|Year : 2021 | Volume
| Issue : 1 | Page : 13-20
Prevalence and outcome of severe acute kidney injury in children in a critical care nephrology unit
Shireen Afroz, Tahmina Ferdaus, Farhana Yasmin, Umme Tanjila, Sukriti Baroi
Department of Pediatric Nephrology, Bangladesh Institute of Child Health & Dhaka Shishu (Children) Hospital, Dhaka, Bangladesh
|Date of Submission||02-Sep-2021|
|Date of Acceptance||23-Sep-2021|
|Date of Web Publication||29-Dec-2021|
Professor Dr. Shireen Afroz
Department of Pediatric Nephrology, Bangladesh Institute of Child Health & Dhaka Shishu (Children) Hospital, Sher E Bangla Nagar, Dhaka 1207
Source of Support: None, Conflict of Interest: None
Background: This prospective observational study was conducted to see the prevalence, etiology, clinical profile, and immediate outcome of community-acquired acute kidney injury (AKI) in a pediatric critical care nephrology setup in Bangladesh. Materials and Methods: The prevalence, etiology, outcome, and fatality predictors of critically ill children with AKI, aged 5 days to 17 years from January 2016 to June 2018 were studied at Dhaka Shishu (Children) Hospital, Bangladesh. AKIN criteria were used to screen AKI. They were given supportive care and dialysis. Results: The prevalence of AKI among 725 patients was 61%. All the AKI cases were at AKIN stage III. Pre-renal cause accounted for 63%, renal 19% and post-renal 18%. The most common etiology of pre-renal AKI was post-diarrheal hypovolemia (50%), renal cause of AKI includes glomerulonephritis (45%) and among post-renal cause posterior urethral valves was 78%. Hypovolemia and shock were found in 12% of cases. Congestive cardiac failure (10%), hypertensive crisis (7%), severe hypernatremia (24%), severe metabolic acidosis (11%), and dialysis requirement (76%) were found to be associated with the worst outcome. Fifty-one percent improved with normal renal function. Of 441 AKI cases, 201 (46%) improved and among them 102 (51%) regained with normal renal functions. Approximately 99 (49%) with partial renal recovery and most (41) of them were due to renal cause of AKI. The overall worst outcome was observed in 54% and mortality in 40%. The highest mortality was found among neonates (60%) and infants (41%). Glasgow coma scale was <3 in 16% cases. Need for mechanical ventilation (11%) and longer hospital stay >30 days (9%) were the important predictors of fatality in AKI. Conclusion: Higher prevalence of severe AKI was associated with high mortality in neonates and infants in critical-care setup. Longer hospital stay and need for dialysis and mechanical ventilator predicted worst outcome.
Keywords: Acute kidney injury, critically ill-children, pediatric critical care nephrology and dialysis
|How to cite this article:|
Afroz S, Ferdaus T, Yasmin F, Tanjila U, Baroi S. Prevalence and outcome of severe acute kidney injury in children in a critical care nephrology unit. Paediatr Nephrol J Bangladesh 2021;6:13-20
|How to cite this URL:|
Afroz S, Ferdaus T, Yasmin F, Tanjila U, Baroi S. Prevalence and outcome of severe acute kidney injury in children in a critical care nephrology unit. Paediatr Nephrol J Bangladesh [serial online] 2021 [cited 2022 Jun 30];6:13-20. Available from: http://www.pnjb-online.org/text.asp?2021/6/1/13/334116
| Introduction|| |
Acute kidney injury (AKI) is associated with severe complications in pediatric intensive care units (PICU), with a mortality rate between 30% and 44%.,,,, Previous studies have shown the different impacts of AKI on critically ill children. However, all have found that AKI is associated with a longer hospital stay and higher mortality.,, The burden of AKI has increased in both developed and developing countries. Etiological spectrum of AKI as reviewed in medical literature shows wide variation between developed and developing countries. In the developed world, AKI is usually a hospital-acquired disease, whereas in developing countries, community-acquired AKI is frequently reported.,, There is a lack of data regarding etiology and outcome of community-acquired AKI in children.
As critically ill children with AKI have high morbidity and mortality, it is necessary to investigate prevalent causes at the regional level and to see the predictors of the worst outcome. So that we can detect patients at an early stage, and identify risk group that may benefit from prompt treatment.,
In Bangladesh, the availability of separate critical care nephrology and dialysis (CCN and D) services for children were not available till 2015. Before that, critically ill children with kidney diseases were usually being managed in PICU. After the establishment of CCNandD at Dhaka Shishu (Children’s) Hospital (DSH) since November 2015 we have been managing critically ill patients with different renal problems. DSH is the largest Children’s Hospital in Bangladesh with 665 beds, located at the Centre of Dhaka city, Sher e Bangla Nagar. In DSH, we have four ICUs. There are 8 beds in CCNandD unit, 16 in PICU, 8 in neonatal ICU, and 8 in cardiac ICU. The ratio of hospital beds to ICU beds is 665:40 (16.62:1) at DSH. AKI is associated with adverse outcomes, especially in children admitted to the PICU. Most of the studies done in developed countries on the incidence of AKI in critically ill-children are often retrospective in nature.,, But as a whole incidence of AKI in a critical-care nephrology setup especially in pediatric age groups is not reflected in most of the study reports. The objective of this study was to describe the prevalence, etiology, clinical outcomes, and fatality predictors of AKI in Bangladeshi children who were admitted in a critical-care nephrology set p.
| Materials and Methods|| |
This observational study was conducted over a period of 2 and half years from January 2016 to June 2018. A total of 725 critically ill children with different kidney diseases along with fluid electrolytes and acid-base imbalances were admitted to the CCNandD unit during this study period. The patients were referred from different upazilas, districts, and cities of Bangladesh. Among 725 patients, 441 were with AKI. Age ranged from 5 days to 17 years. The diagnosis of AKI was based on AKIN definition and classification. Neonatal AKI was also categorized by KDIGO Proposed criteria for AKI. AKI stage III was considered when (i) either serum creatinine ≥ 4 mg/dL on admission or (ii) oliguria <0.3 mL/kg/h or anuria for >12 h along with raised serum creatinine >3 times from baseline normal creatinine for age. For neonate AKI stage III was considered when (i) either serum creatinine ≥ 2.5 mg/dL on admission or (ii) oliguria <0.3 mL/kg/h for 24 h or anuria for >12 h along with raised serum creatinine >3 times from baseline normal creatinine for age. All AKI cases were at AKIN stage III. The etiology of AKI was divided in to pre-renal, renal and post-renal. History and clinical presentations suggestive of pre-renal cause along with blood urea to creatinine ratio >20:1 were used to categorize pre-renal AKI. Similarly history, clinical presentations, biochemistry, immunological parameters suggestive of intrinsic renal cause and blood urea to creatinine ratio <20:1 was considered intrinsic renal AKI. Any history, clinical features suggestive of obstructive uropathy along with previous medical records and investigations, known case of obstructive uropathy when admitted with AKI following surgical intervention or urosepsis were considered as post-renal causes. As the majority of cases were anuric, so we could not perform fractional excretion of sodium (FE Na %). These 441 children were analyzed regarding their cause of admission, disease pattern, duration of hospital stay, and immediate hospital outcome. Children presented with AKI on preexisting chronic kidney disease (CKD), renal tubular disorders with comorbidities were excluded from this study.
Informed consent was obtained from the parent or legal guardian before any intervention. Ethical clearance was taken from Institutional Ethical Review Committee, Bangladesh Institute of Child Health (BICH) No. BICH-ERC-04/02/2019.
At admission all patients underwent several investigations; complete blood count (CBC), arterial blood gas (ABG), serum electrolytes, serum albumin, serum creatinine, urea, serum calcium, inorganic phosphate, blood grouping, and other necessary investigations. Only children with the following were judged to require dialysis: symptomatic fluid overload such as difficult to control blood pressure and or pulmonary edema in the presence of oliguria; features of uremia manifesting as poorly controlled seizures, deterioration in level of consciousness, intractable vomiting, or bleeding from mucosal surfaces; severe hyperkalemia; severe metabolic acidosis or severe hyponatremia (serum sodium <110 mmol/L) or hypernatremia(serum sodium >170 mmol/L) not amenable to medical interventions. Serum creatinine or urea levels were not the only parameters used as the sole basis for dialysis. Intermittent hemodialysis (IHD) and sustained low-efficiency dialysis (SLED) facilities are available in CCNandD. Emergency hemodialysis was chosen for those who did not respond to intermittent peritoneal dialysis (IPD) or had rapidly progressive glomerulonephritis (RPGN). Kidney biopsy was performed in patients who had features of rapid deterioration of kidney functions over a period of days, weeks, or months and where pre-renal and post-renal causes were not present. Biopsy-proven crescentic GN were only included under crescentic GN category and other renal histopathology who had features like RPGN but histopathology did not show crescents were kept under acute GN.
Shock was defined as the presence of at least two of the following: tachycardia (heart rate > 2SD for age and sex) or capillary refill time> 3 s. Hypotension was called when systolic blood pressure falls below <70+ (age in year x 2) mmHg. Hypertension was defined as >95th percentile blood pressure for age, height, and gender. Hypertensive crisis was defined as blood pressure >99th centile with convulsion. Metabolic acidosis was considered severe when pH<7.1, moderate if pH >7.1–7.2, mild pH>7.2–7.35. Duration of hospital stay was categorized as <7 days, 7–14 days, 15–30 days, and >30 days.
Patients were followed up until discharge. Demographic parameters and short-term outcomes, complete recovery, leave against medical advice (LAMA) and death were recorded. Complete renal recovery in the case of AKI was defined as normal serum creatinine for age (0.2–0.4 mg/dL for infants, 0.3–0.7 mg/dL for 1–12 years, 0.5–1 mg/dL >12 years) and normal blood pressure at discharge. Partial renal recovery was defined as serum creatinine >1 mg/dL. Of 441 cases of AKI, 201 (46%) were improved and discharged. Among them 102 (51%) were improved with normal renal function and most of them (n = 99) were with pre-renal cause of AKI. Among rest of the patients 178 (40%) had died and 68 (16%) had taken LAMA at the late stage (with persistently raised serum creatinine even after dialysis and multi-organ involvement) due to hopeless outcome and financial constraint. All death and LAMA cases (54%, n = 240) were considered as the worst outcome.
Statistical analysis was performed by Statistical Package for the Social Sciences (SPSS) software program, version 23.0, chi-square test was performed to find out the predictor of poor outcome, and a value of P < 0.05 was considered significant.
| Results|| |
In this series from January 2016 to June 2018 a total of 725 patients were admitted. Prevalence of AKI was 441(61%). Male-to-female ratio was 2:1. Age ranged from 5 days to 17 years.
Among 441 cases of AKI, 108 were neonate, 202 were infants, 67 were between 1year to 5 year age, and 64 were older than 5 years. There were higher numbers of infants with AKI in this series [Table 1]. Most (46%) of the study patients [Table 1] were from lower-income families, 25% were from lower middle-income families, 18% from middle-income families, and 11% from higher-income families. Among the study patients 37% were urban residents, 29% rural residents, and 34% from urban slum. Regarding parental educational status it was found that 12% of the parents were illiterate but among the rest 21% primary grade, 24% secondary grade, 24% higher secondary grade, and 18% were university graduates.
Among the 441 cases of AKI, 277 (63%) were pre-renal, 86 (19%) were renal, and 78 (18%) were post-renal. In pre-renal cases 57% had improved and 43% died. In renal cases, 72% had improved and 28% died. In post-renal cases 56% improved and 44% had died. The majority of deaths were found in pre-renal and post-renal cases of AKI [Figure 1].
Pre-renal causes [Table 2] are mostly (50%) due to hypovolemia and shock following diarrhea, vomiting, sepsis, congestive heart failure, and perinatal asphyxia. The renal causes of AKI comprised 19%. Among them, acute glomerulonephritis (AGN, other than APSGN) was common (45%) followed by hemolytic uremic syndrome (20%). Those who were clinically sick presented with RPGN like features n = 46, among them seven showed crescents in histopathology, and rest (39) were with other varieties of GN. Post-renal causes comprised 18% of AKI. Among them, obstructive uropathy due to posterior urethral valve (PUV) was the most common (78%) cause.
|Table 2: Distribution of causative diseases of the studied children (n = 441)|
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Most (64%) pre-renal AKI responded to intermittent peritoneal dialysis (IPD) and only 8.3% needed hemodialysis [Table 3].
|Table 3: Pre-renal causes of AKI (n = 277) and frequency of dialysis needed|
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The renal causes of AKI [Table 1] comprised 19%. Among them, severe AGN was common (45%) followed by hemolytic uremic syndrome (20%). Those who were clinically presented with RPGN like features n = 46, among them seven showed crescents in histopathology and rest (39) were with other variety of AGN. All intrinsic renal causes of AKI patients required dialysis; most (77%) needed IHD [Table 4].
Post-renal causes [Table 1] comprised 18% of AKI. Among them obstructive uropathy due to PUV was the most common (78%) cause and most of them responded to IPD [Table 5].
Of 441 cases of AKI [Figure 2], 201 (46%) had improved and were discharged. Among them 102 (51%) improved with normal renal function and most of them (n = 99) were with pre-renal cause of AKI.
|Figure 2: Number of acute kidney injury cases survived with complete renal recovery (n = 102)|
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Among the survived cases 99 (49%) had partial renal recovery [Figure 3] and most (n = 41) of them were with renal and post-renal cause of AKI.
|Figure 3: Number of acute kidney injury cases survived with partial renal recovery (n = 99)|
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Overall [Table 6], 40% died, 46% improved and 14% had taken LAMA. Critical stage of the patients made the parents hopeless and poor financial status was the cause of higher rate (14%) of LAMA in this series. Of 108 neonatal AKI, 60% died. Among 202 infants, 41% had died, between 1-year and 5-year age group 11% had died, among 64 children in older than 5years group, 6% had died. The highest recorded mortality was found in neonates and infants.
Among the neonatal AKI [Table 7], neonatal sepsis (43%) was the most common cause. The overall outcome was worst and the highest mortality was seen in all cases. Sixty percent of neonates with AKI had died which comprised 15% of total death.
Chi-square test was performed to see the predictors of outcome [Table 8]. Of 441 cases 178 had died and 68 had taken LAMA at late stage. All deaths and LAMA cases 54% (n = 240) were considered as the worst outcome. Congestive cardiac failure (CCF), hypertensive emergency, severe hypernatremia, severe metabolic acidosis had significant (P < 0.001) association with poor outcome. Need for IPD (P < 0.01), HD (P < 0.001) and mechanical ventilator (MV) (P < 0.001) were also found to be associated with worst outcome. Longer hospital stay was associated with significantly (P < 0.001) poorer outcome. When hospital stay <7 days compared to 7–14 days showed no significance (0.27), but <7 days versus 15–30 days and <7 days versus >30days showed significant (0.001 and 0.009) association with the worst outcome.
| Discussion|| |
In this study, very high prevalence of AKI (61%) with higher rate of mortality (40%) in critically ill children with kidney disease had been found. Similar to the published literature, on the state of ICUs in severe AKI carries a high risk of death.,,,,, In this series pre-renal (63%) cause of AKI was higher; post diarrheal hypovolemic AKI and sepsis were most common. A higher rate of death was found in pre and post-renal cases of AKI. Among 19% of renal causes, RPGN and HUS were the most common. Mortality due to renal cause of AKI was 28%. Most renal causes of AKI needed dialysis. Crescentic GN was found in seven cases and in rest of the RPGN biopsy was suggestive of other renal histopathology. PNA, congenital heart diseases were commonly found in neonatal AKI. PUV was the most common post-renal cause of AKI.
A previous study of AKI in Bangladeshi children showed similar results of 63% pre-renal AKI mostly diarrheal, higher rate of mortality was found in infants with AKI. HUS, wasp envenomation, and AGN were the common renal cause of AKI in the previous study. Various studies of AKI in the PICU have reported incidence ranging widely from 4.5–70%.,,, In another study, the most frequent etiologies were heart surgery, septic processes, and nephrological causes. In a recent publication from northern India, Mehta et al. reported a 36.1% incidence of AKI in the critically ill children. Mehta found that shock was the only independent predictor of mortality. In this study, 12% of cases were with shock and most of them had the worst outcome, although not statistically significant.
In many studies, HUS was found as the major renal cause of AKI in children, but in this study RPGN was higher. Most probably in critical care setup severe hypertensive crisis and associated comorbidities, need for ICU all were important factors for higher number of RPGN in this study. There was a significant trend of higher mortality with higher AKI stage. Young age was associated with higher mortality rate in children with severe AKI in keeping consistency with previous reports.,,,,, The reasons for this finding are not known but may be related to the relatively high prevalence of sepsis in younger children and hemodynamic instability.
Most of the children with AKI had more than one indication for dialysis, which might be one of the important causes of increased risk of death. CCF, hypertensive emergency, severe hypernatremia, severe metabolic acidosis had significant (P < 0.001) association with poor outcomes. In contrast, other features of AKI such as shock, hypovolemia, hypokalemia, hyperkalemia, and hyponatremia were not significantly associated with in-hospital mortality. In the published literature, these features have also been inconsistently associated with mortality. Tresa et al. showed GN and obstructive stone disease as the major bulk of pediatric AKI in Pakistan as stone disease is more prevalent there, which is completely opposite to this study. The epidemiology of AKI has changed due to therapeutic advances and a growing trend to present secondary to other pathologies. Patients undergoing cardiac surgery are at high risk of AKI. But in this study, no AKI patients were admitted after cardiac surgery although in this children’s hospital regular cardiac surgeries are conducted, possibly due to standard postsurgical management in the cardiac intensive care unit at this hospital. Severe sepsis and septic shock are risk factors for AKI. In this study, 20% of post-renal AKI occurred due to sepsis in postsurgical obstructive uropathy cases. Flynn JT. also reported post-operative sepsis as a predominant cause of AKI in pediatric population.
All patients followed up until discharge and among them 51% improved with normal renal function. Approximately 49% had partial renal recovery and most (n = 41) of them were due to renal cause of AKI. Most (100%) AKI with renal or intrinsic causes showed poorer outcomes. In this study most deaths were found in pre-renal and post-renal cases and increased morbidity was observed in renal cause of AKI, which is similar to that reported by previous studies.,
Features of sepsis, shock, hypertensive crisis, hypernatremia, and the need for dialysis and mechanical ventilator were the most significant factors associated with mortality during hospitalization. Longest hospital stay was also an important predictor of poorer outcome, which is also consistent with previous study report.,,
In this study, 68 patients had taken LAMA at the late stage due to financial constraint and hopeless outcomes. All death and LAMA cases (240) were considered as the worst outcome because when they left hospital most of them were either with poor score Glasgow coma scale (GCS) (<3) or with indications for mechanical ventilator or with sepsis and multiple complications and sometimes parent prefer to take LAMA to avoid mechanical ventilator support.
All previous studies, reported the prevalence of AKI in critically ill children getting treatment in ICU. But this study differs with the previous studies. This study is showing the prevalence, outcome, and predictors of poor outcomes of those critically ill AKI children who got admitted in a critical care nephrology setup along with other critically ill kidney disease children. It is possible that identifying and treating AKI promptly might reduce the prevalence of CKD.
| Conclusion|| |
Higher number of severe AKI was found to be associated with high mortality especially in neonates and infants in critical care nephrology setup. Post diarrheal hypovolemic AKI was the most common cause, followed by sepsis, GN, HUS, and PUVs. AKI with CCF, hypertensive crisis, severe hypernatremia, and severe metabolic acidosis needs to be managed adequately with early dialysis support. Longer hospital stay and need for dialysis and mechanical ventilation predicted an adverse outcome. Pre-renal AKI is mostly showed complete renal recovery as compared with renal cause.
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[Figure 1], [Figure 2], [Figure 3]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6], [Table 7], [Table 8]