Neonatal transient renal failure with renal medullary hyperechogenicity: clinical and laboratory features

Abstract

Sonographic findings of renal medullary hyperechogenicity have been observed in the neonate in association with severe perinatal renal injury, kidney malformations or nephrocalcinosis, and, rarely, in newborn infants with transient renal failure. The aim of the study was to describe the entity of neonatal transient renal failure with renal medullary hyperechogenicity (NTRFMH). We studied nine term neonates, born between August 1999 and February 2004 in our institution (0.1% of the live born infants), who developed transient renal dysfunction after birth, and in whom renal sonograms showed bilateral medullary hyperechogenicity. Seven of the infants (78%) had anuria until 30-45 hours of age, and two (22%) had oliguria. Peak serum creatinine levels ranged between 0.61 and 1.62 mg/dL (mean: 1.09+/-0.27 mg/dL) at 2-3 days of life. Additional findings included proteinuria in nine infants (100%), uric acid crystalluria in seven (78%), hyperuricemia in four (44%), and hypertension in one (11%). Hyperuricosuria was demonstrated in one out of the seven patients in whom this parameter was determined. Urinary excretion rates of calcium, phosphorus and oxalic acid were normal, as were urinary levels of amino acids and organic acids. Full clinical recovery accompanied by normalization of all laboratory parameters was observed in all infants by 4-6 days of life. Subsequent follow-up showed normal renal function, no urinary abnormalities, and normal renal sonograms in all infants. Our summary of the nine infants with NTRFMH reported on here and a review of 19 cases of this condition reported in the literature reveal a not-so-rare entity of unclear etiology, but excellent prognosis. Physicians caring for neonates should be aware of this benign and transient condition.

Transient renal medullary hyperechogenicity in a term neonate

“…Makhoul et al 5 described nine term neonates who, after birth, developed transient renal dysfunction, oligoanuria and bilateral medullary hyperechogenicity, with excellent prognosis. Additional findings included proteinuria (100%), uric acid crystalluria (78%) and hyperuricaemia (44%), with mean creatinine of 1.09 mg/dL.…”

Atypical presentation of congenital diaphragmatic hernia

“…Increased medullary echogenicity disappeared once the dehydration was corrected and renal function improved. 5 When feeding was reinitiated the baby deteriorated possibly due to malrotation and mass effect in the thorax. Bag and facemask ventilation is contraindicated in CDH however, in our case the initial improvement was because the stomach had not herniated into the thoracic cavity.…”

Renal Calcification in NICU Patients

“…Several investigators have reported nonasphyxiated neonates who had transient anuric/oliguric acute renal injury with hyperechoic renal medullary pyramids that returned to normal hypoechoic appearance within 4 to 6 days as well as full clinical recovery and normalization of all laboratory test results. (6) The acute renal injury and hyperechoic renal pyramids are believed to be caused by excess production of Tamm-Horsfall proteins, causing transient renal tubular obstruction.…”