Normal pressure hydrocephalus in children and young adults

X-linked hydrocephalus genes: Their proximity to telomeres and high A + T content compared to Parkinson's disease

Proximity to telomeres (i) and high adenine and thymine (A + T) content (ii) are two factors associated with high mutation rates in human chromosomes. We have previously shown that >100 human genes when mutated to cause congenital hydrocephalus (CH) meet either factor (i) or (ii) at 91% matching, while two factors are poorly satisfied in human genes associated with familial Parkinson's disease (fPD) at 59%. Using the sets of mouse, rat, and human chromosomes, we found that 7 genes associated with CH were located on the X chromosome of mice, rats, and humans. However, genes associated with fPD were in different autosomes depending on species. While the contribution of proximity to telomeres in the autosome was comparable in CH and fPD, high A + T content played a pivotal contribution in X-linked CH (43% in all three species) than in fPD (6% in rodents or 13% in humans). Low A + T content found in fPD cases suggests that PARK family genes harbor roughly 3 times higher chances of methylations in CpG sites or epigenetic changes than X-linked genes.

Somatic Development Disorders in Children and Adolescents Affected by Syndromes and Diseases Associated with Neurodysfunction and Hydrocephalus Treated/Untreated Surgically

Background: This study was conducted to evaluate the co-occurrence of hydrocephalus treated/untreated surgically and congenital nervous system disorders or neurological syndromes with symptoms visible since childhood, and with somatic development disorders, based on significant data obtained during admission to a neurological rehabilitation unit for children and adolescents. Methods: The study applied a retrospective analysis of data collected during hospitalization of 327 children and adolescents, aged 4−18 years, all presenting congenital disorders of the nervous system and/or neurological syndromes associated with at least one neurodysfunction that existed from early childhood. To allow the identification of individuals with somatic development disorders in the group of children and adolescents with hydrocephalus treated/untreated surgically, the adopted criteria considered the z-score values for body height, body weight, head circumference, body mass index, and head circumference index. Results: Treated/untreated hydrocephalus was observed in the study group at the rates of 8% and 0.9%, respectively. Among 239 patients with cerebral palsy, 9 (3.8%) had surgically treated hydrocephalus, 17 (70.8%) of 24 patients with neural tube defects also had hydrocephalus treated with surgery, and 3 (12.5%) of 24 patients with neural tube defects had untreated hydrocephalus. This medical condition was a more frequent comorbidity in subjects with neural tube defects compared with those with cerebral palsy (p < 0.001). Subjects with untreated hydrocephalus most frequently presented macrocephaly (p < 0.001), including absolute macrocephaly (p = 0.001), and with tall stature (p = 0.007). Excessive body mass co-occurred more frequently with surgically untreated hydrocephalus, but the relationship was not statistically significant (p = 0.098). Conclusions: Surgically treated hydrocephalus occurred in patients with cerebral palsy and neural tube defects, and untreated hydrocephalus was present only in patients with neural tube defects. Untreated hydrocephalus negatively changed the course of individual development in the studied group of children, in contrast to surgically treated hydrocephalus.

Reappraisal of Pediatric Normal-Pressure Hydrocephalus

While normal-pressure hydrocephalus (NPH) is most commonly diagnosed in older adulthood, a significant body of literature has accumulated over half a century documenting the clinical phenomenon of an NPH-like syndrome in pediatric patients. As in adult NPH, it is likely that pediatric NPH occurs due to a heterogeneous array of developmental, structural, and neurodegenerative pathologies, ultimately resulting in aberrant cerebrospinal fluid (CSF) flow and distribution within and around the brain. In this review, we aimed to systematically survey the existing clinical evidence supporting the existence of a pediatric form of NPH, dating back to the original recognition of NPH as a clinically significant subtype of communicating hydrocephalus. Leveraging emergent trends from the old and more recent published literature, we then present a modern characterization of pediatric NPH as a disorder firmly within the same disease spectrum as adult NPH, likely with overlapping etiology and pathophysiological mechanisms. Exemplary cases consistent with the diagnosis of pediatric NPH selected from the senior author’s neurosurgical practice are then presented alongside the systematic review to aid in discussion of the typical clinical and radiographic manifestations of pediatric NPH. Common co-morbidities and modern surgical treatment options are also described.

Recent Advances in Rational Diagnosis and Treatment of Normal Pressure Hydrocephalus: A Critical Appraisal on Novel Diagnostic, Therapy Monitoring and Treatment Modalities

BACKGROUND

Normal pressure hydrocephalus (NPH) is a critical brain disorder in which excess Cerebrospinal Fluid (CSF) is accumulated in the brain's ventricles causing damage or disruption of the brain tissues. Amongst various signs and symptoms, difficulty in walking, slurred speech, impaired decision making and critical thinking, and loss of bladder and bowl control are considered the hallmark features of NPH.

OBJECTIVE

The current review was aimed to present a comprehensive overview and critical appraisal of majorly employed neuroimaging techniques for rational diagnosis and effective monitoring of the effectiveness of the employed therapeutic intervention for NPH. Moreover, a critical overview of recent developments and utilization of pharmacological agents for the treatment of hydrocephalus has also been appraised.

RESULTS

Considering the complications associated with the shunt-based surgical operations, consistent monitoring of shunting via neuroimaging techniques hold greater clinical significance. Despite having extensive applicability of MRI and CT scan, these conventional neuroimaging techniques are associated with misdiagnosis or several health risks to patients. Recent advances in MRI (i.e., Sagittal-MRI, coronal-MRI, Time-SLIP (time-spatial-labeling-inversion-pulse), PC-MRI and diffusion-tensor-imaging (DTI)) have shown promising applicability in the diagnosis of NPH. Having associated with several adverse effects with surgical interventions, non-invasive approaches (pharmacological agents) have earned greater interest of scientists, medical professional, and healthcare providers. Amongst pharmacological agents, diuretics, isosorbide, osmotic agents, carbonic anhydrase inhibitors, glucocorticoids, NSAIDs, digoxin, and gold-198 have been employed for the management of NPH and prevention of secondary sensory/intellectual complications.

CONCLUSION

Employment of rational diagnostic tool and therapeutic modalities avoids misleading diagnosis and sophisticated management of hydrocephalus by efficient reduction of Cerebrospinal Fluid (CSF) production, reduction of fibrotic and inflammatory cascades secondary to meningitis and hemorrhage, and protection of brain from further deterioration.

In vitro experiment for verification of the tandem shunt valve system: a novel method for treating hydrocephalus by flexibly controlling cerebrospinal fluid flow and intracranial pressure

OBJECT

The CSF shunt valve is a medical device whose main function is to regulate intracranial pressure and drain excess CSF. The authors have developed a new therapeutic method for treating hydrocephalus, namely the tandem shunt valve system, which has the potential of flexibly controlling the CSF flow rate and intracranial pressure in patients.

METHODS

The properties of the tandem system were verified by performing in vitro experiments. An in vitro system with a manometer was built to measure pressure and flow rates of water in open systems using the Codman Hakim Programmable Valve and the Strata adjustable pressure programmable valve. A single valve and 2 single shunt valves connected in series (the tandem shunt valve system) were connected to the manometer to check the final pressure.

RESULTS

Conventional single shunt valve systems require valve pressures to be set higher to slow down the CSF flow rate, which inevitably results in a higher final pressure. On the other hand, the tandem shunt valve system uses the combination of 2 valves to slow the CSF flow rate without increasing the final pressure.

CONCLUSIONS

The authors succeeded in experimentally demonstrating in vitro results of tandem systems and their effectiveness by applying a model to show that the valve with the higher pressure setting determined the final pressure of the entire system and the flow rate became slower than single shunt valve systems.

The syndrome of hydrocephalus in young and middle-aged adults (SHYMA)

OBJECTIVES

Currently, headache, nausea/vomiting, visual changes, and altered mental status are accepted as indications for the evaluation of hydrocephalus in children; while dementia, gait apraxia, and urinary incontinence remain indications in the elderly. The clinical presentation of hydrocephalus in young and middle-aged adults remains poorly described. Hence, middle-aged patients with mild gait, cognitive, or urinary symptoms unaccompanied by clear exam findings often remain undiagnosed and untreated.

METHODS

We report the clinical presentation, treatment, and outcomes of 46 adults (ages 16-55 years) presenting with congenital, acquired, or idiopathic hydrocephalus with imaging-documented ventriculomegaly and elevated CSF pressure.

RESULTS

Primary symptoms were related to gait (70%), cognition (70%), urinary urgency (48%), and headaches (56%). Eighty-four percent complained of impaired job performance. The exam findings were subtle or absent (no gait apraxia, minor gait changes in 42.9%, mildly abnormal Mini Mental State exams in only 14.3%, and incontinence in only 3.6%). Twenty-nine patients underwent ventriculoperitoneal (VP) shunting, and 11 endoscopic third ventriculostomy, of whom six subsequently required a VP shunt. Symptomatic improvement was observed in 93% of patients 16+/- 11 months after shunting (56% complete resolution, 37% partial resolution). Patients had been followed for their symptoms an average of 6 years (range, 1-30) prior to diagnosis.

DISCUSSION

We propose that there exists a clinically distinct syndrome of hydrocephalus in young and middle-aged adults (SHYMA) that comprises hydrocephalus of all etiologies. SHYMA is characterized by complaints of impaired gait, cognition, bladder control, and headaches, with a discrepancy between the prominence of symptoms and the subtlety of clinical signs. Despite the subtlety of clinical signs, CSF diversion treatment is effective at resolving symptomatology.

Seven years of clinical experience with the programmable Codman Hakim valve: a retrospective study of 583 patients

OBJECT

The goal of this study was to assess the value of the Codman Hakim programmable valve to settings in the range of 30 to 200 mm H2O. This valve can be adjusted noninvasively for cerebrospinal fluid (CSF) drainage.

METHODS

The authors conducted a single-center retrospective study of 583 patients (421 adults and 162 children) suffering from hydrocephalus of various causes (379 patients), normal-pressure hydrocephalus (174 patients), arachnoid cyst (14 patients), and pseudotumor cerebri (16 patients). In all cases a Codman Hakim programmable valve was implanted; in 82.8% of cases it was included during the patient's first shunt implantation. In 42.4% of the cases valve pressure adjustment was required at least once (mean number of adjustments 1.2, maximum 23). The patients' clinical status improved after 64.6% of pressure adjustments. Accidental resetting of opening pressure, other than that caused by magnetic resonance (MR) imaging, was uncommon. Because MR imaging caused resetting in 26.8% of cases in which it was used, it was deemed mandatory to obtain an x-ray film after MR imaging. Valve malfunction, blockage, or adjustment difficulties occurred in 2% of valves implanted, and nontraumatic subdural fluid collections were demonstrated in 5.1% of patients (13 of whom were treated by valve pressure adjustment alone). Five-year shunt survival was 53.1% for first-time shunt implantations. The shunt infection rate was 8.5% of valve implantations. Catheter-related complications and shunt-related infections were the main reasons for surgical revision and the major cause of shunt failure. At follow-up review, 97% of children and 90% of adults had improved.

CONCLUSIONS

Because one cannot know in advance which case will turn out to be complicated, the authors' preference is to use the Codman Hakim programmable valve for all conditions in which CSF should be drained.

Accuracy of intravascular microcatheter pressure measurements: an experimental study

Intravascular pressure measurements are considered useful for the monitoring and assessment of endovascular treatment effects in intracranial vascular malformations. Experimental data on the accuracy of these measurements are limited. A flow phantom with defined intraluminal pressures and pulsatility flow waveforms was used in this study. Microcatheters commercially available for neuroendovascular procedures (length 140-155 cm), with different outer (0.5-0.83 mm) and inner (0.3-0.53 mm) diameters, were introduced into the phantom in the direction of flow. In a static experiment, pressure values from 0 to 75 mmHg were applied, and in the dynamic part of the experiment mean pressure values from 25 to 65 mmHg, with a pulsatile amplitude from 70 to 170 mmHg were employed. In the static experiment, there was a linear relationship between the pressure values obtained through the microcatheters and the local transducer of the flow phantom. The pulsatile experiments showed increased damping of the pressure waveforms with decreasing inner diameter of the microcatheters. However, the mean pressure values remained accurate. This experimental study has shown that mean pressure values can be accurately measured through microcatheters from 0.3-0.5 mm inner diameter and more than 140 cm in length. In vivo pressure measurements during interventional procedures are therefore reproducible and can be used for monitoring of embolization effects in patients.

Chronic ("normal pressure") hydrocephalus in childhood and adolescence. A review of 16 cases and reappraisal of the syndrome

"Normal pressure" hydrocephalus (NPH) is generally considered to be a disorder of the adult and geriatric population. Only a few reports have described the possible occurrence of this condition in children. A series of 16 patients aged less than 20 years forms the basis of the present report. Among these 16 patients, 11 had a clearly identified etiologic factor and 7 had had a shunt previously implanted. The majority of patients exhibited at least two elements of the adult's triad of psychomotor retardation (14 cases) and/or psychotic-like symptoms (4 cases), gait anomalies (8 cases), and sphincter disturbances (3 cases). Six patients had their intracranial pressure (ICP) monitored. ICP values were estimated to be within the normal limits for age. All the 16 patients underwent shunting or shunt revision. Surgical results were as follows (mean follow-up 20 +/- 17.2 months): a good response to shunting was obtained in 12 cases ("cured": 5, improved: 7), while the other 4 patients failed to improve. It seems likely that associated parenchymal disorders have played a major role in therapeutic failures. In children showing ventricular dilation on computed tomographic (CT) analysis and a clinical picture of subtle psychomotor deterioration, it may be difficult to distinguish an active disorder of the CSF dynamics from "arrested hydrocephalus." Since intracranial manometry cannot be undertaken as a routine procedure, less invasive methods such as cerebrospinal fluid (CSF) tap test, psychometric, or urodynamic tests deserve special attention as reliable predictors of outcome after shunting. Because most patients undergo shunting without prior assessment of their CSF pressure, the term "chronic hydrocephalus" is proposed as an alternative designation to "NPH," since there is little argument for maintaining an instrumentally based definition of the syndrome.

Clinical experience with a new pressure-adjustable shunt valve

The pressure-adjustable valve system Codman Medos allows valve pressure adjustment in 18 steps between 30 and 200 mm H2O. A series of 90 patients, 15 children and 75 adults, who were shunted with this new programmable valve, is reported. Indication for shunt insertion were various types of hydrocephalus in 79 cases, malfunction of a medium pressure membrane valve shunt system in 9 cases and an arachnoid cyst and pseudotumour each in one case. The valve pressure was programmed prior to insertion to 200 mm H2O in the adults and according to age in children and was modified postoperatively according to the clinical course. Underdrainage with subdural fluid collections appearing in 5 patients could be managed by valve pressure adjustment alone in 2 cases. One malfunctioning of the valve mechanism was due to mechanical obstruction. At the time of follow-up, 7 to 29 months after operation, outcome was excellent in 64 patients, good with marked improvement but residual symptoms in 19 patients and unchanged in 7 patients. The possibility of adjusting the valve pressure to the patient's demands was frequently used in children and adult normal pressure hydrocephalus patients with satisfying clinical results.

Clinical experience with a pressure-adjustable valve SOPHY in the management of hydrocephalus

Seventy-four patients with hydrocephalus due to a variety of causes were treated with a cerebrospinal fluid (CSF) shunt, incorporating a recently developed pressure-adjustable valve SOPHY (PAVS). The PAVS may be changed percutaneously with the help of an externally applied magnet in order to select a high-, medium- or low-valve opening pressure, whenever the need for a change in pressure characteristics seems necessary to the neurosurgeon. The percutaneous pressure adjustment obviated up- or downgrading of a medium pressure position by surgical means in half of our patients during the follow-up time (up to 39 months; mean follow-up 16.7 months). In 66 patients (89%) decreased ventricle volume and improvement of the clinical sign of increased intracranial pressure were established. In 11 patients a valve or a catheter infection occurred; in 6 of these patients the valve had to be removed. Half of this group consisted of patients under 2 years of age. Significant technical complications related to the PAVS did not occur in our series but until a somewhat smaller PAVS is available, we cannot recommend its use in neonates or in small infants. In all other patients the PAVS is a very valuable instrument in the surgical management of hydrocephalus because it makes shunt revisions for inadequate valve pressure obsolete in individual patients.