A model of pulsations in communicating hydrocephalus

The traditional theory of communicating hydrocephalus has implicated the bulk flow component of CSF motion; that is, hydrocephalus is generally understood as an imbalance between CSF formation and absorption. The theory that the cause of communicating hydrocephalus is malabsorption of CSF at the arachnoid villi is not substantiated by experimental evidence or by physical reasoning. Flow-sensitive MRI has shown that nearly all CSF motion is pulsatile, and there is substantial evidence that hyperdynamic choroid plexus pulsations are necessary and sufficient for ventricular dilation in communicating hydrocephalus. We have developed a model of intracranial pulsations based on the analogy between the pulsatile motion of electrons in an electrical circuit and the pulsatile motion of blood and CSF in the cranium. Increased impedance to the flow of CSF pulsations in the subarachnoid space redistributes the flow of pulsations into the ventricular CSF and into the capillary and venous circulation. The salient features of communicating hydrocephalus, such as ventricular dilation, intracranial pressure waves, narrowing of the CSF-venous pressure gradient, diminished cerebral blood flow, elevated resistive index and malabsorption of CSF, emerge naturally from the model. We propose that communicating hydrocephalus is the result of a redistribution of CSF pulsations in the cranium.     

Two types of umbilical venous pulsations and outcome of high-risk pregnancy

Normally, blood flows evenly in the umbilical vein, without fluctuation. A pulsating pattern has been reported during fetal heart failure and asphyxia. Recently we have noticed two types of pulsating pattern; its relationship to adverse outcome is unclear.In a prospective multicenter study, recording of umbilical cord venous blood flow was conducted in high-risk pregnancies admitted for routine artery Doppler. In cases of pulsating flow or signs of vascular resistance in the umbilical artery, the examination was extended to the intra-abdominal part of the umbilical vein. Venous pulsation, single or double, were noted and correlated to perinatal outcome. Venous flow pulsatility was noted in 83 fetuses during 2 years, 26 had a double pulsating pattern, which was closely related to increased vascular resistance in the umbilical artery and perinatal mortality. A single pulsating venous pattern in one location had a good prognosis. In conclusion a double pulsating venous pattern, especially if extending to the cord, is an ominous finding in high-risk pregnancy associated with poor perinatal outcome. A single pulsating pattern predicted a much better outcome and might be an indication for delivery in the high-risk case.     

The significance of elevated CSF lactate

The final diagnosis of 158 patients who had a cerebrospinal fluid (CSF) lactate concentration greater than 2 mmol/l was ascertained. The conditions included seizures, inflammatory changes, and proven metabolic disorders. For the diagnosis of congenital lactic acidoses, CSF lactate should ideally be measured in a seizure free patient after any acute illness.     

Correlation of MRI and CSF cytology in the diagnosis of medulloblastoma spinal metastases

Background. Medulloblastoma frequently spreads to involve the spinal cord, which significantly reduces patient survival and determines whether chemotherapy is utilised and the dose of irradiation to the neuraxis. Staging is usually achieved by MRI of the spine and/or cytology of CSF, both methods having their limitations. Objective. To determine whether there is a correlation between CSF cytology and the demonstration of spinal metastases by MRI and whether CSF cytology is useful when spinal MRI is equivocal. Materials and methods. All cases of medulloblastoma diagnosed at our hospital between 1992 and 1997 were identified. Of 26 cases, 11 presentations (age range 4 months to 12 years) had both CSF cytology (either from the cisterna magna or lumbar puncture) and spinal MRI. The MR studies were reviewed for the presence of metastases and the CSF cytology for the presence of tumour cells. Results. We found 100 % correlation between MRI and CSF cytology for samples taken by lumbar puncture (four negative and three positive on both investigations). No correlation was demonstrated when CSF samples were taken from the cisterna magna. Conclusions. Our data suggest that lumbar CSF cytology may be useful when the MRI is equivocal for the presence of metastatic involvement of the spine by medulloblastoma. Received: 11 August 1997 Accepted: 26 January 1998     

Anatomy and development of the meninges: implications for subdural collections and CSF circulation

The dura is traditionally viewed as a supportive fibrous covering of the brain containing the dural venous sinuses but otherwise devoid of vessels and lacking any specific function. However, review of the embryology and anatomy reveals the dura to be a complex, vascularized and innervated structure, not a simple fibrous covering. The dura contains an inner vascular plexus that is larger in the infant than in the adult, and this plexus likely plays a role in CSF absorption. This role could be particularly important in the infant whose arachnoid granulations are not completely developed. Although subdural hemorrhage is frequently traumatic, there are nontraumatic conditions associated with subdural hemorrhage, and the inner dural plexus is a likely source of bleeding in these nontraumatic circumstances. This review outlines the development and age-specific vascularity of the dura and offers an alternative perspective on the role of the dura in homeostasis of the central nervous system. Editor’s note: see related articles in this issue: doi: (Commentary) and doi: (Editorial)     

BK virus DNA in CSF of immunocompetent and immunocompromised patients

Aim: To investigate the possible aetiological role of BK and JC viruses in immunocompetent and immunocompromised children with suspected encephalitis and meningoencephalitis. Methods: The polymerase chain reaction and microplate hybridisation method was employed for the detection of polyomavirus DNA in 266 CSF specimens collected from immunocompetent and immunocompromised patients. Results: BK virus DNA was detected in three (2.1%) CSF samples taken from patients aged 2–5 years; two were patients with acute lymphocytic leukaemia without overt neurological symptoms, the other was a patient with suspected encephalitis. BK virus DNA was also detected in two (1.6%) CSF samples taken from older children in the age range 10–16 years; both children had suspected encephalitis. JC virus DNA was not found in any CSF sample from either age group. Conclusions: Detection of BK virus in the CSF of immunocompromised and immunocompetent patients with suspected neurological disease suggests that this virus may have had a pathogenic role in the aetiology of this condition.     

Parent-infant synchrony and the construction of shared timing; physiological precursors, developmental outcomes, and risk conditions

Synchrony, a construct used across multiple fields to denote the temporal relationship between events, is applied to the study of parent-infant interactions and suggested as a model for intersubjectivity. Three types of timed relationships between the parent and child's affective behavior are assessed: concurrent, sequential, and organized in an ongoing patterned format, and the development of each is charted across the first year. Viewed as a formative experience for the maturation of the social brain, synchrony impacts the development of self-regulation, symbol use, and empathy across childhood and adolescence. Different patterns of synchrony with mother, father, and the family and across cultures describe relationship-specific modes of coordination. The capacity to engage in temporally-matched interactions is based on physiological mechanisms, in particular oscillator systems, such as the biological clock and cardiac pacemaker, and attachment-related hormones, such as oxytocin. Specific patterns of synchrony are described in a range of child-, parent- and context-related risk conditions, pointing to its ecological relevance and usefulness for the study of developmental psychopathology. A perspective that underscores the organization of discrete relational behaviors into emergent patterns and considers time a central parameter of emotion and communication systems may be useful to the study of interpersonal intimacy and its potential for personal transformation across the lifespan.     

The significance of elevated CSF lactate.

The final diagnosis of 158 patients who had a cerebrospinal fluid (CSF) lactate concentration greater than 2 mmol/l was ascertained. The conditions included seizures, inflammatory changes, and proven metabolic disorders. For the diagnosis of congenital lactic acidoses, CSF lactate should ideally be measured in a seizure free patient after any acute illness.