How does CSF dynamics change after shunting?

Objective –  Hydrocephalus is much more complex than a simple disorder of cerebrospinal fluid (CSF) circulation. Shunting primarily corrects disturbed fluid flow which may have an impact on cerebral blood flow and metabolism. We studied hydrocephalic patients before and after shunting to characterize changes in their CSF compensatory parameters.
Material and methods –  We selected 25 patients and studied them retrospectively. All patients had ventriculomegaly and clinical symptoms of normal pressure hydrocephalus. After shunting, they were still presenting with some adverse symptoms, mainly headaches, slow improvement or no improvement of ventriculomegaly. Therefore, they underwent further infusion studies to assess shunt function. In all cases, the shunts were confirmed to be draining CSF adequately. Parameters of CSF dynamics: baseline intracranial pressure (ICP), resistance to CSF outflow, cerebrospinal elasticity, content of vasogenic pressure waves (pulse, respiratory and B waves) and compensatory reserve assessed as moving correlation coefficient between mean CSF pressure and pulse amplitude (RAP), were compared before and after shunting.
Results –  Mean ICP and resistance to CSF outflow decreased ( P  < 0.003) after shunting. All vasogenic pressure waves decreased ( P  < 0.005). Compensatory reserve (RAP) significantly improved ( P  < 0.005).
Conclusion –  A functioning shunt has an important impact on CSF circulation and pressure–volume compensation. Infusion studies can demonstrate the return of disturbed CSF dynamics to normal values even if clinical or radiological changes are not dramatic.     

Hydrocephalus: the zero ICP ventricle shunt (ZIPS) to control gravity shunt flow

Significant morbidity from ventricle shunt overdrainage at 6–7 years after initial shunt placement for hydrocephalus is increasingly recognized as due to excessive gravity-flow of shunted CSF when upright. Shunts are designed primarily to control high ICP. Shunts should also mimic normal upright ICP. Normal upright ICP is -65 mm of water (vertex reference), indicating that a level of zero ICP exists at 65 mm below the brain vertex, with negative ICP above and positive ICP below that level. This normal zero ICP level must be maintained by CSF shunts to mimic normal upright ICP. This will prevent and correct CSF shunt overdrainage. The zero ICP shunt (ZIPS) by design controls this zero level with a zero pressure device (ZPD; siphon control device) installed at the normal vertical level of zero ICP (cm/mm) below the vertex (65 mm). The shunt thus prevents excessive gravity-induced CSF shunt flow. Successful use of ZIPS in 56 patients is reported (low ICP group: n = 42; high ICP group: n = 14). Follow-up is up to 4.5 years. Results show that: (1) adjustability of ZPD level can achieve the desired clinical results; (2) the level of ZPD installed correlates within 4 mm of upright ICP attained; (3) the optimal level of ZPD installation to produce normal upright ICP is 65 mm below the vertex; (4) CT ventricle size, both slit ventricles and large ventricles, may or may not normalize when normal upright ICP is attained in this group of complex, previously shunted patients.Presented at the Consensus Conference: Hydrocephalus '92, Assisi, Italy, 26–30 April 1992     

Long-term results of hydrocephalus with myelomeningocele

This paper reviews long-term follow-up studies of 78 hydrocephalic patients with myelomeningocele. Seventy-eight (95%) out of 82 patients with myelomeningocele had hydrocephalus. CT, MRI, CT cisternography, and monitoring of intracranial pressure (ICP) with infusion methods were performed to evaluate the indication of shunt insertion or shunt independency. These hydrocephalic patients consisted of the following two groups: (1) Early treated group. Sixty-four cases received initial cerebrospinal fluid (CSF) diversion operation within 2 years of life. Sixty-three patients had a ventriculoperitoneal (VP) or a ventriculoatrial (VA) shunt. All the patients of this group showed progressive signs and symptoms of increased ICP due to hydrocephalus. The mean age at the initial shunt placement was 10 weeks. The mean value of Evans' index before shunting was 47%, which corresponded to moderate ventriculomegaly. 48% of this group showed slit-like ventricles on postoperative CT scans, where 52% had normal or only mildly dilated ventricles subsequent to shunting. There were two instances (3%) of the so-called "slit ventricle syndrome" and one instance of "isolated fourth ventricle", who had undergone multiple shunt revisions. Shunt revisions were performed on fifty-two occasions in this group. The mean number of shunt revisions per child was 2.8. Sixty among 64 patients of this group were suitable for evaluating shunt dependency with long-term follow-up period. Forty-two out of 60 patients were considered to be shunt dependent, who underwent multiple shunt revisions after 6 months of age. These patients had signs and symptoms of increased ICP, neurological deterioration, and enlarged ventricles when their shunts were blocked. There were four cases of slowly progressive (shunt dependent) hydrocephalus, who did not show clinical signs and symptoms of shunts malfunction in spite of progressive ventriculomegaly and abnormal findings of CT cisternography and ICP monitoring. Only two patients (3%) proved to be shunt independent. Consistently their ventricles were mildly dilated. These results suggest a very low incidence of true arrest of hydrocephalus after shunt operation. (2) Late treated group. Fourteen cases were diagnosed or treated for hydrocephalus after 7 years of age. Six out of fourteen patients had remarkable hydrocephalus whose Evans' index exceeded 51%. The mean value of Evans' index was 48% in this group. Six patients had progressive signs and symptoms of hydrocephalus and were shunted. ICP monitoring and studies of CSF dynamics revealed abnormal findings in ten out of 14 cases in spite of preservation of good intelligence.(ABSTRACT TRUNCATED AT 400 WORDS)     

Complications of elective intracranial pressure monitoring in adult hydrocephalus

Continuous invasive monitoring of intracranial pressure (ICP) can be used in the diagnosis and management of various types of chronic cerebrospinal fluid (CSF) circulation disorders, such as hydrocephalus, shunt dysfunction and idiopathic intracranial hypertension. The risk profile and incidence of adverse events of this surgical procedure in this patient population is not well established. We aimed to investigate and describe the risks of ICP monitoring in adult patients with chronic CSF circulation disorders. We analysed 152 patients undergoing continuous ICP monitoring between 2010 and 2019, mainly for idiopathic normal pressure hydrocephalus. The average duration of ICP monitoring was 17 h 51 min. We observed no major adverse events, such as symptomatic intracranial haemorrhage, intracranial infection, or persistent neurological deficit. Minor complications were seen in 7% of patients and included accidental removal of the ICP probe in 4 patients, inability to remove the probe requiring surgical removal in 2 patients and single generalised seizures in 2 patients. In summary, the risk of serious adverse events and complications from invasive ICP monitoring in chronic CSF circulation disorders in adult patients appears to be low.     

Use of transcranial real-time ultrasonography for programming a shunt valve system

For patients who suffer from hydrocephalus that is difficult to treat because of impaired intracranial compliance, a programmable shunt system may be a helpful alternative. However, especially during the first weeks after implantation, many radiological follow-up studies are necessary to achieve the optimum pressure level. The authors present the case of a 7-year-old boy who suffered from posthemorrhagic hydrocephalus and did not respond to conventional shunt valve systems. After implantation of a programmable shunt system, achieving the optimum craniospinal fluid (CSF) pressure level was difficult because the symptoms of over-and under-drainage were similar. Using transcranial real-time ultrasonography for evaluation of the diameter of the intracranial CSF spaces, we were able to adjust the correct pressure level without long-term intracranial pressure monitoring or daily computed tomography, which otherwise would have been necessary because of the ambiguous symptomatology. Transcranial real-time ultrasonography (TCUS) displays an image of the intracranial parenchyma and CSF spaces through the intact temporal bone and is a valuable, serially applicable bedside monitoring technique for patients requiring close imaging follow-up     

Evaluation of the lumbar and ventricular infusion test in the diagnostic strategy of pediatric hydrocephalus and the therapeutic implications

Aim To evaluate the infusion test as a diagnostic tool behind the choice of intervention in pediatric hydrocephalus.Materials and methods Intracranial pressure (ICP) measurement and infusion test were performed intraventricularly, by lumbar route, or combined in 40 consecutive children as a part of the standard diagnostic program in 1996–1999.Results The median age was 18.5 months, ranging from 2 weeks to 13 years. In the subgroup of patients with radiological aqueductal stenosis (N=14), mean lumbar/intraventricular ICP was 13 (3–35)/10 (2–27). Mean lumbar/ventricular R _out were 18 (4–49)/17 (6–37). For patients with radiological communication between the third and fourth ventricles (N=14), the mean lumbar/intraventricular ICP was 11 (7–17)/9 (1–16). Mean lumbar/ventricular R _out were 8 (3–11)/8 (4–12). A total of 13 patients had a shunt insertion, 10 had an endoscopic third ventriculostomy (ETV), 5 had endoscopic fenestration of a cyst, and 12 had no surgery. Of the patients initially treated with EVT, 50% had a shunt insertrion shortly after. For communicating hydrocephalus, 75% of the patients initially not operated based on normal R _out values ended up having a shunt insertion.Discussion R _out has doubtful value as an indicator for conducting an operation or not and in the choice between EVT and shunt in chiladren. This should be interpreted in the light of a growing understanding of hydrocephalus on a molecular level.     

Pressure compensation in shunt-dependent hydrocephalus with CSF shunt malfunction

This study is a retrospective analysis of intracranial pressure (ICP) and cerebral perfusion pressure (CPP) data from 56 children with active hydrocephalus and cerebrospinal fluid (CSF) shunt malfunction. The pressures were measured from a separately sited CSF access device placed in the frontal horn of the lateral ventricle. Of the patients, 79% had an elevated ICP (mean 20±12 mmHg). A subgroup of patients demonstrated ten different forms of CSF-filled swelling. This group had significantly lower ICP recordings (P=0.000075) with a mean ICP of 8.5 mmHg compared with the remainder (22.9 mmHg). This pressure ’compensation’ was because of additional nonphysiological accommodation of CSF volume. Overall the CPP was normal in 35% of cases despite normal ICP occurring in only 11% of cases. The CPPs were not significantly different in those with and without compensation. Measurement of ICP may not always be a reliable indicator of shunt malfunction in shunt- dependent children who present with compensatory CSF-filled spaces. Received: 10 March 2000     

Intracranial pressure monitoring in children with single suture and complex craniosynostosis: a review

Introduction One third of patients with craniofacial dysostosis syndromes and about 15–20% of children with single suture craniostenosis have a documented increase in intracranial pressure (ICP). The early detection of intracranial hypertension is important in order to reduce the risks for brain development and visual function. However, in children with craniosynostosis, the clinical manifestations of abnormally increased ICP are difficult to detect, as the majority of patients may have neither warning signs nor symptoms for a long period of time.Review Moreover, data from the literature suggest that neither fundoscopic nor radiological findings are necessarily related to intracranial pressure recordings in this type of pathology. In this context prolonged ICP monitoring seems actually to be the most valuable diagnostic tool. Extradural, subdural, and intraparenchymal devices have been used, and different softwares have been employed for PC storage and analysis of the data obtained. Most recent series consider mean ICP combined with plateaux waves as the most sensitive indicators in the final evaluation of the results. Conclusions The analysis of the literature demonstrates a significant difference in the prevalence of raised ICP preoperatively between non-syndromic and syndromic patients. Among the non-syndromic children, a direct relation between the number of sutures involved and raised ICP is documented. The analysis of plateaux waves seems to be particularly important in children with borderline mean ICP values. Persistent postoperative raised ICP has been described in 6–15% of patients with craniofacial dysostosis. It must be related to the multifactorial etiology of increased ICP in these patients, which includes cerebral venous congestion, upper airway obstruction, and hydrocephalus.     

Isolated diastasis of cranial sutures: unusual presentation of a blocked shunt in an infant

Introduction Ventriculo-peritoneal (VP) shunt malfunction is usually due to blockage of the ventricular catheter and this is typically apparent as enlarged ventricles on a CT scan of the brain. We describe a less common radiological finding in an infant with a blocked shunt.Case report A male infant presenting with hydrocephalus in the neonatal period underwent insertion of a VP shunt. He represented at 17 months of age with the clinical features of raised intracranial pressure. A CT scan of the brain revealed that the ventricles were smaller compared with his previous scan, but X-rays taken as part of the shunt series revealed diastasis of the sagittal, coronal and lambdoid sutures. The shunt was explored and the ventricular catheter was found to be blocked and was replaced. Post-operatively there was complete resolution of the symptoms and the suture diastasis.Conclusions Suture diastasis with small ventricles on a CT scan of the brain is an unusual radiological finding in an infant with a blocked shunt. Suture diastasis in this patient suggests raised intracranial volume and this may be due to the transependymal absorption of CSF into the white matter.     

Intracranial pressure,its components and cerebrospinal fluid pressure–volume compensation

Clinical measurement of intracranial pressure (ICP) is often performed to aid diagnosis of hydrocephalus. This review discusses analysis of ICP and its components' for the investigation of cerebrospinal fluid (CSF) dynamics. The role of pulse, slow and respiratory waveforms of ICP in diagnosis, prognostication and management of hydrocephalus is presented. Two methods related to ICP measurement are listed: an overnight monitoring of ICP and a constant‐rate infusion study. Due to the dynamic nature of ICP, a ‘snapshot’ manometric measurement of ICP is of limited use as it might lead to unreliable results. Therefore, monitoring of ICP over longer time combined with analysis of its waveforms provides more detailed information on the state of pressure–volume compensation. The infusion study implements ICP signal processing and CSF circulation model analysis in order to assess the cerebrospinal dynamics variables, such as CSF outflow resistance, compliance of CSF space, pressure amplitude, reference pressure, and CSF formation. These parameters act as an aid tool in diagnosis and prognostication of hydrocephalus and can be helpful in the assessment of a shunt malfunction.     

INTRACRANIAL PRESSURE MONITORING IN TUBERCULOUS MENINGITIS: CLINICAL AND COMPUTERIZED TOMOGRAPHIC CORRELATION

Cerebrospinal fluid (CSF) pressure was monitored in 24 children with acute tuberculous meningitis. 19 had raised intracranial pressure (ICP) as reflected by increased baseline pressure, pressure waves (e.g. B-waves) and increased amplitude of the pulse wave. Correlation between clinical signs of raised ICP and monitored CSF pressure showed that clinical diagnosis of the presence and degree of raised ICP is unreliable, especially in children with a closed anterior fontanelle. Computerized tomographic (CT) scans showed that hydrocephalus was present in all children with raised CSF pressure. No direct correlation was found between the degree of hydrocephalus and the degree of raised ICP. The r?le of ICP monitoring in the diagnosis and management of raised ICP in children with tuberculous meningitis is discussed.     

Pseudotumor cerebri

Pseudotumor cerebri (PTC) is a syndrome of increased intracranial pressure without hydrocephalus or mass lesion and with normal cerebrospinal fluid (CSF) composition. Although often considered to be “idiopathic,” detailed investigation has revealed a high incidence of venous outflow abnormalities in PTC syndrome patients. The thought that elevated intracranial venous sinus pressure is a “universal mechanism” for PTC syndrome of varying etiologies has been called into question by a study indicating that the increased venous pressure in idiopathic PTC patients is caused by the elevated intracranial pressure and not the reverse, suggesting that “the chicken is the CSF pressure elevation and the egg is the venous sinus pressure elevation.” Vitamin A toxicity may play a role in the pathogenesis of idiopathic PTC. The treatment of PTC has two major goals: the alleviation of symptoms and preservation of visual function. When medical therapy fails or when visual dysfunction deteriorates, surgical therapies for PTC should be considered. The two main procedures performed include lumboperitoneal shunt and optic nerve sheath fenestration. Because of the association of PTC with venous sinus hypertension, some authors are considering venous sinus stenting for refractory cases of PTC. It is still unclear if primary treatment of the observed venous stenosis benefits patients with idiopathic PTC. This should be no surprise, as it is not certain whether the stenoses are the cause or the result of idiopathic PTC.     

Alteration in the lower limit of autoregulation with elevations in cephalic venous pressure

Abstract

Objectives:

Recent studies suggest that elevated intracranial pressure (ICP), created by hydrocephalus, can alter the lower limit of cerebrovascular autoregulation (LLA). Our objective in the present study was to determine if ICP elevation from cerebral venous outflow obstruction would result in comparable alterations in the LLA.

Methods:

Anesthetized juvenile pigs were assigned to one of two groups: naïve ICP (n = 15) or high ICP (>20 mmHg; n = 20). To elevate ICP through venous obstruction, a modified 5F esophageal balloon catheter was inserted via the right external jugular vein into the superior vena cava (SVC) and inflated to maintain an ICP of >20 mmHg. To calculate the LLA, gradual hypotension was induced by continuous hemorrhage from a catheter in the femoral vein. The LLA was determined by monitoring cortical laser Doppler flux (LDF).

Results:

The naïve and high ICP groups had LLAs of 45 mmHg (95% CI: 41–49 mmHg) and 71 mmHg (95% CI: 66–77 mmHg) respectively by LDF. The LLA was significantly different between the two groups and correlated significantly with ICP.

Discussion:

Elevated ICP from cephalic venous engorgement leads to an increase in the LLA. These findings suggest that pathologic processes resulting in cephalic venous outflow obstruction and intracranial venous congestion can acutely elevate ICP and may place the brain at risk for impaired cerebrovascular autoregulation.     

Comparison of ventricular drainage in poor grade patients after intracranial hemorrhage

Abstract

Objectives: The selection of patients and treatment criteria for acute hydrocephalus and intracranial pressure (ICP) after intracranial hemorrhage remains unclear. In general neurosurgical practice, there is a tendency to use external ventricular drainage (EVD) for the patients. This study was undertaken to analyse the complications and efficiency of the different treatment modalities.

Methods: The effects, complications and outcome of ventricular drainage on high ICP and hydrocephalus were analysed retrospectively in 109 patients with intracranial hemorrhage. All the patients were assessed using the Glasgow Coma Scale, computed tomography and ICP monitoring. We excluded patients over the GCS of 8. All patients underwent a procedure for ICP monitoring plus ventricular cerebrospinal fluid (CSF) drainage. Sixty-one patients were managed with one (single) EVD system; 12 patients needed two EVD systems consecutively, while 23 patients underwent an EVD procedure followed by permanent ventriculoperitoneal (VP) shunt insertion. Thirteen patients were treated only by VP shunt for ventricular drainage. The infection rate and outcome 9 months after hemorrhage were analysed.

Results: The infection rates were 8.1% in the one-EVD group, 33.3% in the two-EVD group (one EVD versus two EVD, p<0.05), 8.6% in the EVD-VP group and 7.7% in the VP shunt group. The mortality rates were 73.7% in the one-EVD group, 83.8% in the two-EVD group, 47.8% (p<0.05) in the EVD-VP group and 53.8% (p<0.01) in the VP shunt group.

Discussion: This study indicates that single and short-term use of EVD and/or early VP shunting are associated with a low risk of infection. Furthermore, early VP shunting may protect the brain from the irregular control of intracranial hypertension and may allow more time for resolution of CSF circulation and significantly lowers the mortality rates.     

Intracranial pressure monitoring and CSF dynamics in patients with neurological disorders: indications and practical considerations

The study of cerebrospinal fluid (CSF) dynamics is central to the diagnosis of adult chronic hydrocephalus (ACH). At present, many neurology and neurosurgery departments use one or more tests to guide diagnosis of this syndrome and to predict patient response to shunting. In specialised centres, the study of CSF dynamics is combined with continuous intracranial pressure (ICP) monitoring. Determination of several variables of CSF dynamics and definitions of qualitative and quantitative characteristics of ICP can be used to establish whether the hydrocephalus is active, compensated or arrested. CSF dynamics and ICP monitoring can also be used to check the correct functioning of the shunt and can be of use in the clinical management of patients with pseudotumor cerebri. Moreover, ICP monitoring is used to guide the treatment of several acute neurological processes. The aim of this review is to describe the fundamentals of CSF dynamics studies and the bases of continuous ICP monitoring. The advantages and disadvantages of several hydrodynamic tests that can be performed by lumbar puncture, as well as the normal and abnormal characteristics of an ICP recording, are discussed.     

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.     

Lactate dehydrogenase enzyme as a metabolic marker for the evaluation of shunting in infants with non-tumoral hydrocephalus

Lactate dehydrogenase (LDH) enzyme activity has not been analyzed in neonatal nontumoral hydrocephalus. We studied 14 patients with nontumoral hydrocephalus (7 males and 7 females) with ages ranging between 1 and 18 months. All patients were treated by ventriculo-peritoneal shunt, and evaluated clinically and by meassurement of LDH activity in cerebrospinal fluid (CSF) and blood, both, preoperatively and 10 days after the placement of the shunt.All patients showed high levels of LDH in the CSF, and high CSF/Blood LDH ratio in the preoperative samples. Although all the patients had clinical improvement, and some of them showed radiological improvement, most retained high levels of LDH activity in the CSF (13 out of 14 patients), and high CSF/Blood ratio (9 out of 14 patients).In spite of the clinical and radiological improvement due to the control of raised intracranial pressure by shunting, the improvement of metabolic activity of the brain, as measured by LDH activity was not normalized during the investigation periodo Therefore, we feel that the follow-up of such patients using metabolic activity of the brain by monitoring LDH as a marker might be more sensitive than the morphological and clinical parameters.     

Classification of hydrocephalus: critical analysis of classification categories and advantages of ��Multi-categorical Hydrocephalus Classification�� (Mc HC)

Objective  

Hydrocephalus is a complex pathophysiology with disturbed cerebrospinal fluid (CSF) circulation. There are numerous numbers of classification trials published focusing on various criteria, such as associated anomalies/underlying lesions, CSF circulation/intracranial pressure patterns, clinical features, and other categories. However, no definitive classification exists comprehensively to cover the variety of these aspects. The new classification of hydrocephalus, “Multi-categorical Hydrocephalus Classification” (Mc HC), was invented and developed to cover the entire aspects of hydrocephalus with all considerable classification items and categories.     

Monitoring and interpretation of intracranial pressure

Intracranial pressure (ICP) is derived from cerebral blood and cerebrospinal fluid (CSF) circulatory dynamics and can be affected in the course of many diseases of the central nervous system. Monitoring of ICP requires an invasive transducer, although some attempts have been made to measure it non-invasively. Because of its dynamic nature, instant CSF pressure measurement using the height of a fluid column via lumbar puncture may be misleading. An averaging over 30 minutes should be the minimum, with a period of overnight monitoring in conscious patients providing the optimal standard. Computer-aided recording with online waveform analysis of ICP is very helpful. Although there is no "Class I" evidence, ICP monitoring is useful, if not essential, in head injury, poor grade subarachnoid haemorrhage, stroke, intracerebral haematoma, meningitis, acute liver failure, hydrocephalus, benign intracranial hypertension, craniosynostosis etc. Information which can be derived from ICP and its waveforms includes cerebral perfusion pressure (CPP), regulation of cerebral blood flow and volume, CSF absorption capacity, brain compensatory reserve, and content of vasogenic events. Some of these parameters allow prediction of prognosis of survival following head injury and optimisation of "CPP-guided therapy". In hydrocephalus CSF dynamic tests aid diagnosis and subsequent monitoring of shunt function.     

An unusual parasagittal tumour with acute blindness and response to cerebrospinal fluid shunting.

We report a seven-year-old girl who presented with a sudden tumor apoplexy due to a parasagittal hemangiopericytoma. Following tumor excision, the child was noted to have bilateral optic nerve dysfunction and progressive papilledema, despite rapid overall neurological improvement. Based on the clinical features, we feel that this case represents an unusual form of visual deterioration related to impaired CSF absorption somehow precipitated by the acute tumour apoplexy. This unusual case of blindness responded significantly to CSF shunting. Several reports exist describing raised intracranial pressure with papilledema caused by nonthrombotic sinus occlusion due to tumors in proximity to the posterior superior sagittal sinus, torcular herophili and the jugular outlet. Communicating hydrocephalus, pseudotumor syndrome or intracranial venous sinus obstruction should be considered when otherwise inexplicable visual loss coexists with optic nerve dysfunction and papilledema. We emphasize the importance of a thorough search for the cause of visual loss.