Nephrocalcinosis in Bartter's syndrome. Demonstration by ultrasonography

Nephrocalcinosis in preterm neonates

The prevalence of nephrocalcinosis (NC) in preterm neonates in recent reports is 7-41%. The wide range in prevalence is a consequence of different study populations and ultrasound equipment and criteria, in addition to a moderate interobserver variation. NC in preterm neonates has a multifactorial aetiology, consisting of low gestational age and birth weight, often in combination with severe respiratory disease, and occurs as a result of an imbalance between stone-promoting and stone-inhibiting factors. A limited number of histological studies suggest that calcium oxalate crystals play an important role in NC in premature neonates. In 85% of children resolution of NC occurs in the first years of life. Prematurity, per se, is associated with high blood pressure, relatively small kidneys, and (distal) tubular dysfunction. In addition, NC in preterm neonates can have long-term sequelae for glomerular and tubular function. Long-term follow-up of blood pressure and renal function of prematurely born children, especially with neonatal NC, is recommended. Prevention of NC with (low) oral doses of citrate has not resulted in a significant decrease in the prevalence of NC; a higher citrate dosage deserves further study. Future research pertaining to prevention of NC in preterm neonates is crucial.

Renal sonographic patterns in Bartter's syndrome

The renal sonographic findings in ten cases of Bartter s syndrome investigated at the King Khalid University Hospital, Riyadh, Saudi Arabia are described. There were various sonographic abnormalities other than those of hyperechoic pyramids as previously described. These were diffuse increased renal echogenicity and hyperechoic echogenicity in the kidneys with the exception of the pyramids. This condition can be suspected early if nephrocalcinosis is present in a child with a history of polyhydramnios and premature delivery.

Causes of increased renal medullary echogenicity in Turkish children

The primary disorders of 50 children with increased renal medullary echogenicity on renal ultrasound were studied; 28 girls and 22 boys aged from 1 month to 16 years were classified into four groups based on underlying disease and ultrasound findings. Group 1 was composed of 17 patients with distal renal tubular acidosis (34%); intense echoes throughout the pyramid were predominant. Group 2 consisted of 14 patients with vitamin D toxicity (28%) and an intense echogenic rim around the pyramids. Group 3 included 10 patients with different types of tubulopathies. A slight hyperechogenic rim around the sides and tip of the medullary pyramids was detected. Group 4 was made up of 9 patients with rare underlying conditions. Abdominal X-rays detected medullary calcinosis in only 12 (24%) of the total 50 patients. Ultrasonography appears to be an important tool in the early diagnosis of increased renal medullary echogenicity and medullary nephrocalcinosis.

Nephrocalcinosis in a child with autosomal dominant polycystic kidney disease and a prolapsing ectopic ureterocele

Although autosomal dominant polycystic kidney disease commonly presents in adults, it can occur in children. Usually, renal calcification in patients with autosomal dominant polycystic kidney disease is manifested as calculi or as hemorrhage into a renal cyst. An ectopic ureterocele is a well-known finding in patients with renal duplication. To our knowledge, this is the first case report of a child who had combined findings of autosomal dominant polycystic kidney disease, nephrocalcinosis, and an obstructing ectopic ureterocele.

Hypokalemia with nephrocalcinosis: a variant of Bartter's syndrome

A 28-year-old male presented with profound hypokalemia and was found to have a variant of Bartter's syndrome with nephrocalcinosis, hypercalciuria, normal distal fractional reabsorption of chloride and normal sodium delivery to the distal tubule.

Nephrocalcinosis in Bartter's syndrome

Nephrocalcinosis was demonstrated by computerized tomography (CT) in all five children with Bartter's syndrome followed at our institution. In three of these five patients, nephrocalcinosis was also noted on ultrasound examination. Hypercalciuria was present in only one case. The mechanism leading to renal calcification remains unclear in this disease. It is noteworthy, however, that Bartter's syndrome is associated with such a high incidence of nephrocalcinosis.