Rhombencephalosynapsis as a cause of aqueductal stenosis: an under-recognized association in hydrocephalic children

Background

Rhombencephalosynapsis is a rare genetic aberration characterized by variable vermian hypoplasia/aplasia in conjunction with united cerebellar hemispheres. Genetic defects in the isthmic organizer at the mesencephalic–metencephalic junction are presumably responsible for the associated aqueductal stenosis.

Objective

We performed a retrospective review of 20 children with rhombencephalosynapsis to evaluate for and emphasize the association of aqueductal stenosis and hydrocephalus.

Materials and methods

We retrospectively reviewed the MR and CT images of 20 children (0–11 years old) with rhombencephalosynapsis encountered at two academic children’s hospitals. Rhombencephalosynapsis spectrum severity was graded based on pre-existing literature. We analyzed examinations for ventriculomegaly and degree of aqueductal stenosis. The collicular distances were measured from the collicular apices. Imaging studies were also analyzed for malformations of cortical and cerebellar development.

Results

Thirteen of the 20 children (65%) with rhombencephalosynapsis presented with clinical or imaging evidence of hydrocephalus and aqueductal stenosis, principally involving the caudal cerebral aqueduct. All children with aqueductal stenosis had collicular fusion. All six children with complete rhombencephalosynapsis had aqueductal stenosis. The cerebral aqueduct varied from normal to stenotic in children with incomplete rhombencephalosynapsis. Corpus callosum dysgenesis was present in four children.

Conclusion

Aqueductal stenosis in the setting of rhombencephalosynapsis is an under-recognized cause of noncommunicating hydrocephalus. Our findings support the hypothesis that a defect involving the common gene(s) responsible for the differentiation and development of both the roof plate and midline cerebellar primordium at the mesencephalon/first rhombomere junction may be responsible for the association of aqueductal stenosis and rhombencephalosynapsis.     

Neuropathology and immunohistochemistry of the brain-stem in neonates with congenital hydrocephalus: Comparative studies between aqueductal stenosis and Arnold-Chiari malformation

Neuropathological and immunohistochemical studies were done on the brain-stem of neonates who had congenital hydrocephalus with aqueductal stenosis or Arnold-Chiari malformation (ACM). The infants with aqueductal stenosis showed heterogeneity in their clinicopathological findings while the infants with ACM were relatively similar in neuropathological findings. There were prominent astrogliosis, decreased immunoreactivity with antisera to tyrosine hydroxylase and myelin basic protein in the periaqueductal area, and an increased reactivity with antiserum to substance P in the tegmentum of most patients with aqueductal stenosis and other malformations. In ACM, there was little gliosis in the tegmentum and periaqueductal area and minimal immunoreactivity of tyrosine hydroxylase, myelin basic protein and substance P. In both groups of cases, the cells in the periaqueductal region differ in neurotransmitter/neuromodulator immunoreactivity and degree of myelination reflecting a difference possibly in their maldevelopment.     

Experimental Hydrocephalus in Suckling Hamster Induced by Myxovirus Infection

Abstract This study was undertaken to elucidate the pathogenesis of the hydrocephalus and aqueductal stenosis induced by intracerebral mumps virus inoculation in suckling hamsters.
Mild ventricular dilatation became apparent after 5 days of inoculation. Focal denuding of the ependymal layer and subsequent aqueductal stenosis were observed by 14 days after inoculation. The virus antigen was detected not only in the ependymal cells and choroid plexus, but also in some neurons in the cerebral cortex, hippocampus, midbrain and cerebellum. In the cerebral aqueduct, the orderly arrangement of the cilialy clusters was destroyed on the 5th day after inoculation. After 10 days, proliferation of GFAP positive cells was noticed around the cerebral aqueduct and subsequently caused aqueductal stenosis. In the advanced state of hydrocephalus, the cerebellum was displaced downward and showed an elongated, atrophic and sleevelike structure similar to the Arnold-Chiari malformation. It was suggested that the extensive damage of the ependymal cilia may account for early ventricular dilatation, and subsequent aqueductal stenosis with glial proliferation is the main cause of the advanced hydrocephalus. It has not yet been determined whether the mumps virus can pass through the human placenta or not. If it can, however, our results strongly suggest that mumps virus infection in the human fetus will cause congenital hydrocephalus.     

Aqueductal stenosis presenting as isolated tremor: case report and review of the literature

Essential tremor is rare in children, particularly in the absence of a significant family history. We report the case of a child with compensated hydrocephalus secondary to aqueductal stenosis whose sole presenting symptom was tremor. An otherwise healthy 6-year-old male developed a fine hand tremor, which over the course of 4 years both increased in intensity and spread to involve the lower limbs and head. After an MRI had confirmed hydrocephalus due to aqueductal stenosis, the patient underwent an endoscopic third ventriculostomy. His tremor improved markedly, but did not completely resolve. Occult hydrocephalus should be considered in the differential diagnosis of new-onset tremor. Progression of the tremor should halt with treatment of the hydrocephalus, and clinical improvement may be seen.     

Bobble-head doll syndrome

A new case of Bobble-head doll syndrome with aqueductal stenosis is presented in a 14 year-old boy. Ventriculocisternostomy performed 8 years after the onset of the abnormal movement resulted in moderate reduction of the head bobbling. Twenty-two cases were found in a review of the literature. In all cases there was a chronic slowly progressive hydrocephalus with usually a cyst of the third ventricle; aqueductal stenosis was less frequent. When recorded, psychomotor development was impaired. Treatment is neurosurgical. Pathogenesis remains unknown.     

Visual pathway tumors and hydrocephalus

The authors evaluated the impact of hydrocephalus on the clinical picture of children with visua pathway tumor (VPT) with or without neurofibromatosis (NF).Charts of children with VPT treated in the authors' center since 1985 were retrospectively reviewed, and those with hydrocephalus were selected and summarized. Thirty-five children with VPT were found, of whom 20 had NF.Hydrocephalus was found in 4 children with NF (20% ) and in 5 without NF (33.3% ). In 6 ofthechildren, ventricular dilatation with signs of acute increased intracranial pressure already existed at the time of diagnosis and the hydrocephalus was shunted at this time. In the other 3 children, all with NF,the hydrocephalus resulted from slowly developing aqueductal stenosis, leading in 2 to severe visual acuity deterioration. The results suggest that in children with VPT and NF, hydrocephalus, and especially hydrocephalus resulting from aqueductal stenosis, is more frequent than in the general population of NF patients, and less frequent than in VPT patients without NF. The possibility of the indolent development of hydrocephalus should be borne in mind while following children with NF. The optic nerve, when already involved with a glioma, is more vulnerable to increased pressure. Thus, in children with VPT and NF, any ventricular dilatation should lead to a consideration of early shunting.     

VISUAL PATHWAY TUMORS AND HYDROCEPHALUS

The authors evaluated the impact of hydrocephalus on the clinical picture of children with visua pathway tumor (VPT) with or without neurofibromatosis (NF).Charts of children with VPT treated in the authors' center since 1985 were retrospectively reviewed, and those with hydrocephalus were selected and summarized. Thirty-five children with VPT were found, of whom 20 had NF.Hydrocephalus was found in 4 children with NF (20% ) and in 5 without NF (33.3% ). In 6 ofthechildren, ventricular dilatation with signs of acute increased intracranial pressure already existed at the time of diagnosis and the hydrocephalus was shunted at this time. In the other 3 children, all with NF,the hydrocephalus resulted from slowly developing aqueductal stenosis, leading in 2 to severe visual acuity deterioration. The results suggest that in children with VPT and NF, hydrocephalus, and especially hydrocephalus resulting from aqueductal stenosis, is more frequent than in the general population of NF patients, and less frequent than in VPT patients without NF. The possibility of the indolent development of hydrocephalus should be borne in mind while following children with NF. The optic nerve, when already involved with a glioma, is more vulnerable to increased pressure. Thus, in children with VPT and NF, any ventricular dilatation should lead to a consideration of early shunting.     

Long-term outcome for endoscopic third ventriculostomy alone or in combination with choroid plexus cauterization for congenital aqueductal stenosis in African infants

Object The authors have previously reported on the overall improved efficacy of endoscopic third ventriculostomy (ETV) combined with choroid plexus cauterization (CPC) for infants younger than 1 year of age. In the present study they specifically examined the long-term efficacy of ETV with or without CPC in 35 infants with congenital aqueduct stenosis treated at CURE Children's Hospital of Uganda during the years 2001-2006. Methods Infants with congenital aqueductal stenosis were treated during 2 distinct treatment epochs: all underwent ETV alone, and subsequently all underwent ETV-CPC. Prospectively collected data in the clinical database were reviewed for all infants with an age < 1 year who had been treated for hydrocephalus due to congenital aqueductal stenosis. Study exclusion criteria included: 1) a history or findings on imaging or at the time of ventriculoscopy that suggested a possible infectious cause of the hydrocephalus, including scarred choroid plexus; 2) an open aqueduct or an aqueduct obstructed by a membrane or cyst rather than by stenosis; 3) severe malformations of the cerebral hemispheres including hydranencephaly, significant segments of undeveloped brain, or schizencephaly; 4) myelomeningocele, encephalocele, Dandy-Walker complex, or tumor; or 5) previous shunt insertion. The time to treatment failure was analyzed using the Kaplan-Meier method to construct survival curves. Log-rank (Mantel-Cox) and Gehan-Breslow-Wilcoxon tests were used to determine whether differences between the 2 treatment groups were significant. Results Thirty-five patients met the study criteria. Endoscopic third ventriculostomy alone was performed in 12 patients (mean age 4.7 months), and combined ETV-CPC was performed in 23 patients (mean age 3.5 months). For patients without treatment failure, the mean and median follow-ups were, respectively, 51.6 and 48.0 months in the ETV group and 31.2 and 26.4 months in the ETV-CPC group. Treatment was successful in 48.6% of the patients who underwent ETV alone, as accurately predicted by the Endoscopic Third Ventriculostomy Success Score (ETVSS), and in 81.9% of the patients who underwent ETV-CPC (p = 0.0119, log-rank test; p = 0.0041, Gehan-Breslow-Wilcoxon test; HR 6.42 [95% CI 1.51-27.36]). Conclusions Combined ETV-CPC is significantly superior to ETV alone for infants younger than 1 year of age with congenital aqueductal stenosis. The fact that the outcome for ETV alone was accurately predicted by the ETVSS suggests that these results are applicable in developed countries.     

Congenital intracerebral teratoma: a rare differential diagnosis in newborn hydrocephalus

Congenital hydrocephalus is caused by a broad spectrum of underlying disorders. In the majority of cases it is due to aqueductal stenosis and other distinct congenital anomalies, like Arnold-Chiari malformation. Nevertheless, in the differential diagnosis rare conditions such as cerebral malignancies must also be considered. We present two cases of congenital intracerebral teratoma as a differential diagnosis in congenital obstructive hydrocephalus. A teratoma is suggested when a rapidly growing hydrocephalus with a central calcified and vascularized mass is found sonographically. Regular cerebral structures usually cannot be detected. Early diagnosis in such cases is of clinical importance as the prognosis of congenital intracerebral teratoma is generally very poor. Received: 22 May 1996 Accepted: 10 August 1996     

Congenital chylothorax in siblings

We describe two cases of congenital chylothorax in siblings with important differences from previously described familial cases. Our findings support the likelihood of an autosomal recessive inheritance in some cases of this condition, rather than X-linked recessive inheritance, which has also been suggested. Autopsy findings from one of these cases and others previously described suggest that the pathophysiological mechanisms involved may be variable.     

Congenital hydrocephalus internus and aqueduct stenosis: aetiology and implications for genetic counselling

Genetic counselling in families with congenital hydrocephalus internus (CHI) in combination with aqueduct stenosis (AS) is often difficult due to an uncertain aetiology. We present a series of 35 patients with CHI and AS focusing on the aetiology and presumed recurrence risk for siblings. In 13 patients (37.1%) a genetic aetiology was identified with an increased recurrence risk for siblings. The relative frequency of patients with X-linked hydrocephalus in our sample was in accordance with the literature (2/35), but was more frequent in other diseases with Mendelian inheritance. Conclusion In addition to the well-known X-linked and autosomal recessive forms of aqueduct stenosis with hydrocephalus, this malformation can occur in other diseases with Mendelian inheritance. This finding is of considerable importance for genetic counselling and prognosis. Received: 29 May 1998 / Accepted in revised form: 25 August 1998     

Intraventricular neurocysticercus cyst(s) in Indian children

Eleven cases of intraventricular neurocysticercosis were managed over a 10-year period. All patients presented with features of hydrocephalus. In 9 cases the cysts were blocking the cerebrospinal fluid (CSF) pathway resulting in hydrocephalus. The 4 cases of lateral ventricular cyst had communicating hydrocephalus, while 2 of these had asymmetrical ventriculomegaly. Two of 4 cases had more than one cyst. One of 4 children with lateral ventricular cyst had narrowing of the foramen of Monro causing asymmetrical hydrocephalus. Following cyst removal, CSF diversion was not required in 6 cases, while 5 required CSF diversion despite removal of their cysts in 4 of 5. One patient had a cyst at the aqueductal inlet and he was managed by shunt and albendazole therapy. Thus, we managed 6 of our cases with excision of the cysts obstructing the CSF pathway, and in 4 cases excision of cysts with ventriculoperitoneal shunt was adequate.     

The prognosis of children with hydrocephalus and congenital heart disease

The association of congenital hydrocephalus and heart disease in children is infrequent, but may present considerable dilemmas in management. This report describes the treatment and prognosis of 11 children with both clinical problems. There were 5 males and 6 females. Hydrocephalus occurred following aqueductal stenosis in 5 children and the Dandy-Walker malformation in 3. Three children were diagnosed with idiopathic hydrocephalus. Ten children underwent cerebrospinal fluid diversion procedures for control of hydrocephalus. Five children received pharmacological therapy for cardiac disease; 4 children required surgical correction. Two children died from medical conditions; 2 families declined treatment. Follow-up from 2 to 7 years in the remaining 7 children demonstrated moderate or severe neurodevelopmental disability in 5. One child at 2 years of age showed borderline developmental disability while 1 child is developing normally at 10 years of age. Overall the occurrence of symptomatic hydrocephalus and heart disease in the perinatal period resulted in mortality or neurodevelopmental disability in 9/11 children.     

Idiopathic hydrocephalus in adolescence]

BACKGROUND: Decompensation of chronic idiopathic hydrocephalus can occur at every age, but seems to be rather frequent in the middle of the second decade. From this observation, the question arises, whether or not in these cases a special manifestation of hydrocephalus occurs and, should the situation arise, whether this finding might influence the discussion about pathogenesis. METHODS: We give some casuistic material about six hydrocephalic patients who became symptomatic between their 12th and 16th year of life. RESULTS: All of these patients showed a tri-ventricular appearance of hydrocephalus as well as radiological signs of chronicly elevated intracranial pressure, while clinical signs and symptoms differed considerably. These findings are linked to the discussion of the pathogenesis of so-called aqueductal stenosis. CONCLUSIONS: Whenever, after normal development in childhood, symptoms like increasing headache, poor concentration, dizziness or disturbances of gait appear during puberty, X-ray diagnosis of the skull is recommended. If it shows the signs of chronic elevated intracranial pressure, further investigations are necessary.     

Hydatid cyst of the ambient cistern radiologically mimicking an arachnoid cyst

Hydatid cysts of the posterior fossa are extremely rare. Intracranial hydatid cysts are more common in children and occur more frequently in the supratentorial space. A 7-year-old boy was admitted to the emergency department because of intense headache, nausea, vomiting, and progressive drowsiness that developed within the period of a week. On radiological examination a round, 2.5 × 2.5-cm cystic lesion appeared in the ambient cistern and caused hydrocephalus as a result of extrinsic aqueductal stenosis. The cyst was successfully removed using the puncture, aspiration, irrigation, and resection technique via an infratentorial-supracerebellar approach with the patient in the sitting position. The authors here described an unusual case of a hydatid cyst in the left ambient cistern with hydrocephalus due to extrinsic aqueductal stenosis, which seems to be the first such case in the literature. Hydatid cyst may be considered in the differential diagnosis of arachnoid cysts of the quadrigeminal cistern to determine which surgical procedure to perform and to avoid unexpected complications.     

Non-tumoral neonatal hydrocephalus. Results of surgical treatment in the first month of life]

Two hundred eight patients with non-tumoral congenital hydrocephalus underwent CSF shunting below the age of one month. Ultrasonography was the most frequently utilized tool; hydrocephalus was recognized during pregnancy in 52% of the cases. Hydrocephalus was associated with myelomeningocele in 97 infants; in 38 subjects ventricular dilation was secondary to aqueductal stenosis. Post-hemorrhagic and post-infective hydrocephalus accounted for only 20 and 13 cases respectively. At the follow-up observation, a normal psychomotor development was recorded in 67.3% of the cases. Seventeen patients died. CSF infection was the most common cause of death (41%); in 6 patients the exitus was determined by the natural evolution of congenital associated malformations. Shunt revision did not influence the morbidity and the mortality significantly. On the other hand, CSF infections appeared to influence the prognosis negatively. In our experience, the prognosis of hydrocephalus operated on in the first month of life does not differ from that of hydrocephalus operated on late in life.     

Shunt revision in hydrocephalus

Objective : A retrospective analysis of 50 hydrocephalic children having a minimum follow-up of 6 months was carried out to see their etiology, clinical features, complications, incidence of shunt revisions, outcome and the variation from their Western counterparts.Methods : Clinical features, image findings and treatment of all the cases were recorded from their discharge summaries. Record of shunt revision complications and outcome was maintained by the principal author. The data of all the cases were analyzed.Results : The age of children varied from 1 month to 12 yr (mean 2.2 yr). The most common etiology of hydrocephalus was aqueductal stenosis in 18 (36%) children. Post infective hydrocephalus, either of post-tubercular meningitis (TBM) or following bacterial meningitis, remained the cause in 15 children (30%). Congenital TORCH infection was responsible for 3 cases of hydrocephalus making infective etiology as the cause in 18 (36%) cases. Intra 4^th ventricular neurocysticercus cyst caused blockade of CSF pathway in 2 children. 15 out of 50 children required shunt revision, either due to infection (8,16%) or shunt obstruction (7, 14%). Multiple shunt revisions were required in 2 children only. These revisions were required due to infection, obstruction or malfunction of the shunt.Conclusions : Infective etiology is responsible for hydrocephalus in significant number of children (36%). The possibility of TORCH infection, as a cause of hydrocephalus should be considered even amongst the children of screened mothers during antenatal check-up. Pure intra 4^th ventricular neurocysticercus cysts (without intraparenchymal cyst), though rare, can manifest with outlet obstruction. Incidence of shunt revision using Chhabra’s medium pressure shunt is very high in children at an average follow up of 1.6 yr. Post infective hydrocephalus is a major cause of delayed milestones, contributing to mental retardation.     

Longitudinal comparison of diffusion tensor imaging parameters and neuropsychological measures following endoscopic third ventriculostomy for hydrocephalus

The authors report the case of a 25-month-old boy who underwent endoscopic third ventriculostomy (ETV) for hydrocephalus resulting from aqueductal stenosis. The patient's recovery was monitored longitudinally and prospectively using MR diffusion tensor imaging (DTI) and formal neuropsychological testing. Despite minimal change in ventricle size, improvement in the DTI characteristics and neurodevelopmental trajectory was observed following ETV. These data support the use of DTI as a biomarker to assess therapeutic response in children undergoing surgical treatment for hydrocephalus. In the patient featured in this report, DTI appeared to provide more information regarding postoperative neurodevelopmental outcome than ventricle size alone.     

Regional Ependymal Upregulation of Vimentin in Chiari II Malformation,Aqueductal Stenosis,and Hydromyelia

Vimentin, glial fibrillary acidic protein (GFAP) and S-100 protein were studied by immunocytochemistry in the ependyma of patients with Chiari II malformations, congenital aqueductal stenosis, and hydromyelia. Paraffin sections of brains and spinal cords of 16 patients were examined, 14 with Chiari II malformations, most with aqueductal stenosis and/or hydromyelia as associated features, and 2 patients with congenital aqueductal stenosis without Chiari malformation. Patients ranged in age from 20-wk gestation to 48 years. The results demonstrated: 1) in the fetus and young infant with Chiari II malformations, congenital aqueductal stenosis, and hydromyelia, vimentin is focally upregulated in the ependyma only in areas of dysgenesis and not in the ependyma throughout the ventricular system; 2) GFAP and S-100 protein are not coexpressed, indicating that the selective upregulation of vimentin is not simple maturational delay; 3) vimentin upregulation also is seen in the ependymal remnants of the congenital atretic cerebral aqueduct, not associated with Chiari malformation; 4) in the older child and adult with Chiari II malformation, vimentin overexpression in the ependyma becomes more generalized in the lateral ventricles as well, hence evolves into a nonspecific upregulation. The interpretation from these findings leads to speculation that it is unlikely that ependymal vimentin is directly involved in the pathogenesis of Chiari II malformation, but may reflect a secondary upregulation due to defective expression of another gene. This gene may be one of rhombomeric segmentation that also plays a role in defective programming of the paraxial mesoderm for the basioccipital and supraoccipital bones resulting in a small posterior fossa. This interpretation supports the hypothesis of a molecular genetic defect, rather than a mechanical cause, as the etiology of the Chiari II malformation.     

Unusual mesencephalic developmental venous anomaly causing obstructive hydrocephalus due to aqueductal stenosis

Developmental venous anomalies (DVAs) are benign vascular malformations that rarely become symptomatic. They are anatomical variations of the venous drainage system and most are incidentally discovered. Mechanical (obstruction and compression of cerebral and neural structures) and flow-related pathological mechanisms have been described in rare cases of symptomatic DVAs. The authors present the case of a 10-month-old boy with a mesencephalic DVA compressing the aqueduct and causing occlusive hydrocephalus. Endoscopic inspection confirmed the venous malformation causing aqueductal stenosis. The authors successfully performed endoscopic third ventriculostomy, resulting in decrease in the size of the ventricles. At the 6-month follow-up after surgery, the patient had significantly progressed in his psychomotor development. One year postsurgery the patient is doing fine, with no neurological or developmental deficits.