Hydrocephalic Infants Research Articles

Cerebral blood flow velocity before and after cerebrospinal fluid drainage in infants with posthemorrhagic hydrocephalus.

Currently, the timing and volume of cerebrospinal fluid (CSF) drainage are determined by subjective clinical findings in infants with posthemorrhagic hydrocephalus. The aim of this study was to determine whether measurement of the resistive index is useful for management of CSF drainage in these infants. We measured the resistive index in the anterior cerebral artery (RI-ACA) by using pulsed Doppler sonography before and after lumbar or subcutaneous ventricular catheter reservoir punctures in 7 infants with posthemorrhagic hydrocephalus. The increased RI-ACA values (mean +/- SD, 0.86 +/- 0.04; range, 0.80-0.89) decreased significantly (0.76 +/- 0.05; 0.64-0.83) after removal of CSF at a rate of 5 to 10 mL/kg (P <.0001). We suggest that measurement of the RI-ACA may be useful for evaluating the efficacy of CSF drainage and to determine how much CSF should be removed in hydrocephalic infants.

Chronic maternal methanol inhalation in nonhuman primates ( Macaca fascicularis): reproductive performance and birth outcome

The present study was designed to characterize maternal reproductive performance and early offspring effects following exposure to methanol (MeOH) vapor in a nonhuman primate model. The two-cohort study design used 48 adult female Macaca fascicularis (24/cohort) monkeys exposed to 0, 200, 600, or 1800 ppm MeOH vapor for approximately 2.5 h/day, 7 days/week prior to breeding and throughout pregnancy. Maternal body weight measurement, clinical observations and health assessments were conducted routinely throughout the study. Menstrual cyclicity was monitored during the pre-breeding and breeding periods and timed matings were conducted with nonexposed males. Females were monitored closely during the last month of pregnancy. At birth, infant physical characteristics were measured and a newborn health assessment was conducted. Methanol exposure did not alter menstrual cycles, the number of breedings to conception or conception rate. A total of 34 live-born infants were delivered (control=8, 200 ppm=9, 600 ppm=8, 1800 ppm=9). One female each in the control and 600-ppm group delivered a stillborn infant and a cesarean section (C-section) was required to deliver a hydrocephalic infant who died in utero in the maternal 1800-ppm group. Although not statistically significant, five MeOH-exposed females were C-sectioned due to pregnancy complications such as uterine bleeding and prolonged unproductive labor. These complications were not observed in the control group. The mean length of pregnancy in the MeOH-exposed groups was significantly decreased by 6 to 8 days when compared to controls. There were no MeOH-related effects on offspring birthweight or newborn health status. The consistent reduction in length of pregnancy observed in the MeOH females may reflect a treatment effect on the fetal neuroendocrine system. Given that the fetal hypothalamic–-pituitary–adrenal axis controls pregnancy length in most species, these results suggest a modest but significant effect of MeOH on the biochemical events that control the timing of birth.

Quantitative follow-up analysis by computed tomographic imaging in neonatal hydrocephalus

We sought a simple and accurate method to monitor neonatal hydrocephalic infants using standard computed tomographic scans. Volume measurements were made by means of pixel counting using a personal computer and a drawing device, as a graphic tablet system, over computed tomographic scans of six infants with neonatal hydrocephalus and four age-matched control infants. The mean value (763.9 ± 83.3 cm 3) of the volume of the cranium in the hydrocephalic group was two times higher than that in the age-matched control infants (360.4 ± 41.4 cm 3), P < 0.00001. Sequential changes of the ventricular/intracranial volume ratio steadily decreased after cerebrospinal fluid diversion by means of a “two-step procedure” as early in postnatal life as feasible. The mean value (0.67 ± 0.12) of the lateral ventricle/intracranial volume ratio at birth improved to 12 months of age (0.26 ± 0.14), P < 0.05. This study has documented, by means of quantitative analysis of serial scans, a statistically significant increase in the neonatal hydrocephalic brain volume after cerebrospinal fluid shunting.

A comparison of visual function scores in hydrocephalic infants with and without lumbosacral myelomeningocoele.

The cerebrum is frequently malformed in children with myelomeningocoele. This anomaly renders them potentially susceptible to cerebral visual impairment. In these patients, hydrocephalus is an important and frequent complicating lesion which compromises intellectual function and may also cause cerebral visual impairment. In this study, we determined whether hydrocephalic patients with lumbar myelomeningocoele (HLM) are at a greater risk of visual impairment than hydrocephalic patients without this lesion (H). In this prospective study, we assessed five parameters of visual function in 20 hydrocephalic children with lumbar myelomeningocoele and compared the total visual function scores (TVFS) obtained with those from hydrocephalic children without overt spinal dysraphism, but similar in age, sex and ventricular size. The parameters, which were assessed with the aid of a quantitative grading scale, were pupillary size and reaction, optic atrophy, visual fixation and tracking. The age and sex distributions of the patients in the two groups were similar. The anterior and posterior dimensions of the lateral ventricles were also similar. The mean (SD) of the TVFS were 24.25 (3.63) and 24.20 (3.47) respectively for the two groups (P = 0.90). The results suggest that, in hydrocephalic infants with lumbar myelomeningocoele, visual function is not further diminished by the associated dysraphism and that ventricular dilatation is the major determinant of visual impairment.

The Impact of Endoscopic Third Ventriculostomy on the Management of Newly Diagnosed Hydrocephalus in Infants

Objectives: To evaluate the role of endoscopic third ventriculostomy (ETV) as a primary treatment for hydrocephalus in children less than 1 year old and to determine its impact as a whole on the reduction of shunts necessary in a new population of hydrocephalic infants. Methods: Data were collected prospectively on 47 infants with newly diagnosed hydrocephalus of all aetiologies who were referred between 1st April 1998 and 30th September 2000. Twenty-one patients (median age 6 weeks, range 34 weeks of gestation to 10 months) underwent ETV, while the remaining 26 patients had insertion of a ventriculoperitoneal shunt. Anatomical criteria and demonstration of third ventricle outflow obstruction on preoperative magnetic resonance imaging were used to select patients for ETV. Results: There was no mortality or major morbidity following ETV. The median follow-up period was 18 (range 8–36) months. During the follow-up period, the ETV remained patent in 7 (33%) of the 21 patients. Of the 14 patients with failed ETV, 11 had insertion of a ventriculoperitoneal shunt, while 3 have undergone successful redo ETV. Therefore, in total 10 patients (48%) of the ETV group remain shunt independent. The best results were obtained in patients with congenital aqueduct stenosis with 71% (5 of 7 patients) success rate, while patients with posthaemorrhagic hydrocephalus did particularly badly with only 1 of 10 patients having a successful ETV. Overall, 10 of 47 (21%) infants with newly diagnosed hydrocephalus have avoided a shunt. Conclusions: Our results suggest that the selective use of ETV as the primary treatment in infants with hydrocephalus is safe and can lead to a reduction in the shunted population of all newly diagnosed hydrocephalic infants by up to 21%. Success of ETV is aetiology, not age dependent.

The effect of intracranial pressure on myelination and the relationship with neurodevelopment in infantile hydrocephalus.

The effect of raised intracranial pressure (ICP), due to infantile hydrocephalus, on the process of myelination has been suggested in the literature. In this study 19 hydrocephalic infants were followed-up with anterior fontanelle pressure (AFP) measurement (assessment of ICP), MRI (assessment of the myelination process and the CSF volume), and neurodevelopmental testing (NDT). There was a high correlation (r = 0.80) between the myelination and NDT scores. The size of the CSF volume showed a poor correlation with the mean AFP, the degree of myelination and the NDT scores. There was, however, a significant correlation between the mean AFP and the degree of myelination (r = 0.67) and also between the mean AFP and the NDT scores (r = 0.70). Longer-term follow-up (mean = 27 months) showed a significant correlation between the early progress of myelination and later developmental level (r = 0.78). Most of the children with a severely delayed myelination, preoperatively, showed a recovery of myelination following CSF drainage. It was concluded that: (1) raised ICP is related to developmental outcome, through the process of myelination; (2) the delay in myelination can be (partially) reversible; and (3) CSF volume is of minor importance regarding neurodevelopment.

Overexpression of nestin and vimentin in the ependyma of spinal cords from hydrocephalic infants

The ependyma of the spinal central canal in cases of hydrocephalus shows abnormalities which vary with the aetiology of ventricular dilatation. To determine whether these ependymal changes are developmental or reactive in nature, immunohistochemical findings were compared between nine normal controls and 12 cases of hydrocephalus (three each of congenital aqueductal stenosis. Dandy-Walker malformation, Chiari type II malformation, and post-haemorrhagic hydrocephalus) using antisera to nestin, vimentin and glial fibrillary acidic protein. The main pathological findings were disruption of ependymal layer, apparent pseudostratification of ependyma, expansion, cleft or syrinx formation in relation to the central canal, and ependymal rosette formation. In normal developing fetal spinal cord, nestin and vimentin were expressed mainly in pseudostratified ependymal cells and radial fibres in the median septum. In cases with congenital hydrocephalus (congenital aqueductal stenosis. Dandy-Walker malformation, and Chiari type II malformation), nestin was overexpressed in immature ependymal cells, and strong vimentin immunoreactivity was detected in the long tract of radial fibres in the median septum. Nestin and vimentin were also expressed in small cells and their fibres which covered areas denuded of ependymal cells in cases of Chiari type II malformation and post-haemorrhagic hydrocephalus. Two conclusions are suggested by this report. First, the ependyma of the spinal central canal in congenital hydrocephalus shows a delay in maturation of radial glial cells into mature astrocytes and ependymal cells. Second, areas of ependymal denudation may be repaired by the immature glial cells derived from subependymal cells.

Overexpression of nestin and vimentin in the ependyma of spinal cords from hydrocephalic infants

Overexpression of nestin and vimentin in the ependyma of spinal cords from hydrocephalic infants

Neonatal hydrocephalus: hemodynamic response to fontanelle compression-- correlation with intracranial pressure and need for shunt placement.

To determine whether the hemodynamic response to fontanelle compression during Doppler sonography can be used to indirectly assess intracranial pressure and help determine the need for shunt placement in hydrocephalic infants. Sixty Doppler sonographic examinations were performed to obtain resistive indexes before and during fontanelle compression in 14 hydrocephalic infants. Twenty-five intracranial pressure measurements were obtained in 12 infants during cerebrospinal fluid removal and correlated with the change in resistive index during compression of the anterior fontanelle. Baseline resistive index without fontanelle compression was not correlated with intracranial pressure (r = .1, P = .63). A statistically significant correlation was found between the change in resistive index during compression and elevated intracranial pressure (r = .8, P < .0001). Maximum change in resistive index was significantly higher (P < .001) in infants who subsequently required surgical intervention (mean [+/- standard deviation], 74% +/- 9; range, 47%-132%) than in infants who did not require ventricular drainage (mean, 19% +/- 6; range, 3%-29%, P < .0003). Hemodynamic response to fontanelle compression can be used as a noninvasive predictor of progressive or persistently elevated intracranial pressure in newborns with hydrocephalus and may be helpful in predicting need for shunt placement.

Relationship between anterior fontanelle pressure measurements and clinical signs in infantile hydrocephalus.

The treatment of choice in progressive hydrocephalus is drainage of cerebrospinal fluid in order to reduce elevated intracranial pressure (ICP). Defining the right moment for surgical intervention, however, in a hydrocephalic infant on the basis of clinical signs alone can be a difficult task. Clinical signs of raised ICP are known to be unreliable and sometimes even misleading. In the present study, the relationship between long-term anterior fontanelle pressure (AFP) measurements and clinical signs was investigated in 37 infants with hydrocephalus. The decision as to whether to operate or not was based on clinical signs alone; AFP values were not taken into account. There was an overall difference between the non-operated group and the preoperative measurements in the operated group, and also between the preoperative and the postoperative measurements in the latter, in regard to both AFP measurements and clinical signs. Almost all preoperative AFP values were increased. The direct correlation (phi) between most individual clinical signs and AFP levels, however, was low (phi = 0.15-0.41). The clinical sign "tense fontanelle" showed the best correlation with the AFP levels (phi = 0.75). Furthermore, using logistic regression analysis, no combination of clinical signs could be found which reliably predicted the AFP. The relationship between the AFP pressure variables and clinical signs was also examined. The pathological A-waves occurred only in the presence of raised (baseline) AFP, a situation in which considerably more frequent B-waves were observed as well. It was concluded that clinical signs of raised ICP in infantile hydrocephalus are not very reliable and AFP monitoring can therefore provide valuable information on intracranial dynamics in patients with dubious neurological manifestations of progressive hydrocephalus.

Infantile hydrocephalus epidemiology: an indicator of enhanced survival.

The epidemiology of infantile hydrocephalus in the birth years 1973-90 was investigated in west Sweden. The study revealed a significant increase in prevalence from 1973-8 and 1979-82 considered due to the enhanced survival of very and extremely preterm infants. The increase did not continue from 1983-90. This could indicate an improved outcome in preterm survivors as the neonatal survival rate continued to increase. The striking predominance of a perinatal/neonatal aetiology in very preterm hydrocephalic infants could be confirmed: 89% born from 1983-90 had suffered a confirmed postpartum intraventricular haemorrhage. In infants born at term, prenatal origins, mainly maldevelopments, dominated. The outcome in very preterm surviving infants with infantile hydrocephalus was poor: 73% had cerebral palsy, 52% epilepsy, 22% severe visual disability, and 55% were mentally retarded. Despite the increased survival resulting in a majority of healthy infants, there is an accumulating cohort of hydrocephalic children.

Cerebral blood flow and oxygen metabolism in infants with hydrocephalus

In this study, regional cerebral blood flow (rCBF) and the cerebral metabolic rate of oxygen (rCMRO2) were measured using positron emission tomography (PET) with oxygen-15 radiopharmaceuticals to clarify the pathophysiology of ventriculomegaly in the developing brain. Four hydrocephalic infants without severe neurological deficit were studied. Hypoperfusion was observed in the frontal, parietal, and visual association cortices which surrounded dilated anterior or posterior horns of the lateral ventricle. Lower rCMRO2 values than adult rates were observed in all cases. In the infants with markedly enlarged anterior or posterior horns, the surrounding cortices showed relatively lower rCMRO2 values with the fall of rCBF. Postoperative studies were performed in two infants. rCMRO2 increased in every region after ventriculoperitoneal shunting, but little change was observed in rCBF. These results indicate that metabolic deterioration occurs in the developing brain with hydrocephalus.

MYELINATION AS AN EXPRESSION OF THE FUNCTIONAL MATURITY OF THE BRAIN

A prospective cross-sectional study was performed on hydrocephalic infants and children. MRI was used to assess the state of myelination and to quantify the intracranial cerebrospinal fluid (CSF) volume repeatedly in all children. At the same time, neurodevelopmental testing was performed. A positive correlation was found between the progress of myelination and psychomotor development, but there were no significant correlations between CSF volume and myelination or between CSF volume and psychomotor development. This study provides strong evidence in favour of Flechsig's thesis that myelination expresses the functional maturity of the brain. The interdependency of neuronal maturation and progress of myelination are discussed.

Endoscopic Coagulation of the Choroid Plexus using the Nd:YAG Laser: Initial Experience and Proposal for Management

Although most patients with hydrocephalus are treated effectively with ventriculoperitoneal shunts, a small group fails to respond to diversion procedures. In some patients within this group, hydrocephalus may be caused in part by the overproduction of the cerebrospinal fluid (CSF). In other patients, previous shunt infections may limit the ability of the peritoneum to absorb fluid, and patient response to a ventriculoperitoneal shunt may be improved by reducing CSF production. We discuss a case of a 29-month-old hydrocephalic infant with a ventriculoperitoneal shunt who had ascites. Computed tomography showed bilateral symmetrical enlargement of the choroid plexus. Repeated cultures of the CSF and shunt tubing were sterile, and the daily production of the CSF exceeded 1000 ml. Therapy with acetazolamide decreased the CSF output temporarily, but it was discontinued after serious electrolyte abnormalities occurred. The endoscopic coagulation of the choroid plexus with a neodymium:YAG laser transmitted through a flexible quartz fiber decreased CSF production effectively. This procedure may be useful in a variety of clinical conditions associated with hydrocephalus or with other intraventricular lesions.

Ultrasound of the septum pellucidum. Recognition of evolving fenestrations in the hydrocephalic infant.

Fenestrations of the septum pellucidum may be noted in hydrocephalic infants. This finding and its changing image was noted in six premature infants evaluated by neurosonography over time periods ranging from weeks to months. Breaks in the septum were noted to occur from 14 days to 23 weeks after the sonographic diagnosis of hydrocephalus. Some of these fenestrations were noted to increase in size and/or become bilateral over time. The awareness of evolving fenestrations and their late-stage images helps avoid confusion with partial and complete agenesis of the septum pellucidum and their possible associated neuroanatomical abnormalities.

Transcranial Doppler and real-time cranial sonography in neonatal hydrocephalus.

Nine hydrocephalic infants who were less than 1 year old and 7 age-matched control subjects were examined by real-time and transcranial Doppler sonography to evaluate cerebral blood flow and to correlate it to ventricular size. These 16 infants were placed in one of three groups: infants in group 1 (n = 7) had a normal ventricular size, infants in group 2 (n = 3) had a progressively increasing ventricular size, and infants in group 3 (n = 6) had ventriculomegaly with either stable or decreasing ventricular size or a functioning ventriculoperitoneal shunt. All scans performed on group-2 infants showed markedly increased ventricular size and increased pulsatility index, while those on group-1 infants showed a normal ventricular size and pulsatility index. However, the scans of group-3 infants revealed increased ventricular size and pulsatility index for all groups. Regression analysis of the data showed rather weak correlations between ventricular size and pulsatility index for all groups. The regression data suggest that ventricular size is not the main determinant of cerebral blood flow in the neonate with hydrocephalus and that intracranial pressure may be a more critical factor. These data suggest that pulsatility index, as measured by transcranial Doppler, can be clinically more important than just the anatomical data alone in the evaluation of hydrocephaly. This points to a possible use of transcranial Doppler sonography in the evaluation of hydrocephalic patients for placement of ventriculoperitoneal shunts.

Threshold of cerebral perfusion pressure as a prognostic factor in hydrocephalus during infancy.

An analysis of the intracranial pressure (ICP) was done on 30 hydrocephalic infants using a newly devised computerized analyzing system. As a cerebrovascularly compromised index of the ICP, the transmission ratio of systemic arterial pulse pressure (SABP) to ICP as defined by Ikeyama [eta HB (PP of ICP/PP of SABP)] was used. Cerebral perfusion pressure (CPP) versus eta HB showed significant bilinear relationship. From this correlation the threshold of CPP in relation to ICP level was calculated. A reduction of CPP below this level abruptly reduced the correlation with ICP. Thus, the CPP threshold showed an increase related to age (from 20 mm Hg in preterm babies at birth to 80 mm Hg at 12 months of age) and is correlated with the psychomotor development evaluated 6-36 months after shunting. The abnormal waves that appear when there is a high level of eta HB and that also appear below the threshold level of CPP can be defined as pressure waves, based on the physiological findings. It was shown that in hydrocephalus during infancy, a prolonged ICP below the threshold of CPP is one of the cerebrohemodynamic factors that can adversely affect the outcome of psychomotor development.

Alterations in cerebrospinal fluid uridine, hypoxanthine, and xanthine in head-injured patients.

1. Examination of the cerebrospinal fluid (CSF) of head-injured patients reveals that the concentration of intraventricular xanthine is elevated and that of uridine is decreased relative to those of adult lumbar CSF. 2. No correlations were observed between CSF lactate and CSF hypoxanthine, xanthine, or uridine, suggesting that changes in purine metabolites and the pyrimidine nucleoside do not index similar cellular events as does lactic acid production. 3. Ventricular CSF from hydrocephalic infants had uridine and hypoxanthine concentrations not significantly different from those of normal adult lumbar CSF, but xanthine was significantly elevated. 4. Since uridine has anticonvulsant properties and is a crucial substrate for cerebral metabolism, it may be useful to evaluate this pyrimidine for use in the management of patients with head injury.

Developmental Outcome Following Posthemorrhagic Hydrocephalus in Preterm Infants

The mental development and neurologic outcome of four sets of preterm twins, in whom one infant within each pair developed posthemorrhagic hydrocephalus during the neonatal period, were assessed. Each hydrocephalic infant presented with signs of increased intracranial pressure and required placement of a ventriculoperitoneal shunt. Three of the four hydrocephalic infants required revision or replacement of the shunt during the first year. The four nonhydrocephalic infants had normal neurologic outcomes. All four hydrocephalic infants had some neurologic abnormalities on follow-up examination. Neurologic abnormalities were transient in one infant and persistent in three others, each of whom showed evidence of mild right hemiparesis. Within each twin pair, developmental rates and mental test scores were strikingly similar throughout infancy and early childhood. Two of the twin pairs have undergone psychological assessments at 8 and 11 years of age. Relatively lower IQ scores were obtained for the hydrocephalic child in each twin pair at these ages.

Cranial duplex sonography of the infant.

Duplex sonography was used to evaluate the cranial contents of 75 infants. The first 35 were scanned to establish technique and evaluate basic flow patterns. All cranial vessels scanned in healthy term infants produced diphasic (low-resistance) waveforms, although certain cerebral vessels had characteristic Doppler signatures. The pericallosal, callosomarginal, anterior cerebral, basilar, middle cerebral, and internal carotid arteries and the vein of Galen were isolated and evaluated in almost every subject. In the second part of the study duplex characteristics of healthy term infants, healthy preterm infants, preterm infants with intracranial hemorrhages, and hydrocephalic infants were evaluated. Relative flow velocity at peak systole and end diastole and pulsatility index were investigated. The most significant variable was gestational age. Preterm infants frequently had no forward flow during diastole. Duplex sonography does not appear to add significant diagnostic information to routine real-time cranial studies. It does, however, permit more exact evaluation of cerebral blood flow than does non-pulse-gated, nondirected Doppler scanning.