Venous subtypes of preterm periventricular haemorrhagic infarction.

BACKGROUND: Periventricular haemorrhagic infarction (PVHI) is a complication of preterm birth that may lead to impairment and disability. Early diagnosis is possible by cranial ultrasonography (CUS). Extensive PVHI lesions can be graded using a scoring system that relates to outcome, based on CUS characteristics. Data on more subtle unilateral forms of PVHI are lacking. OBJECTIVE: To refine the PVHI classification by relating subtypes to affected veins and to evaluate the effects of these anatomical subtypes on neurological outcome. METHODS: Retrospective analysis of images and neurological outcome of 20 preterm infants with unilateral PVHI. Based on affected veins, PVHI was classified into six subtypes. Sonographic templates of infarct types are provided in the coronal and parasagittal planes. Standardised neurological examinations were done (according to Amiel-Tison and Touwen examinations) and children were classified as: normal, mildly or definitely abnormal. The outcome was based on the most recent neurological examination, at a corrected age of 1 (n = 7), 2 (n = 5), 3 (n = 5) or 5 (n = 3) years. RESULTS: PVHI classification of the 20 patients was as follows: temporal (n = 3), pure caudate (n = 3), anterior terminal (n = 6), complete terminal (n = 3), extensive (n = 4), other (n = 1). With one exception, only PVHI patients showing the latter three subtypes had developed severe spastic contralesional hemiplegia. CONCLUSIONS: The classification was developed for PVHI correlates with neurological outcome. This refined classification can help clinicians in predicting neurological outcome at an early stage, with a subsequent targeted rehabilitation schedule instituted early in life.

Prolonged T*2 values in newborn versus adult brain: Implications for fMRI studies of newborns.

The neonatal brain possesses higher water content, lower macromolecular concentration, and reduced synaptic density than is found in the brain of a 1-year-old child. Changes in MRI characteristics of brain such as relaxation times accompany rapid changes in brain during early postnatal development. It was hypothesized that T(*)(2) values found in newborns would be significantly higher than those found in 9-month-old children and adults as measured at 1.5 T. Spoiled gradient echo measurements of T(*)(2) within the brains of newborns, 9-month-olds, and adults confirmed this hypothesis. The results have implications with regard to functional MRI studies in newborns since, in general, BOLD signal optimization is achieved when echo times TE are set equal to the T(*)(2) values of the tissue of interest. Since significantly longer T(*)(2) values are found in newborns, it is suggested that the TE values employed for fMRI studies of newborns should be increased to maximize BOLD signal intensity changes and improve the overall reliability of fMRI results in newborns.

Etiology of nephrocalcinosis in preterm neonates: association of nutritional intake and urinary parameters.

BACKGROUND: Nephrocalcinosis (NC) in preterm neonates has been described frequently, and small-scale studies suggest an unfavorable effect on renal function. The etiologic factors have not yet been fully clarified. We performed a prospective observational study to identify factors that influence the development of NC. METHODS: The study population consisted of 215 preterm neonates with a gestational age <32 weeks. Clinical characteristics and intake in the first four weeks of calcium, phosphorus, vitamin D, protein, and ascorbic acid were noted. Serum calcium, phosphate, vitamin D, magnesium, uric acid, creatinine, urea and urinary calcium, phosphate, oxalate, citrate, magnesium, uric acid, and creatinine were assessed at four weeks of age and at term. Renal ultrasonography (US) was performed at four weeks and at term. At term was defined as a postconceptional age of 38 to 42 weeks. RESULTS: NC was diagnosed by means of US in 33% at four weeks and in 41% at term. Patients with NC at four weeks had a significantly higher mean intake of calcium (P < 0.05), phosphorus (P < 0.05), and ascorbic acid (P < 0.01) than patients without NC. They had a higher mean serum calcium (2.55 vs. 2.46 mmol/L, P < 0.01) and a higher mean urinary calcium/creatinine ratio (2.6 vs. 2.1 mmol/mmol, P < 0.05). Patients with NC at term had a lower birth weight (1142 vs. 1260 g, P < 0.05) and a lower gestational age (28.8 vs. 29.4 weeks, P < 0.05), were treated significantly longer with furosemide, dexamethasone, theophylline, and thiazides, developed chronic lung disease more frequently (40 vs. 16%, P < 0.001), and had a higher mean urinary calcium/creatinine ratio (2.7 vs. 2.3 mmol/mmol, P < 0.05) and a lower mean urinary citrate/calcium ratio (1.1 vs. 1.7 mmol/mmol, P = 0.005). CONCLUSIONS: NC develops as a result of an imbalance between stone-inhibiting and stone-promoting factors. A high intake of calcium, phosphorus, and ascorbic acid, a low urinary citrate/calcium ratio, a high urinary calcium/creatinine ratio, immaturity, and medication to prevent or treat chronic lung disease with hypercalciuric side effects appear to contribute to the high incidence of NC in preterm neonates.

Ultrasonographic features of nephrocalcinosis in preterm neonates.

Nephrocalcinosis (NC) in preterm neonates has been reported frequently and small studies suggest an unfavourable effect on renal function. Data on ultrasonic features are limited and the reproducibility of ultrasonography (US) in detecting NC in preterm neonates is unknown. In this study, interobserver and intraobserver agreement of US was determined through videotape recordings of US examinations of preterm neonates. Furthermore, a prospective US study was performed in 215 preterm neonates (gestational age < 32 weeks) to evaluate ultrasonic characteristics, incidence, time course and effect on kidney length of NC. Patients were studied at 4 weeks after birth and at term. Patients with NC were followed for 2 years. NC was defined as bright reflections in the medulla or cortex seen in both transverse and longitudinal direction. The length of the kidneys was noted. The kappa value was 0.84 for intraobserver and 0.46 for interobserver agreement, whereas the overall agreement was 73%. NC was found in 50 of 150 (33%) patients at 4 weeks and in 83 of 201 patients (41%) at term. NC was localized mainly in the medulla. At 1 and 2 years, NC had persisted in 36% and 26%, respectively, of the patients with NC at term. Kidney length was comparable with normal values. In conclusion, US has a very good intraobserver agreement but a moderate interobserver agreement in detecting NC. Medullary NC is common among preterm neonates. During the first 2 years of life, the incidence decreases spontaneously and NC does not influence kidney length.