The moment of intraventricular hemorrhage

A Systematic Review and Meta-analysis of the Timing of Early Intraventricular Hemorrhage in Preterm Neonates: Clinical and Research Implications

A considerable number of intraventricular hemorrhages (IVH) occur within the first hours of life (HOL). Temporality between IVH and its antecedents as well as a consistent definition of "early IVH" is lacking in a large and growing body of literature. We performed a systematic review of prospective studies that reported onset of IVH in preterm neonates within the first HOL and afterwards. The English literature was searched using three databases up to March 2013. Four timing periods of IVH can be compared in 16 identified studies: 0-6; 7-12; 13-24; after 24 HOL. The 0-6 and after 24 HOL were the major modes of IVH timing. Pooled IVH proportions were estimated through a meta-analysis of studies that were conducted after antenatal steroid and surfactant era. In neonates weighing ≤1500 g at birth: 48% of IVH (95% CI: 42-58%, 5 studies, 279 IVH cases) occurred during 0-6 HOL and 38% (95% CI: 19-57%, 4 studies, 241 IVH cases) after 24 HOL. The 0-6 HOL is the shortest, most vulnerable period for IVH, thus, an early IVH is an IVH occurs in it. Such early IVH had prognostic, etiological/preventive and medicolegal implications. Accordingly, preterm neonates at risk of IVH should have their first routine screening head ultrasound at about 6 HOL. Future research exploring the antecedents of IVH should guaranty the temporality between these antecedents and IVH. Additional research will be required to determine whether the long term neurological outcomes of early and late IVH are the same.

Background patterns and sleep-wake cycles on amplitude-integrated electroencephalography in preterms younger than 30 weeks gestational age with peri-/intraventricular haemorrhage

AIM

The objective of this prospective study was to evaluate the influence of peri-/intraventricular haemorrhage (PIVH) grades I-IV on amplitude-integrated electroencephalographic (aEEG) activity in preterm infants<30 weeks gestational age (GA).

METHODS

The aEEG tracings of the first 2 weeks of life of 56 preterm infants younger than 30 weeks GA (2 groups: group A=23-26 weeks GA, group B=27-29 weeks GA) born during a 4-year period with PIVH grades I-IV were assessed for the relative duration of four background aEEG activity patterns (continuous pattern, discontinuous high-voltage pattern, discontinuous low-voltage pattern and nearly isoelectric pattern), the presence of seizure activity and the appearance of sleep-wake cycles and compared to the tracings of 75 neurologically healthy preterms without PIVH.

RESULTS

Analysis of aEEG background activity showed a decrease of continuous activity whereas discontinuous activity increased in both groups with larger haemorrhages (grades III and IV) and when compared to controls. Suspected seizure activity was more common with increasing degree of bleeding in group A (50% with PIVH I or II, 75% with PIVH III or IV) and when compared to controls and was the same with increasing degree of bleeding in group B (47% with PIVH I or II, 45% with PIVH III or IV). Sleep-wake cycles were less common with larger haemorrhages in both groups (group A: 41% with PIVH I or II, 25% with PIVH III or IV; group B: 52% with PIVH I or II, 9% with PIVH III or IV) and when compared to controls.

CONCLUSIONS

The aEEG characteristics of severe PIVH consist in a combination of a more discontinuous background pattern, a lack of sleep-wake cycles and a higher likelihood of seizure activity when compared to age-matched controls.

The incidence of acute and remote seizures in children with intraventricular hemorrhage

Seizures are a well-known complication of intraventricular hemorrhage (IVH) in premature infants; however, the rate at which they occur is not known. The authors decided, therefore, to investigate both the incidence of acute and remote seizures in infants with IVH and the association with the grade of hemorrhage. One hundred and three infants with IVH were identified and their records were reviewed for acute seizures, remote seizures, and associated morbidity and mortality. The average gestational age of these infants was 29 weeks (range, 23-40 weeks). Of the 103 infants, 32 (31%) developed grade 4 IVH; 19 (18%), grade 3 IVH; and 52 (50%), grades 1 and 2 IVH. Seventeen (17%) patients had acute seizures during their first month of life. Six of the 61 patients (10%) who survived the neonatal period and for whom follow-up data were available had remote seizures. Infants with grade 4 IVH had significantly more acute seizures than infants with grades 1 and 2. In this cohort, only infants with grades 3 and 4 IVH developed remote seizures. Furthermore, among infants with grade 4 IVH acute seizures were a significant risk factor for development of remote seizures. The use of long-term antiepileptic drug therapy in neonates with a history of acute seizures is not established. These results suggest that antiepileptic drug therapy beyond the neonatal period should be reserved for infants with grade 4 IVH with history of acute seizures.

Metabolic changes in the striatum after germinal matrix hemorrhage in the preterm infant

To investigate the metabolic consequences of germinal matrix hemorrhage (GMH) we used volume-selective 1H magnetic resonance spectroscopy in the striatal region in 12 preterm infants with predominantly small GMH. Both sides of the brain were investigated twice. Metabolite indices were calculated as the metabolite signal, recorded with TR = 1.6 s and TE = 272 ms, divided by the fully relaxed water signal corrected for transverse relaxation time constant (T2) decay. At the first investigation, when the infants were 32.5 +/- 2.0 (mean +/- SD) wk postmenstrual age, the hemorrhage was unilateral or markedly asymmetrical in size in 10 of 12 infants. The lactate index was higher (p < 0.01) and the phosphocreatine + creatine (Cr) (p < 0.05) and N-acetyl-L-aspartate (NAA) (p < 0.05) indices lower in the side with the larger hemorrhage. At the second investigation, 54.1 +/- 2.7 wk postmenstrual age, no sign of a previous GMH could be seen on magnetic resonance imaging in three of 10 infants. Lactate could be detected in two of 10 infants only, and the Cr and NAA indices did not differ between sides. However, the choline index was significantly higher in the side with the larger hemorrhage (p < 0.01). We conclude that GMH is initially followed by lactate accumulation and possibly a delay in maturation as indicated by the transiently low Cr and NAA indices. Moreover, an increased choline index at the corrected age of 3 mo indicates a more persistent metabolic change after small GMH.

Control of cerebral and ocular blood flow autoregulation in neonates

Several factors have been implicated in the regulation of cerebral and ocular vasomotor tone in the newborn: the interrelationship between prostanoids, NO, and other vasoactive mediators remains a subject of interest and active investigation. Pharmacologic modulation may provide new treatment modalities for diseases of the newborn that are mostly hemodynamic and vascular in nature.

Etiology and pathogenesis of attention-deficit hyperactivity disorder (ADHD): significance of prematurity and perinatal hypoxic-haemodynamic encephalopathy

Attention-deficit Hyperactivity Disorder (ADHD), defined as a disorder of awareness with impulsivity, has lately been characterized as a dysfunction of the striatum (neostriatum = globus pallidus + putamen). This structure is in a unique position of contextual analysis and samples information samples information from almost the entire cortex through its spiny neurons. The etiology is heterogeneous, with genetic as well as lesional factors. Among the latter, pre- and perinatal events are prominent. Advances in the understanding of the role of fetal circulatory insufficiency with loss of autoregulation and systemic hypotension have drawn attention to the vulnerability of watershed regions, including the striatum. Not only circulatory facts are important for this selectivity, however. The anatomical characteristics, with convergent glutaminergic afferent synaptic transmission from almost the entire cortex contribute to the vulnerability in ischemia-induced liberation of glutamate: The striatum becomes the victim of its virtue. Repeated hypoxic-ischemic events are particularly common in prematurity, a fact which seems to explain the high incidence of ADHD in this patient group. The magnitude, of the problem is increasing with the increased survival rate among premature infants.

Hypoxic-hemodynamic pathogenesis of brain lesions in the newborn

For more than a century two opposing views on the pathogenetic mechanisms and the timing of the origin of cerebral palsy (CP) have prevailed: the idea first formulated by Little attributing CP to "difficult deliveries" has been opposed by the view by Freud recognizing fetal influences, and the issue seems to be unsettled. The present review seeks to bridge the gap by recognizing that late prenatal or perinatal hypoxic-hemodynamic insult is a dominating final common path in the pathogenesis of static encephalopathies during development, in particular in premature infants. In turn, however, such lesions are determined by early genetic and environmental influences. The pathogenesis of static encephalopathy should therefore be seen as a chain of events, with its origin before gestation.

Clinical events in association with timing of intraventricular hemorrhage in preterm infants

To ascertain whether any routine practices or clinical manipulations in a neonatal intensive care unit could induce intraventricular hemorrhage (IVH) in preterm infants, we performed ultrasonic monitoring of the germinal layer continuously for 48 hours in 33 extremely premature infants with respiratory distress. Intraventricular hemorrhage developed in 16 of these infants. In four infants the timing of the germinal layer hemorrhage was confirmed with ultrasonic monitoring. Three of the four cases were apparently associated with clinical events occurring at the moment of IVH: manual ventilation for improvement of hypercapnia associated with primary pulmonary hypertension of the newborn; correction of hyperkalemia, which was causing an arrhythmia, with administration of calcium gluconate and sodium bicarbonate; and administration of surfactant-TA to improve respiratory failure caused by pulmonary hemorrhage. In these three infants it appeared that one of the basic factors inducing IVH might be an increase in blood pressure with or without hypercapnia, causing cerebral reperfusion after ischemic damage of the germinal layer.