Renal cortical necrosis is a disappearing entity in obstetric acute kidney injury in developing countries: our three decade of experience from India

Miscarriage-Related Acute Kidney Injury: A Case Report

Background

Pregnancy-related acute kidney injury (Pr-AKI) is associated with significant maternal and fetal morbidity and mortality, with a three- to four-fold increase in perinatal mortality. Pr-AKI can arise from various obstetric complications, such as hyperemesis gravidarum, septic abortion, hypertensive disorders of pregnancy, pyelonephritis, and antiphospholipid antibody syndrome. Therefore, early diagnosis and appropriate intervention, including the identification of the underlying etiology, are important to effectively manage Pr-AKI. Therefore, we report a case of Pr-AKI after early miscarriage in a patient without hyperemesis gravidarum or septic abortion whose renal function gradually improved postoperatively for miscarriage.

Case Presentation

A 34-year-old primigravid woman was referred to us for perinatal management at 6 weeks of gestation. Unfortunately, she was diagnosed with miscarriage 1 week later. The patient had no history of hyperemesis gravidarum or septic abortion; however, she developed oliguria, and her serum creatinine and blood urea nitrogen levels were abnormally increased. Consequently, she underwent a renal biopsy to evaluate renal dysfunction, which indicated tubulointerstitial damage. The patient also underwent manual vacuum aspiration for a miscarriage. Postoperatively, her urine output increased, and her renal function improved. She was determined to have experienced Pr-AKI due to her miscarriage.

Conclusion

Our patient had Pr-AKI after a miscarriage in the absence of other causes. This case report highlights the presence of unknown causes of Pr-AKI, warranting further research for the development of preventive interventions.

Pregnancy-Associated Renal Cortical Necrosis and Nonenhanced Functional MRI: A Case Series

Rationale & Objective

Pregnancy-associated renal cortical necrosis is a critical illness with a poor prognosis. We aimed to describe the clinical and magnetic resonance imaging (MRI) characteristics of a case series of patients with acute kidney injury in the setting of pregnancy-associated renal cortical necrosis.

Study Design

Case series.

Setting & Participants

Seventeen patients from a single center diagnosed by nonenhanced functional MRI and/or kidney pathology.

Results

All patients presented with postpartum acute kidney injury stage 3. Of the 17 patients, 15 (88%) had pregnancy-associated atypical hemolytic uremic syndrome, 11 (65%) had postpartum hemorrhage, 7 (41%) had preeclampsia/hemolysis elevated liver enzymes low platelet count syndrome, and 4 (24%) had disseminated intravascular coagulation. On T2-weighted MRI, the diffuse phenotype showed outer cortex swelling in the early phase, with a dark signal rim involving the inner cortex and Bertin column, which became more apparent over time along with cortical thinning, substantially decreasing T2 signal intensity. The focal phenotype showed focally distributed hypointense signals in the cortex. After 8-101 (median: 60) months of follow-up, 4 individuals had estimated glomerular filtration rates ≥60 mL/min/1.73 m², 6 had estimated glomerular filtration rates of 15-60 mL/min/1.73 m², and 7 had kidney failure requiring kidney replacement therapy. The diffuse phenotype was present in all of the individuals who remained kidney replacement therapy dependent.

Limitations

Retrospective study; small sample size.

Conclusions

Different forms of pregnancy-associated thrombotic microangiopathy were the major causative diseases in our pregnancy-associated renal cortical necrosis case series. Nonenhanced functional MRI may provide valuable data for establishing diagnosis and kidney prognosis.

Pregnancy-Associated Acute Kidney Injury in Low-Resource Settings: Progress Over the Last Decade

Despite immense global effort, the maternal mortality rate in low-resource settings remains unacceptably high. Globally, this reflects the grave inequalities in access to health and reproductive services. Pregnancy-associated acute kidney injury (PRAKI) is an independent risk factor for mortality. The reported incidence of PRAKI in low- and middle-income countries is higher than that of high-income countries (4%-26% versus 1%-2.8%, respectively). Hypertensive disorders are now the leading cause of PRAKI in many regions, followed by hemorrhage and sepsis. PRAKI in low-resource settings carries a high mortality for both mother and child. Outcome studies suggest that PRAKI is associated with residual kidney dysfunction and may lead to dialysis dependence. This can be a death sentence in many regions with limited kidney replacement therapy. This review will summarize data on PRAKI on the African, Latin American, and Asian continents over the past decade. It will include the progress in published data, mortality, and treatment interventions and provide recommendations for the next decade.

The changing face of pregnancy-related acute kidney injury from eastern part of India: A hospital-based, prospective, observational study

This study was initiated to look into the etiologies, prevalence, and outcome of pregnancy-related acute kidney injury (PRAKI) in a tertiary care hospital. Women admitted with PRAKI from January 2015 to December 2016 were included in the study. All patients were investigated and treated and followed up for the next six months.. For statistical analysis, Chi- square test and analysis of variance were performed to analyze the data. Multivariate analysis was applied to compare the risk of nonrecovery of renal function in different etiologies of PRAKI. During the study period, 81 patients were admitted with PRAKI, of whom 68 (84%) received hemodialysis (HD). A total of 449 patients including all cases of AKI underwent HD from January 2015 to June 2016. The incidence of dialysis requiring PRAKI was 68 out of the 449 patients (15%). Sixty-eight (84%) patients required dialysis support while the most common cause was sepsis (49%), with the second being pregnancy-associated atypical hemolytic-uremic syndrome (P-aHUS) (17%) followed by obstetric hemorrhages (16%). There was a significant reduction of first-trimester AKI (8.6%) compared to a previous study published from this institute (19.3%). The maternal mortality (25%) and fetal mortality (23.5%) were high. Nearly 39% of the patients had complete recovery of renal function. This study revealed significant PRAKI burden due to a largely preventable cause, puerperal sepsis. Renal survival was poor in P- aHUS. The gaps in the obstetric care may be identified for the improvement of fetomaternal outcome.

Multiparametric ultrasound findings in acute kidney failure due to rare renal cortical necrosis

Renal cortical necrosis (RCN) is a rare cause of acute kidney failure and is usually diagnosed on the basis of characteristic enhancement patterns on cross-sectional imaging. Contrast-enhanced ultrasound (CEUS) offers benefits in patients with kidney failure in the clinical setting including the use of a nonnephrotoxic intravascular contrast agent and the fact that it can be performed at the bedside in critical cases. Therefore, the aim of this study is to investigate whether CEUS can reliably identify typical imaging features of RCN. We retrospectively analyzed 12 patients with RCN examined in our department and confirmation of the diagnosis by either histopathology, other contrast-enhanced cross-sectional imaging tests, and/or CEUS follow-up. Assessed parameters in conventional US were reduced echogenicity, loss of corticomedullary differentiation, length and width of kidney, hypoechoic rim, resistance index and in CEUS delayed wash-in of contrast agent (> 20 s), reverse rim sign, maximum nonenhancing rim and additional renal infarction. Furthermore, imaging features in RCN were compared with the findings in renal vein thrombosis (RVT), among them echogenicity, corticomedullar differentiation, hypoechoic rim, RI value, delayed cortical enhancement, total loss of cortical perfusion and enhancement of renal medulla. All 12 patients showed the reverse rim sign, while a hypoechogenic subcapsular rim was only visible in four patients on B-mode ultrasound. A resistance index (RI) was available in 10 cases and was always less than 1. RI was a strong differentiator in separating RVT from RCN (RI > 1 or not measurable due to hypoperfusion as differentiator, p = 0.001). CEUS showed total loss of medullary enhancement in all cases of RVT. With its higher temporal resolution, CEUS allows dynamic assessment of renal macro- and microcirculation and identification of the typical imaging findings of RCN with use of a nonnephrotoxic contrast agent.

Prevention and Therapy of AKI in Asia: A Big Challenge

Asia is the largest and most populous continent and has huge differences in socioeconomic status, development, and health care between the different countries and regions within each country. This manifests in the varied causes of acute kidney injury (AKI), particularly higher rates of community-acquired AKI and in the differential access to health care for the population. Because of resource limitations, prevention and treatment of AKI is a difficult challenge. This review highlights the differences in AKI in Asia compared with the developed world and discusses prevention and treatment of AKI within the context of resource limitations.

Postpartum Renal Cortical Necrosis Is Associated With Atypical Hemolytic Uremic Syndrome in Developing Countries

Introduction

Pregnancy-related acute kidney injury is the most common cause of renal cortical necrosis (RCN). Atypical hemolytic uremic syndrome (aHUS) as a cause of RCN in pregnant/postpartum is underevaluated. In the current article, we describe a series of cases of pregnancy-related RCN.

Methods

All cases with acute kidney injury (AKI) in the setting of pregnancy and postpartum state were included. Diagnosis of RCN was made by contrast-enhanced computerized tomography (nonenhancing renal cortex, enhancing medulla, and no excretion of contrast medium) or on a renal biopsy. aHUS was diagnosed in the presence of microangiopathic hemolytic anemia (thrombocytopenia, elevated lactate dehydrogenase with schistocytes on peripheral smear examination, or low haptoglobin).

Results

A total of 21 (17.5%) patients presented with RCN during pregnancy, all in the postpartum state. Twenty patients (95.2%) showed microangiopathic hemolytic anemia consistent with HUS and 1 (4.8%) patient had biopsy-proven thrombotic microangiopathy. Low complement 3 or activation of an alternate complement pathway was seen in 9 of 15 patients in which it was done. At the end of 6 months, only 2 (9.5%) patients had partial recovery of renal functions, 5 (23.8%) patients died, and 14 remained (66.7%) on hemodialysis.

Conclusion

The clinical and laboratory features are highly suggestive of aHUS in more than three-fourths of cases with postpartum RCN. Investigations are needed to look for genetic abnormalities in the complement pathway.

Acute kidney injury in pregnancy with special reference to pregnancy-specific disorders: a hospital based study (2014-2016)

INTRODUCTION

There are numerous reports in the literature describing acute kidney injury in pregnancy (P-AKI) due to various obstetric complications. However, there is a dearth of studies on AKI related to pregnancy-specific disorders from India. We aimed to analyze clinical features and outcome of P-AKI related to pregnancy-specific disorders compared to total pregnancy, in India.

METHOD

All pregnant women attending the department of Obstetrics and Gynecology from November 2014 to July 2016 were screened for AKI based on: (1) sudden elevation of serum creatinine ≥ 1 mg/dl; (2) oligoanuria for > 12 h; and (3) need for dialysis. The detailed clinical profile of AKI in patients with preeclampsia/eclampsia (PE/E), hemolysis/elevated liver enzymes/low platelet count (HELLP) syndrome, acute fatty liver of pregnancy (AFLP), and pregnancy-associated thrombotic microangiopathy (P-TMA) was analyzed. Laboratory investigations included: complete blood count, renal function tests, urinalysis, coagulation profile (platelet count, INR, prothrombin time and activated partial thromboplastin time), and immunological assay (C3, C4, ANA, anti-dsDNA antibody, antiphospholipid antibody). Contrast-enhanced CT scan of kidney ureter and bladder (KUB) and renal biopsy were performed in selected cases. Maternal and fetal outcome were analyzed individually. The patients were followed for 3 months or longer to determine the recovery of renal function or progression to chronic kidney disease (CKD).

RESULTS

Overall, 4741 pregnant women (mean age 26.8 ± 4.8 years) were evaluated for AKI. P-AKI was found in 132/4741 (2.78%) patients. In the majority (91.6%), AKI developed in the late 3rd trimester and post-partum period. P-AKI was related to obstetric complications (in 61.4%), pregnancy-specific disorders (in 57.5%) and miscellaneous factors (7.5%). Puerperal sepsis, ante-partum and post-partum hemorrhage were contributing factors for P-AKI in 34 (25.8%), 11 (8.3%) and 28 (21.2%) patients, respectively. P-AKI due to pregnancy-specific disorders developed in 76/4741 patients, i.e. in 1:62 pregnancies. PE/E was the cause of P-AKI in 62 patients (46.9%) followed by HELLP syndrome in 9 (6.8%) and AFLP in 05 (3.8%). P-TMA causing AKI was not observed. Complete recovery of renal function occurred in 89.4% of patients while 6 (4.6%) progressed to CKD (ESRD: 3 and CKD stage IV: 3). Maternal mortality was 6%. Puerperal sepsis was the sole cause of patchy cortical necrosis in 5 (3.7%) cases. Premature delivery occurred in 40.9% patients and full-term delivery in 35.6%. Perinatal mortality was 23.5%, mainly due to intrauterine death (17.5%) and prematurity (6%).

CONCLUSION

PE/E was the commonest cause of P-AKI in our study, similar to the situation in developed countries. Post-partum hemorrhage was the second-most common (21.5%) cause. Puerperal sepsis contributed to AKI in one-fourth of pregnant women. P-TMA was not recorded in this study and AFLP was an uncommon cause of P-AKI in our country. Renal function returned to normal in all patients with P-AKI due to pregnancy-specific disorders. However, perinatal mortality was high despite the good prognosis of P-AKI.

Diagnostic work-up and specific causes of acute kidney injury

Acute kidney injury (AKI) is common in critically ill patients and associated with grim short- and long-term outcome. Although in the vast majority of cases AKI is multifactorial, with sepsis, shock and nephrotoxicity accounting for most episodes, specific causes of AKI are not uncommon. Despite remaining uncertainties regarding their prevalence in the ICU, prompt recognition of specific aetiologies of AKI is likely to ensure timely management, limit worsening of renal dysfunction, and ultimately limit renal and systemic consequences of AKI. The ability to recognize conditions that may be associated with specific aetiologies and the appropriate use of clinical imaging, biological and immunological tests, along with optimal assessment of the need for renal biopsies, should be part of routine ICU care. In this review, we summarize uncertainties, current knowledge and recent advances regarding specific types of AKI. We describe the most common specific causes as well as rare aetiologies requiring urgent management, and outline available tools that may be used during the diagnostic work-up along with their limitations.

Acute Kidney Injury Recognition in Low- and Middle-Income Countries

Acute kidney injury (AKI) is increasingly common around the world. Because of the low availability of effective therapies and resource limitations, early preventive and therapeutic measures are essential to decrease morbidity, mortality, and cost. Timely recognition and diagnosis of AKI requires a heightened degree of suspicion in the appropriate clinical and environmental context. In low- and middle-income countries (LMICs), early detection is impaired by limited resources and low awareness. In this article, we report the consensus recommendations of the 18th Acute Dialysis Quality Initiative meeting in Hyderabad, India, on how to improve recognition of AKI. We expect these recommendations will lead to an earlier and more accurate diagnosis of AKI, and improved research to promote a better understanding of the epidemiology, etiology, and histopathology of AKI in LMICs.

Changing picture of renal cortical necrosis in acute kidney injury in developing country

Renal cortical necrosis (RCN) is characterized by patchy or diffuse ischemic destruction of all the elements of renal cortex resulting from significantly diminished renal arterial perfusion due to vascular spasm and microvascular injury. In addition, direct endothelial injury particularly in setting of sepsis, eclampsia, haemolytic uremic syndrome (HUS) and snake bite may lead to endovascular thrombosis with subsequent renal ischemia. Progression to end stage renal disease is a rule in diffuse cortical necrosis. It is a rare cause of acute kidney injury (AKI) in developed countries with frequency of 1.9%-2% of all patients with AKI. In contrast, RCN incidence is higher in developing countries ranging between 6%-7% of all causes of AKI. Obstetric complications (septic abortion, puerperal sepsis, abruptio placentae, postpartum haemorrhage and eclampsia) are the main (60%-70%) causes of RCN in developing countries. The remaining 30%-40% cases of RCN are caused by non-obstetrical causes, mostly due to sepsis and HUS. The incidence of RCN ranges from 10% to 30% of all cases of obstetric AKI compared with only 5% in non-gravid patients. In the developed countries, RCN accounts for 2% of all cases of AKI in adults and more than 20% of AKI during the third trimester of pregnancy. The reported incidence of RCN in obstetrical AKI varies between 18%-42.8% in different Indian studies. However, the overall incidence of RCN in pregnancy related AKI has decreased from 20%-30% to 5% in the past two decades in India. Currently RCN accounts for 3% of all causes of AKI. The incidence of RCN in obstetrical AKI was 1.44% in our recent study. HUS is most common cause of RCN in non-obstetrical group, while puerperal sepsis is leading cause of RCN in obstetric group. Because of the catastrophic sequelae of RCN, its prevention and aggressive management should always be important for the better renal outcome and prognosis of the patients.