Clinical characteristics of nephrocalcinosis in preterm infants / 中国新生儿科杂志

ABSTRACT

Objective:To study the clinical characteristics and risk factors of nephrocalcinosis in preterm infants.Methods:From March 2021 to August 2021, all preterm infants admitted to NICU of our hospital were retrospectively analyzed. The infants were assigned into nephrocalcinosis group and non-nephrocalcinosis group according to urinary tract ultrasound. Clinical data including gestational age, birth weight(BW), nutritional support strategy and complications were reviewed.Results:A total of 40 preterm infants (<34 weeks) were enrolled. 9 cases were in the nephrocalcinosis group and 31 cases in the non-nephrocalcinosis group. The nephrocalcinosis group had lower BW[(1 167±214) g vs.(1 586±215) g], higher calcium [6.9 (5.1, 8.7) g vs.3.3 (2.1, 6.8) g] and vitamin D intake [3.2(2.5, 4.2)×10 4U vs.1.7(1.1, 3.2)×10 4U] during hospitalization. No significant differences existed between the two groups on the following items:blood calcium and phosphate, 25-hydroxyvitamin D, feeding strategy, time to reach full enteral feeding(TFF), furosemide dosage and respiratory support duration ( P>0.05). In the nephrocalcinosis group, the median age of diagnosing nephrocalcinosis was 40.0(30.0, 52.5)d after birth. 5 cases showed bilateral nephrocalcinosis. 5 cases in the nephrocalcinosis group received renal tubule function examination,4 cases had increased urine β2 microglobulin and 2 cases had increased urine α1 microglobulin. 7 cases had elevated urine calcium in the nephrocalcinosis group. Follow-up showed that nephrocalcinosis disappeared 3-9 months after birth. Conclusions:BW, total calcium and vitamin D intake are risk factors for nephrocalcinosis in preterm infants. Increased urine β2 microglobulin and calcium levels are common co-morbidities in preterm infants with nephrocalcinosis.