Postnatal dexamethasone therapy and cerebral tissue volumes in extremely low birth weight infants.
OBJECTIVE
Our goal was to relate postnatal dexamethasone therapy in extremely low birth weight infants (birth weight of < or = 1000 g) to their total and regional brain volumes, as measured by volumetric MRI performed at term-equivalent age.


METHODS
Among 53 extremely low birth weight infants discharged between June 1 and December 31, 2003, 41 had high-quality MRI studies; 30 of those infants had not received postnatal steroid treatment and 11 had received dexamethasone, all after postnatal age of 28 days, for a mean duration of 6.8 days and a mean cumulative dose of 2.8 mg/kg. Anatomic brain MRI scans obtained at 39.5 weeks (mean) postmenstrual age were segmented by using semiautomated and manual, pretested, scoring algorithms to generate three-dimensional cerebral component volumes. Volumes were adjusted according to postmenstrual age at MRI.


RESULTS
After controlling for postmenstrual age at MRI, we observed a 10.2% smaller total cerebral tissue volume in the dexamethasone-treated group, compared with the untreated group. Cortical tissue volume was 8.7% smaller in the treated infants, compared with untreated infants. Regional volume analysis revealed a 20.6% smaller cerebellum and a 19.9% reduction in subcortical gray matter in the dexamethasone-treated infants, compared with untreated infants. In a series of regression analyses, the reductions in total cerebral tissue, subcortical gray matter, and cerebellar volumes associated with dexamethasone administration remained significant after controlling not only for postmenstrual age but also for bronchopulmonary dysplasia and birth weight.


CONCLUSIONS
We identified smaller total and regional cerebral tissue volumes in extremely low birth weight infants treated with relatively conservative regimens of dexamethasone. These volume deficits may be the structural antecedents of neuromotor and cognitive abnormalities reported after postnatal dexamethasone treatment.
Parikh
Nehal A
NA
Division of Neonatal-Perinatal Medicine, Department of Pediatrics, University of Texas Medical School at Houston, Houston, TX 77030, USA. nehal.a.parikh@uth.tmc.edu
Lasky
Robert E
RE
Kennedy
Kathleen A
KA
Moya
Fernando R
FR
Hochhauser
Leo
L
Romo
Seferino
S
Tyson
Jon E
JE
D001921:Brain / Q000033:anatomy & histology*; D003907:Dexamethasone / Q000627:therapeutic use*; D005260:Female; D005938:Glucocorticoids / Q000627:therapeutic use*; D006801:Humans; D052577:Infant, Extremely Low Birth Weight; D007231:Infant, Newborn; D008279:Magnetic Resonance Imaging; D008297:Male; D009929:Organ Size
D005938:Glucocorticoids; D003907:Dexamethasone