhood cancer survivors experience adverse drug events leading to lifelong health issues. The Applying Biomarkers to Minimize Long-Term Effects of Childhood/Adolescent Cancer Treatment (ABLE) team was established to validate and apply biomarkers of cancer treatment effects, with a goal of identifying children at high risk of developing cancer treatment complications associated with thrombosis, graft-versus-host disease, hearing loss, and kidney damage. Cisplatin is a chemotherapy well known to cause acute and chronic nephrotoxicity. Data on biomarkers of acute kidney injury (AKI) and late renal outcomes in children treated with cisplatin are limited.

OBJECTIVE

To describe the design and methods of the pan-Canadian ABLE Nephrotoxicity study, which aims to evaluate urine biomarkers (neutrophil gelatinase-associated lipocalin [NGAL] and kidney injury molecule-1 [KIM-1]) for AKI diagnosis, and determine whether they predict risk of long-term renal outcomes (chronic kidney disease [CKD], hypertension).

DESIGN

This is a 3-year observational prospective cohort study.

SETTING

The study includes 12 Canadian pediatric oncology centers.

PATIENTS

The target recruitment goal is 150 patients aged less than 18 years receiving cisplatin. Exclusion criteria: Patients with an estimated glomerular filtration rate (eGFR) <30 mL/min/1.73 m2 or a pre-existing renal transplantation at baseline.

MEASUREMENTS

Serum creatinine (SCr), urine NGAL, and KIM-1 are measured during cisplatin infusion episodes (pre-infusion, immediate post-infusion, discharge sampling). At follow-up visits, eGFR, microalbuminuria, and blood pressure are measured and outcomes are collected.

METHODS

Outcomes: AKI is defined as per SCr criteria of the Kidney Disease: Improving Global Outcomes (KDIGO) guidelines. CKD is defined as eGFR <90 mL/min/1.73m2 or albumin-to-creatinine ratio≥3mg/mmol. Hypertension is defined as per guidelines. Procedure: Patients are recruited before their first or second cisplatin cycle. Participants are evaluated during 2 cisplatin infusion episodes (AKI biomarker validation) and at 3, 12, and 36 months post-cisplatin treatment (late outcomes).

LIMITATIONS

The study has a relatively moderate sample size and short follow-up duration. There is potential for variability in data collection since multiple sites are involved.

CONCLUSIONS

ABLE will provide a national platform to study biomarkers of late cancer treatment complications. The Nephrotoxicity study is a novel study of AKI biomarkers in children treated with cisplatin that will greatly inform on late cisplatin renal outcomes and follow-up needs.

Mortality and cost of acute and chronic kidney disease after cardiac surgery

PURPOSE OF REVIEW

Acute and chronic kidney diseases (AKI and CKD) have far-reaching implications for surgical patients in regards to postoperative outcomes and hospital cost. We review the recent literature on the effects of AKI and CKD on morbidity, mortality, and resource utilization among cardiac surgery patients.

RECENT FINDINGS

Both AKI and CKD increase the risk for short-term and long-term mortalities, morbidity, length of stay, and hospital cost among postoperative patients, with increasing disease stage correlating with worse outcomes. Even the mildest forms of AKI (RIFLE-R) and CKD (proteinuria without an observed reduction in estimated glomerular filtration rate) demonstrate worse clinical outcomes compared with patients with no AKI or CKD. Outcomes are worse even in patients who achieve full renal recovery before hospital discharge. These complications dramatically increase ICU length of stay, hospital length of stay, resource utilization, and both in-hospital and postdischarge costs, as evidenced by lower rates of discharges to home.

SUMMARY

AKI and CKD remain prevalent, morbid, and costly conditions for cardiac surgery patients. Better risk stratification, early diagnosis, and earlier interventions are needed to prevent the consequences of these diseases.

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.

Stop adding insult to injury-identifying and managing risk factors for the progression of acute kidney injury in children

Acute kidney injury (AKI) is common in children admitted to hospital. Whilst some recover normal kidney function following an acute kidney insult, a significant proportion experience long-term sequelae. The aim of this review is to summarize current understanding of the processes that can lead to sequelae following AKI. Kidney injury, repair, recovery and progression are described. Risk factors for progression are outlined, and potential strategies to stratify the risk of progression in children with AKI are discussed. Clinical management priorities to minimize sequelae are suggested. Looking ahead, novel therapeutic targets are discussed with the potential to accelerate adaptive repair and ameliorate the progression and sequelae of AKI in the future.

Drug-associated acute kidney injury: who's at risk?

The contribution of nephrotoxic medications to the development of acute kidney injury (AKI) is becoming better understood concomitant with the increased incidence of AKI in children. Treatment of AKI is not yet available, so prevention continues to be the most effective approach. There is an opportunity to mitigate severity and prevent the occurrence of AKI if children at increased risk are identified early and nephrotoxins are used judiciously. Early detection of AKI is limited by the dependence of nephrologists on serum creatinine as an indicator. Promising new biomarkers may offer early detection of AKI prior to the rise in serum creatinine. Early detection of evolving AKI is improving and offers opportunities for better management of nephrotoxins. However, the identification of patients at increased risk will remain an important first step, with a focus on the use of biomarker testing and interpretation of the results.

Recent developments in the detection and management of acute kidney injury

Acute kidney injury (AKI) is a common condition in children admitted to hospital and existing serum and urine biomarkers are insensitive. There have been significant developments in stratifying the risk of AKI in children and also in the identification of new AKI biomarkers. Risk stratification coupled with a panel of AKI biomarkers will improve future detection of AKI, however, paediatric validation studies in mixed patient cohorts are required. The principles of effective management rely on treating the underlying cause and preventing secondary AKI by the appropriate use of fluids and medication. Further therapeutic innovation will depend on improving our understanding of the basic mechanisms underlying AKI in children.

Understanding the Full Spectrum of Organ Injury Following Intrapartum Asphyxia

Birth asphyxia is a significant global health problem, responsible for ~1.2 million neonatal deaths each year worldwide. Those who survive often suffer from a range of health issues including brain damage-manifesting as cerebral palsy (CP)-respiratory insufficiency, cardiovascular collapse, and renal dysfunction, to name a few. Although the majority of research is directed toward reducing the brain injury that results from intrapartum birth asphyxia, the multi-organ injury observed in surviving neonates is of equal importance. Despite the advent of hypothermia therapy for the treatment of hypoxic-ischemic encephalopathy (HIE), treatment options following asphyxia at birth remain limited, particularly in low-resource settings where the incidence of birth asphyxia is highest. Furthermore, although cooling of the neonate results in improved neurological outcomes for a small proportion of treated infants, it does not provide any benefit to the other organ systems affected by asphyxia at birth. The aim of this review is to summarize the current knowledge of the multi-organ effects of intrapartum asphyxia, with particular reference to the findings from our laboratory using the precocial spiny mouse to model birth asphyxia. Furthermore, we reviewed the current treatments available for neonates who have undergone intrapartum asphyxia, and highlight the emergence of maternal dietary creatine supplementation as a preventative therapy, which has been shown to provide multi-organ protection from birth asphyxia-induced injury in our preclinical studies. This cheap and effective nutritional supplement may be the key to reducing birth asphyxia-induced death and disability, particularly in low-resource settings where current treatments are unavailable.

Acute kidney injury in the perioperative period and in intensive care units (excluding renal replacement therapies)

Acute kidney injury (AKI) is a syndrome that has progressed a great deal over the last 20 years. The decrease in urine output and the increase in classical renal biomarkers, such as blood urea nitrogen and serum creatinine, have largely been used as surrogate markers for decreased glomerular filtration rate (GFR), which defines AKI. However, using such markers of GFR as criteria for diagnosing AKI has several limits including the difficult diagnosis of non-organic AKI, also called "functional renal insufficiency" or "pre-renal insufficiency". This situation is characterized by an oliguria and an increase in creatininemia as a consequence of a reduction in renal blood flow related to systemic haemodynamic abnormalities. In this situation, "renal insufficiency" seems rather inappropriate as kidney function is not impaired. On the contrary, the kidney delivers an appropriate response aiming to recover optimal systemic physiological haemodynamic conditions. Considering the kidney as insufficient is erroneous because this suggests that it does not work correctly, whereas the opposite is occurring, because the kidney is healthy even in a threatening situation. With current definitions of AKI, normalization of volaemia is needed before defining AKI in order to avoid this pitfall.

Rescue therapy with Tanshinone IIA hinders transition of acute kidney injury to chronic kidney disease via targeting GSK3β

Acute kidney injury (AKI) remains challenging for clinical practice and poses a risk of developing progressive chronic kidney disease (CKD) with no definitive treatment available yet. Tanshinone IIA, an active ingredient of Chinese herbal Salvia miltiorrhiza, has been widely used in Asia for the remarkable organoprotective activities. Its effect on established AKI, however, remains unknown. In mice with folic acid-induced AKI, delayed treatment with Tanshinone IIA, commenced early or late after injury, diminished renal expression of kidney injury markers, reduced apoptosis and improved kidney dysfunction, concomitant with mitigated histologic signs of AKI to CKD transition, including interstitial fibrosis and tubular atrophy, and with an ameliorated inflammatory infiltration in tubulointerstitium and a favored M2-skewed macrophage polarization. Mechanistically, Tanshinone IIA blunted glycogen synthase kinase (GSK)3β overactivity and hyperactivation of its downstream mitogen-activated protein kinases that are centrally implicated in renal fibrogenesis and inflammation. Inhibition of GSK3β is likely a key mechanism mediating the therapeutic activity of Tanshinone IIA, because sodium nitroprusside, a GSK3β activator, largely offset its renoprotective effect. In confirmatory studies, rescue treatment with Tanshinone IIA likewise ameliorated ischemia/reperfusion-induced kidney destruction in mice. Our data suggest that Tanshinone IIA represents a valuable treatment that improves post-AKI kidney salvage via targeting GSK3β.

The Kidney in Critical Cardiac Disease: Proceedings From the 10th International Conference of the Pediatric Cardiac Intensive Care Society

The field of cardiac intensive care continues to advance in tandem with congenital heart surgery. The focus of intensive care unit care has now shifted to that of morbidity reduction and eventual elimination. Acute kidney injury (AKI) after cardiac surgery is associated with adverse outcomes, including prolonged intensive care and hospital stays, diminished quality of life, and increased long-term mortality. Acute kidney injury occurs frequently, complicating the care of both postoperative patients and those with heart failure. Patients who become fluid overloaded and/or require dialysis are at high risk of mortality, but even minor degrees of AKI portend a significant increase in mortality and morbidity. Clinicians continue to seek methods of early diagnosis and risk stratification of AKI to prevent its adverse sequelae. Previous conventional wisdom that survivors of AKI fully recover renal function without subsequent consequences may be flawed.

Statin Use and Survival After Acute Kidney Injury

INTRODUCTION

The incidence of acute kidney injury (AKI) in hospitalized patients is rising, and survivors are at high risk for cardiovascular events and mortality. Effective strategies that improve long-term outcomes of AKI are unknown.

METHODS

A retrospective cohort study was performed between 2008 and 2011. All subjects were followed until 31 March 2013, with a minimum follow-up of 2 years. Participants were adults 18 years of age or older, who developed AKI during a hospitalization and had chronic kidney disease (CKD) following discharge (n = 19,707 mean age 69.9 years, mean postdischarge estimated glomerular filtration rate (eGFR) 43.0 ml/min/1.73 m2). Exposure to statins was examined prior to the index hospitalization as well as within 2 years following hospital discharge. The primary outcome was mortality; secondary outcomes included all-cause re-hospitalization and cardiovascular events.

RESULTS

Within 2 years of discharge, only 38.3% of the participants were prescribed a statin. After adjustment for comorbidities, statin use prior to admission, demographics, baseline kidney function, and a number of other factors, statin use was associated with lower mortality (hazard ratio, 0.74; 95% confidence interval, 0.69, 0.79) in AKI survivors with CKD. Patients who received a statin also had a lower risk of all cause rehospitalization (adjusted hazarad ratio, 0.90; 95% confidence interval, 0.85, 0.94). Statin use was not associated with a reduction in cardiovascular events.

DISCUSSION

Among AKI survivors with CKD, statin use was associated with a lower risk of mortality and rehospitalization rates. This finding suggests that there is an opportunity to improve postdischarge care in AKI survivors.

Non-dialytic management of acute kidney injury in newborns

Treating acute kidney injury (AKI) in newborns is often challenging due to the functional immaturity of the neonatal kidney. Because of this physiological limitation, renal replacement therapy (RRT) in this particular patient population is difficult to execute and may lead to unwanted complications. Although fluid overload and electrolyte abnormalities, as seen in neonatal AKI, are indications for RRT initiation, there is limited evidence that RRT initiated in the first year of life improves long-term outcome. The underlying cause of AKI in a newborn patient should determine the treatment strategies to restore appropriate renal function. However, our understanding of this common clinical condition remains limited, as no standardized, evidence-based definition of neonatal AKI currently exists. Non-dialytic management of AKI in these patients may restore appropriate renal function to these patients without exposure to complications often encountered with RRT.

Etiology, clinical profile and short-term outcome of acute kidney injury in children at a tertiary care pediatric nephrology center in Pakistan

Background: The reported prevalence rates and etiologies of acute kidney injury (AKI) are quite variable in different regions of the world. The current study was planned to determine the etiology, clinical profile, and short-term outcome of pediatric AKI at our hospital.

Methods: A prospective, observational study was carried out from April 2014 to March 2015. All pediatric patients (1 month to ≤15 years) diagnosed as AKI using modified pRIFLE criteria were studied and followed for 3 months to document short-term outcome.

Results: AKI was diagnosed in 116 children. The mean age was 7.5 ± 4.4 years and males were predominant (60.3%). At presentation, 83.6% had oliguria/anuria, 37.1% hypertension and 17.2% severe anemia. Etiology included primary renal (74/116; 63.8%), postrenal (28/116; 24.1%) and prerenal (11/116; 9.5%) causes. Postinfectious glomerulonephritis (PIGN) and crescentic glomerulonephritis in primary renal, obstructive urolithiasis in postrenal and sepsis in prerenal, were the most common etiologies. At presentation, 89/116 (76.7%) patients were in pRIFLE Failure category. Regarding outcome, 68 (58.6%) patients recovered, six (5.2%) died, 18 (15.5%) developed chronic kidney disease (CKD) and 22 (19%) end-stage renal disease (ESRD). Comparison of recovered and unrecovered AKI showed that characteristics such as hypertension, severe anemia, edema, volume overload, requirement of mechanical ventilation, initiation of dialysis and need of >5 sessions of dialysis had statistically significant (p <0.05) association with nonrecovery.

Conclusion: Glomerulonephritides (PIGN and crescentic) and obstructive urolithiasis are major causes of pediatric AKI at our center. A fairly high percentage of cases recovered and these mainly comprised of PIGN and obstructive urolithiasis.

Acute Kidney Injury in Pediatric Heart Failure

Acute kidney injury (AKI) is very common in pediatric medical and surgical cardiac patients. Not only is it an independent risk factor for increased morbidity and mortality in the short run, but repeated episodes of AKI lead to chronic kidney disease (CKD) especially in the most vulnerable hosts with multiple risk factors, such as heart transplant recipients. The cardiorenal syndrome, a term coined to emphasize the bidirectional nature of simultaneous or sequential cardiac-renal dysfunction both in acute and chronic settings, has been recently described in adults but scarcely reported in children. Despite the common occurrence and clinical and financial impact, AKI in pediatric heart failure outside of cardiac surgery populations remains poorly studied and there are no large-scale pediatric specific preventive or therapeutic studies to date. This article will review pediatric aspects of the cardiorenal syndrome in terms of pathophysiology, clinical impact and treatment options.

Relationship of clusterin with renal inflammation and fibrosis after the recovery phase of ischemia-reperfusion injury

Background

Long-term outcomes after acute kidney injury (AKI) include incremental loss of function and progression towards chronic kidney disease (CKD); however, the pathogenesis of AKI to CKD remains largely unknown. Clusterin (CLU) is a chaperone-like protein that reduces ischemia-reperfusion injury (IRI) and enhances tissue repair after IRI in the kidney. This study investigated the role of CLU in the transition of IRI to renal fibrosis.

Methods

IRI was induced in the left kidneys of wild type (WT) C57BL/6J (B6) versus CLU knockout (KO) B6 mice by clamping the renal pedicles for 28 min at the body temperature of 32 °C. Tissue damage was examined by histology, infiltrate phenotypes by flow cytometry analysis, and fibrosis-related gene expression by PCR array.

Results

Reduction of kidney weight was induced by IRI, but was not affected by CLU KO. Both WT and KO kidneys had similar function with minimal cellular infiltration and fibrosis at day 14 of reperfusion. After 30 days, KO kidneys had greater loss in function than WT, indicated by the higher levels of both serum creatinine and BUN in KO mice, and exhibited more cellular infiltration (CD8 cells and macrophages), more tubular damage and more severe tissue fibrosis (glomerulopathy, interstitial fibrosis and vascular fibrosis). PCR array showed the association of CLU deficiency with up-regulation of CCL12, Col3a1, MMP9 and TIMP1 and down-regulation of EGF in these kidneys.

Conclusion

Our data suggest that CLU deficiency worsens renal inflammation and tissue fibrosis after IRI in the kidney, which may be mediated through multiple pathways.

Electronic supplementary material

The online version of this article (doi:10.1186/s12882-016-0348-x) contains supplementary material, which is available to authorized users.

Acute Kidney Injury and Cardiorenal Syndromes in Pediatric Cardiac Intensive Care

OBJECTIVES

The objectives of this review are to discuss the definition, diagnosis, and pathophysiology of acute kidney injury and its impact on immediate, short-, and long-term outcomes. In addition, the spectrum of cardiorenal syndromes will be reviewed including the pathophysiology on this interaction and its impact on outcomes.

DATA SOURCE

MEDLINE and PubMed.

CONCLUSION

The field of cardiac intensive care continues to advance in tandem with congenital heart surgery. As mortality has become a rare occurrence, the focus of cardiac intensive care has shifted to that of morbidity reduction. Acute kidney injury adversely impact outcomes of patients following surgery for congenital heart disease as well as in those with heart failure (cardiorenal syndrome). Patients who become fluid overloaded and/or require dialysis are at a higher risk of mortality, but even minor degrees of acute kidney injury portend a significant increase in mortality and morbidity. Clinicians continue to seek methods of early diagnosis and risk stratification of acute kidney injury to prevent its adverse sequelae.

Incidence of contrast-induced acute kidney injury in a pediatric setting: a cohort study

BACKGROUND

Contrast-induced acute kidney injury (CI-AKI) is a common pathology among adult patients, with an incidence ranging from 3-25 % depending on risk factors. Little information is available regarding CI-AKI incidence, risk factors, and prognostic impact in the pediatric population.

METHODS

We performed a retrospective study of pediatric patients who underwent computed tomography (CT) scan with iodinated contrast media injection between 2005 and 2014 in five pediatric units of a university hospital. CI-AKI was defined according to Kidney Disease/Improving Global Outcomes (KDIGO) criteria.

RESULTS

Of 346 identified patients, 233 had renal function follow-up and were included in our analyses. CI-AKI incidence was 10.3 % [95 % confidence interval (CI) 6.4-14.2 %]. CI-AKI was associated with 30-day unfavorable outcome before (45.8 % vs. 19.7 %, P = 0.007) and after [odds ratio (OR) 3.6; 95 % CI 1.4-9.5] adjustment for confounders. No independent risk factors of CI-AKI were identified.

CONCLUSIONS

CI-AKI incidence was as high as 10.3 % following intravenous contrast media administration in the pediatric setting. As reported among adults, CI-AKI was associated with unfavorable outcome after adjustment for confounders. Although additional studies are needed in the pediatric setting, our data suggest that physicians should maintain a high degree of suspicion toward this complication among pediatric patients.

The Role of Acute Kidney Injury in Chronic Kidney Disease

There is increasing recognition that acute kidney injury (AKI) and chronic kidney disease (CKD) are closely linked and likely promote one another. Underlying CKD now is recognized as a clear risk factor for AKI because both decreased glomerular filtration rate and increased proteinuria have been shown to be associated strongly with AKI. A growing body of literature also provides evidence that AKI accelerates the progression of CKD. Individuals who suffered dialysis-requiring AKI are particularly vulnerable to worse long-term renal outcomes, including end-stage renal disease. The association between AKI and subsequent renal function decline is amplified by pre-existing severity of CKD, higher stage of AKI, and the cumulative number of AKI episodes. However, residual confounding and ascertainment bias may partly explain the epidemiologic association between AKI and CKD in observational studies. As the number of AKI survivors increases, we need to better understand other clinically important outcomes after AKI, identify those at highest risk for the most adverse sequelae, and develop strategies to optimize their care.

The proximal tubule is the primary target of injury and progression of kidney disease: role of the glomerulotubular junction

There is an alarming global increase in the incidence of end-stage kidney disease, for which early biomarkers and effective treatment options are lacking. Largely based on the histology of the end-stage kidney and on the model of unilateral ureteral obstruction, current investigation is focused on the pathogenesis of renal interstitial fibrosis as a central mechanism in the progression of chronic kidney disease (CKD). It is now recognized that cumulative episodes of acute kidney injury (AKI) can lead to CKD, and, conversely, CKD is a risk factor for AKI. Based on recent and historic studies, this review shifts attention from the glomerulus and interstitium to the proximal tubule as the primary sensor and effector in the progression of CKD as well as AKI. Packed with mitochondria and dependent on oxidative phosphorylation, the proximal tubule is particularly vulnerable to injury (obstructive, ischemic, hypoxic, oxidative, metabolic), resulting in cell death and ultimately in the formation of atubular glomeruli. Animal models of human glomerular and tubular disorders have provided evidence for a broad repertoire of morphological and functional responses of the proximal tubule, revealing processes of degeneration and repair that may lead to new therapeutic strategies. Most promising are studies that encompass the entire life cycle from fetus to senescence, recognizing epigenetic factors. The application of techniques in molecular characterization of tubule segments and the development of human kidney organoids may provide new insights into the mammalian kidney subjected to stress or injury, leading to biomarkers of early CKD and new therapies.

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.

Tanshinone IIA Protects Against Folic Acid-Induced Acute Kidney Injury

Tanshinone IIA is a diterpene extracted from Salvia miltiorrhiza, a popular and safe herb medicine that has been widely used in China and other Asian countries. Previous studies have demonstrated the pleiotropic effects of Tanshinone IIA on many disease treatments via its antitoxicity, anti-inflammation, anti-oxidative stress, as well as antifibrosis activities. However, its effect on acute kidney injury (AKI) has not been fully investigated. Here, we show for the first time that systemic administration of Tanshinone IIA can lead to improved kidney function in folic acid-induced kidney injury mice. In the acute phase of AKI, Tanshinone IIA attenuated renal tubular epithelial injury, as determined by histologic changes and the detection of Neutrophil gelatinase-associated lipocalin (NGAL) in the kidney and urine. Additionally, Tanshinone IIA treatment resulted in elevated proliferating cell nuclear antigen (PCNA) expression and decreased inflammatory cells infiltration as well as chemokine expression, suggesting that Tanshinone IIA promoted renal repair following AKI and inhibited local inflammatory response in the injured kidney. This led to decreased long-term fibrosis in the injured kidney, characterized by less accumulation of fibronectin and collagen I in tubulointerstitium. Taken together, these results suggest that Tanshinone IIA may represent a potential approach for AKI treatment.

Delayed Consequences of Acute Kidney Injury

Acute kidney injury (AKI) is an increasingly common complication of hospitalization and acute illness. Experimental data indicate that AKI may cause permanent kidney damage through tubulointerstitial fibrosis and progressive nephron loss, while also lowering the threshold for subsequent injury. Furthermore, preclinical data suggest that AKI may also cause distant organ dysfunction. The extension of these findings to human studies suggests long-term consequences of AKI including, but not limited to recurrent AKI, progressive kidney disease, elevated blood pressure, cardiovascular events, and mortality. As the number of AKI survivors increases, the need to better understand the mechanisms driving these processes becomes paramount. Optimizing care for AKI survivors will require understanding the short- and long-term risks associated with AKI, identifying patients at highest risk for poor outcomes, and testing interventions that target modifiable risk factors. In this review, we examine the literature describing the association between AKI and long-term outcomes and highlight opportunities for further research and potential intervention.

Epidemiology and Outcome of Acute Kidney Injury According to Pediatric Risk, Injury, Failure, Loss, End-Stage Renal Disease and Kidney Disease: Improving Global Outcomes Criteria in Critically Ill Children-A Prospective Study

OBJECTIVE

We aimed to investigate the epidemiology, risk factors, and short- and medium-term outcome of acute kidney injury classified according to pediatric Risk, Injury, Failure, Loss, End-Stage Renal Disease, and Kidney Disease: Improving Global Outcomes criteria in critically ill children.

DESIGN

Prospective observational cohort study.

SETTING

Two eight-bed PICUs of a tertiary-care university hospital.

PATIENTS

A heterogeneous population of critically ill children.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Demographic, clinical, laboratory, and outcome data were collected on all patients admitted to the PICUs from August 2011 to January 2012, with at least 24 hours of PICU stay. Of the 214 consecutive admissions, 160 were analyzed. The prevalence of acute kidney injury according to pediatric Risk, Injury, Failure, Loss, End-Stage Renal Disease and Kidney Disease: Improving Global Outcomes criteria was 49.4% vs. 46.2%, respectively. A larger proportion of acute kidney injury episodes was categorized as Kidney Disease: Improving Global Outcomes stage 3 (50%) compared with pediatric Risk, Injury, Failure, Loss, End-Stage Renal Disease F (39.2%). Inotropic score greater than 10 was a risk factor for acute kidney injury severity. About 35% of patients with acute kidney injury who survived were discharged from the PICU with an estimated creatinine clearance less than 75 mL/min/1.73 m and one persisted with altered renal function 6 months after PICU discharge. Age 12 months old or younger was a risk factor for estimated creatinine clearance less than 75 mL/min/1.73 m at PICU discharge. Acute kidney injury and its severity were associated with increased PICU length of stay and longer duration of mechanical ventilation. Eleven patients died; nine had acute kidney injury (p < 0.05). The only risk factor associated with death after multivariate adjustment was Pediatric Risk of Mortality score greater than or equal to 10.

CONCLUSIONS

Acute kidney injury defined by both pediatric Risk, Injury, Failure, Loss, End-Stage Renal Disease and Kidney Disease: Improving Global Outcomes criteria was associated with increased morbidity and mortality, and may lead to long-term renal dysfunction.

Severe acute kidney injury as presentation of Burkitt's lymphoma

We discuss a case of acute kidney injury (AKI) at a very young age caused by primary lymphomatous renal infiltration due to Burkitt's lymphoma and analyse the literature on this rare condition. At presentation, clinical examination showed impressive bilateral nephromegaly and hypertension. Blood analysis indicated severe AKI, mild anaemia and normal serum electrolytes. There were no signs of tumour lysis syndrome. Urine sediment was normal, with neither haematuria nor proteinuria. Abdominal ultrasound demonstrated bilateral renal enlargement (+12 SD), with increased corticomedullar differentiation. MRI demonstrated the presence of a homogenous renal enlargement with features of an infiltrative lesion. Ultimately, microscopic and immunohistochemical analysis of the renal biopsy confirmed the diagnosis of Burkitt's lymphoma. Early and aggressive therapy is the key to ensure a good outcome.

Drug-induced acute kidney injury in neonates

PURPOSE OF REVIEW

Acute kidney injury (AKI) is an independent risk factor for morbidity and mortality in critically ill neonates. Nephrotoxic medication exposure is common in neonates. Nephrotoxicity represents the most potentially avoidable cause of AKI in this population.

RECENT FINDINGS

Recent studies in critically ill children revealed the importance of recognizing AKI and potentially modifiable risk factors for the development of AKI such as nephrotoxic medication exposures. Data from critically ill children who have AKI suggest that survivors are at risk for the development of chronic kidney disease. Premature infants are born with incomplete nephrogenesis and are at risk for chronic kidney disease. The use of nephrotoxic medications in the neonatal intensive care unit is very common; yet the effects of medication nephrotoxicity on the short and long-term outcomes remains highly understudied.

SUMMARY

The neonatal kidney is predisposed to nephrotoxic AKI. Our ability to improve outcomes for this vulnerable group depends on a heightened awareness of this issue. It is important for clinicians to develop methods to minimize and prevent nephrotoxic AKI in neonates through a multidisciplinary approach aiming at earlier recognition and close monitoring of nephrotoxin-induced AKI.

Hypoxia: The Force that Drives Chronic Kidney Disease

In the United States the prevalence of end-stage renal disease (ESRD) reached epidemic proportions in 2012 with over 600,000 patients being treated. The rates of ESRD among the elderly are disproportionally high. Consequently, as life expectancy increases and the baby-boom generation reaches retirement age, the already heavy burden imposed by ESRD on the US health care system is set to increase dramatically. ESRD represents the terminal stage of chronic kidney disease (CKD). A large body of evidence indicating that CKD is driven by renal tissue hypoxia has led to the development of therapeutic strategies that increase kidney oxygenation and the contention that chronic hypoxia is the final common pathway to end-stage renal failure. Numerous studies have demonstrated that one of the most potent means by which hypoxic conditions within the kidney produce CKD is by inducing a sustained inflammatory attack by infiltrating leukocytes. Indispensable to this attack is the acquisition by leukocytes of an adhesive phenotype. It was thought that this process resulted exclusively from leukocytes responding to cytokines released from ischemic renal endothelium. However, recently it has been demonstrated that leukocytes also become activated independent of the hypoxic response of endothelial cells. It was found that this endothelium-independent mechanism involves leukocytes directly sensing hypoxia and responding by transcriptional induction of the genes that encode the β2-integrin family of adhesion molecules. This induction likely maintains the long-term inflammation by which hypoxia drives the pathogenesis of CKD. Consequently, targeting these transcriptional mechanisms would appear to represent a promising new therapeutic strategy.

Acute Kidney Injury Incidence in Noncritically Ill Hospitalized Children, Adolescents, and Young Adults: A Retrospective Observational Study

BACKGROUND

Acute kidney injury (AKI) has been characterized in high-risk pediatric hospital inpatients, in whom AKI is frequent and associated with increased mortality, morbidity, and length of stay. The incidence of AKI among patients not requiring intensive care is unknown.

STUDY DESIGN

Retrospective cohort study.

SETTING & PARTICIPANTS

13,914 noncritical admissions during 2011 and 2012 at our tertiary referral pediatric hospital were evaluated. Patients younger than 28 days or older than 21 years of age or with chronic kidney disease (CKD) were excluded. Admissions with 2 or more serum creatinine measurements were evaluated.

FACTORS

Demographic features, laboratory measurements, medication exposures, and length of stay.

OUTCOME

AKI defined as increased serum creatinine level in accordance with KDIGO (Kidney Disease: Improving Global Outcomes) criteria. Based on time of admission, time interval requirements were met in 97% of cases, but KDIGO time window criteria were not strictly enforced to allow implementation using clinically obtained data.

RESULTS

2 or more creatinine measurements (one baseline before or during admission and a second during admission) in 2,374 of 13,914 (17%) patients allowed for AKI evaluation. A serum creatinine difference ≥0.3mg/dL or ≥1.5 times baseline was seen in 722 of 2,374 (30%) patients. A minimum of 5% of all noncritical inpatients without CKD in pediatric wards have an episode of AKI during routine hospital admission.

LIMITATIONS

Urine output, glomerular filtration rate, and time interval criteria for AKI were not applied secondary to study design and available data. The evaluated cohort was restricted to patients with 2 or more clinically obtained serum creatinine measurements, and baseline creatinine level may have been measured after the AKI episode.

CONCLUSIONS

AKI occurs in at least 5% of all noncritically ill hospitalized children, adolescents, and young adults without known CKD. Physicians should increase their awareness of AKI and improve surveillance strategies with serum creatinine measurements in this population so that exacerbating factors such as nephrotoxic medication exposures may be modified as indicated.