Biochemical profile of human infant cerebrospinal fluid in intraventricular hemorrhage and post-hemorrhagic hydrocephalus of prematurity

Posthemorrhagic Hydrocephalus in Patients with Subarachnoid Hemorrhage Occurs Independently of CSF Osmolality

The molecular mechanisms underlying the development of posthemorrhagic hydrocephalus (PHH) remain incompletely understood. As the disease pathogenesis often cannot be attributed to visible cerebrospinal fluid (CSF) drainage obstructions, we here aimed to elucidate whether elevated CSF osmolality following subarachnoid hemorrhage (SAH) could potentiate the formation of ventricular fluid, and thereby contribute to the pathological CSF accumulation observed in PHH. The CSF osmolality was determined in 32 patients with acute SAH after external ventricular drainage (EVD) placement and again upon EVD removal and compared with the CSF osmolality from 14 healthy control subjects undergoing vascular clipping of an unruptured aneurism. However, we found no evidence of elevated CSF osmolality or electrolyte concentration in patients with SAH when compared to that of healthy control subjects. We detected no difference in CSF osmolality and electrolyte content in patients with successful EVD weaning versus those that were shunted due to PHH. Taken together, elevated CSF osmolality does not appear to underlie the development of PHH following SAH. The pathological CSF accumulation observed in this patient group must thus instead be attributed to other pathological alterations associated with the abnormal presence of blood within the CSF compartments following SAH.

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.

New insights into the management of post-hemorrhagic hydrocephalus

During the last decade, an increasing number of studies have been conducted to improve the outcome of post-hemorrhagic hydrocephalus (PHH), a complication of severe intraventricular hemorrhage (IVH) in preterm infants. Two randomized controlled trials have shown that treatment should be initiated prior to the onset of clinical symptoms. Ventricular access devices and subgaleal shunts are used as temporary neurosurgical interventions whereas ventriculoperitoneal shunts are performed for infants with progressive hydrocephalus. Recently, techniques such as neuro-endoscopic lavage have also been introduced to eliminate toxic blood products and debris from the cerebral ventricles and have shown promise in early clinical studies. The objective of this review is to provide an update on management of PHVD and PHH in the preterm infant.

Risk Factor of Posthemorrhagic Hydrocephalus: Cerebrospinal Fluid Total Protein

Objective

Cerebrospinal fluid total protein (CSF-TP) levels in adults with posthemorrhagic hydrocephalus (PHH) are poorly studied. The objective of this study was to explore the characteristics of CSF-TP levels in patients with PHH.

Methods

The clinical data of 156 patients with hemorrhagic brain disease were retrospectively studied and divided into PHH and NPHH groups. Single-factor and multi-factor analyses were performed, and the key role of CSF-TP was evaluated using linear analysis.

Results

Among the 156 patients, 85 (54.5%) had PHH and 34 (21.8%) underwent surgeries. Hypertension (p = 0.017), days [total fever time when body temperature ≥ 38.5°C (p = 0.04)], Glasgow Coma Scale (GCS) score (p < 0.001), and time (from the onset of the disease to the obtainment of CSF-TP after lumbar puncture (p < 0.001) were important factors for PHH. Logistic regression analysis revealed that GCS score < 8 [odds ratio (OR) = 2.943 (1.421–6.097), p = 0.004] and CSF-TP × time ≥ 9,600 [OR = 2.317 (1.108–4.849), p = 0.026] were independent risk factors for PHH. All CSF-TP values were averaged every 2 days. CSF-TP was negatively correlated with time. Linear analysis showed that CSF-TP in the PHH group was higher than that in the NPHH group at the same onset time, and that the duration of detectionin the CSF was longer.

Conclusion

Cerebrospinal fluid total protein (CSF-TP) × time ≥ 9,600 and GCS score <8 were independent risk factors for PHH. CSF-TP was higher in the PHH group than in the NPHH group.

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.