Diffuse basal ganglia or thalamus hyperechogenicity in preterm infants

OBJECTIVE

To determine the incidence and factors associated with diffuse basal ganglia or thalamus hyperechogenicity (BGTH) in preterm infants.

STUDY DESIGN

(1) Review of serial neurosonograms among neonates with gestational age (GA) <34 weeks born at Weiler Hospital during a 21-month period; (2) Color Doppler flow imaging; (3) Case-control study using GA group-matched controls; and (4) Blind reading of CT scans or MRIs in patients with BGTH.

RESULTS

Among 289 infants, 24 (8.3%) had diffuse BGTH. Color Doppler flow imaging was normal in nine patients. The incidence of diffuse BGTH was inversely related to GA (P<0.01). Logistic regression (n=96) showed that diffuse BGTH was significantly associated with requirement of high-frequency oscillation (HFO) (P=0.031), severe intraventricular hemorrhage (IVH) (P=0.004), hypotension requiring vasopressors (P=0.040), hypoglycemia (P=0.031) and male gender (P=0.014). Most patients with diffuse BGTH had normal basal ganglia and thalamus on CT/MRI, one had a hemorrhage, and one had an ischemic infarction.

CONCLUSIONS

In our series, diffuse BGTH occurred in 8.3%, and was associated with factors similar to those previously reported. In contrast, several series have reported almost exclusively linear or punctuate hyperechoic foci, corresponding to hyperechogenicity of the lenticulostriate vessels. Our data provide further evidence to suggest that diffuse BGTH and hyperechogenicity of the lenticulostriate vessels are two different entities. Additional studies are required to determine the long-term significance of diffuse BGTH.

Branched-chain amino acids and respiratory pattern and function in the neonate

Branched-chain amino acids (BCAA) increase respiratory drive in adults and improve diaphragmatic function in vitro. This study was designed to examine the effects of increased amounts of BCAA in intravenous nutrition on respiratory function and episodes of apnea in premature infants. An open cross-over design was used, with each patient serving as his own control. Ten premature infants, 34 weeks' gestation or less, were observed. Mean gestational age was 30.6 weeks (range 27 to 33 weeks), mean birth weight was 1487 gm +/- 300 gm, and the age at study was 5 to 33 days. For three consecutive 24-hour periods, the infants received routine total parenteral nutrition (TPN) (30% BCAA), enriched TPN (53% BCAA), and routine TPN (30% BCAA). Pulmonary function, apnea frequency, blood chemistry, and amino acid pattern were measured. Enriched TPN resulted in significant increases in all infants in dynamic compliance, from 2.41 +/- 1.07 to 4.55 +/- 2.78 ml/cm H2O (p < 0.025), and in specific dynamic compliance from 1.67 +/- 0.64 to 3.1 +/- 1.51 ml/cm H2O/kg (p < 0.005). Total pulmonary resistance decreased from 40.3 +/- 23.3 to 24.0 +/- 20.9 cm H2O/L/sec (p < 0.05), and peak-to-peak pressure decreased from 5.96 +/- 0.93 to 4.09 +/- 2.34 cm H2O (p < 0.05). All values returned to baseline with resumption of the routine TPN. In four infants with significant apnea, the average number of episodes of apnea decreased from 58 during standard TPN to 11 with the enriched solution infusion during matched 12-hour periods (p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Intestinal glucose metabolism during development. II. The role of glucocorticoids and weaning

Prolonged suckling, until 25 postnatal days, delays the increase in jejunal oxidation of glucose both to lactate and to CO2 that occurs after artificial weaning at 20 days of age. The cortisone-mediated increase in intestinal sucrase activity which normally occurs by 20 days is not effected by prolonged suckling. Following precocious weaning at 16 days, the rate of jejunal glucose oxidation to lactate and to CO2 increases, over a 48-h period, to adult rates. Exogenous cortisone treatment at 10-13 postnatal days, before the endogenous steroid burst, does not change the rate of glucose oxidation in suckling animals. After weaning, both at 20 days of age and precociously at 16 days, the rate of glucose oxidation to lactate and to CO2 increases within 24 h in those animals who received early steroid treatment, in comparison to 48-72 h in untreated controls. After prolonged suckling until 25 days, there is no effect of early steroid treatment. We conclude that neither endogenous glucocorticoid secretion nor exogenous cortisone treatment alters the rate of glucose oxidation in jejunum of suckling animals despite the induction of jejunal sucrase activity. After early cortisone treatment, glucose oxidation increases within 24 h of normal of precocious weaning.