Can we prevent cerebral palsy?

Immature mouse unilateral carotid ligation model of stroke

Cerebral palsy in humans results from a diverse group of disorders that produce nonprogressive motor impairments in the developing brain. Stroke is an important cause of hemiparetic cerebral palsy in neonates and young children. We recently developed a new immature mouse model of stroke that demonstrates seizures, the severity of which correlates with brain injury. This model has strengths compared with other immature rodent models of ischemic injury, such as relative technical ease and the presence of seizures, as is seen in humans. This model also has relative weaknesses, such as the inability to titrate the severity of the injury with different periods of hypoxia. In addition, more work is needed to delineate the long-term consequences of the insult in this new model.

Postnatal laboratory timers of antenatal hypoxemic-ischemic brain damage

OBJECTIVE

Markers were sought to identify the antenatal starting times and rates at which brain damage advanced in children with hypoxemic-ischemic cerebral palsy.

STUDY DESIGN

Fetal bradycardia's onset marked the damage's start. Using this baseline, the following were tested as additional timers of the damage's onset: serial blood counts of neonates' normoblasts, platelets, lymphocytes,differences at birth between base excess values in umbilical arterial and venous bloods,brain damage patterns.

RESULTS

Each timer had a broad antenatal time frame within which it could identify specific damage starting times. The broad time frames are as follows: Blood lymphocyte counts: 0.45 to 13.8 hours before birth, blood normoblast counts: 0.45 to 55.0 hours before birth, blood platelet counts: 0.5 to >72 hours before birth. Brain damage patterns: 0.4 to >0.7 hour before birth. Hyperventilating and hyperoxygenating neonates greatly accelerated the damage's advance.

CONCLUSIONS

Commonly obtained laboratory values and brain images can identify when such brain damage began and the rate at which it advanced.

The evolution of neonatology

In 1960, the terms "neonatology" and "neonatologist" were introduced. Thereafter, an increasing number of pediatricians devoted themselves to full-time neonatology. In 1975, the first examination of the Sub-Board of Neonatal-Perinatal Medicine of the American Board of Pediatrics and the first meeting of the Perinatal Section of the American Academy of Pediatrics were held. One of the most important factors that improved the care of the neonate was the miniaturization of blood samples needed to determine blood gases, serum electrolytes, glucose, calcium, bilirubin, and other biochemical measurements. Another factor was the ability to provide nutrition intravenously, and the third was the maintenance of normal body temperature. The management of respiratory distress syndrome improved with i.v. glucose and correction of metabolic acidosis, followed by assisted ventilation, continuous positive airway pressure, antenatal corticosteroid administration, and the introduction of exogenous surfactant. Pharmacologic manipulation of the ductus arteriosus, support of blood pressure, echocardiography, and changes in the management of persistent pulmonary hypertension, including the use of nitric oxide and extracorporeal membrane oxygenation, all have influenced the cardiopulmonary management of the neonate. Regionalization of neonatal care; changes in parent-infant interaction; and technological changes such as phototherapy, oxygen saturation monitors, and brain imaging techniques are among the important advances reviewed in this report. Most remarkable, a 1-kg infant who was born in 1960 had a mortality risk of 95% but had a 95% probability of survival by 2000. However, errors in neonatology are acknowledged, and potential directions for the future are explored.

Cerebral palsy-definition, classification, etiology and early diagnosis

Cerebral palsy is a common neurodevelopmental condition encountered by pediatricians. The condition may present itself in many different clinical spectra. The etiological and risk factors are many and an awareness of the interplay of multiple factors in the causation of CP is crucial. In many cases, the cause of Cerebral palsy may not be apparent. Cerebral palsy is invariably associated with many deficits such as mental retardation, speech and language and oromotor problems. A thorough neurodevelopmental assessment of the child with Cerebral Palsy should include evaluation of associated deficits so that a comprehensive early intervention program an be planned and executed.

Use of opioids in asphyxiated term neonates: effects on neuroimaging and clinical outcome

Perinatal asphyxia is a common cause of neurologic morbidity in neonates who are born at term. Asphyxiated neonates are frequently treated with analgesic medications, including opioids, for pain and discomfort associated with their care. On the basis of previous laboratory studies suggesting that opioids may have neuroprotective effects, we conducted a retrospective review of medical records of 52 neonates who were admitted to our neonatal intensive care unit between 1995 and 2002 and had undergone magnetic resonance imaging (MRI) of the brain. Our review revealed that 33% of neonates received morphine or fentanyl. The neonates who received opioids also had experienced hypoxic/ischemic insults of greater magnitude as suggested by higher plasma lactate levels and lower 5-min Apgar scores. It is interesting that the MRI studies of neonates who were treated with opioids during the first week of life demonstrated significantly less brain injury in all regions studied. More important, follow-up studies of a subgroup of opioid-treated neonates whose MRI scans were obtained in the second postnatal week had better long-term neurologic outcomes. Our results suggest that the use of opioids in the first week of life after perinatal asphyxia have no significant long-term detrimental effects and may increase the brain's resistance to hypoxic-ischemic insults.

The changing panorama of cerebral palsy in Sweden. IX. Prevalence and origin in the birth-year period 1995-1998

AIM

This is the ninth report from the western-Swedish study of the prevalence and origin of cerebral palsy.

METHODS

A population-based study covering the 88 371 live births in the area in 1995-1998. Birth characteristics, neuroimaging findings and risk factors in children with cerebral palsy were recorded, prevalence was calculated, and aetiology was analysed.

RESULTS

The study comprised 170 children with cerebral palsy, i.e. a prevalence of 1.92 per 1000 live births. Excluding eight post-neonatally derived cases, the gestational age-specific prevalences were 77 per 1000 for children born before 28 wk of gestation, 40 for children born at 28-31 wk, 7 for children born at 32-36 wk and 1.1 for children born after 36 wk of gestation. Spastic hemiplegia, diplegia and tetraplegia accounted for 38%, 35% and 6%, respectively, dyskinetic cerebral palsy for 15%, and ataxia for 6%. For the first time, hemiplegia was now most common, due to the decline in preterm diplegia. There was a further increase in full-term dyskinetic cerebral palsy. The origin of cerebral palsy in children born at term was considered to be prenatal in 38%, peri/neonatal in 35% and unclassifiable in 27%, while in children born preterm it was 17%, 49% and 33%, respectively.

CONCLUSION

The decreasing trend from the period 1991-1994 continued, both in children born at term and especially in those born preterm. However, the increase in dyskinetic cerebral palsy in children born at term was a matter of concern. In this group, a perinatal hypoxic ischaemic encephalopathy had been present in 71%.

Maternal infection and risk of cerebral palsy in term and preterm infants

OBJECTIVE

We tested the hypothesis that term and preterm infants exposed to maternal infection at the time of delivery are at increased risk of developing cerebral palsy (CP).

STUDY DESIGN

A population-based case-control study was conducted using Washington State birth certificate data linked to hospital discharge data. Cases (688) were children <or=6 years old, singleton births, hospitalized during 1987 to 1999 with an ICD-9 diagnosis code for CP. Controls were 3,068 singleton birth infants randomly selected from birth records for the same years without CP-related hospitalizations. Infection information was available only for the birth hospitalization.

RESULTS

Infants of women who had any infection during their hospitalization for delivery were at increased risk of CP (odds ratio (OR) 3.1, 95% confidence interval (CI) 2.3 to 4.2). This was observed for term deliveries (OR 1.8, 95% CI 1.1 to 2.8) and preterm deliveries (OR 2.3, 95% CI 1.3 to 4.2).

CONCLUSIONS

Our results suggest that maternal infection is a risk factor for CP in both term and preterm infants.

Term neonatal asphyxial seizures and peripartum deaths: lack of correlation with a rising cesarean delivery rate

OBJECTIVE

The purpose of this analysis was to study the relationship between an increasing cesarean delivery rate and term neonatal seizures and peripartum deaths.

STUDY DESIGN

This was a retrospective analysis of annually collated institutional data on cesarean delivery and perinatal outcome.

RESULTS

Of 77,350 women who delivered at 37 weeks' gestation or more through 12 years (1989 to 2000), the cesarean rate increased from 6.9% to 15.1%; perinatal mortality at term, average 3.1/1000, was unchanged. The cesarean rate for nulliparas doubled from 8.3% to 17.5%. The overall neonatal term seizure rate (overall 1.3/1000; and for nulliparas 2.5/1000) did not change. The overall peripartum death rate (0.8/1000) was unchanged, although the rate for nulliparas (1.5/1000) showed a significant decline. Overall seizure rate in nulliparas was 5-fold higher than in multiparas; presumed intrapartum asphyxia was associated with 84% of both seizures and neonatal deaths in nulliparas. Among 2547 prelabor cesarean deliveries, there were no peripartum deaths and one neonatal seizure, an incidence comparable with that in multiparas who labored.

CONCLUSION

Despite a greater than 2-fold rise in cesarean section rate, the seizure rate and overall peripartum death rate at term did not alter significantly. Neonatal seizures occurred 5 times more often following first deliveries.

Declining diagnosis of birth asphyxia in California: 1991-2000

OBJECTIVE

Birth asphyxia is recognized as an important cause of neonatal morbidity and mortality. Whether advances in perinatal care have altered the incidence of birth asphyxia is unknown. We determined the incidence of birth asphyxia diagnoses made over a 10-year period in California.

METHODS

In a population-based retrospective cohort study of 5,364,663 live births, we determined the incidence and case fatality of birth asphyxia between 1991 and 2000. Using a statewide administrative hospital discharge database, we identified all newborn admissions that generated a diagnosis of birth asphyxia (International Classification of Diseases, Ninth Revision, Clinical Modification codes 768.5, 768.6, or 768.9) or a diagnosis that overlaps with birth asphyxia, such as congenital encephalopathy or fetal distress. We determined incidence and in-hospital case fatality rates adjusted for birth weight and demographic characteristics and stratified by associated perinatal complications.

RESULTS

The 24 330 newborns who received a diagnosis of birth asphyxia yielded a population incidence of 4.5 per 1000 live births. Black ethnicity (relative risk [RR]: 1.3; 95% confidence interval [CI]: 1.2-1.3), male gender (RR: 1.2; 95% CI: 1.1-1.2), and low socioeconomic status (RR: 1.2; 95% CI: 1.1-1.2) all were associated with increased risk. The diagnosis of birth asphyxia decreased by 91% from 14.8 to 1.3 per 1000 live births during the study years. This decrease could not be explained by an increased diagnosis of overlapping conditions. Overall case fatality was 4%, and the majority of deaths in infants >2000 g occurred in the presence of congenital anomalies, cord abnormalities, or maternal hemorrhage. In newborns <2000 g, case fatality was highest in the presence of chorioamnionitis (48%).

CONCLUSION

The diagnosis of birth asphyxia has decreased dramatically in recent years. The factors that are responsible for this decline are unclear and deserve additional investigation.

Primary nonmedically indicated cesarean section ("section on request"): evidence based or modern vogue?

Cesarean section, initially described as an emergency operative procedure for delivering moribund parturients, is now advocated by many as a routine technique with major advantages over vagi-nal delivery. In fact, it has been suggested that labor and vaginal delivery are no longer the desired consequence of pregnancy, a conclusion that reflects perceived medical advantages and patient and physician convenience. This article systematically reviews the various medical implications to the mother and infant of this procedure in the hope of facilitating a more rational approach to this spreading and controversial phenomenon.

Second overview of relationships between antenatal pharmacologic magnesium sulfate and neurologic outcomes in children

In the last ten years, the body of scientific knowledge concerning the use of antenatal pharmacologic magnesium sulfate (MgSO4) has become substantially larger. Several randomized controlled trials have provided compelling evidence that MgSO4 is the drug of choice for maternal seizure prophylaxis in toxemia. In contrast, the recent Cochrane Systematic Review, as well as other studies, have shown there is no evidence basis for the use of MgSO4 for tocolysis. Furthermore, when tocolytic-strength doses of MgSO4 are employed, there is an excess risk for total pediatric mortality (Cochrane Systematic Review and our own previous work). It is conceivable, nonetheless, that low doses of MgSO4, when used as prophylaxis in some selected cases of preterm labor, may ultimately be shown to be neuroprotective for a relatively small number of children. Unfortunately, the indiscriminate use of high-dosage MgSO4 for attempted tocolysis in preterm labor is much more likely to cause harm than do good.

The value of autopsy in determining the cause of failure to respond to resuscitation at birth

Autopsy is invaluable in identifying the causes of severe depression and very low Apgar score after birth and in assessing contributory conditions. Brain scans are increasingly used in the care of neonates who fail to respond to resuscitation at birth but their interpretation depends on the information gained from sound neuropathological studies. Asphyxia, both acute intrapartum asphyxia and chronic asphyxia, is an important cause of low Apgar scores. The gestational age and the nature of the asphyxial insult both have a profound influence on the ultimate pattern of injury. Asphyxia in the preterm brain tends to damage preferentially the white matter but some white matter damage is also seen in many infants who have an hypoxia-ischaemic insult at term though the predominant site of injury is to the central grey matter. The nature of the cellular damage and reactive change seen at autopsy is described. There is an association between low Apgar scores and intrauterine exposure to infection and maternal pyrexia. Detailed autopsy examination should include the search for infection. The placenta, cord and membranes should be examined in view of the mounting evidence of the association between intrauterine infection of the placenta and fetal membranes and prenatal brain damage. Additionally, the presence of placental thrombosis and infarction should be sought in relation to focal and global injury in the full term infant. Acquired prepartum lesions rarely cause the infant to present with a low Apgar score. The exception to this is severe damage to the brainstem and basal ganglia. Traumatic injury to the brain is now much less common than in previous decades. Subdural haemorrhage occurs more frequently than intraventricular or subarachnoid haemorrhage. Instrumental and assisted deliveries are associated with an increased incidence of subdural haemorrhage though these rarely cause significant long term damage. Careful autopsy, particularly of the neck and paravertebral tissues, spinal cord, brainstem and nerve roots is important where trauma is suspected. Tearing of nerve roots or fibre bundles in the spinal cord is readily demonstrated under the microscope using immunocytochemistry to beta-amyloid precursor protein. Disorders of the spinal cord, peripheral nerve and muscle as well as some metabolic diseases may cause a baby to be both floppy and weak. Metabolic disease, including peroxisomal disorders, non-ketotic hyperglycinaemia, lipid and glycogen storage disorders and mitochondrial diseases may cause profound hypotonia and respiratory failure at birth or shortly afterwards.

The CTG and the timing and mechanism of fetal neurological injuries

Defining the relationship between the cardiotocograph (CTG) pattern and subsequent neurological injury is confounded by the requirement that certain clinical and biochemical perinatal findings are essential for relating intrapartum events to subsequent neurological injury. Similarly, the value of CTG analysis in these cases has been compromised by antiquated terminology focused on hypoxia but not neurological behavior. Strong evidence suggests that the evaluation of umbilical artery acidosis, low Apgar score and neonatal encephalopathy are limited in their ability to either include or exclude intrapartum injury. Proper evaluation of the CTG requires that trends and the rapidity of changes in patterns of decelerations are necessary to confidently define the normal-behaving fetus, the hypoxemic but uninjured fetus, the injured but non-hypoxic fetus, and finally to distinguish ischemic events from other forms of hypoxia. A newly defined CTG pattern, the 'conversion' pattern, appears to be a specific marker of ischemic injury and could help to redefine the role of CTG monitoring.

New directions in the outcome evaluation of children with cerebral palsy

This article addresses newly emerging concepts regarding the examination of outcomes in children with cerebral palsy (CP). Three important factors have prompted a change toward a broader approach to outcome measurement: (1) the recent endorsement of the World Health Organization classification scheme of functioning, disability, and health; (2) recognition of the importance of the role of child and environmental factors in modifying outcome; and (3) appreciation of the challenges faced at key transitions during development. Comparison of the literature on outcomes in children with CP published in 2002 with studies published 10 years earlier demonstrates an increased number of studies and a wider range of outcome measures used to characterize the functioning of these children. A better understanding of the extent and nature of the outcomes and their determinants is critical to guide clinical decision making and program planning to maximize community integration, social participation, and overall well-being of the child and family.

Does the risk of cerebral palsy increase or decrease with increasing gestational age?

BACKGROUND: It is generally accepted that the risk of cerebral palsy decreases with increasing gestational age of live born infants. However, recent studies have shown that cerebral palsy often has prenatal antecedents including congenital malformations, vascular insults and maternal infection. Cerebral palsy is therefore better viewed as occurring among fetuses, rather than among infants. We explored the epidemiologic implications of this change in perspective. METHODS: We used recently published data from Shiga Prefecture, Japan and from North-East England to examine the pattern of gestational age-specific rates of cerebral palsy under these alternative perspectives. We first calculated gestational age-specific rates of cerebral palsy as per convention, by dividing the number of cases of cerebral palsy identified among live births within any gestational age category by the number of live births in that gestational age category. Under the alternative formulation, we calculated gestational age-specific rates of cerebral palsy by dividing the number of cases of cerebral palsy identified among live births within any gestational age category by the number of fetuses who were at risk of being born at that gestation and being afflicted with cerebral palsy. RESULTS: Under the conventional formulation, cerebral palsy rates decreased with increasing gestational age from 63.9 per 1,000 live births at <28 weeks gestation to 0.9 per 1,000 live births at 37 or more weeks gestation. When fetuses were viewed as potential candidates for cerebral palsy, cerebral palsy rates increased with increasing gestational age from 0.08 per 1,000 fetuses at risk at <28 weeks gestation to 0.9 per 1,000 fetuses at risk at 37 or more weeks gestation. CONCLUSIONS: The fetuses-at-risk approach is the appropriate epidemiologic formulation for calculating the gestational age-specific rate of cerebral palsy from a causal perspective. It shows that the risk of cerebral palsy increases as gestational duration increases. This compelling view of cerebral palsy risk may help refocus research aimed at understanding and preventing cerebral palsy.