Therapeutic criteria in hydrocephalic children

The xanthine, hypoxanthine, and total oxypurine levels were determined in the CSF of 28 hydrocephalic patients (age from newborn to 2 years) and 8 healthy controls using HPLC. The Evans' index, the mean weekly increase in cranial circumference, and the intracranial pressure were also measured. Of the hydrocephalic patients 13 were self-compensated and the other 15 had a shunt implanted during the course of the study. The mean xanthine, hypoxanthine, and total oxypurine levels in the normal children were 5.20, 5.94, and 11.29 mol/l, respectively. In the self-compensated hydrocephalics these levels were 5.17, 5.71, and 10.79 mol/l, respectively. In the noncompensated hydrocephalics, they were 9.90, 9.91, and 19.82 mol/l. The differences between the latter group and the first two are statistically significant (P<0.001). The mean Evans' index and the mean weakly increase in cranial circumference in the self-compensated hydrocephalics were 0.35 and 0.25 cm, respectively. In the noncompensated hydrocephalics, they were 0.55 and 0.95 cm. The differences between the two groups are statistically significant (P<0.001). Two weeks after implantation of shunts in the noncompensated cases, the mean xanthine, hypoxanthine, and total oxypurine levels fell to 4.22, 4.57, and 8.80 mol/l, respectively. These changes are statistically significant (P<0.001). We think that the two criteria (clinical and biochemical) are equally useful for the prediction of self-compensation in hydrocephalic children and that the oxypurine values after shunt implantation can be used to monitor progress in noncompensated cases.     

Abdominal cerebrospinal fluid pseudocysts

Abdominal cerebrospinal fluid pseudocyst is an infrequent complication of ventriculoperitoneal (VP) shunts. We reviewed ten patients with abdominal pseudocyst. There were five girls and five boys, aged between 4 months and 14 years. The number of shunt procedures prior to the presentation varied between one and five. Only one patient had had a previous shunt infection. No patients had undergone prior abdominal surgery other than VP shunting. The time from the last shunting procedure to the development of abdominal pseudocyst ranged from 3 weeks to 5 years. Presenting symptoms and signs were mainly related to abdominal complaints in all patients. Three patients also had the signs of shunt malfunction. The diagnosis was made by ultrasound in all patients. Shunt infection was determined in six patients. Repositioning of the peritoneal catheter seemed to have a higher rate of recurrence. The diagnosis of abdominal pseudocyst should be considered in VP-shunted patients presenting with abdominal complaints.     

Imaging of cerebrospinal fluid space and movement of hydrocephalus mice using near infrared fluorescence

Abstract We have studied optical imaging of mice cerebrospinal fluid (CSF) space and flow using near infrared (NIR) fluorescence. We applied our method to image CSF space and flow in a mice hydrocephalus model. Hydrocephalus was induced in mice with intracranial injections of transforming growth factor. Hydrocephalic and control mice were imaged using our NIR fluorescence imaging system. Hydrocephalic mice showed diminished intracranial CSF flow. Our system is sufficient to show altered CSF flow in a mouse hydrocephalus model. Optical imaging using near infrared is an effective modality to image CSF space and movement.     

Intracranial venous pressures,hydrocephalus and effects of cerebrospinal fluid shunts

Data concerning venous anatomy, interstitial fluid pressure and cerebral blood flow indicate that obstruction of cerebral venous outflow (as a whole or involving the deep venous system alone) is the essential cause of hydrocephalus. Choroidal and ventricular veins both belong to the deep system. Choroidal venous pressure determines cerebrospinal fluid pressure; pressure in the ventricular veins determines interstitial fluid pressure in the paraventricular white matter. A decrease in deep cerebral blood flow causes paraventricular atrophy. CSFP is higher than interstitial fluid pressure, normally and in venous obstruction. Thus, CSFP prevents venocongestive edema (but not inflammatory edema) of the brain. Collateral venous pathways are described. Venous obstruction causes hydrocephalus only when it leads to insufficient blood flow. Cerebrospinal fluid shunting causes increased CBF as essential therapeutic effect in hydrocephalus, but also causes venocongestive brain edema, which explains the decrease in ventricle size and the side effects of shunting.Presented at the XVI Annual Meeting of the International Society for Pediatric Neurosurgery, Rome 1988     

Doppler flow velocities in children with controlled hydrocephalus: reference values for the diagnosis of blocked cerebrospinal fluid shunts

Doppler flow velocities in the middle cerebral artery of children with blocked cerebrospinal fluid shunts show changes that can be used as a non-invasive method for assessing shunt function. The velocities also change with age, and the purpose of this study was to define a reference range of values for children with controlled hydrocephalus. Flow velocities were measured in 248 asymptomatic children with shunts and an age-reference range was derived. Twenty children were subsequently admitted with suspected shunt malfunction and 11 of these required a shunt revision. On admission 9 of the 11 children requiring operation had Doppler values outside the reference range, whereas none of the children whose symptoms settled without surgery had abnormal values. The reference range will facilitate the use of transcranial Doppler for the assessment of children with suspected shunt malfunction.     

The CSF myelin basic protein in pediatric hydrocephalus

Concentrations of myelin basic protein (MBP) in ventricular and lumbar cerebrospinal fluid (CSF) of 20 pediatric hydrocephalic patients were reviewed. Raised values were found to be particularly significant in children aged more than 1 year. Control measurements after shunt placement showed an important drop in the MBP concentration, which could therefore be considered a marker for correct functioning of the shunt. The dosage of MBP could play a role in assessing the activity of an hydrocephalic process. Preliminary data gained from monitoring of MBP in the lumbar CSF in posthemorrhagic neonatal hydrocephalus could yield further criteria for indication of a shunt operation.Presented at the Consensus Conference: Hydrocephalus '92, Assisi, Italy, 26–30 April 1992     

Evaluation of cerebrospinal fluid shunt function in hydrocephalic children using 99mTc-DTPA

The increasing numbers and survival of children with shunt-treated hydrocephalus make it mandatory to refine the methods for cerebrospinal fluid (CSF) shunt function evaluation. Radionuclide shuntography with ^99mTc-DTPA, which has proved to be a safe and effective method, was performed in eight children with suspected CSF-shunt dysfunction. Characteristic shuntography patterns were found for proximal and distal CSF-shunt catheter obstruction as well as for overdrainage and normal CSF-shunt function. Shuntography contributed to the explanation of suspected CSF-shunt dysfunction in all children investigated.     

Non-invasive assessment of cerebrospinal fluid flow dynamics using phase-contrast magnetic resonance imaging in communicating hydrocephalus

This work aims to evaluate the changes in cerebrospinal fluid (CSF) hydrodynamics in patients diagnosed with communicating hydrocephalus. Besides, we establish the relationship between CSF flow dynamic parameters on the midbrain aqueduct and intracranial pressure (ICP). CSF hydrodynamics analysis was performed using Phase-Contrast Magnetic Resonance Imaging (PC‐MRI) techniques on the midbrain aqueduct of 41 patients diagnosed with communicating hydrocephalus and 22 healthy volunteers. The correlation between CSF average flow in the midbrain aqueduct and intracranial pressure measured by Lumbar Puncture (LP) was assessed in patients with hydrocephalus. Pearson correlation coefficient was used to establish the correction between the average CSF flow of midbrain aqueduct and ICP. CSF dynamic parameters of the midbrain aqueduct in hydrocephalus patients, including peak positive velocity (7.348 cm/s), average velocity (0.623 cm/s), average flow (50.799 mm³/s), and regions of interest (ROI) area (9.978 mm²) were significantly higher than in the healthy controls (p < 0.05). This was after adjusting the age, gender, heart rate, systolic blood pressure, diastolic blood pressure, and body mass index. However, only the peak negative velocity of the midbrain aqueduct did not significantly differ between the groups (p = 0.209). A positive correlation was noted between the average flow (AF) of the midbrain aqueducts and ICP in hydrocephalus patients (y (AF) = 0.386× (ICP)−33.738, r = 0.787, p < 0.05). Reference data of CSF flow dynamic parameters was obtained through the PC-MRI in middle-aged healthy volunteers and communicating hydrocephalus patients. Although the sample size was constrained, this study has significant contributions. For instance, a significant correlation was noted between the average CSF flow of the aqueduct and ICP. This therefore provides a reference for clinicians to monitor ICP in patients with hydrocephalus.     

Dynamic changes of cerebrospinal fluid shunt flow in patient's daily life

The shunt flow rate will be greatly influenced by the changing posture of the patient. A newly designed method of assessing shunt flow rate by isotope clearance is described and the results of phantom experiments and clinical data are presented. This method makes it possible to assess shunt flow rates in a variety of postures, such as recumbent, or head raised or as posture changes from recumbent to sitting and eventually to upright. As patients changed from the recumbent to the sitting position, shunt flow rates ceased in some cases. In cases with low flow rates in the recumbent position, shunt flow rate increased with any elevation of the upper half of the body. In many cases, flow rates increased as the patient's position changed from recumbent to sitting and then to the upright position. The results suggest that shunt flow rates vary substantially as postures alter in a patient's daily life.     

Cerebrospinal fluid and extracellular fluid: their relationship to pressure and duration of canine hydrocephalus

Fifteen greyhound dogs were made hydrocephalic by the transsphenoidal injection of silicone into the basal cisterns at the level of the tentorial incisura. Six of these animals had ventriculocisternal perfusions 4 weeks later and six at 8 weeks, half at 150 and half at 100 mm H₂O. Three 12-week dogs were perfused at 150 mm H₂O. Serial sections of brain from the ependyma of the left frontal horn to the overlying pia were counted for¹⁴C inulin and³H methotrexate uptake. Tissue concentrations of both markers varied indirectly with distance from ependyma and from pia, and varied directly with perfusion pressure. The data indicate that the diffusional pathway between cere-brospinal fluid (CSF) and extracellular fluid (ECF) can be modified by CSF pressure changes, i.e., CSF flows from the ventricles and subarachnoid space into the extracellular space when CSF pressures are raised. Brain uptake of inulin and methotrexate was significantly increased in the dogs made hydrocephalic 4 weeks prior to perfusion, but was less so in the 8-week hydrocephalics. Uptake of the tracers in three 12-week animals was similar to that found previously in normal dogs at elevated pressures. These findings correspond in location and time to the periventricular lucencies that are seen by computed tomography in human subacute hydrocephalus. They are apparently due to pressure-related changes in the volume of the ECF.     

动脉瘤性蛛网膜下腔出血后脑脊液引流时间与引流量对脑积水的影响

目的讨论脑脊液腰大池引流时间长短及引流量对动脉瘤性蛛网膜下腔出血患者术后脑积水发生的影响。方法回顾性分析97例患者临床资料,依据脑脊液引流时间长短及引流量分为短时程、长时程及低流量和高流量组,分析引流时程及引流量对脑积水的影响及关系。结果 97例患者出现脑积水34例、硬膜下积液41例、颅内感染3例。短时程组41例、平均引流时间(10±3.6) d,长时程组56例、平均引流时间(21±4.1) d,组间引流时间差异具统计学意义(P 0.001),组间发生脑积水(22.0%vs 44.6%,P=0.021)、硬膜下积液(26.8%vs 53.6%,P=0.008)差异均具统计学意义,颅内感染差异无统计学意义(3.2%vs 3.6%,P=0.750)。低流量组53例、平均引流量(183±42) ml,高流量组44例、平均引流量(285±34) ml。组间引流量差异具有统计学意义(P 0.001),组间发生脑积水(20.8%vs 52.3%,P=0.001)、硬膜下积液(30.2%vs 56.8%,P=0.008)差异均具统计学意义,颅内感染方面(3.8%vs 2.3%,P=0.067 1)差异无统计学意义。结论动脉瘤性蛛网膜下腔出血术后脑脊液引流时间、引流量可能是脑积水发生的重要影响因素,长时程及高流量引流脑脊液的患者更易出现脑积水及硬膜下积液。     

Arginine vasopressin concentrations in the cerebrospinal fluid of children

Cerebrospinal fluid (CSF) arginine vasopressin (AVP) levels are reported in a group of 22 children (median age 24 months) investigated for possible bacterial meningitis and subsequently found not to be suffering from this disease. The mean CSF AVP concentration was 0.80±0.33 pg/ml. The results obtained in patients suffering from febrile convulsions (mean 0.71 pg/ml), other convulsive disorders (mean 0.80 pg/ml) and miscellaneous infectious disease (mean 0.85 pg/ml) did not differ significantly from one another. Our findings confirm the presence of AVP in the CSF of children and provide reference values for further investigations into the functions of CSF AVP in children.     

Quantification of cerebrospinal fluid shunt flow rates

Shunt placement diverting cerebrospinal fluid (CSF) has been the treatment of choice for hydrocephalus for the past several decades. However, the procedure often requires revisions owing to excessive drainage, low CSF flow rates, or infections within the system. With regard to valve pressure, selection of an appropriate valve for a specific patient prior to surgery is not always a simple task. Further, an optimal valve selected at the time of implantation may no longer be appropriate given changing pathophysiological conditions as time passes. It is thus desirable to provide a single valve in which the pressure may be modified when necessary without revision. A programmable pressure valve (designed by Sophysa of France) comes in one model which accommodates different pressure settings obviating revision when pressure changes are needed. Pressure changes can be achieved externally by means of a special magnet which allows precise adjustments in valve pressure to be made through the scalp. The authors introduce the mechanism and describe the cases treated using this valve.Presented at the 15th Annual Meeting of the International Society for Pediatric Neurosurgery, New York 1987     

Hydrocephalus due to cerebrospinal fluid overproduction by bilateral choroid plexus papillomas

Case report A 10-month-old boy, with congenital deafness and blindness associated with chromosomal deletion [46XY, del(13)(q32)], presented with intractable ascites 9 months after ventriculo-peritoneal shunting for congenital hydrocephalus. Revision of the ventriculo-atrial shunt resulted in shunt failure 1 month later. External ventricular drainage revealed cerebrospinal fluid (CSF) overproduction (2,000 ml/day). Magnetic resonance imaging showed marked lobular enlargement of the bilateral choroid plexuses extending from the trigone to the body and inferior horn of the lateral ventricle. Multi-staged resection was performed via bilateral temporo-occipital transcortical approaches, and CSF production significantly decreased to 100 ml/day postoperatively. Histological assessment of the villous surface suggested villous hyperplasia of the choroid plexus and thorough evaluation including the proximal portion of the lobular lesion near the attachment revealed choroid plexus papilloma. He was discharged after ventriculo-peritoneal shunting without additional neurological deficits except for hyperreflexia of the left extremities.Conclusion CSF overproduction caused by bilateral choroid plexus papillomas can result in hydrocephalus. Radical resection of the bilateral ventricular lesions should be considered for this entity. Thorough evaluation of the surgical specimen is recommended because histological examination of only the lobular surface of the choroid plexus lesion may fail to identify choroid plexus neoplasm.     

A nonlinear biomechanical model for evaluation of cerebrospinal fluid shunt systems

In view of complications arising from physical properties of cerebrospinal fluid shunts, a biomechanical model of hydrocephalus was set up to study in vivo parameters that may influence their function. These include: intracranial pressure, compliance and pulses, intrathoracic, intra-abdominal, and subcutaneous pressures, and the effects of siphonage and repeated valve flushing. Each of these factors was studied separately upon shunt implantation in the model. Results of testing of a sample lowpressure valve with antisiphon device conformed with consumer information in regard to valve opening pressure and pressure flow measurements. No customer information, however, was supplied concerning the deleterious effects of direct subcutaneous pressure, variable degrees of siphonage, and repeated valve flushing that were demonstrated by the model. Such results indicate that shunts should be similarly tested prior to marketing and implantation in patients.     

Concentration of malonic dialdehyde in the cerebrospinal fluid as a measure of the intensity of lipid peroxidation processes in intracranial hypertension in small children

The authors analyzed the concentration of malonic dialdehyde (MDA) in the cerebrospinal fluid (CSF) of children with intracranial hypertension. For the control group an intracranial pressure (ICP) of 250 mm H₂O was taken as a reference point. The concentration of MDA was determined by a method using thiobarbituric acid. In a group of children with ICP values greater than the limiting value, the concentration of malonic dialdehyde was 0.629 mmol/mg protein, while in the control group with an ICP below 250 mm H₂O, this value was 0.610 mmol/mg protein. The differences between the two groups were not statistically significant, from the results obtained it can be concluded that the concentration of MDA, as an isolated parameter, does not constitute a good measure of intensity of the lipid peroxidation processes in central nervous system (CNS) tissues, taken as an indicator of their disintegration in cases of hydrocephalus with intracranial hypertension.     

Ion concentrations in serum and cerebrospinal fluid of patients with neuromuscular diseases

Summary The Na⁺, K⁺, Ca²⁺, Mg²⁺, Cl^–, and P_i concentrations in serum and lumbar CSF of 17 controls and 62 patients with neuromuscular diseases were determined and the values statistically evaluated. Although alterations in ion concentrations specifical to different groups were not observed in either of these biological fluids, the significant increase in serum P_i concentration in Duchenne muscular dystrophy seems to be remarkable. It is suggested that the possible alterations in the ion content of the serum and CSF may contribute additional data to the diagnosis of various neuromuscular diseases.Supported by Ministry of Health, Hungary-/2-20-0303-01-0/M.     

The cerebrospinal fluid in myasthenia gravis

We examined the number of leucocytes and the concentration of total protein, albumin and IgG in the cerebrospinal fluid (CSF) from 46 patients with myasthenia gravis (MG) and 50 controls. Mean leucocyte number in the MG patients was 1634 cells/ml (controls 1244), mean total protein 0.38 g/l (controls 0.32), mean IgG 0.034 g/l (controls 0.025) and mean albumin 0.199 g/l (controls 0.176). No evidence of intrathecal IgG synthesis was demonstrated. The CSF was normal in most cases. When pathological changes occurred they were slight and could be attributed to associated diseases or to iatrogenic blood contamination of the CSF. We demonstrated that an artificial blood contamination of the CSF, although macroscopically undetectable, increased the CSF albumin concentration and the CSF albumin/serum albumin ratio considerably.     

Plasma and cerebrospinal fluid concentrations of magnesium in epileptic children

In order to discriminate between conflicting reports in the literature, plasma and cerebrospinal fluid magnesium levels from epileptic children were compared with those of control children. To exclude the possibility of methodological artifacts, two methods for Mg determination were used: atomic absorption spectrophotometry and a colorimetric procedure. By both methods a significantly decreased concentration of Mg in plasma was found in epileptics. A positive correlation of the hypomagnesemia with the severity of epilepsy was found: the more severe the epilepsy, the lower was the plasma Mg. A significant increase of Mg concentration in CSF of epileptics was found. The most likely origin of Mg in CSF in epilepsy is the CNS tissue from which Mg is released. It is suggested that these alterations of Mg concentrations in plasma and CSF originate from a functional impairment of the cell membranes which might occur in epilepsy.     

Idiopathic normal-pressure hydrocephalus,cerebrospinal fluid biomarkers,and the cerebrospinal fluid tap test

Cerebrospinal fluid (CSF) biomarkers, including soluble amyloid β-42 (Aβ-42) and phosphorylated-tau (P-tau), reflect core pathophysiological features of Alzheimer’s disease (AD). AD is frequently a concomitant pathology in older patients with idiopathic normal-pressure hydrocephalus (iNPH), and somewhat similar altered CSF dynamics exist in both AD and iNPH. We therefore investigated relationships between lumbar CSF biomarkers Aβ-42 and P-tau and clinical parameters in iNPH patients, along with differences in these biomarkers between CSF tap test (CSFTT) responders and non-responders. Thirty-one iNPH patients (14 CSFTT responders and 17 CSFTT non-responders) were included in the final analysis. We found lower CSF Aβ-42 correlated with poor cognitive performance (r = 0.687, p < 0.001 for Korean Mini Mental State Examination; r = 0.568, p = 0.001 for Frontal Assessment Battery; r = −0.439, p = 0.014 for iNPH grading scale [iNPHGS] cognitive score; r = −0.588, p = 0.001 for Clinical Dementia Rating Scale), and lower CSF P-tau correlated with gait dysfunction (r = −0.624, p < 0.001 for Timed Up and Go Test; r = −0.652, p < 0.001 for 10 meter walking test; r = −0.578, p = 0.001 for Gait Status Scale; r = −0.543, p = 0.002 for iNPHGS gait score). In subgroup analysis, CSF P-tau/Aβ-42 ratios were significantly higher in CSFTT non-responders compared to responders (p = 0.027). Two conjectures are suggested. One, CSF biomarkers may play different and characteristic roles in relation to different iNPH symptoms such as cognition and gait. Two, comorbid AD pathology in iNPH patients may affect the response to the CSFTT. Larger studies using combinations of other biomarkers associated with AD would be necessary to evaluate these hypotheses.