High incidence of nephrocalcinosis in extremely preterm infants treated with dexamethasone.
BACKGROUND
The use of postnatal corticosteroids to treat or prevent chronic lung disease is common in very preterm infants. Medullary nephrocalcinosis has been noted as a possible side effect.


OBJECTIVE
This prospective study was designed to assess the incidence of nephrocalcinosis in extremely preterm infants exposed to dexamethasone.


METHODS
A prospective study of extremely preterm infants, recruited to a randomized trial of dexamethasone treatment for chronic lung disease, was initiated. Infants had US of the renal tract scheduled on entry into the study, at day 28 and at discharge or at the corrected gestational age of 36 weeks.


RESULTS
Thirty-three infants were enrolled in the study. Birth weight ranged between 440 and 990 g and gestation between 24 and 28 weeks. Nine infants died and six had incomplete data. Because there was no difference in incidence of calcification between those on the short course and those on the long course of dexamethasone, analysis was made on the entire cohort. One infant had nephrocalcinosis at the time of the initial US examination on day 26 of life. By day 28, nephrocalcinosis was present in 31% of those with complete data. By discharge, or corrected gestational age of 36 weeks, US evidence of nephrocalcinosis was present in 15 (83%) of 18 infants. All infants had at least one course of an aminoglycoside antibiotic during the study. All infants had parenteral nutrition. Only four infants received furosemide more regularly than single doses. The longest course was 10 days, received by an infant who did not develop nephrocalcinosis.


CONCLUSIONS
The incidence of nephrocalcinosis is high in this group of sick, extremely preterm infants. Dexamethasone may be a factor in the development of nephrocalcinosis. Future research should focus on the natural history of nephrocalcinosis in extremely preterm infants.
Cranefield
David J
DJ
Department of Radiology, National Women's Hospital, Private Bag 92189, Auckland, New Zealand.
Odd
David E
DE
Harding
Jane E
JE
Teele
Rita L
RL
D000617:Aminoglycosides / Q000008:administration & dosage; D000900:Anti-Bacterial Agents / Q000008:administration & dosage; D003907:Dexamethasone / Q000009:adverse effects*; D005865:Gestational Age; D005938:Glucocorticoids / Q000009:adverse effects*; D006801:Humans; D007231:Infant, Newborn; D007235:Infant, Premature, Diseases / Q000139:chemically induced* / Q000188:drug therapy; D019102:Infant, Very Low Birth Weight; D007668:Kidney / Q000000981:diagnostic imaging; D008171:Lung Diseases / Q000188:drug therapy; D009397:Nephrocalcinosis / Q000139:chemically induced* / Q000000981:diagnostic imaging; D011446:Prospective Studies; D014463:Ultrasonography
D000617:Aminoglycosides; D000900:Anti-Bacterial Agents; D005938:Glucocorticoids; D003907:Dexamethasone