Congenital Obstructive Hydrocephalus Research Articles

Audiological findings of shunt-treated hydrocephalus in children

47 hydrocephalic children (mean age 10.4 years) were examined on average 7.9 years after initial shunting. The etiology of hydrocephalus was classified into 5 groups as follows: perinatal intraventricular hemorrhage 19, congenital obstructive hydrocephalus 15, intracranial cysts 5, severe intracranial anomalies 4 and central nervous system infections 4 children. Audiological examination included pure-tone audiometry, tympanometry, registration of stapedius reflex thresholds and adaptation. A sensorineural high-frequency hearing loss was found in 18 (38%) of 47 examined shunt-treated hydrocephalic children, and 11 of the losses could be classified as the retrocochlear type. The differences of the mean hearing thresholds between the etiological groups of childhood hydrocephalus were minimal.

Ventricular diverticulum.

A ventricular diverticulum was found on computed tomography in six out of 25 cases of congenital obstructive hydrocephalus. In all six cases, the diverticulum was located on the medial wall of the trigone. In three cases, it was restricted to the tentorial hiatus with a recognisable superior cerebellar cistern (small). In two cases, it occupied the tentorial hiatus without a recognisable cistern (medium). The remaining case had a diverticulum extending into the posterior fossa that caused cerebellar ataxia (large). In all patients, the diverticulum regressed after ventriculo-peritoneal shunt. The characteristics of the computed tomograms, the clinical significance and the pathogenesis of this phenomenon are discussed.

Correction of congenital hydrocephalus in utero I. The model: Intracisternal kaolin produces hydrocephalus in fetal lambs and rhesus monkeys

In the fetus with congenital hydrocephalus, obstruction to the flow of cerebrospinal fluid (CSF) results in ventricular dilation and neurologic impairment. Decompression of the obstructed ventricles before birth may ameliorate the damage and allow normal development to proceed. Although appealing, this pathophysiologic rationale has not been adequately tested because a satisfactory fetal model has not been available. We have developed a model of obstructive hydrocephalus in the fetal lamb and rhesus monkey by injecting kaolin into the cisterna magna through the posterior atlanto-occipital membrane early in the last trimester. Preliminary studies injecting silicone oil were unsuccessful. The development of fetal ventriculomegaly was followed using prenatal ultrasonography. Massive hydrocephalus developed in six sheep, three liveborn at term and three stillborn after premature vaginal delivery, and in 2 fetal rhesus monkeys. All treated animals had external signs of hydrocephalus with marked cranial enlargement. Neuropathologic examinations demonstrated fibrosis of the leptomeninges and subarachnoid spaces around the fourth ventricle. Dilation of the lateral and third ventricles resulted, with attenuation of the cerebral white matter. On histologic examination, the grey matter was relatively well preserved, while the white matter was severely attenuated. This model mimics the clinical and pathologic picture seen in human infants and should allow us to study the pathophysiology of congenital obstructive hydrocephalus and the efficacy and feasibility of its correction in utero.

Cerebral oxidative metabolism in perinatal post-hemorrhagic hydrocephalus.

Survivors of perinatal intraventricular hemorrhage often develop a distinct clinical syndrome characterized by hydrocephalus and biochemical abnormalities in cerebrospinal fluid. The authors investigated six neonates with post-hemorrhagic obstructive hydrocephalus in order to identify cerebral metabolic disturbances responsible for the hypoglycorrhachia observed in this disorder. Lactic acid concentraions and lactate/pyruvate ratios in ventricular fluid were significantly elevated in infants with post-hemorrhagic hydrocephalus compared with the values in five with congenital (non-hemorrhagic) obstructive hydrocephalus. Comparable degrees of ventricular dilatation and intracranial hypertension were present in the two groups. There is evidence that neither residual cellular elements in ventricular fluid nor a disrupted blood-CSF barrier can fully explain the observed alterations in ventricular-fluid glucose, lactate or lactate/pyruvate ratios. It is suggested that when periventricular hemorrhage occurs, the associated cerebral ischemia leads to focal anaerobic glycolysis and increased glucose requirement. With inadequate cerebral glucose glycolysis and increased glucose requirement. With inadequate cerebral glucose delivery from the blood, glucose diffuses into the brain from the ventricular fluid, resulting in hypoglycorrhachia. Cerebral lactic acid production is enhanced, which accumulates in ventricular fluid in the presence of ventricular obstruction.

The subarachnoid space in congenital obstructive hydrocephalus

✓ The leptomeninges of 52 patients who died with a diagnosis of congenital or early acquired obstructive hydrocephalus were examined microscopically. In each case a well-developed subarachnoid space was present and in no cases were the leptomeninges congenitally absent. Thus, the commonly held belief that the subarachnoid space may fail to develop in congenital obstructive hydrocephalus was not supported by this study. Pathological findings in the leptomeninges were common, however, and were generally related to the following factors: the severity of the hydrocephalus, the duration of the hydrocephalus, the success or failure of surgical management, past infection (both intrauterine and postnatal), and subarachnoid hemorrhage. The type of ventricular obstruction did not seem to be a significant factor. Certain embryological considerations raised by the current findings are discussed.

The subarachnoid space in congenital obstructive hydrocephalus. 1. Cisternographic findings.

✓ In congenital obstructive (internal) hydrocephalus, a coexisting obstruction of the subarachnoid space is frequently present. In the current study, cisternographic evidence is provided that considerable re-expansion of the subarachnoid space may occur after temporary ventricular drainage. These findings suggest that in at least some cases of obstructive hydrocephalus, the subarachnoid space is potentially open but mechanically compressed. The therapeutic significance of re-expanding the subarachnoid space by temporary ventricular shunts is discussed.