Choroid plexus and cerebrospinal fluid production.

Acute progressive hydrocephalus occurred in 76 rhesus monkeys undergoing ventricular obstruction 2 to 6 months after choroid plexectomy and was only slightly less pronounced than in 73 nonplexectomized animals with similar ventricular obstructions. The composition of cerebrospinal fluid after choroid plexectomy was essentially normal. Experiments with ventricular perfusion techniques indicate only a slight reduction in cerebrospinal fluid production after choroid plexectomy. Thus, the choroid plexus is probably not the sole or even the major source of cerebrospinal fluid within the primate ventricular system.

Cerebrospinal fluid production by the choroid plexus and brain.

The production of cerebrospinal fluid and the transport of (24)Na from the blood to the cerebrospinal fluid were studied simultaneously in normal and choroid plexectomized rhesus monkeys. Choroid plexectomy reduced the production of cerebrospinal fluid by an average of 33 to 40 percent and the rate of appearance of (24)Na in the cerebrospinal fluid and its final concentration were proportionately reduced. In both normal and plexectomized animals, (24)Na levels were found to be markedly greater in the gray matter surrounding the ventricles and in the gray matter bordering the subarachnoid space. That sodium exchanges in these two general areas of the brain may be linked to the formation of the cerebrospinal fluid is discussed here.

Unreliability of combined pneumoencephalography and scinticisternography.

Evidence is presented that the radiopharmaceutical flow in cerebrospinal fluid may be significantly altered by pneumoencephalography. When both pneumoencephalography and scinticisternography are required in the same patient, the studies should be performed separately rather than as a combined procedure.

Nerve endings in the choroid plexus of the fourth ventricle of the rat: electron microscopic study.

Nerve fibers and nerve endings in the fourth ventricle choroid plexus of the adult rat were studied with the electron microscope. Nerve endings were found at two sites within the plexus: (1) on the smooth musculature of the blood vessels (i.e. vascular nerve endings), and (2) in the stroma between the choroidal epithelium and the fibrovascular core. Ultrastructurally all fibers were of the efferent type, and the majority were unmyelinated. No ganglion cell bodies were identified. Fibers ending in relation to the smooth muscle of the vessels presumably control the calibre of these vascular channels. Although the role of the stromal nerve endings is as yet unknown, these fibers may influence epithelial cell functions and thus indirectly regulate choroidal cerebrospinal fluid production.

Stimulation of brain metabolism by perinatal cocaine exposure.

Cocaine was administered to neonatal rats between day 1 and day 10, which in the rat falls within a developmental stage roughly equivalent to the third trimester of gestation in human fetuses. At 60 days of age, when the animals had reached adulthood, cerebral glucose metabolic patterns were examined by quantitative autoradiography. Adult females, but not adult males, exhibited significant increases in metabolic activity in a number of cerebral structures, including those of the limbic, motor, and sensory systems. Many of these structures are the same as those which are excited in adult rats by the acute administration of cocaine and other stimulants. These data suggest that cocaine consumption during pregnancy may constitute a risk factor leading to long-term alterations in brain function in the adult.

Hemangioendothelioma of frontal bone.

Radiographic studies disclosed that a 5-year-old girl with proptosis and inferior displacement of her left globe had a lytic lesion in the superior orbital rim. Tissue removed at the time of the initial biopsy was not sufficiently distinctive for a definitive diagnosis, but microscopic examination of residual tumor clearly established the diagnosis of hemangioendothelioma of the frontal bone. Electron microscopic studies demonstrated that the vascular structures, which resembled endothelium, contained many thin microfilaments and mitochondria and scattered dense bodies. Each vessel was surrounded by a prominent mantle of pericytes.

Acute hydrocephalus after aneurysmal subarachnoid hemorrhage.

The incidence and clinical aspects of acute hydrocephalus were examined in 200 patients with recently ruptured intracranial aneurysms. The following conclusions were reached: Acute hydrocephalus is an important complication of aneurysmal subarachnoid hemorrhage that occurs in approximately 20% of all cases and exhibits an incidence that tends to parallel clinical grade (Grade I, 3%; Grade II, 5%; "Good" Grade III, 21%; "Bad"Grade III, 40%; Grade IV, 42%; Grade V, 26%). Impaired consciousness leading to a general downgrading of clinical status was the predominant clinical finding (93%), but neither this nor other nonspecific signs of increased intracranial pressure were distinguishable from the effects of the precipitating hemorrhage. The computed tomographic signs of acute hydrocephalus are distinctive and consist of selective ballooning of the frontal horns, rostral-caudal enlargement of the cerebral ventricles, and a halo of periventricular hyperdensity (edema) that evolves in sequence with ventricular changes. The treatment of choice is external ventricular drainage, which results in prompt and often dramatic improvement in approximately two-thirds of the patients.

Resolution of chronic cluster headache after resection of a tentorial meningioma: case report.

Cluster headache is almost always idiopathic, but, in rare cases, associated intracranial lesions have been found. We describe a patient who had chronic cluster headache for more than 20 years. The headache immediately resolved upon resection of a tentorial meningioma. Prior reports of cluster headache as a manifestation of structural disease are briefly reviewed. In the patient described, the pain was referred from the right tentorium cerebelli to the right side of the face, in accordance with reported studies on the subjective localization of pain referred from posterior fossa structures. The accompanying abnormalities of autonomic function may have been mediated by central autonomic reflexes that are also involved in the pathogenesis of idiopathic cluster headache.

Treatment of rhinocerebral mucormycosis with intravenous interstitial, and cerebrospinal fluid administration of amphotericin B: case report.

IMPORTANCE: Rhinocerebral mucormycosis is extremely difficult to treat. Approximately 70% of patients are poorly controlled diabetics, and many of the remainder are immunocompromised as a consequence of cytotoxic drugs, burn injuries, or end-stage renal disease. Despite standard treatment consisting of surgical debridement and the intravenous administration of amphotericin B, rhinocerebral mucormycosis is usually a fatal disease. CLINICAL PRESENTATION: We describe the case of a 16-year-old male patient with juvenile onset diabetes mellitus who presented with fever, right-sided hemiparesis, and dysarthria. Axial view computed tomography revealed abscess formation in the left basal ganglia and frontal lobe, which was proven by stereotactic biopsy to contain Rhizopus oryzae. INTERVENTION: Intravenous administration of amphotericin B (30-280 mg/dose) was begun on the day of admission. On hospital Day 20, after the occurrence of frank abscess formation, the lesion was aggressively debrided. Despite these therapies, there was neurological deterioration characterized by the development of hemiplegia and aphasia. Sequential computed tomographic scans enhanced with contrast medium demonstrated progressively enlarging lesions. Ommaya reservoirs were placed into the abscess cavity and the frontal horn of the contralateral lateral ventricle. The patient was then treated with intracavitary/interstitial injections of amphotericin B during the course of 80 days and three doses of intraventricular amphotericin B. Clinical and radiographic improvement was achieved after treatment. Two years after the initial diagnosis, magnetic resonance imaging of the brain showed no evidence of disease and an examination revealed a neurologically intact and fully functional patient. CONCLUSION: We conclude that with an infection as morbid as rhinocerebral mucormycosis, it is advisable to use surgical debridement and all available routes for delivering amphotericin B to infected cerebral parenchyma, which include intravenous, intracavitary/interstitial, and cerebrospinal fluid perfusion pathways.

Spontaneous movement of bullets in the brain.

We report two patients in whom bullets in the brain migrated into the adjacent lateral ventricle and moved freely as a consequence of gravity. A review of the literature suggests that the spontaneous migration of intracerebral bullets is influenced by cerebral softening, the specific gravity of the bullet compared with brain tissue, and the sink function of the cerebral ventricles. In patients undergoing the surgical removal of intracerebral or intraventricular bullets, it is recommended that an x-ray be obtained after the final positioning of the head.

Clinicopathological correlations in syringomyelia using axial magnetic resonance imaging.

Axial magnetic resonance (MR) images of non-neoplastic spinal cord cavities were reviewed in 115 patients with otherwise complete neurological and neuroradiological findings. The variations in axial morphology revealed three distinct cavitary patterns. These patterns were as follows: 1) symmetrically enlarged central cavities (28 patients); 2) central cavities that expanded paracentrally in one or more focal areas (36 patients); and 3) eccentric cavities that were off-center, frequently irregular, and sometimes associated with myelomalacia (51 patients). The radiological patterns of spinal cord cavitation correlated well with recently reported histopathological findings that distinguish simple dilations of the central canal, dilations of the central canal that dissect paracentrally, and primary cavitations of the spinal cord parenchyma (extracanalicular syringes). Like histologically confirmed central canal syringes, MR-defined central cavities were associated with pathogenic factors that affect the dynamics of the cerebrospinal fluid, including hindbrain malformations, hydrocephalus, and extramedullary obstructive lesions. Eccentric cavities resembled extracanalicular syringes and occurred typically with disorders that damage spinal cord tissue (e.g., trauma, infarction, meningitis/arachnoiditis, spondylosis/disc herniation, radiation necrosis, and transverse myelitis). Analysis of clinical findings at the time of MR imaging established the following correlations. 1) Symmetrically enlarged central cavities were asymptomatic or produced nonspecific neurological signs. 2) Central cavities that expanded paracentrally were associated with segmental signs referable to the paracentral component. 3) Eccentric cavities produced various combinations of long tract and segmental signs that could usually be related to the level, side, and specific quadrant of spinal cord cavitation.(ABSTRACT TRUNCATED AT 250 WORDS)

Anatomical basis of syringomyelia occurring with hindbrain lesions.

Hindbrain lesions that distort or compress the cervicomedullary junction are commonly associated with syringomyelia. As a basis for discussing pathogenetic mechanisms, the upper end of the central canal of the spinal cord was examined histologically in six aborted fetuses and 14 adults dying of natural causes; the results were correlated with magnetic resonance images in 40 normal subjects. The central canal of the medulla, which extends from the cervicomedullary junction to the fourth ventricle, was found to migrate dorsally, elongate in dorsoventral diameter, and dilate beneath the tip of the obex to form a large, everted aperture. This opening communicates directly with the subarachnoid space through the foramen of Magendie and is indirectly continuous with the main body of the fourth ventricle. In adults, the aperture of the central canal is located approximately 1.0 cm below the tela choroidea inferior and 3.5 cm below the midpoint of the fourth ventricle. Analysis of magnetic resonance imaging scans in 45 patients with syringomyelia and simple hindbrain lesions revealed two patterns of cavity formation: 1) lesions that obstructed the upper end of the central canal or its continuity with the subarachnoid space produced a noncommunicating type of syringomyelia; and 2) lesions that obstructed the basilar cisterns or the foraminal outlets of the fourth ventricle produced a communicating type of syringomyelia (hydromyelia) in association with hydrocephalus. Evidence is presented that syrinxes occurring with hindbrain lesions are not caused by a caudal flow of cerebrospinal fluid from the fourth ventricle into the central canal of the spinal cord.

Dysesthetic pain in patients with syringomyelia.

Dysesthethic pain is a common complaint of patients with syringomyelia, traumatic paraplegia, and various myelopathic conditions. Because cavitary lesions of the spinal cord can be defined with good resolution by magnetic resonance imaging, syringomyelia provides a potential model for examining anatomic correlates of central pain. In this study, a syndrome of segmental dysesthesias, characterized by burning pain, hyperesthesia, and a variable incidence of trophic changes, was described by 51 of 137 patients (37%) with syringomyelia at the time of clinical presentation. Complete magnetic resonance scans, including axial images, demonstrated extension of the syrinx into the dorsolateral quadrant of the spinal cord on the same side and at the level of pain in 43 of 51 patients (84%). Surgical treatment of syringomyelia resulted in the relief or improvement of dysesthetic pain in 22 of 37 patients (59%), but 15 patients (41%) reported no improvement or an intensification of pain despite collapse of the syrinx. Postoperative dysesthetic pain was often a disabling complaint that responded poorly to medical therapy, including analgesics, sedatives, antiepileptics, antispasmodics, and anti-inflammatory agents. In most cases, there was a gradual improvement of symptoms, although six patients continued to complain of pain 24 to 74 months postoperatively. Prompt but transient relief was achieved in two of two patients with regional sympathetic blocks, and prolonged relief was achieved in one patient by stellate ganglionectomy. We conclude that painful dysesthesias can be caused by a disturbance of pain-modulating centers in the dorsolateral quadrant of the spinal cord and have certain causalgia-like features that respond in an unpredictable way to surgical collapse of the syrinx.

Surgical treatment of syringomyelia based on magnetic resonance imaging criteria.

The treatment of syringomyelia includes many surgical options. We report a retrospective study of 65 patients with cavitary lesions of the spinal cord in whom the results of magnetic resonance imaging were used to develop specific treatment strategies. Intramedullary cavities were classified into three general types: 1) communicating syrinxes, which occurred with hydrocephalus and were anatomically continuous with the 4th ventricle (9 patients); 2) noncommunicating syrinxes, which were separated from the 4th ventricle by a syrinx-free segment of spinal cord (42 patients); and 3) atrophic syrinxes, which occurred with myelomalacia (14 patients). Noncommunicating syrinxes were further subdivided according to type: Chiari II malformations with hydrocephalus (5 patients), Chiari I malformations without hydrocephalus (11 patients), extramedullary compressive lesions (12 patients), spinal cord trauma (6 patients), intramedullary tumors and infections (6 patients), and multiple sclerosis (2 patients). Of the 65 patients, 39 underwent surgical treatment for progressive symptoms. Syrinxes occurring with hydrocephalus were treated empirically with a ventriculoperitoneal shunt. Excellent results were achieved in 7 of 7 patients with communicating syrinxes and in all 5 patients with Chiari II malformations. Two approaches were used in the treatment of syrinxes occurring with Chiari I malformations: Posterior fossa decompression improved symptoms but did not reduce syrinx size in 2 of 3 patients. In the third patient and in 3 patients who were not treated with decompression, shunting from the syrinx to the cerebellopontine angle cistern collapsed the cavity and resolved symptoms over the interval of follow-up (average follow-up, 1.5 years). Excision of extramedullary obstructions at the rostral end of noncommunicating syrinxes resulted in collapse or disappearance of the cavity in 6 of 7 patients. The remaining patient was treated effectively by a syringocisternal shunt. In all 4 patients with posttraumatic syringomyelia, good results were achieved by a spinal or syringocisternal shunt. Syrinxes associated with intramedullary masses were managed by biopsy or excision of the causal lesion and appropriate adjunctive therapy (6 patients). Patients with atrophic syrinxes were not operated upon except to relieve symptoms referrable to the causal lesion (4 patients). Recurrent syrinxes were not encountered in the 35 surviving patients over an average follow-up of 2.5 years. It is concluded that syringomyelia is a complex pathological disorder with several mechanisms of pathogenesis that requires a number of different treatment strategies.

Intramedullary pressure in syringomyelia: clinical and pathophysiological correlates of syrinx distension.

OBJECTIVE: The pathophysiological effects of syrinx distension are incompletely understood. Although it is generally assumed that the accumulation of fluid within syrinx cavities can contribute to neurological dysfunction, there are no reports describing intramedullary pressure in syringomyelia. The purpose of the current study was to measure syrinx pressures in patients with progressive clinical deterioration and to correlate these data with neurological deficits and intraoperative physiological findings. METHODS: Intramedullary fluid pressure was measured manometrically in 32 patients undergoing syrinx shunting procedures. The data were correlated with syrinx morphology, intraoperative somatosensory evoked potentials, laser Doppler measurements of local spinal cord blood flow (six patients), and neurological findings before and after syrinx decompression. RESULTS: Syrinx pressures recorded under atmospheric conditions ranged from 0.5 to 22.0 cm H2O (mean = 7.7 cm). There was a significant elevation of the cardiac pulse (mean = 0.7 cm H2O) and the respiratory pulse (mean = 1.1 cm H2O) that was consistent with raised cerebrospinal fluid pressure. Syrinx pressures decreased to subatmospheric levels after surgical drainage. In 18 of 24 patients with predrainage somatosensory evoked potential abnormalities, syrinx decompression produced a consistent reduction of N20 latencies (mean change = 0.49 ms +/- 0.094 SE right, P = 0.002; 0.61 ms +/- 0.089 SE left, P = 0.001) and a similar but less consistent increase in N20 amplitudes (mean change = 0.17 mV +/- 0.103 SE right, P = 0.115; 0.31 mV +/- 0.097 SE left, P = 0.027). Measurements of local spinal cord blood flow revealed very low baseline values (mean = 12.2 arbitrary units +/- 13.9 standard deviation), which increased to intermediate levels (mean = 144.7 arbitrary units +/- 42.6 standard deviation) after syrinx decompression. Patients with syrinx pressures greater than 7.7 cm H2O tended to have more rapidly progressive symptoms, exhibited greater improvements after shunting, and had a higher incidence of postoperative dysesthetic pain. CONCLUSION: The current study is the first to measure intramedullary pressure in a human disease. Evidence is presented that distended syringes are associated with varying levels of raised intramedullary pressure that can accentuate or induce neurological dysfunction by the compression of long tracts, neurons, and the microcirculation. Symptoms referrable to raised intramedullary pressure are potentially reversible by syrinx decompression.

Chiari I malformation redefined: clinical and radiographic findings for 364 symptomatic patients.

OBJECTIVE: Chiari malformations are regarded as a pathological continuum of hindbrain maldevelopments characterized by downward herniation of the cerebellar tonsils. The Chiari I malformation (CMI) is defined as tonsillar herniation of at least 3 to 5 mm below the foramen magnum. Increased detection of CMI has emphasized the need for more information regarding the clinical features of the disorder. METHODS: We examined a prospective cohort of 364 symptomatic patients. All patients underwent magnetic resonance imaging of the head and spine, and some were evaluated using CINE-magnetic resonance imaging and other neurodiagnostic tests. For 50 patients and 50 age- and gender-matched control subjects, the volume of the posterior cranial fossa was calculated by the Cavalieri method. The families of 21 patients participated in a study of familial aggregation. RESULTS: There were 275 female and 89 male patients. The age of onset was 24.9+/-15.8 years (mean +/- standard deviation), and 89 patients (24%) cited trauma as the precipitating event. Common associated problems included syringomyelia (65%), scoliosis (42%), and basilar invagination (12%). Forty-three patients (12%) reported positive family histories of CMI or syringomyelia. Pedigrees for 21 families showed patterns consistent with autosomal dominant or recessive inheritance. The clinical syndrome of CMI was found to consist of the following: 1) headaches, 2) pseudotumor-like episodes, 3) a Meniere's disease-like syndrome, 4) lower cranial nerve signs, and 5) spinal cord disturbances in the absence of syringomyelia. The most consistent magnetic resonance imaging findings were obliteration of the retrocerebellar cerebrospinal fluid spaces (364 patients), tonsillar herniation of at least 5 mm (332 patients), and varying degrees of cranial base dysplasia. Volumetric calculations for the posterior cranial fossa revealed a significant reduction of total volume (mean, 13.4 ml) and a 40% reduction of cerebrospinal fluid volume (mean, 10.8 ml), with normal brain volume. CONCLUSION: These data support accumulating evidence that CMI is a disorder of the para-axial mesoderm that is characterized by underdevelopment of the posterior cranial fossa and overcrowding of the normally developed hindbrain. Tonsillar herniation of less than 5 mm does not exclude the diagnosis. Clinical manifestations of CMI seem to be related to cerebrospinal fluid disturbances (which are responsible for headaches, pseudotumor-like episodes, endolymphatic hydrops, syringomyelia, and hydrocephalus) and direct compression of nervous tissue. The demonstration of familial aggregation suggests a genetic component of transmission.

The third circulation revisited.

The author reviews modern information concerning the formation, flow and functions of the cerebrospinal fluid. Particular attention is given to the lymphatic-like features of the third circulation and to its importance as an internal milieu for nervous tissue.

Stenosis of the central canal of the spinal cord following inoculation of suckling hamsters with reovirus type I.

The central canal of the human spinal cord is partially or completely occluded in the vast majority of individuals by the early years of adult life. The authors describe an experimental lesion following virus-induced ependymitis that bears a striking resemblance to the condition in man. Suckling hamsters were inoculated with 0.06 ml of 10(-3) infectivity titer of reovirus type I between the 2nd and 5th days of life. The pathological events consisted of necrotizing ependymitis, healing of the ependyma by gliovascular scarring, and obstruction of narrow bottlenecks such as the central canal. Histological findings were characterized by disorganization of the ependyma, formation of ependymal rosettes and microtubules, subependymal gliovascular scarring, and intracanalicular gliosis. These features are the same as those encountered clinically and provide strong evidence that stenosis of the central canal in man is a pathological lesion involving ependymal injury and scarring.

Direct cardiac shunt for hydrocephalus of infancy and childhood. Technical note.

The authors describe a technique for direct cardiac shunting in which an adult-size ventriculoatrial catheter is coiled in an intrathoracic Silastic pouch and implanted in infants with hydrocephalus. In three patients so treated, serial chest films have shown progressive uncoiling of the catheter over a follow-up interval of 6 to 14 months.

Noncommunicating syringomyelia following occlusion of central canal in rats. Experimental model and histological findings.

This report describes a new and reliable technique for producing experimental noncommunicating syringomyelia. In 30 rats, 1.2 to 1.6 microliters of kaolin was microinjected into the dorsal columns and central gray matter of the spinal cord at C-6. The inoculations caused transient neurological deficits in four animals and no deficits in 26 animals. Within 24 hours, kaolin and polymorphonuclear leukocytes entered the central canal and drained rostrally. The clearance of inflammatory products induced a proliferation of ependymal cells and periependymal fibrous astrocytes, which formed synechiae and obstructed the canal at the level of injection and at one or more levels up to C-1. In 22 animals followed for 48 hours or longer, the upper end of the central canal became acutely dilated and formed an ependyma-lined syrinx that enlarged to massive dimensions within 6 weeks. The rostral syrinxes did not communicate with the fourth ventricle and were not associated with hydrocephalus. The histological findings in acute noncommunicating syringomyelia were characterized by progressive stretching and thinning of the ependyma, elongation of intracanalicular septae, and the formation of periependymal edema. After 3 weeks, there was progressive compression of the periependymal tissues associated with stretching of axons, fragmentation of myelin sheaths, and the formation of myelin droplets. These findings and the sequence in which they evolved were identical in most respects to those occurring in acute and subacute noncommunicating hydrocephalus.