Acute renal failure: nephrosonographic findings in asphyxiated neonates

To determine the incidence of acute renal failure (ARF) and nephrosonographic findings among asphyxiated neonates, and to correlate this with uric acid levels and the severity of hypoxic encephalopathy, we studied 80 full-term appropriate-for-date singleton neonates with perinatal asphyxia, and 30 healthy full-term neonates as controls from March 2006 to February 2007. A detailed history, thorough clinical examination along with investigations, including urine examination, 24-h urine collection, ultrasonography of abdomen and cranium, serum electrolytes, blood urea nitrogen, serum creatinine, and serum uric acid were obtained. ARF developed in 45% (36/80) of the asphyxiated neonates. Forty-eight (60%) neonates showed significant elevation of blood urea and 41 (51.3%) neonates had significant elevation of serum creatinine than the control group (P < 0.001). Sixty-two (77.5%) neonates developed significant elevation of serum uric acid levels, and nephrosonography revealed hyperechogenicity in all of them, while only two among the healthy neonates showed the raised uric acid levels (P < 0.001). Nonoliguric renal failure was seen 28/36 (77.8%) of the neonates with ARF, whereas eight (22.2%) neonates had oliguric renal failure. Eight (27.8%) patients among ARF patients maintained abnormal biochemical parameters after 2 weeks, and of whom four patients died after variable lengths of time with a mortality rate of 11.11%. Kidneys are the most common organs involved in perinatal asphyxia, and uric acid might be a causative factor for failure in addition to hypoxic insult. Routine use of kidney function test, along with abdominal ultrasonography form an important screening tool to detect any additional morbidity in these patients.