Urinary B-2 microglobulin and retinol binding protein and microalbuminuria in perinatal asphyxia

ABSTRACT

This study was carried out on twenty-eight full term neonates with perinatal asphyxia with average one, five and ten minutes Apgar scores of 1.6, 4.3 and 3.7, respectively. Ten full term healthy neonates were included as a control group with one, five and ten minutes Apgar scores of 7.3, 9.4 and 9.6, respectively. Both groups were tested on the second and fifth days of postnatal life as regards complete blood picture, complete urine analysis, culture and sensitivity for urine and blood, investigations for renal glomerular function included urinary concentration of albumin, blood urea and serum creatinine, investigations for renal tubular function included urinary beta-2-microglobulin [B2-m] and retinol binding protein [RBP], fractional excretion of sodium [FENa] and urine output per unit body weight per hour [ml/kg/hr]. Abdominal sonography was done for all cases to exclude any surgical problems. Renal failure index [RFI] was calculated at second and fifth days of postnatal life. It was concluded that measurement of urinary B2-m and RBP are convenient, sensitive, specific and early diagnostic tools for the detection of tubular damage in asphyxiated neonates. Blood urea and serum creatinine are good indicators of glomerular impairment only after the first two days of life. The tubular function is more sensitive than glomerular function in neonates. A low Apgar score, arterial PO2 and pH are good indicators of hypoxia. Oliguria is already considered as an ambiguous indicator of ARF and could indicate poor neurologic outcome in asphyxiated neonates