What Is Neonatal Acute Kidney Injury?
The buildup of waste products, impairment of electrolyte and fluid equilibrium, and change of acid-base homeostasis characterize acute kidney injury (AKI). AKI is the abrupt decline or loss of kidney function. It is a typical ailment among critically ill babies admitted to neonatal intensive care units (NICUs), and it is regarded as a separate risk factor that raises mortality, duration of stay, and medical expenses. AKI cannot yet be treated with any specific medicinal therapy.
The fundamental strategy for managing AKI should be planned following the underlying cause. The doctor must assist the cardiorespiratory system, ensure optimal nutrition, maintain homeostasis, and manage the effects of AKI to increase the likelihood of survival. Mortality rates for newborns with acute renal injury range from 14 % to 73 %. The prognosis is unpredictable and primarily dependent on the infant's underlying medical state.
What Are the Risk Factors and Causes of Neonatal Acute Kidney Injury?
The risk factors for the development of neonatal acute kidney injury include the following:
-
The current study has verified a link between low birth weight, early gestational age, and acute kidney injury.
-
Infants with perinatal asphyxia, commonly known as HIE (hypoxic ischemic encephalopathy), frequently experience multiorgan failure, affecting almost all organ systems. Infants with HIE have been observed to experience AKI often, with incidence rates varying from 38 % to 72 %.
-
Neonates and infants having heart surgery constitute patients at risk of developing AKI most.
-
Necrotizing enterocolitis (NEC) is a serious cause of morbidity and mortality, affecting between two and five percent of NICU admissions. Sepsis, hemodynamic instability, NTX (nephrotoxic medications) exposure, systemic inflammation, elevated intrabdominal pressure, and usually preterm are among the several risk factors for AKI in infants with NEC. Very unwell newborns are regularly exposed to NTX in the NICU.
Numerous potential causes of neonatal acute kidney injury can be categorized into prerenal, renal, and postrenal groups.
-
Prerenal Azotemia: The majority (up to 85%) of cases of acute kidney damage in neonates are caused by prerenal azotemia. Prerenal azotemia is characterized by insufficient renal perfusion. If treated right away, renal function and urine production improve.
-
Intrinsic Acute Kidney Injury (Renal): Acute tubular necrosis (ATN) is the most frequent cause of acute kidney damage in neonates. Perinatal asphyxia, sepsis, heart surgery, a protracted prerenal state, and the use of nephrotoxic drugs are some of the factors that contribute to ATN. Renal tubular cellular damage, modifications to adhesion molecules, and variations to renal hemodynamics are thought to play a role in the pathogenesis of ATN.
-
Acute Kidney Damage Due to Obstruction (Postrenal): Bilateral urinary system obstruction is the leading cause of acute kidney damage, typically reversible when the obstruction is removed.
What Are the Diagnostic Techniques Available for Neonatal Acute Kidney Injury?
There are no effective therapies for AKI that have already been developed. Despite numerous clinical trials in critical care nephrology, no evidence exists that treatment strategies work in patients with AKI. Therefore, efforts to enhance the area are now focused on developing better diagnoses, strategies for preventing and reducing complications, and treatments for the consequences of neonatal AKI.
Although serum creatinine (SCr) is now the "gold standard" for identifying AKI, using SCr as a biomarker comes with a number of difficulties. The most significant benefit of SCr is that it measures renal function rather than damage. Additionally, SCr is a late (up to 48 to 72 hours) indication of renal function, and it might remain constant until between 25% and 50% of kidney function has been compromised.
The creation of new biomarkers due to efforts to identify AKI sooner resulted in better clinical trials, enhanced outcomes, and the ability to diagnose AKI early. Numerous of these biomarkers promise to provide an early and precise diagnosis of newborn AKI. The novel biomarker neutrophil gelatinase-associated lipocalin (NGAL) could detect AKI sooner than fluctuations in SCr in several neonates.
What Are the Preventive and Mitigation Measures for Neonatal Acute Kidney Injury?
Stratification of Risk:
The early identification of people at risk for developing AKI is a crucial step toward enhancing AKI outcomes. Critical care nephrology researchers are actively exploring the idea of risk stratification, which is symbolized by the term "renal angina." The "Renal Angina Index" for pediatric patients has been created based on clinical risk factors and damage indicators. This research has led to the careful use of biomarkers in determining patients most likely to experience severe AKI early on.
Theophylline and Caffeine in Methylxanthine Therapy:
Methylxanthines are inhibitors of the adenosine receptor. Methylxanthines have been demonstrated to stop the adenosine-driven pre- and post-glomerular vasoconstriction and vasodilation that leads to AKI in populations at increased risk. Numerous studies have been conducted on Theophylline in newborns with hypoxic-ischemic encephalopathy (brain injury due to inadequate oxygen). Theophylline is risk-free, lowers the incidence of AKI, safeguards the renal tubule, and enhances fluid balance, filtration rate, and urine production. Caffeine is frequently used in preterm newborns to prevent or treat prematurity-related apnea (temporary pause in breathing). In a single-site cohort of 140 VLBW (very low birth weight) neonates, Carmody et al. evaluated the effect of caffeine during the first postnatal week on the risk of AKI. According to this study, coffee use during the first postnatal week was linked to a lower risk of AKI.
Kidney Support Therapy (KST):
Newborn indications for KST include uremia (a potentially fatal condition that develops when waste products linked to impaired kidney function accumulate in the blood), aberrant electrolytes, metabolic disorders, and failure to deliver appropriate nourishment. These indications are identical to those for older children. Peritoneal dialysis (PD) and continuous kidney support therapy (CKST) are the two KST techniques most frequently applied to newborns. The clinical situation, institutional competence, and resource availability frequently influence the use of these two modalities.
Conclusion
Most neonates who developed acquired AKI were very sick, and the condition is linked to high morbidity and mortality rates in both preterm and term newborns. AKI episodes were often brief and self-limiting. A current research topic focuses on identifying newborns most at risk for acute kidney injury utilizing new biomarkers. Avoiding NTX and administering methylxanthines to particular, vulnerable people may lower the likelihood of AKI or lessen the effects of AKI that already took place.
