Hydrocephalus is appointed as one of intractable diseases by the Ministry of Health and Welfare of Japan. The research committee on intractable hydrocephalus has proposed the definition, clinical classification and diagnostic criteria of hydrocephalus in the CT and MRI era. To establish the diagnosis of congenital hydrocephalus, we set up inclusion and exclusion criteria, in addition to supplements which are useful for its diagnosis. In this symposium, we will report and discuss the results obtained so far in the research committee.

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Several pediatric cases of hydrocephalus after mumps virus infection, have been reported. These cases are thought to be caused by ependymitis due to mumps virus infection. Clinical cases of congenital hydrocephalus possibly caused by intrauterine mumps virus infection are also accumulating. However, it has not yet been made clear whether mumps virus can pass through the human placenta and cause hydrocephalus. Our experimental studies demonstrated that mumps and parainfluenza virus type 3 could induce hydrocephalus by destructive ependymal infection in suckling hamsters, when they were inoculated intracerebrally or intraperitoneally. However, the transplacental infection of these viruses was extremely rare. These results show that myxoviruses such as mumps and parainfluenza virus may have a strong affinity to ependymal cells, and then they cause resultant ependymal destruction. Therefore, when the placenta is impaired so severely that these viruses are able to pass through the placental barrier, maternal infection wouldcause the hydrocephalus to the infant.

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A nation-wide survey on congenital hydrocephalus, including secondary hydrocephalus occurring within one year after birth, was carried out in 1988. The number of patients with congenital hydrocephalus treated during the previous one year was estimated to be 3, 200-3, 500 throughout Japan. The number of new cases of this disease which occurred during the year was calculated to be 800. This indicates a rate of 0.58 per 1, 000 live births. Clinico-epidemiologic features were compared with regard to three subjects listed below.
(1) The difference between the epidemiologic profile of term and preterm infants with hydrocephalus was investigated. As for etiology, the incidences of primary hydrocephalus and hydrocephalus complicated by Arnold-Chiari malformation type IL and meningocele were significantly higher in term infants than in preterm infants. It was estimated that about 30% of the hydrocephalus in preterm infants and only 7.7% in term infants occurred as a consequence of intracranial hemorrhage. The degree of neurological impairment and the mortality rate were higher in preterm infants than term infants.
(2) The changing panorama of infantile hydrocephalus in Japan was investigated comparing the epidemiologic data of four groups according to the birth year. As for pregnancy period, preterm infants with hydrocephalus were gradually increasing recently. Hydrocephalus secondary to intracranial hemorrhage was increasing and that secondary to intracranial infection was decreasing. The rate of shunt malfunction was decreasing significantly.
(3) Clinico-epidemiologic features of intractable hydrocephalus based on the diagnostic criteria of the researchcommittee was investigated comparing intractable with non-intractable groups. The patients in the intractable group were severely handicapped in mental and physical development with CNS malformations, brain damage, or frequent operations. Secondary hydrocephalus showed poorer prognosis than primary hydrocephalus. Among the primary hydrocephalus patients, severe CNS malformations, such as Dandy-Walkercyst, holoprosencephaly, porencephaly and hydranencephaly were the risk factors for poor outcome. In secondary hydrocephalus, intracranial infection and intracranial hemorrhage were risk factors for severe handicaps. The patients operated within 2 months from the birth or within 1 month from the onset showed better outcome. The patients with shunt malfunction or post-operative infection showed inevitably poor prognosis.

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The brainstems of children with congenital aqueductal stenosis or posthemorrhagic hydrocephalus were examined histologically and immunohistochemically. Congenital aqueductal stenosis occurs in various stages of CNS development, and is associated with microdysplasia and maturational abnormalities including astrogliosis, loss of neurons (tyrosine hydroxylase reactivity) and decreased myelination (myelin basic protein reactivity) in the periaqueductal gray matter. In Arnold- Chiari type II malformation there are few dysplasias, and poor development of glial and neural components in the periventricular brainstem. On the other hand, there are marked astroglial proliferation and defects of neural fibers in the periaqueductal area in children with posthemorrhagic hydrocephalus. Fibrous proliferation in aqueduct makes stenosis, and its pathogenesis seems to be caused by edema, ependymal cell desquamation, microglial proliferation and astrogliosis in parts of hemosiderin deposition. Thus, different CSF circulation disturbance and neural transmission disorder of the brainstem may develop with occurrence time, etiology or secondary complication of hydrocephalus.

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The intracranial pressure buffering capacity in 8 infants with hydrocephalus of varying etiologies were assessed by measuring opening pressure (PO), pressure volume index (PVI), outflow resistance (Ro), and absorption pressure (Abs) of cerebrospinal fluid before and after placement of a ventriculoperitoneal (V-P) shunt. The correlation among changes in these parameters, size of the lateral ventricles, and neurological status were compared simultaneously. Consequently, the significance of assessing the intracranial pressure buffering capacity in connection with an indication for V-P shunt was discussed.

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We investigated factors relating to intellectual outcome in 21 patients with infantile hydrocephalus. Every patient had received V-P shunt operation before, and was followed up for at least one year. The intellectual development was evaluated with multivariate analysis, and was found to be contributed independently by etiology of hydrocephalus, age at onset, association of epilepsy, and shunt troubles. Thus, those with congenital hydrocephalus, onset after the neonatal period, epilepsy or shunt troubles were related to poor intelligence, while those with acquired hydrocephalus, onset during the neonatal period, and without epilepsy were related to favorable outcome. Among the patients, early onset was correlated with early surgical intervention, which also may have been a determining factor.
We also conducted multivariate analysis with the results of somatosensory evoked potentials (SEPs) and visual evoked potentials (VEPs) as objective variables. For both SEPs and VEPs, etiology was considered to be the most important, but other factors also contributed considerably, including CT scan findings, current developmental status, and association of congenital anomalies and epilepsy. Clinical pictures of patients with infantile hydrocephalus apparently are very complicated, being determined by multiple factors, but these cerebral evoked potentials are thought to be useful in the evaluation and follow-up of the patients with infantile hydrocephalus.

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Seventy cases of neonatal hydrocephalus were analyzed regarding the prognosis using the newly developed concept, namely “Perspective Classification of Congenital Hydrocephalus [PCCH]”. The results revealed that the prognosis of premature-neonatal hydrocephalus is not necessarily poor even in the early periods of the neuronal maturation (PCCH Stage-II/III). It was suggested that the major underlying pathophysiological difference beteween the premature-neonatal and fetal hydrocephalus in the same stage of neuronal maturation is the intracranial pressure dynamics. It was concluded that the fetal hydrocephalus should be treated in the early period of neuronal maturation as the form of neonatal hydrocephalus to avoid the insult of such high intracranial pressure dynamics in utero.

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In order to clarify the mechanism of the effect of sodium valproate (VPA) on absence seizures, we performed sleep polygraph recordings in 10 patients with typical absence. VPA was effective in six cases (group A), partially effective in two (group B), and ineffective in two (group C). In 5 of 9 cases, the tonic sleep components were abnormal. In 4 cases, the percentage of slow wave sleep increased before administration of VPA, and did not change remarkably by its administration. In group A and B, twitch movements (TM), one of the phasic sleep components detected in the mentalis muscle on surface EMG, decreased or were unchanged after administration of VPA, especially during the REM period. In contrast, TM increased in group C. We speculate that the changes of TM (especially in the REM periods) after administration of VPA are well related to its effectiveness. Since TMs are thought to be controlled by the nigrostriatal dopaminergic pathway, the different response of basal ganglia to VPA among cases with absence epilepsy would have some relation to the different effectiveness of VPA in controlling seizures.

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Experimental production of congenital hydrocephalus was undertaken by inoculating mumps virus into pregnant hamsters intravenously or intraplacentally. When the mumps virus was inoculated intravenously on the 8th, 10th, 12th, or 14th day of gestation, some fetuses were aborted and those which could come to term did not develop hydrocephalus after birth. Offsprings from the mothers, which had had intraplacental inoculation on the 14th day of gestation, showed ventricular dilatation in about 28%. Histological examination revealed inflammatory infiltration on the surface of ependymal layers, subependymal edema and microglial activation in the underlying ependyma of the aqueduct. These findings were thought to have resulted from ependymitis caused by mumps virus. The transplacental infection of mumps virus is considered to be extremely rare. However, in such conditions as the placental barrier is impaired, mumps virus will possibly pass through the placenta, and will cause hydrocephalus to the infant.

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We experienced a 6-month-old girl with infantile spasms who had localized cerebral lesion detected by ^99mTcHMPAO-SPECT. She was born vaginally after a full term uncomplicated deliverywith a birth weight of 3, 100g. She developed emprosthotonic spasms with series formation and EEG showed asymmetric periodic hypsarrhythmia which was predominant in the right hemisphere. While MRI could not detected any focal lesion, ^99mTcHMPAO-SPECT disclosed hypoperfusion at the right anterior temporal and frontal areas. Although vitamin B6, clonazepam and sodium valproate were administered with no remarkable benefit, the treatment with ACTH-Z or carbamazepine resulted in cessation of spasms and improvement of the EEG findings. Consequently, the study with ^99mTcHMPAO-SPECT was useful to clarify the pathology of infantile spasms, and we concluded that a patient with localized cerebral lesions should be given carbamazepine.

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We reported a case of a fifteen-year-old boy with metatropic dysplasia. He showed short-limbed dwarfism at the age of 1 year and 2 months. Roentgenograms of the bone revealed generalized platyspondyly, enlargement of the epiphyseal-metaphyseal regions of long bones and halberd- shaped pelvis. Scoliosis progressed and he evolved to short-trunk dwarfism. When he was 10 years old, he developed gait disturbance gradually due to muscle weakness of lower extremities. He was examined at the age of 15 years. Motor nerve conduction velocity was reduced to 21 m/sec in left median nerve and 18.5 m/sec in left peroneus nerve. Needle EMG showed neurogenic pattern. We performed sural nerve biopsy and obtained histopathological findings. Fiber density of myelinated axons decreased. Electron microscopic examination revealed onion bulb formation surrounding a myelinated fiber and a storage in the rough-surfaced endoplasmic reticulum of Schwann cell. These inclusions were similar to those of cartilage of his long bone. We supposed that the neuropathy would have relation to this bone dysplasia.

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A patient with Lennox-Gastaut syndrome developed an unusual feature of periodic spasms (PS), intermixed with tonic seizures. At age 14, she began to have unilateral seizures on awaking, followed by series of spasms Each spasm consisted of rotation of the head to the left and global muscle contraction of the whole body lasting for 0.5-1 second. Ictal EEGs revealed diffuse high voltage slow waves (HVSW), sometimes superimposed upon by diffuse low voltage fast activity, which was related to the increase of muscle activity following the spasms. When the duration of the fast activity on EEG became longer than 2 seconds, the peculiar seizures consisting of combination of asymmetrical spasms and tonic seizures occurred. It is speculated that the fast activity superimposed on HVSW seen in PS represents a transition from PS to tonic seizures.

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We report a case of juvenile Parkinson's disease which initially presented as bulbar incoordination at the age 12. The condition was characterized by dystonia of the upper extremities. The patient was a 14-year-old female. The patient's main symptoms were bulbar dysfunction. Resting and action tremor, akinesia, stoopedposture, distortion of the trunk, dystonia of the upper extremities, oculogyric crisis, and impairment of the postural reflex were seen. The bulbar symptoms were considered to be attributable to circumoral uncoordination. Although L-dopa decarboxylase inhibitors were markedly effective in alleviating these symptoms, anadverse reaction due to the agent was observed as the form of oral dyskinesia. Since the changes in blood concentration of L-dopa after administration of the agent was clearly reflected in the surface electromyogram, we concluded that this diagnostic procedure is useful in evaluating the therapeutic efficacy of L-dopa.

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[in Japanese]

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[in Japanese]

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