Diuretic therapy for newborn infants with posthemorrhagic ventricular dilatation

Dual function of the choroid plexus: Cerebrospinal fluid production and control of brain ion homeostasis

The choroid plexus is a small monolayered epithelium located in the brain ventricles and serves to secrete the cerebrospinal fluid (CSF) that envelops the brain and fills the central ventricles. The CSF secretion is sustained with a concerted effort of a range of membrane transporters located in a polarized fashion in this tissue. Prominent amongst these are the Na+/K+-ATPase, the Na+,K+,2Cl- cotransporter (NKCC1), and several HCO3- transporters, which together support the net transepithelial transport of the major electrolytes, Na+ and Cl-, and thus drive the CSF secretion. The choroid plexus, in addition, serves an important role in keeping the CSF K+ concentration at a level compatible with normal brain function. The choroid plexus Na+/K+-ATPase represents a key factor in the barrier-mediated control of the CSF K+ homeostasis, as it increases its K+ uptake activity when faced with elevated extracellular K+ ([K+]o). In certain developmental or pathological conditions, the NKCC1 may revert its net transport direction to contribute to CSF K+ homeostasis. The choroid plexus ion transport machinery thus serves dual, yet interconnected, functions with its contribution to electrolyte and fluid secretion in combination with its control of brain K+ levels.

Interventions for reducing late-onset sepsis in neonates: an umbrella review

OBJECTIVES

Neonatal sepsis is one of the leading causes of neonatal deaths in neonatal intensive care units. Hence, it is essential to review the evidence from systematic reviews on interventions for reducing late-onset sepsis (LOS) in neonates.

METHODS

PubMed and the Cochrane Central were searched from inception through August 2020 without any language restriction. Cochrane reviews of randomized clinical trials (RCTs) assessing any intervention in the neonatal period and including one or more RCTs reporting LOS. Two authors independently performed screening, data extraction, assessed the quality of evidence using Cochrane Grading of Recommendations Assessment, Development and Evaluation, and assessed the quality of reviews using a measurement tool to assess of multiple systematic reviews 2 tool.

RESULTS

A total of 101 high-quality Cochrane reviews involving 612 RCTs and 193,713 neonates, evaluating 141 interventions were included. High-quality evidence showed a reduction in any or culture-proven LOS using antibiotic lock therapy for neonates with central venous catheters (CVC). Moderate-quality evidence showed a decrease in any LOS with antibiotic prophylaxis or vancomycin prophylaxis for neonates with CVC, chlorhexidine for skin or cord care, and kangaroo care for low birth weight babies. Similarly, moderate-quality evidence showed reduced culture-proven LOS with intravenous immunoglobulin prophylaxis for preterm infants and probiotic supplementation for very low birth weight (VLBW) infants. Lastly, moderate-quality evidence showed a reduction in fungal LOS with the use of systemic antifungal prophylaxis in VLBW infants.

CONCLUSIONS

The overview summarizes the evidence from the Cochrane reviews assessing interventions for reducing LOS in neonates, and can be utilized by clinicians, researchers, policymakers, and consumers for decision-making and translating evidence into clinical practice.

Revision rates of flow- versus pressure-regulated ventricular shunt valves for the treatment of hydrocephalus in neonates following germinal matrix haemorrhage-a retrospective review

PURPOSE

Neonates with ventricular shunts inserted for hydrocephalus following germinal matrix haemorrhage (GMH) have high rates of shunt revision. The shunt valve plays a key role in regulating the function of the shunt. In this study, we aim to determine if the choice of flow-regulated or pressure-regulated valve used in the initial implantation of a shunt affects the rate of shunt revision.

METHODS

A retrospective cohort comparison study was performed on 34 neonates with hydrocephalus following GMH who underwent placement of a ventricular shunt at the Queensland Children's Hospital from November 2014 to June 2020. The primary outcome examined was the need for revision or replacement of the ventricular shunt after successful initial placement within 2 years of implantation. The secondary outcome examined was the survival time of the shunt.

RESULTS

16 patients had placement of a flow-regulated valve, and 18 patients had placement of a pressure-regulated valve. 14 (87.5%) patients with flow-regulated valves required replacement during the follow-up period. 2 (18.18%) patients with a fixed pressure regulated underwent revision, while 2 (28.57%) programmable pressure-regulated shunts required revision. Patients that had a flow-regulated valve had a statistically significant higher rate of revision compared to those who had a pressure-regulated valve, (87.5% flow vs 22.22% pressure) with a P-value of < 0.001. Valve obstruction was also more common in patients with flow-regulated valves than pressure-regulated valves (4 vs 0) with a P-value of 0.010. Overall mean median survival time was 22.06 months, shunts with flow-regulated valves had a shorter median survival time of 3.19 months compared with over 24 months for pressure-regulated valves with a P-value of < 0.001.

CONCLUSION

Our study suggests that the initial implantation of flow-regulated valves may carry an increased total rate of shunt revision and valve obstruction within the first 2 years following implantation compared to pressure-regulated valves in patients with hydrocephalus following GMH.

Hydrocephalus: historical analysis and considerations for treatment

Hydrocephalus is a serious condition that affects patients of all ages, resulting from a multitude of causes. While the etiologies of hydrocephalus are numerous, many of the acute and chronic symptoms of the condition are shared. These symptoms include disorientation and pain (headaches), cognitive and developmental changes, vision and sleep disturbances, and gait abnormalities. This collective group of symptoms combined with the effectiveness of CSF diversion as a surgical intervention for many types of the condition suggest that the various etiologies may share common cellular and molecular dysfunctions. The incidence rate of pediatric hydrocephalus is approximately 0.1–0.6% of live births, making it as common as Down syndrome in infants. Diagnosis and treatment of various forms of adult hydrocephalus remain understudied and underreported. Surgical interventions to treat hydrocephalus, though lifesaving, have a high incidence of failure. Previously tested pharmacotherapies for the treatment of hydrocephalus have resulted in net zero or negative outcomes for patients potentially due to the lack of understanding of the cellular and molecular mechanisms that contribute to the development of hydrocephalus. Very few well-validated drug targets have been proposed for therapy; most of these have been within the last 5 years. Within the last 50 years, there have been only incremental improvements in surgical treatments for hydrocephalus, and there has been little progress made towards prevention or cure. This demonstrates the need to develop nonsurgical interventions for the treatment of hydrocephalus regardless of etiology. The development of new treatment paradigms relies heavily on investment in researching the common molecular mechanisms that contribute to all of the forms of hydrocephalus, and requires the concerted support of patient advocacy organizations, government- and private-funded research, biotechnology and pharmaceutical companies, the medical device industry, and the vast network of healthcare professionals.

Acetazolamide modulates intracranial pressure directly by its action on the cerebrospinal fluid secretion apparatus

Background

Elevated intracranial pressure (ICP) is observed in many neurological pathologies, e.g. hydrocephalus and stroke. This condition is routinely relieved with neurosurgical approaches, since effective and targeted pharmacological tools are still lacking. The carbonic anhydrase inhibitor, acetazolamide (AZE), may be employed to treat elevated ICP. However, its effectiveness is questioned, its location of action unresolved, and its tolerability low. Here, we determined the efficacy and mode of action of AZE in the rat .

Methods

We employed in vivo approaches including ICP and cerebrospinal fluid secretion measurements in anaesthetized rats and telemetric monitoring of ICP and blood pressure in awake rats in combination with ex vivo choroidal radioisotope flux assays and transcriptomic analysis.

Results

AZE effectively reduced the ICP, irrespective of the mode of drug administration and level of anaesthesia. The effect appeared to occur via a direct action on the choroid plexus and an associated decrease in cerebrospinal fluid secretion, and not indirectly via the systemic action of AZE on renal and vascular processes. Upon a single administration, the reduced ICP endured for approximately 10 h post-AZE delivery with no long-term changes of brain water content or choroidal transporter expression. However, a persistent reduction of ICP was secured with repeated AZE administrations throughout the day.

Conclusions

AZE lowers ICP directly via its ability to reduce the choroid plexus CSF secretion, irrespective of mode of drug administration.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12987-022-00348-6.

Secondary Brain Injury Following Neonatal Intraventricular Hemorrhage: The Role of the Ciliated Ependyma

Intraventricular hemorrhage is recognized as a leading cause of hydrocephalus in the developed world and a key determinant of neurodevelopmental outcome following premature birth. Even in the absence of haemorrhagic infarction or posthaemorrhagic hydrocephalus, there is increasing evidence of neuropsychiatric and neurodevelopmental sequelae. The pathophysiology underlying this injury is thought to be due to a primary destructive and secondary developmental insult, but the exact mechanisms remain elusive and this has resulted in a paucity of therapeutic interventions. The presence of blood within the cerebrospinal fluid results in the loss of the delicate neurohumoral gradient within the developing brain, adversely impacting on the tightly regulated temporal and spatial control of cell proliferation and migration of the neural stem progenitor cells within the subventricular zone. In addition, haemolysis of the erythrocytes, associated with the release of clotting factors and leucocytes into the cerebrospinal (CSF), results in a toxic and inflammatory CSF microenvironment which is harmful to the periventricular tissues, resulting in damage and denudation of the multiciliated ependymal cells which line the choroid plexus and ventricular system. The ependyma plays a critical role in the developing brain and beyond, acting as both a protector and gatekeeper to the underlying parenchyma, controlling influx and efflux across the CSF to brain interstitial fluid interface. In this review I explore the hypothesis that damage and denudation of the ependymal layer at this critical juncture in the developing brain, seen following IVH, may adversely impact on the brain microenvironment, exposing the underlying periventricular tissues to toxic and inflammatory CSF, further exacerbating disordered activity within the subventricular zone (SVZ). By understanding the impact that intraventricular hemorrhage has on the microenvironment within the CSF, and the consequences that this has on the multiciliated ependymal cells which line the neuraxis, we can begin to develop and test novel therapeutic interventions to mitigate damage and reduce the associated morbidity.

Turkish Neonatal Society Guideline on the Diagnosis and Management of Germinal Matrix Hemorrhage-Intraventricular Hemorrhage and Related Complications

Germinal matrix hemorrhage-intraventricular hemorrhage (GMH-IVH) remains an important cause of brain injury in preterm infants, and is associated with high rates of mortality and adverse neurodevelopmental outcomes, despite the recent advances in perinatal care. Close neuroimaging is recommended for both the detection of GMH-IVH and for the follow-up of serious complications, such as post-hemorrhagic ventricular dilatation (PHVD). Although the question when best to treat PHVD remains a matter of debate, recent literature on this topic shows that later timing of interventions predicted higher rates of neurodevelopmental impairment, emphasizing the importance of a well-structured neuroimaging protocol and timely interventions. In this guideline, pathophysiologic mechanisms, preventive measures, and clinical presentations of GMH-IVH and PHVD will be presented, and a neuroimaging protocol as well as an optimal treatment approach will be proposed in light of the recent literature.

Multi-omic analysis elucidates the genetic basis of hydrocephalus

We conducted PrediXcan analysis of hydrocephalus risk in ten neurological tissues and whole blood. Decreased expression of MAEL in the brain was significantly associated (Bonferroni-adjusted p < 0.05) with hydrocephalus. PrediXcan analysis of brain imaging and genomics data in the independent UK Biobank (N = 8,428) revealed that MAEL expression in the frontal cortex is associated with white matter and total brain volumes. Among the top differentially expressed genes in brain, we observed a significant enrichment for gene-level associations with these structural phenotypes, suggesting an effect on disease risk through regulation of brain structure and integrity. We found additional support for these genes through analysis of the choroid plexus transcriptome of a murine model of hydrocephalus. Finally, differential protein expression analysis in patient cerebrospinal fluid recapitulated disease-associated expression changes in neurological tissues, but not in whole blood. Our findings provide convergent evidence highlighting the importance of tissue-specific pathways and mechanisms in the pathophysiology of hydrocephalus.

Hale et al. present an integrated omics approach to characterize the genetic basis of hydrocephalus. They reveal tissue-specific genetic associations and enrichment of genes associated with human brain structure phenotypes. Validation of hydrocephalus-associated genes in mouse choroid plexus and human cerebrospinal fluid supports polygenic contributions to hydrocephalus risk.

Intraventricular hemorrhage in preterm babies

Germinal matrix-intraventricular hemorrhage (GM-IVH) is a major complication of prematurity and inversely associated with gestational age and birth weight. The hemorrhage originates from the germinal matrix with an immature capillary bed where vascularization is intense and active cell proliferation is high. It occurs in around 20% of very low-birth-weight preterm neonates. Germinal matrix-intraventricular hemorrhage is less common in females, the black race, and with antenatal steroid use, but is more common in the presence of mechanical ventilation, respiratory distress, pulmonary bleeding, pneumothorax, chorioamnionitis, asphyxia, and sepsis. Ultrasonography is the diagnostic tool of choice for intraventricular hemorrhage and its complications. Approximately 25-50% of the germinal matrix-intraventricular hemorrhage cases are asymptomatic and diagnosed during routine screening. These cases are usually patients with low-grade hemorrhage. Neurologic findings are prominent in severe intraventricular hemorrhage cases. The major complications of the germinal matrix-intraventricular hemorrhage in preterm babies are periventricular hemorrhagic infarction, posthemorrhagic ventricular dilatation, periventricular leukomalacia, and cerebellar hemorrhage. It is an important cause of mortality and morbidity. The management of hemodynamics and ventilation of patients, appropriate follow-up, and early diagnosis and treatment can minimize morbidity. Prognosis in intraventricular hemorrhage is related to the severity of bleeding, parenchymal damage, and the presence of seizures and shunt surgery. The main determinant of prognosis is periventricular hemorrhagic infarction and its severity. Moderate-severe intraventricular hemorrhage can cause posthemorrhagic hydrocephalus, cerebral palsy, and mental retardation. Even mild germinal matrix-intraventricular hemorrhage can result in developmental disorders. Long-term problems such as neurodevelopmental disorders and cerebral palsy are as important as short-term problems. Improving the quality of life of these babies should be aimed through appropriate treatment and follow-up. In this review, intraventricular hemorrhage and complications are discussed.

Treatment for Post-hemorrhagic Ventricular Dilatation: A Multiple-Treatment Meta-Analysis

Objective: To perform a systematic review and multiple-treatment meta-analysis for the treatment of premature infants with post-hemorrhagic ventricular dilatation (PHVD), to prevent death or long-term neuro-disability. Design/Method: A systematic review was performed using PubMed, EMBASE, and the Cochrane Library. A free-word search was performed to identify likely relevant literature intervention trials of PHVD in preterm infants. Initially, network mapping was performed followed by performing a Bayesian random-effects model using the Markov chain Monte Carlo method. Areas under the cumulative ranking curve (SUCRA) were calculated as a measure of the probability that each intervention was likely to be the 1st, 2nd, 3rd, etc. best therapy. Primary outcome measure was death or moderate or severe neurodevelopmental outcome at or beyond 12 months of corrected age. Results: Ten different trials were identified, enrolling 700 individuals (449 for the primary outcome). Seven intervention categories were identified, and of the 15 possible pair comparisons, 6 have been studied directly. In the multiple-treatment meta-analysis, no comparison reached conventional levels of statistical significance. Drainage Irrigation and Fibrinolytic Therapy (DRIFT) had the highest probability of being the best treatment for the primary outcome (82.1%), followed by CSF removal (10.8%), conservative management (6.7%), and then diuretic therapy (0.4%). Conclusions: PHVD is a significant cause of death and disability in developed countries, yet few therapeutic options have so far been trialed. While new therapies are urgently needed for these infants, at present, NMA shows that DRIFT appears to be the most likely candidate to improve outcomes after sIVH.

Posthemorrhagic hydrocephalus development after germinal matrix hemorrhage: Established mechanisms and proposed pathways

In addition to being the leading cause of morbidity and mortality in premature infants, germinal matrix hemorrhage (GMH) is also the leading cause of acquired infantile hydrocephalus. The pathophysiology of posthemorrhagic hydrocephalus (PHH) development after GMH is complex and vaguely understood, although evidence suggests fibrosis and gliosis in the periventricular and subarachnoid spaces disrupts normal cerebrospinal fluid (CSF) dynamics. Theories explaining general hydrocephalus etiology have substantially evolved from the original bulk flow theory developed by Dr. Dandy over a century ago. Current clinical and experimental evidence supports a new hydrodynamic theory for hydrocephalus development involving redistribution of vascular pulsations and disruption of Starling forces in the brain microcirculation. In this review, we discuss CSF flow dynamics, history and development of theoretical hydrocephalus pathophysiology, and GMH epidemiology and etiology as it relates to PHH development. We highlight known mechanisms and propose new avenues that will further elucidate GMH pathophysiology, specifically related to hydrocephalus.

Neonatal interventions for preventing cerebral palsy: an overview of Cochrane Systematic Reviews

BACKGROUND

Cerebral palsy is an umbrella term that encompasses disorders of movement and posture attributed to non-progressive disturbances occurring in the developing foetal or infant brain. As there are diverse risk factors and aetiologies, no one strategy will prevent cerebral palsy. Therefore, there is a need to systematically consider all potentially relevant interventions for prevention.

OBJECTIVES

PrimaryTo summarise the evidence from Cochrane Systematic Reviews regarding effects of neonatal interventions for preventing cerebral palsy (reducing cerebral palsy risk).SecondaryTo summarise the evidence from Cochrane Systematic Reviews regarding effects of neonatal interventions that may increase cerebral palsy risk.

METHODS

We searched the Cochrane Database of Systematic Reviews (27 November 2016) for reviews of neonatal interventions reporting on cerebral palsy. Two review authors assessed reviews for inclusion, extracted data, and assessed review quality (using AMSTAR and ROBIS) and quality of the evidence (using the GRADE approach). Reviews were organised by topic; findings were summarised in text and were tabulated. Interventions were categorised as effective (high-quality evidence of effectiveness); possibly effective (moderate-quality evidence of effectiveness); ineffective (high-quality evidence of harm); probably ineffective (moderate-quality evidence of harm or lack of effectiveness); and no conclusions possible (low- to very low-quality evidence).

MAIN RESULTS

Forty-three Cochrane Reviews were included. A further 102 reviews pre-specified the outcome cerebral palsy, but none of the included randomised controlled trials (RCTs) reported this outcome. Included reviews were generally of high quality and had low risk of bias, as determined by AMSTAR and ROBIS. These reviews involved 454 RCTs; data for cerebral palsy were available from 96 (21%) RCTs involving 15,885 children. Review authors considered interventions for neonates with perinatal asphyxia or with evidence of neonatal encephalopathy (3); interventions for neonates born preterm and/or at low or very low birthweight (33); and interventions for other specific groups of 'at risk' neonates (7). Quality of evidence (GRADE) ranged from very low to high.Interventions for neonates with perinatal asphyxia or with evidence of neonatal encephalopathyEffective interventions: high-quality evidence of effectivenessResearchers found a reduction in cerebral palsy following therapeutic hypothermia versus standard care for newborns with hypoxic ischaemic encephalopathy (risk ratio (RR) 0.66, 95% confidence interval (CI) 0.54 to 0.82; seven trials; 881 children).No conclusions possible: very low-quality evidenceOne review observed no clear differences in cerebral palsy following therapeutic hypothermia versus standard care.Interventions for neonates born preterm and/or at low or very low birthweightPossibly effective interventions: moderate-quality evidence of effectivenessResearchers found a reduction in cerebral palsy with prophylactic methylxanthines (caffeine) versus placebo for endotracheal extubation in preterm infants (RR 0.54, 95% CI 0.32 to 0.92; one trial; 644 children).Probably ineffective interventions: moderate-quality evidence of harmResearchers reported an increase in cerebral palsy (RR 1.45, 95% CI 1.06 to 1.98; 12 trials; 1452 children) and cerebral palsy in assessed survivors (RR 1.50, 95% CI 1.13 to 2.00; 12 trials; 959 children) following early (at less than eight days of age) postnatal corticosteroids versus placebo or no treatment for preventing chronic lung disease in preterm infants.Probably ineffective interventions: moderate-quality evidence of lack of effectivenessTrial results showed no clear differences in cerebral palsy following ethamsylate versus placebo for prevention of morbidity and mortality in preterm or very low birthweight infants (RR 1.13, 95% CI 0.64 to 2.00; three trials, 532 children); volume expansion versus no treatment (RR 0.76, 95% CI 0.48 to 1.20; one trial; 604 children); gelatin versus fresh frozen plasma (RR 0.94, 95% CI 0.52 to 1.69; one trial, 399 children) for prevention of morbidity and mortality in very preterm infants; prophylactic indomethacin versus placebo for preventing mortality and morbidity in preterm infants (RR 1.04, 95% CI 0.77 to 1.40; four trials; 1372 children); synthetic surfactant versus placebo for respiratory distress syndrome in preterm infants (RR 0.76, 95% CI 0.55 to 1.05; five trials; 1557 children); or prophylactic phototherapy versus standard care (starting phototherapy when serum bilirubin reached a pre-specified level) for preventing jaundice in preterm or low birthweight infants (RR 0.96, 95% CI 0.50 to 1.85; two trials; 756 children).No conclusions possible: low- to very low-quality evidenceNo clear differences in cerebral palsy were observed with interventions assessed in 21 reviews.Interventions for other specific groups of 'at risk' neonatesNo conclusions possible: low- to very low-quality evidenceReview authors observed no clear differences in cerebral palsy with interventions assessed in five reviews.

AUTHORS' CONCLUSIONS

This overview summarises evidence from Cochrane Systematic Reviews regarding effects of neonatal interventions on cerebral palsy, and can be used by researchers, funding bodies, policy makers, clinicians, and consumers to aid decision-making and evidence translation. To formally assess other benefits and/or harms of included interventions, including impact on risk factors for cerebral palsy, review of the included Reviews is recommended.Therapeutic hypothermia versus standard care for newborns with hypoxic ischaemic encephalopathy can prevent cerebral palsy, and prophylactic methylxanthines (caffeine) versus placebo for endotracheal extubation in preterm infants may reduce cerebral palsy risk. Early (at less than eight days of age) postnatal corticosteroids versus placebo or no treatment for preventing chronic lung disease in preterm infants may increase cerebral palsy risk.Cerebral palsy is rarely identified at birth, has diverse risk factors and aetiologies, and is diagnosed in approximately one in 500 children. To date, only a small proportion of Cochrane Systematic Reviews assessing neonatal interventions have been able to report on this outcome. There is an urgent need for long-term follow-up of RCTs of such interventions addressing risk factors for cerebral palsy (through strategies such as data linkage with registries) and for consideration of the use of relatively new interim assessments (including the General Movements Assessment). Such RCTs must be rigorous in their design and must aim for consistency in cerebral palsy outcome measurement and reporting to facilitate pooling of data and thus to maximise research efforts focused on prevention.

Opportunities in posthemorrhagic hydrocephalus research: outcomes of the Hydrocephalus Association Posthemorrhagic Hydrocephalus Workshop

The Hydrocephalus Association Posthemorrhagic Hydrocephalus Workshop was held on July 25 and 26, 2016 at the National Institutes of Health. The workshop brought together a diverse group of researchers including pediatric neurosurgeons, neurologists, and neuropsychologists with scientists in the fields of brain injury and development, cerebrospinal and interstitial fluid dynamics, and the blood-brain and blood-CSF barriers. The goals of the workshop were to identify areas of opportunity in posthemorrhagic hydrocephalus research and encourage scientific collaboration across a diverse set of fields. This report details the major themes discussed during the workshop and research opportunities identified for posthemorrhagic hydrocephalus. The primary areas include (1) preventing intraventricular hemorrhage, (2) stopping primary and secondary brain damage, (3) preventing hydrocephalus, (4) repairing brain damage, and (5) improving neurodevelopment outcomes in posthemorrhagic hydrocephalus.

Inflammation-dependent cerebrospinal fluid hypersecretion by the choroid plexus epithelium in posthemorrhagic hydrocephalus

The choroid plexus epithelium (CPE) secretes higher volumes of fluid (cerebrospinal fluid, CSF) than any other epithelium and simultaneously functions as the blood-CSF barrier to gate immune cell entry into the central nervous system. Posthemorrhagic hydrocephalus (PHH), an expansion of the cerebral ventricles due to CSF accumulation following intraventricular hemorrhage (IVH), is a common disease usually treated by suboptimal CSF shunting techniques. PHH is classically attributed to primary impairments in CSF reabsorption, but little experimental evidence supports this concept. In contrast, the potential contribution of CSF secretion to PHH has received little attention. In a rat model of PHH, we demonstrate that IVH causes a Toll-like receptor 4 (TLR4)- and NF-κB-dependent inflammatory response in the CPE that is associated with a ∼3-fold increase in bumetanide-sensitive CSF secretion. IVH-induced hypersecretion of CSF is mediated by TLR4-dependent activation of the Ste20-type stress kinase SPAK, which binds, phosphorylates, and stimulates the NKCC1 co-transporter at the CPE apical membrane. Genetic depletion of TLR4 or SPAK normalizes hyperactive CSF secretion rates and reduces PHH symptoms, as does treatment with drugs that antagonize TLR4-NF-κB signaling or the SPAK-NKCC1 co-transporter complex. These data uncover a previously unrecognized contribution of CSF hypersecretion to the pathogenesis of PHH, demonstrate a new role for TLRs in regulation of the internal brain milieu, and identify a kinase-regulated mechanism of CSF secretion that could be targeted by repurposed US Food and Drug Administration (FDA)-approved drugs to treat hydrocephalus.

Repeated lumbar or ventricular punctures in newborns with intraventricular haemorrhage

BACKGROUND

Although in recent years the percentage of preterm infants who suffer intraventricular haemorrhage (IVH) has reduced, posthaemorrhagic hydrocephalus (PHH) remains a serious problem with a high rate of cerebral palsy and no evidence-based treatment. Survivors often have to undergo ventriculoperitoneal shunt (VPS) surgery, which makes the child permanently dependent on a valve and catheter system. This carries a significant risk of infection and the need for surgical revision of the shunt. Repeated removal of cerebrospinal fluid (CSF) by either lumbar puncture, ventricular puncture, or from a ventricular reservoir in preterm babies with IVH has been suggested as a treatment to reduce the risk of PHH development.

OBJECTIVES

To determine the effect of repeated cerebrospinal fluid (CSF) removal (by lumbar/ventricular puncture or removal from a ventricular reservoir) compared to conservative management, where removal is limited to when there are signs of raised intracranial pressure (ICP), on reduction in the risk of permanent shunt dependence, neurodevelopmental disability, and death in neonates with or at risk of developing posthaemorrhagic hydrocephalus (PHH).

SEARCH METHODS

We used the standard search strategy of Cochrane Neonatal to search the Cochrane Central Register of Controlled Trials (CENTRAL; 2016, Issue 3), MEDLINE via PubMed (1966 to 24 March 2016), Embase (1980 to 24 March 2016), and CINAHL (1982 to 24 March 2016). We also searched clinical trials databases, conference proceedings, and the reference lists of retrieved articles for randomised controlled trials (RCTs) and quasi-RCTs.

SELECTION CRITERIA

RCTs and quasi-RCTs that compared serial removal of CSF (via lumbar puncture, ventricular puncture, or from a ventricular reservoir) with conservative management (removing CSF only when there were symptoms of raised ICP). Trials also had to report on at least one of the specified outcomes of death, disability, or shunt insertion.

DATA COLLECTION AND ANALYSIS

We extracted details of the participant selection, participant allocation and the interventions. We assessed the following outcomes: VPS, death, death or shunt, disability, multiple disability, death or disability, and CSF infection. We assessed the quality of the evidence using the GRADE approach.

MAIN RESULTS

Four trials (five articles) met the inclusion criteria of this review; three were RCTs and one was a quasi-RCT; and included a total of 280 participants treated in neonatal intensive care units in the UK. The trials were published between 1980 and 1990. The studies were sufficiently similar regarding the research question they asked and the interventions that we could combine the trials to assess the effect of the intervention.Meta-analysis showed that the intervention produced no significant difference when compared to conservative management for the outcomes of: placement of hydrocephalus shunt (typical risk ratio (RR) 0.96, 95% confidence interval (CI) 0.73 to 1.26; 3 trials, 233 infants; I² statistic = 0%; moderate quality evidence), death (RR 0.88, 95% CI 0.53 to 1.44; 4 trials, 280 infants; I² statistic = 0%; low quality evidence), major disability in survivors (RR 0.98, 95% CI 0.81 to 1.18; 2 trials, 141 infants; I² statistic = 11%; high quality evidence), multiple disability in survivors (RR 0.9, 95% CI 0.66 to 1.24; 2 trials, 141 infants; I² statistic = 0%; high quality evidence), death or disability (RR 0.99, 95% CI 0.86 to 1.14; 2 trials, 180 infants; I² statistic = 0%; high quality evidence), death or shunt (RR 0.91, 95% CI 0.75 to 1.11; 3 trials, 233 infants; I² statistic = 0%; moderate quality evidence), and infection of CSF presurgery (RR 1.73, 95% CI 0.53 to 5.67; 2 trials, 195 infants; low quality evidence).We assessed the quality of the evidence as high for the outcomes of major disability, multiple disability, and disability or death. We rated the evidence for the outcomes of shunt insertion, and death or shunt insertion as of moderate quality as one included trial used an alternation method of randomisation. For the outcomes of death and infection of CSF presurgery, the quality of the evidence was low as one trial used an alternation method, the number of participants was too low to assess the objectives with sufficient precision, and there was inconsistency regarding the findings in the included trials regarding the outcome of infection of CSF presurgery.

AUTHORS' CONCLUSIONS

There was no evidence that repeated removal of CSF via lumbar puncture, ventricular puncture or from a ventricular reservoir produces any benefit over conservative management in neonates with or at risk for developing PHH in terms of reduction of disability, death, or need for placement of a permanent shunt.

Hydrocephalus in children

Hydrocephalus is a common disorder of cerebral spinal fluid (CSF) physiology resulting in abnormal expansion of the cerebral ventricles. Infants commonly present with progressive macrocephaly whereas children older than 2 years generally present with signs and symptoms of intracranial hypertension. The classic understanding of hydrocephalus as the result of obstruction to bulk flow of CSF is evolving to models that incorporate dysfunctional cerebral pulsations, brain compliance, and newly characterised water-transport mechanisms. Hydrocephalus has many causes. Congenital hydrocephalus, most commonly involving aqueduct stenosis, has been linked to genes that regulate brain growth and development. Hydrocephalus can also be acquired, mostly from pathological processes that affect ventricular outflow, subarachnoid space function, or cerebral venous compliance. Treatment options include shunt and endoscopic approaches, which should be individualised to the child. The long-term outcome for children that have received treatment for hydrocephalus varies. Advances in brain imaging, technology, and understanding of the pathophysiology should ultimately lead to improved treatment of the disorder.

Nonsurgical therapy for hydrocephalus: a comprehensive and critical review

Pharmacological interventions have been tested experimentally and clinically to prevent hydrocephalus and avoid the need for shunting beginning in the 1950s. Clinical trials of varied quality have not demonstrated lasting and convincing protective effects through manipulation of cerebrospinal fluid production, diuresis, blood clot fibrinolysis, or manipulation of fibrosis in the subarachnoid compartment, although there remains some promise in the latter areas. Acetazolamide bolus seems to be useful for predicting shunt response in adults with hydrocephalus. Neuroprotection in the situation of established hydrocephalus has been tested experimentally beginning more recently. Therapies designed to modify blood flow or pulsation, reduce inflammation, reduce oxidative damage, or protect neurons are so far of limited success; more experimental work is needed in these areas. As has been recommended for preclinical studies in stroke and brain trauma, stringent conditions should be met for preclinical studies in hydrocephalus.

Mechanisms of hydrocephalus after neonatal and adult intraventricular hemorrhage

Intraventricular hemorrhage (IVH) is a cause of significant morbidity and mortality and is an independent predictor of a worse outcome in intracerebral hemorrhage (ICH) and germinal matrix hemorrhage (GMH). IVH may result in both injuries to the brain as well as hydrocephalus. This paper reviews evidence on the mechanisms and potential treatments for IVH-induced hydrocephalus. One frequently cited theory to explain hydrocephalus after IVH involves obliteration of the arachnoid villi by microthrombi with subsequent inflammation and fibrosis causing CSF outflow obstruction. Although there is some evidence to support this theory, there may be other mechanisms involved, which contribute to the development of hydrocephalus. It is also unclear whether the causes of acute and chronic hydrocephalus after hemorrhage occur via different mechanisms; mechanical obstruction by blood in the former, and inflammation and fibrosis in the latter. Management of IVH and strategies for prevention of brain injury and hydrocephalus are areas requiring further study. A better understanding of the pathogenesis of hydrocephalus after IVH, may lead to improved strategies to prevent and treat post-hemorrhagic hydrocephalus.

Clinical pharmacology of furosemide in neonates: a review

Furosemide is the diuretic most used in newborn infants. It blocks the Na⁺-K⁺-2Cl⁻ symporter in the thick ascending limb of the loop of Henle increasing urinary excretion of Na⁺ and Cl⁻. This article aimed to review the published data on the clinical pharmacology of furosemide in neonates to provide a critical, comprehensive, authoritative and, updated survey on the metabolism, pharmacokinetics, pharmacodynamics and side-effects of furosemide in neonates. The bibliographic search was performed using PubMed and EMBASE databases as search engines; January 2013 was the cutoff point. Furosemide half-life (t_1/2) is 6 to 20-fold longer, clearance (Cl) is 1.2 to 14-fold smaller and volume of distribution (Vd) is 1.3 to 6-fold larger than the adult values. t_1/2 shortens and Cl increases as the neonatal maturation proceeds. Continuous intravenous infusion of furosemide yields more controlled diuresis than the intermittent intravenous infusion. Furosemide may be administered by inhalation to infants with chronic lung disease to improve pulmonary mechanics. Furosemide stimulates prostaglandin E2 synthesis, a potent dilator of the patent ductus arteriosus, and the administration of furosemide to any preterm infants should be carefully weighed against the risk of precipitation of a symptomatic patent ductus arteriosus. Infants with low birthweight treated with chronic furosemide are at risk for the development of intra-renal calcifications.

Postnatal phenobarbital for the prevention of intraventricular haemorrhage in preterm infants

BACKGROUND

Intraventricular haemorrhage (IVH) is a major complication of preterm birth. Large haemorrhages are associated with a high risk of disability and hydrocephalus. Instability of blood pressure and cerebral blood flow are postulated as causative factors. Another mechanism may involve reperfusion damage from oxygen free radicals. Phenobarbital has been suggested as a safe treatment that stabilises blood pressure and may protect against free radicals.

OBJECTIVES

To determine the effect of postnatal administration of phenobarbital on the risk of IVH, neurodevelopmental impairment or death in preterm infants.

SEARCH METHODS

We used the search strategy of the Neonatal Collaborative Review Group. The original review author (A Whitelaw) was an active trialist in this area and had personal contact with many groups in this field. He handsearched journals from 1976 (when cranial computed tomography (CT) scanning started) to October 2000; these included: Pediatrics, Journal of Pediatrics, Archives of Disease in Childhood, Pediatric Research, Developmental Medicine and Child Neurology, Acta Paediatrica, European Journal of Pediatrics, Neuropediatrics, New England Journal of Medicine, Lancet and British Medical Journal. We searched the National Library of Medicine (USA) database (via PubMed) and the Cochrane Central Register of Controlled Trials (CENTRAL, 2012, Issue 10) through to 31 October 2012. We did not limit the searches to the English language, as long as the article included an English abstract. We read identified articles in the original language or translated.

SELECTION CRITERIA

We included randomised or quasi-randomised controlled trials in which phenobarbital was given to preterm infants identified as being at risk of IVH because of gestational age below 34 weeks, birthweight below 1500 g or respiratory failure. Adequate determination of IVH by ultrasound or CT was also required.

DATA COLLECTION AND ANALYSIS

In addition to details of patient selection and control of bias, we extracted the details of the administration of phenobarbital. We searched for the following endpoints: IVH (with grading), posthaemorrhagic ventricular dilation or hydrocephalus, neurodevelopmental impairment and death. In addition, we searched for possible adverse effects of phenobarbitone, for example hypotension, mechanical ventilation, pneumothorax, hypercapnia and acidosis.

MAIN RESULTS

We included 12 controlled trials that recruited 982 infants. There was heterogeneity between trials for the outcome IVH, with three trials finding a significant decrease in IVH and one trial finding an increase in IVH in the group receiving phenobarbital. Meta-analysis showed no difference between the phenobarbital-treated group and the control group in either all IVH (typical risk ratio (RR) 0.91; 95% CI 0.77 to 1.08), severe IVH (typical RR 0.77; 95% CI 0.58 to 1.04), posthaemorrhagic ventricular dilation (typical RR 0.89; 95% CI 0.38 to 2.08), severe neurodevelopmental impairment (typical RR 1.44; 95% CI 0.41 to 5.04) or death before hospital discharge (typical RR 0.88; 95% CI 0.64 to 1.21). There was a consistent trend in the trials towards increased use of mechanical ventilation in the phenobarbital-treated group, which was supported by the meta-analysis (typical RR 1.18; 95% CI 1.06 to 1.32; typical risk difference 0.129; 95% CI 0.04 to 0.21), but there was no significant difference in pneumothorax, acidosis or hypercapnia.

AUTHORS' CONCLUSIONS

Postnatal administration of phenobarbital cannot be recommended as prophylaxis to prevent IVH in preterm infants and is associated with an increased need for mechanical ventilation.

Periventricular hemorrhage: a problem still today

Periventricular hemorrhage (PVH) is the result of "temporary" fragile blood vessels and unstable circulation in the brain of very premature infants. Antenatal corticosteroids have substantially reduced PVH. Avoidance of intrapartum hypoxia and birth trauma has probably helped as has better cardio-respiratory stabilization after delivery. Increased survival of the highest risk infants under 26weeks gestation means that there are probably 800-900 infants with severe PVH annually in the UK. Delayed cord clamping could probably reduce PVH further. Various medications can reduce PVH but have not been widely adopted as the imaging has not translated into reduced disability. Posthemorrhagic ventricular dilatation (PHVD) and parenchymal hemorrhagic infarction both greatly increase disability. Treatment of PHVD is based on avoiding pressure and gross distortion of the vulnerable white matter. Further research needs to investigate whether treating subtle seizures, removing blood or blocking free radicals or inflammation will improve prognosis.

Timing of external ventricular drainage and neurodevelopmental outcome in preterm infants with posthemorrhagic hydrocephalus

OBJECTIVE

To delineate the impact of early (≤ 25 days of life) versus late (> 25 days) external ventricular drainage (EVD) on the neurodevelopmental outcome of preterm infants with posthemorrhagic hydrocephalus (PHH) following intraventricular hemorrhage (IVH).

METHODS

We retrospectively categorized 32 premature infants with PHH into two groups according to whether they underwent early (n = 10) or late (n = 22) EVD. We administered the Battelle Developmental Inventory II and a neuromotor examination (median age, 73 months, range: 29-100).

RESULTS

In adjusted comparisons, early EVD was associated with better scores than late EVD in adaptive (79 ± 22.6 vs. 58.8 ± 8.1, P = .01), personal social (90.7 ± 26 vs. 67.3 ± 15.9, P = .02), communication (95.4 ± 27.5 vs. 69.6 ± 20.5, P = .04) and cognitive (78.9 ± 24.4 vs. 60.7 ± 11.5, P = .055) functions. Three (30%) early EVD infants had severe (<2.5 standard deviation) cognitive disability compared to 18 (82%) late EVD infants (P = .03). The incidences of cerebral palsy and neurosurgical complications were equal for the two groups. Subgroup analyses suggested that early EVD was beneficial in infants with original grade III IVH (n = 15, P < 0.05), but that it had no beneficial effects in infants with prior parenchymal injury (n = 17, P = NS).

CONCLUSION

In this small retrospective series, early EVD is associated with lower rates of cognitive, communication and social disabilities than later EVD in infants with PHH without prior parenchymal injury. A randomized prospective trial is warranted.

Neonatal posthemorrhagic hydrocephalus from prematurity: pathophysiology and current treatment concepts

OBJECT

Preterm infants are at risk for perinatal complications, including germinal matrix-intraventricular hemorrhage (IVH) and subsequent posthemorrhagic hydrocephalus (PHH). This review summarizes the current understanding of the epidemiology, pathophysiology, management, and outcomes of IVH and PHH in preterm infants.

METHODS

The MEDLINE database was systematically searched using terms related to IVH, PHH, and relevant neurosurgical procedures to identify publications in the English medical literature. To complement information from the systematic search, pertinent articles were selected from the references of articles identified in the initial search.

RESULTS

This review summarizes the current knowledge regarding the epidemiology and pathophysiology of IVH and PHH, primarily using evidence-based studies. Advances in obstetrics and neonatology over the past few decades have contributed to a marked improvement in the survival of preterm infants, and neurological morbidity is also starting to decrease. The incidence of IVH is declining, and the incidence of PHH will likely follow. Currently, approximately 15% of preterm infants who suffer severe IVH will require permanent CSF diversion. The clinical presentation and surgical management of symptomatic PHH with temporary ventricular reservoirs (ventricular access devices) and ventriculosubgaleal shunts and permanent ventriculoperitoneal shunts are discussed. Preterm infants who develop PHH that requires surgical treatment remain at high risk for other related neurological problems, including cerebral palsy, epilepsy, and cognitive and behavioral delay. This review highlights numerous opportunities for further study to improve the care of these children.

CONCLUSIONS

A better grasp of the pathophysiology of IVH is beginning to impact the incidence of IVH and PHH. Neonatologists conduct rigorous Class I and II studies to advance the outcomes of preterm infants. The need for well-designed multicenter trials is essential because of the declining incidence of IVH and PHH, variations in referral patterns, and neonatal ICU and neurosurgical management. Well-designed multicenter trials will eventually produce evidence to enable neurosurgeons to provide their smallest, most vulnerable patients with the best practices to minimize perioperative complications and permanent shunt dependence, and most importantly, optimize long-term neurodevelopmental outcomes.

Infantile posthemorrhagic hydrocephalus

INTRODUCTION

Intraventricular/germinal matrix hemorrhage affects 7-30% of premature neonates, 25-80% of whom (depending on the grade of the hemorrhage) will develop hydrocephalus requiring shunting. Predisposing factors are low birth weight and gestational age.

MATERIAL

There is increasing evidence for the role of TGF-β1 in the pathogenesis of hydrocephalus, but attempts to develop treatment modalities to clear the cerebrospinal fluid (CSF) from blood degradation products have not succeeded so far. Ultrasound is a valuable screening tool for high-risk infants and magnetic resonance imaging is increasingly utilized to differentiate progressive hydrocephalus from ex vacuo ventriculomegaly, evaluate periventricular parenchymal damage, decide on the surgical treatment of hydrocephalus, and follow up these patients in the long term. Treatment of increasing ventriculomegaly and intracranial hypertension in the presence of hemorrhagic CSF can involve a variety of strategies, all with relative drawbacks, aiming to drain the CSF while gaining time for it to clear and the neonate to reach term and become a suitable candidate for shunting. Eventually, patients with progressive ventriculomegaly causing intracranial hypertension, who have reached term and their CSF has cleared from blood products, will need shunting.

CONCLUSION

Cognitive long-term outcome is influenced more by the effect of the initial hemorrhage and other perinatal events and less by hydrocephalus, provided that this has been addressed timely in the early postnatal period. Shunting can have many long-term side effects due to mechanical complications and overdrainage. In particular, patients with posthemorrhagic hydrocephalus are more susceptible to multiloculated hydrocephalus and encysted fourth ventricle, both of which are challenging to treat.

A multicenter retrospective comparison of conversion from temporary to permanent cerebrospinal fluid diversion in very low birth weight infants with posthemorrhagic hydrocephalus

OBJECT

The purpose of this study was to define the incidence of permanent shunt placement and infection in patients who have undergone the 2 most commonly performed temporizing procedures for posthemorrhagic hydrocephalus (PHH) of prematurity: ventriculosubgaleal (VSG) shunt placement and ventricular reservoir placement for intermittent tapping.

METHODS

The 4 centers of the Hydrocephalus Clinical Research Network participated in a retrospective chart review of infants with PHH who underwent treatment at each institution between 2001 and 2006. Patients were included if they had received a diagnosis of Grade 3 or 4 intraventricular hemorrhage, weighed < 1500 g at birth, and had received surgical intervention. The authors determined the incidence of conversion from a temporizing device to a permanent shunt, the incidence of CSF infection during temporization, and the 6-month CSF infection rate after permanent shunt placement.

RESULTS

Thirty-one (86%) of 36 patients who received VSG shunts and 61 (69%) of 88 patients who received ventricular reservoirs received permanent CSF diversion with a shunt (p = 0.05). Five patients (14%) in the VSG shunt group had CSF infections during temporization, compared with 11 patients (13%) in the ventricular reservoir group (p = 0.83). The 6-month incidence of permanent shunt infection in the VSG shunt group was 16% (5 of 31), compared with 12% (7 of 61) in the reservoir placement group (p = 0.65). For the first 6 months after permanent shunt placement, infants with no preceding temporizing procedure had an infection rate of 5% (1 of 20 infants) and those who had undergone a temporizing procedure had an infection rate of 13% (12 of 92; p = 0.45).

CONCLUSIONS

The use of intermittent tapping of ventricular reservoirs in this population appears to lead to a lower incidence of permanent shunt placement than the use of VSG shunts. The incidence of infection during temporization and for the initial 6 months after conversion appears comparable for both groups. The apparent difference identified in this pilot study requires confirmation in a more rigorous study.

A review of the current treatment methods for posthaemorrhagic hydrocephalus of infants

Posthaemorrhagic hydrocephalus (PHH) is a major problem for premature infants, generally requiring lifelong care. It results from small blood clots inducing scarring within CSF channels impeding CSF circulation. Transforming growth factor – beta is released into CSF and cytokines stimulate deposition of extracellular matrix proteins which potentially obstruct CSF pathways. Prolonged raised pressures and free radical damage incur poor neurodevelopmental outcomes. The most common treatment involves permanent ventricular shunting with all its risks and consequences.

This is a review of the current evidence for the treatment and prevention of PHH and shunt dependency. The Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library) and PubMed (from 1966 to August 2008) were searched. Trials using random or quasi-random patient allocation for any intervention were considered in infants less than 12 months old with PHH. Thirteen trials were identified although speculative interventions were also evaluated.

The literature confirms that lumbar punctures, diuretic drugs and intraventricular fibrinolytic therapy can have significant adverse effects and fail to prevent shunt dependence, death or disability. There is no evidence that postnatal phenobarbital administration prevents intraventricular haemorrhage (IVH). Subcutaneous reservoirs and external drains have not been tested in randomized controlled trials, but can be useful as a temporising measure. Drainage, irrigation and fibrinolytic therapy as a way of removing blood to inhibit progressive deposition of matrix proteins, permanent hydrocephalus and shunt dependency, are invasive and experimental. Studies of ventriculo-subgaleal shunts show potential as a temporary method of CSF diversion, but have high infection rates.

At present no clinical intervention has been shown to reduce shunt surgery in these infants. A ventricular shunt is not advisable in the early phase after PHH. Evidence exists that pre-delivery corticosteroid therapy reduces mortality and IVH and there may be trends towards reduced disability in the short term. There is also evidence that postnatal indomethacin reduces IVH but with no effect on mortality or disability. Overall, there is still no definitive algorithm for the treatment of PHH or prevention of shunt dependence. New therapeutic approaches in neonatal care, including those aimed at pre-empting PHH, offer the best hope of improving neurodevelopmental outcomes.

Postnatal phenobarbital for the prevention of intraventricular hemorrhage in preterm infants

BACKGROUND

Intraventricular hemorrhage (IVH) is a major complication of preterm birth. Large hemorrhages are associated with a high risk of disability and hydrocephalus. Instability of blood pressure and cerebral blood flow are postulated as causative factors. Another mechanism may involve reperfusion damage from oxygen free radicals. Phenobarbital has been suggested as a safe treatment that stabilises blood pressure and may protect against free radicals.

OBJECTIVES

To determine the effect of postnatal administration of phenobarbital on the risk of intraventricular hemorrhage (IVH), neurodevelopmental impairment or death in preterm infants.

SEARCH STRATEGY

See the Search Strategy of the Neonatal Collaborative Review Group. The reviewer has been a active trialist in this area and has personal contact with many groups in this field. Journals handsearched from 1976 (when cranial CT scanning started) to October 2000 include: Pediatrics, J Pediatrics, Archives of Disease in Childhood, Pediatric Research, Developmental Medicine and Child Neurology, Acta Paediatrica, European J of Pediatrics, Neuropediatrics, New England J of Medicine, Lancet and British Medical J. The National Library of Medicine (USA) database (via PubMed) and the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library) were searched through to April 2007 using the MeSH terms intraventricular hemorrhage, newborn infants, premature infant, intracranial hemorrhage, phenobarbitone, phenobarbital. The searches were not limited to the English language, as long as the article included an English abstract. Promising articles were read in the original language or translated.

SELECTION CRITERIA

Randomized or quasi-randomized controlled trials in which phenobarbital was given to preterm infants identified as being at risk of IVH because of gestational age below 34 weeks, birthweight below 1500 g, or respiratory failure were included. Adequate determination of IVH by ultrasound or CT was also required.

DATA COLLECTION AND ANALYSIS

In addition to details of patient selection and control of bias, the details of the administration of phenobarbital were extracted. The end-points searched for included: IVH ( with grading), posthemorrhagic ventricular dilatation or hydrocephalus, neurodevelopmental impairment and death. In addition, possible adverse effects of phenobarbitone such as hypotension, mechanical ventilation, pneumothorax, hypercapnia, and acidosis were searched for.

MAIN RESULTS

Ten controlled trials were included with 740 infants recruited. There was heterogeneity between trials for the outcome IVH, with one trial finding a significant decrease in IVH and another trial finding an increase in IVH in the group receiving phenobarbital. Meta-analysis showed no difference between the phenobarbital treated group and the control group in either IVH (typical relative risk 1.04, 95% CI 0.87, 1.25), severe IVH (typical relative risk 0.91, 95% CI 0.66, 1.24), posthemorrhagic ventricular dilatation (typical relative risk 0.89, 95% CI 0.38, 2.08), severe neurodevelopmental impairment (typical relative risk 1.44, 95% CI 0.41, 5.04) or death before hospital discharge (typical relative risk 0.88, 95% CI 0.64, 1.21) There was a consistent trend in the trials towards increased use of mechanical ventilation in the phenobarbital treated group, which was supported by the meta-analysis (typical relative risk 1.18, 95% CI 1.06, 1.32; typical risk difference 0.129, 95% CI 0.045, 0.213), but there was no significant difference in pneumothorax, acidosis or hypercapnia.

AUTHORS' CONCLUSIONS

Postnatal administration of phenobarbital cannot be recommended as prophylaxis to prevent IVH in preterm infants and is associated with an increased need for mechanical ventilation.

Clinical measures to preserve cerebral integrity in preterm infants

Impaired psychomotor development, often anteceded by major intraventricular hemorrhage or periventricular leukomalacia, constitutes the most important long-term morbidity of very preterm infants. We reviewed randomized controlled trials aimed at reducing the incidence of brain damage, as detected by ultrasound, or neurodevelopmental impairment during follow-up of preterm infants. Preliminary reports of reduced rates of intraventricular hemorrhage obtained with administration of fresh frozen plasma, ethamsylate, phenobarbitone, or morphine have not been confirmed in subsequent larger trials. Early administration of indomethacin may reduce intraventricular hemorrhage without affecting long-term outcome. Pancuronium, inositol, and vitamin E decreased intraventricular hemorrhage rates but later psychomotor development was not examined. Thyroxin supplementation failed to improve neurodevelopmental outcome while protein enrichment of formula and individualized developmental care appear to be beneficial. The largest reductions in cerebral palsy and neurodevelopmental impairment were achieved by avoidance of postnatal steroids. This finding emphasizes the need to include these late endpoints in any randomized trial involving preterm infants.

Cellular damage and prevention in childhood hydrocephalus

The literature concerning brain damage due to hydrocephalus, especially in children and animal models, is reviewed. The following conclusions are reached: 1. Hydrocephalus has a deleterious effect on brain that is dependent on magnitude and duration of ventriculomegaly and modified by the age of onset. 2. Animal models have many histopathological similarities to humans and can be used to understand the pathogenesis of brain damage. 3. Periventricular axons and myelin are the primary targets of injury. The pathogenesis has similarities to traumatic and ischemic white matter injury. Secondary changes in neurons reflect compensation to the stress or ultimately the disconnection. 4. Altered efflux of extracellular fluid could result in accumulation of waste products that might interfere with neuron function. Further research is needed in this as well as the blood-brain barrier in hydrocephalus. 5. Some, but not all, of the changes are preventable by shunting CSF. However, axon loss cannot be reversed, therefore shunting in a given case must be considered carefully. 6. Experimental work has so far failed to show any benefit in reducing CSF production. Pharmacologic protection of the brain, at least as a temporary measure, holds some promise but more pre-clinical research is required.

The pathogenesis of neonatal post-hemorrhagic hydrocephalus

Hydrocephalus after intraventricular hemorrhage (IVH) has emerged as a major complication of preterm birth and is especially problematic to treat. The hydrocephalus is usually ascribed to fibrosing arachnoiditis, meningeal fibrosis and subependymal gliosis, which impair flow and resorption of cerebrospinal fluid (CSF). Recent experimental studies have suggested that acute parenchymal compression and ischemic damage, and increased parenchymal and perivascular deposition of extracellular matrix proteins--probably due at least partly to upregulation of transforming growth factor-beta (TGF-beta)--are further important contributors to the development of the hydrocephalus. IVH is associated with damage to periventricular white matter and the damage is exacerbated by the development of hydrocephalus; combinations of pressure, distortion, ischaemia, inflammation, and free radical-mediated injury are probably responsible. The damage to white matter accounts for the high frequency of cerebral palsy in this group of infants. The identification of mechanisms and mediators of hydrocephalus and white matter damage is leading to the development of new treatments to prevent permanent hydrocephalus and its neurological complications, and to avoid shunt dependence.

Neonatal intensive care neurology

The pediatric neurologist's role in the neonatal intensive care unit is described in four clinical settings: (1) assessment of outcome in neonatal encephalopathy, (2) treatment of seizures in full-term infants, (3) assessment and treatment of intraventricular hemorrhage with posthemorrhagic hydrocephalus, and (4) assessment of outcome in preterm infants. Emphasis is placed on the evidenced-based information available in these settings and on new therapies on the horizon. Using evidence-based information, the pediatric neurologist can accurately assess prognosis in the neonatal period, and this can provide the basis for a rational assessment of newer therapies in neonatal intensive care.

Intracranial pressure changes during intermittent CSF drainage

Premature very-low-birth-weight infants with posthemorrhagic hydrocephalus are often managed with intermittent cerebrospinal fluid drainage from a ventricular reservoir. There are little data regarding intracranial pressure changes during intermittent drainage to determine the amount and frequency of cerebrospinal fluid removal or to determine the correct resistance of future programmable shunts. The objective of this study was to determine the feasibility of using a commercially available intracranial pressure transducer to measure changes in pressure associated with this procedure. Continuous intracranial pressure was measured in three infants with a transducer placed at the time of ventricular reservoir insertion. Daily reservoir taps began 48 hours after placement and intracranial pressure was monitored for 7 days. Intracranial pressure before the initial tap was comparable to levels previously reported as normal. The daily removal of 10 cc/kg of cerebrospinal fluid was sufficient to lower intracranial pressure below baseline, however it was associated with wide swings in pressure and, in one patient, sustained negative pressure. The use of direct intracranial pressure monitoring may be useful in determining the optimal amount and frequency of cerebrospinal drainage from infants with posthemorrhagic hydrocephalus managed with a ventricular reservoir, as well as determining resistance settings of subsequent programmable shunts.