The effect of intravenous fluid replacement on the response to mannitol in experimental cerebral edema: an analysis of intracranial pressure, serum osmolality, serum electrolytes, and brain water content

Albino rabbits that had undergone a cryogenic insult over the left parieto-occipital cortex were analyzed for serum osmolality, serum electrolytes, brain water content, and intracranial pressure (ICP) following either a baseline infusion of intravenous (i.v.) fluid (45 mL total) for 3 hours or above-maintenance isotonic saline (73.5 +/- 12 mL or 90.5 +/- 1.5 mL) and mannitol therapy. The subgroups were compared amongst themselves and to sham-operated controls. Serum osmolality was elevated in the higher-dose mannitol subgroup compared with maintenance i.v. fluids subgroup (1 g/kg/h vs 1 g/kg/3 h; p < 0.05), accompanied by an insignificant reduction of serum sodium. A significant reduction in brain water in the injured left hemisphere was seen following high-dose mannitol in the subgroup that received less i.v. (maintenance) fluids than the group that received above-maintenance i.v. fluids (p < 0.025). No reduction in brain water was seen in the subgroup that received above-maintenance i.v. fluids (non-treated groups). Reduction of ICP was not found in the lower mannitol dose group. We conclude that the ability of mannitol to reduce cerebral edema is related to the total amount of i.v. fluid replacement. This implies that the amount of i.v. crystalloid fluid that is administered to patients with cerebral edema and raised ICP requiring mannitol for control needs to be carefully monitored.

Carboplatin is effective therapy for young children with progressive optic pathway tumors: a Pediatric Oncology Group phase II study

The Pediatric Oncology Group conducted a phase II study to evaluate the activity of carboplatin in children 5 years or younger with progressive optic pathway tumors (OPTs). Of the 51 patients accrued to this study, 1 was not eligible because the child was older than 6 years. Fifty patients were eligible and had either neuro-imaging or symptomatic evidence of progressive OPTs. Twenty-one of 50 had evidence of neurofibromatosis type I (NF-1). Therapy consisted of carboplatin 560 mg/m2 at 4-week intervals. Patients with stable disease or better after two courses were continued on therapy for 18 months or until progressive disease. Of the 50 eligible children, 39 had stable disease or better, and 34 completed the 18-month therapy. Our data are sufficient to conclude that the proportion of objective responses (complete, partial, or minor response or stable disease) exceeded 30% (P < 0.00001), and the approximate 95% confidence interval estimate of the objective response rate was 0.665 to 0.895. Twenty-one patients went off protocol because of progressive disease. Fifteen patients progressed during the 18-month therapy, and 6 patients progressed after completing therapy. Six children died with progressive disease. Major toxicities were neutropenia and thrombocytopenia, and 3 children experienced allergic reactions. Carboplatin is active and safe for the treatment of young children with progressive OPTs. The addition of other potentially active drugs may further increase the event-free survival for these children.

The treatment of Candida albicans shunt infections

Cerebrospinal fluid shunting procedures are performed for the treatment of hydrocephalus. Infection of ventriculoperitoneal shunts may create significant clinical management issues in these patients. The majority of these infections are bacterial, but occasionally a Candida albicans shunt infection may occur. We report two patients who acquired Candida albicans shunt infection and discuss their clinical presentation, management, and successful outcome. The treatment with or without removal of the shunt and the correct dosage and route of administration of the antifungal agents is not well documented. The dilemma of treatment of Candida albicans shunt infections in these patients and review of the limited literature on this subject are the subjects of this report.

Pediatric head injury: what is unique and different

Pediatric head injury has unique issues that make patient management and outcome different from that of adult head injury. The differences may be classified in various categories. The mechanism of injury may be that of accidental or non-accidental trauma, and in the latter, repeated secondary insults will affect patient management and outcome. Age related aspects will determine a greater or lesser degree of craniocervical junction injuries (disproportionate cranial size to trunk in infancy and early childhood). Other factors are potential underlying congenital anomalies, physiological factors (cerebrovascular reactivity and blood flow), differing support systems needed from that of adults for neuro imaging and specialized medical, nursing and allied health care support. Pediatric rehabilitation and educational needs and goals are different to that of adult head injury. Neurological recovery in non-accidental trauma is uniformly poor, when compared to accidental trauma. Pediatric head injury has unique requirements in early field management, hospital management, rehabilitation and educational needs, as well as community re-entry programmes.

Cutaneomeningospinal angiomatosis (Cobb syndrome) with tethered cord

A newborn presented with a skin-covered lumbar mass with a subcutaneous hemangioma and on a magnetic resonance image (MRI) revealed a tethered spinal cord with a local mass. The mass had signal characteristics compatible with a lipoma. An initial diagnosis of a lipomeningocele with tethered cord was made, and the patient underwent surgical exploration and subtotal resection of the mass. A follow-up MRI revealed that the cord was still tethered, but an additional mass was present. The initial mass with signal characteristics of lipomatous tissue was accompanied by a low-signal mass in the lumbosacral canal, ventral to the cord, and bilateral enlargement of the foramina at the lumbosacral level. Because of a concern for an intraspinal tumor, a second operative intervention was performed. Multiple biopsies of the mass inside the spinal cord, the nerve roots and at the level of the foramina revealed angiomas that had similar pathology in all the specimens. A partial resection of the masses and a release of the tethered cord was performed by sectioning the thickened filum terminale. The diagnosis of Cobb's syndrome was made. The unique association of a tethered cord and the Cobb syndrome is reported here.

Suprasellar germinoma associated with Cushing's disease and diabetes insipidus in a child

Cushing's disease is described in a child with a suprasellar germinoma. The patient presented with all of the classic stigmata of Cushing's disease as well as diabetes insipidus, but after surgical resection of the lesion was found to have pathology incompatible with an ACTH-secreting tumor. We believe that this is the first reported incidence of Cushing's disease associated with a suprasellar germinoma. The implications of this unusual association are discussed.

Spinal hamartomas: a distinct clinical entity

OBJECT

Congenital spinal hamartomas are defined as tumors of well-differentiated mature elements situated in an abnormal location. In this report, the authors document the clinical and pathological features of spinal hamartomas in 10 patients.

METHODS

Ten patients presented with midline dorsal malformations at birth, initially diagnosed as teratomas or myelomeningoceles. The locations of the masses were variable: two were located in the thoracic region, four at the thoracolumbar junction, two in the lumbar region, one at the lumbosacral junction, and one in the sacral region. The results of the neurological examination were normal in nine patients. All but one mass had intact skin and seven had palpable bone components. Neuroimaging studies revealed widening of the spinal canal, heterotopic bone located dorsally in some patients, and varying degrees of involvement of the intraspinal contents. During surgery, six patients were found to have involvement of the spinal cord or cauda equina. The pathological characteristics of the masses included three or more of the following: bone, cartilage, synovial membrane, urinary tract tissue, cyst wall, yellow or brown fat, and nerves. The well-differentiated cellular elements, which formed mature structures, along with the absence of primitive cellular components and neoplastic characteristics are more consistent with a diagnosis of hamartoma than teratoma.

CONCLUSIONS

In this series, the authors describe a lesion that is overt on physical examination, yet can have occult spinal canal involvement. Complete neurosurgical evaluation is essential to provide appropriate treatment and prognosis.

The Surgical Isolation Bubble System and patient temperature during ventriculoperitoneal shunt insertion in preterm and term newborn infants

The ultraclean air environment in a plastic isolator has been used in cerebrospinal fluid shunt interventions in an attempt to reduce the incidence of infections. The blower that maintains a continuous flow of filtered air in the operative field may create body temperature changes. In this study we assessed the temperature before, during and at the end of the operation in preterm and term infants in whom ventriculoperitoneal shunts were being placed. There were 12 preterm and 9 term infants. The duration of the operative intervention ranged from 25 to 50 min. In the preterm infants the mean initial temperature was 36.2+/-0.2 degrees C, and the final temperature was 35.7+/-0.2 degrees C. This difference was not significant. The initial temperature in the term infants was 36.26+/-0.2 degrees C, and the final temperature was 35.9+/-0.3 degrees C, also not significantly different. The surgical isolation bubble system does not alter the temperature of preterm and term infants significantly during ventriculoperitoneal shunt procedures performed within the operative times seen in this study.

Ventriculoperitoneal shunts for hydrocephalus: a focus group discussion on the selection of shunt systems in pediatrics. A report of the Pediatric Neurosurgery Research Group meeting, December 1992

As part of the Continuing Quality Improvement Study, phase I, 12 pediatric neurosurgeons participated in a discussion group to respond to the various issues related to selection of ventriculoperitoneal shunt systems in their practice. It was estimated that between then all the 12 participants performed approximately 1200 shunt procedures per year in the USA. The data were analyzed by grid and fish-bone charts as part of the data collection. All 12 participants indicated that they preferred a reservoir in the shunt system, 8 of them indicating that they preferred this for a manual test of the system. Three indicated that they did not routinely manipulate the system for testing. One participant stated that he placed a reservoir within the shunt system primarily to prevent migration of the ventricular catheter. Nine neurosurgeons indicated that they employed cranial valves in their shunt systems, and three indicated that they employed slit-end peritoneal catheters only. In reference to Delta valves, nine participants indicated that they employed them on occasions. In reference to pressure in the valve system, one participant employed high-pressure valves at all times, five employed only medium-pressure systems, and the remaining six always employed low-pressure valves. All 12 neurosurgeons stated that the incidence of symptomatic slit ventricle in their practices was between 1% and 5%, in their mind irrespective of the system used. It was concluded that any form of ventriculoperitoneal shunt, with or without valves, with slit-end valves or cranial valves seemed to work equally well in the hands of a dedicated pediatric neurological surgeon.(ABSTRACT TRUNCATED AT 250 WORDS)

Human tails and associated spinal anomalies

Human tails have been described intermittently in the literature, typically as isolated cases with varying forms of malformation. Attempts have been made to differentiate "true" tails from "tail-like" appearances. Unless identified, underlying occult spinal disorders, mass effect, and/or tethering of the spinal cord may lead to progressive neurologic damage. We report three patients with "tails" and the associated spinal anomalies.

Impairment in shifting attention in autistic and cerebellar patients

MRI and autopsy evidence of early maldevelopment of cerebellar vermis and hemispheres in autism raise the question of how cerebellar maldevelopment contributes to the cognitive and social deficits characteristic of autism. Compared with normal controls, autistic patients and patients with acquired cerebellar lesions were similarly impaired in a task requiring rapid and accurate shifts of attention between auditory and visual stimuli. Neurophysiologic and behavioral evidence rules out motor dysfunction as the cause of this deficit. These findings are consistent with the proposal that in autism cerebellar maldevelopment may contribute to an inability to execute rapid attention shifts, which in turn undermines social and cognitive development, and also with the proposal that the human cerebellum is involved in the coordination of rapid attention shifts in a fashion analogous to its role in the coordination of movement.

Cephalocele detection in utero: sonographic and clinical features

Sonographic and clinical features of 26 fetal cephaloceles were reviewed retrospectively. The most frequent reason for referral was elevated maternal serum alpha-fetoprotein levels. The smallest lesion identified was 0.4 x 0.5 cm (frontal, at 20 weeks); the largest was 9.0 x 10.0 cm (frontal, at 27 weeks). Twenty-four of 26 cephaloceles were detected on prenatal ultrasound examination; in 13 of these, more than 50% of the intracranial contents were exteriorized. Fifteen of 24 cephaloceles detected prenatally had a sulcal pattern (identified between 16 and 36 weeks' gestation); five were solid without a sulcal pattern (identified between 13 and 21 weeks' gestation), three were cystic, and one underwent a change in appearance from solid at 21 weeks to cystic at 26 weeks. Other cranial features were evaluated and included visible skull defect, seen in 23/24 (96%), ventriculomegaly, in 6/26 (23%); microcephaly, in 12/24 (50%); beaked tectal plate, in 6/16 (38%); and flattened basiocciput, in 9/24 (38%). Of the 26 cases, 14 had normal amniotic fluid volume, five had oligohydramnios and seven had polyhydramnios. Fetuses with oligohydramnios had the highest incidence of concurrent fetal abnormalities; four of five fetuses (80%) with oligohydramnios had additional structural abnormalities. In the overall population, a very high incidence of other abnormalities was found; 17/26 (65%) cases showed additional abnormalities, some of which were not detected by ultrasound. Five fetuses had Meckel-Gruber syndrome and three had amniotic band syndrome. Only one of the 18 karyotypes obtained was abnormal (trisomy 18). Survival was very poor; only two of the eight who survived until birth are currently living.

Postoperative chemotherapy and delayed radiation in infants and very young children with choroid plexus carcinomas. The Pediatric Oncology Group

Eight infants with choroid plexus carcinomas were treated with surgery, prolonged postoperative chemotherapy and delayed radiation. The results suggest that some infants with choroid plexus carcinomas can be successfully treated with multimodality therapy, even allowing children with less than a gross total resection to have prolonged disease-free intervals.

Syringomyelia of the distal spinal cord in children

The syndrome of syringomyelia in children has been extensively described in the literature and is said to most commonly involve the cervical and thoracic spinal cord. We here present two children who had an unusual constellation of signs and symptoms, characterized by bowel and bladder disturbance in one, and in the other with intermittent paroxysmal severe pain and cramping and flexion of the lower extremities accompanied at times by episodes of incontinence. Both were found on magnetic resonance imaging (MRI) to have a syrinx localized to the most distal cord. This was not associated with Arnold-Chiari malformation, trauma, tumors or any other form of spinal dysraphism. Both patients underwent placement of a syringomyelia-peritoneal shunt with complete resolution of symptomatology. Postoperative MRI revealed a complete collapse of the syringomyelia cavity. In those children presenting with bowel or bladder disturbances, associated or not with intermittent pain, flexion attacks, or cramping in the lower extremities, the differential diagnosis of a syringomyelia of the distal cord should be part of the clinical considerations.

Distal spinal cord pathology in the VATER association

Herein the authors report the pathology of six cases of VATER association and tethered spinal cord that underwent operative intervention for removal of lipomas of the conusfilum terminale and/or release of the tethered cord. In five of the six patients, the excised filum terminale consistently showed excessive mature adipose tissue, normal blood vessels, small myelinated nerve fibers, and fibrous connective tissue. One patient had mature lobulated adipose tissue and vessels only. It is concluded that patients with the VATER association who present with distal spinal cord pathology consistently have abnormal involution of the filum terminale, the hallmark being an abnormal collection of mature fat, thickening of the filum, and extension of the fat into the conus medullaris.

Impairment in shifting attention in autistic and cerebellar patients

MRI and autopsy evidence of early maldevelopment of cerebellar vermis and hemispheres in autism raise the question of how cerebellar maldevelopment contributes to the cognitive and social deficits characteristic of autism. Compared with normal controls, autistic patients and patients with acquired cerebellar lesions were similarly impaired in a task requiring rapid and accurate shifts of attention between auditory and visual stimuli. Neurophysiologic and behavioral evidence rules out motor dysfunction as the cause of this deficit. These findings are consistent with the proposal that in autism cerebellar maldevelopment may contribute to an inability to execute rapid attention shifts, which in turn undermines social and cognitive development, and also with the proposal that the human cerebellum is involved in the coordination of rapid attention shifts in a fashion analogous to its role in the coordination of movement.

Cerebrospinal fluid shunt infection secondary to Escherichia coli bacteriuria

A 10-year-old girl with a lumbosacral myelomeningocele, managed with clean intermittent catheterization, presented with headache, vomiting, and lethargy. The cerebrospinal fluid (CSF) and urine cultures revealed Escherichia coli, documented to be the same subtype. The organisms were subtyped and the E. coli from both the urine and CSF were noted to be of the same strain. Management consisted of intravenous antibiotics and ultimate replacement of the ventriculoperitoneal shunt. Children with myelodysplasia and CSF shunts should be carefully monitored in a multidisciplinary fashion to anticipate, correctly diagnose, and treat CSF shunt infections associated with bacteriuria.

Emergency management of acute coma in children

A deteriorating neurologic state in a child with an acute brain insult is a life-threatening situation, and the decisions made during the first few minutes of management will frequently determine the outcome. Often, the family physician is the first person contacted by the parents to evaluate the sudden change in a child. Attention must be first directed toward ensuring an airway and maintaining adequate circulation. Computed tomographic study, toxicology screen and determination of acid-base status should follow. Possible causes of acute coma in children include trauma, child abuse, intracerebral hemorrhage, tumor, meningitis and poisoning.

Postoperative chemotherapy and delayed radiation in children less than three years of age with malignant brain tumors

BACKGROUND

Among patients with malignant brain tumors, infants and very young children have the worst prognosis and the most severe treatment-related neurotoxic effects. Therefore, in 1986, the Pediatric Oncology Group began a study in which postoperative chemotherapy was given in order to permit a delay in the delivery of radiation to the developing brain.

METHODS

Children under 36 months of age with biopsy-proved malignant brain tumors were treated postoperatively with two 28-day cycles of cyclophosphamide plus vincristine, followed by one 28-day cycle of cisplatin plus etoposide. This sequence was repeated until the disease progressed or for two years in 132 children 24 months of age at diagnosis and for one year in 66 children 24 to 36 months of age at diagnosis. After this, the patients received radiation therapy. The response to the first two cycles of chemotherapy was measured in 102 patients with residual postoperative disease.

RESULTS

The first two cycles of cyclophosphamide and vincristine produced complete or partial responses in 39 percent of the 102 patients who could be evaluated. The response rates were highest among patients with medulloblastomas, malignant gliomas, or ependymomas. Patients with brain-stem gliomas or embryonal tumors (primitive neuroectodermal tumors) had little or no response. The progression-free survival rate was 41 percent at one year for children who were 24 to 36 months old at diagnosis and 39 percent at two years for those under 24 months of age at diagnosis. Multivariate analysis identified embryonal tumors as a significant adverse prognostic feature (relative risk, 2.2; 95 percent confidence interval, 1.4 to 3.4) and complete resection as a favorable feature (relative risk, 0.33; 95 percent confidence interval, 0.20 to 0.54). Complete responses to chemotherapy were associated with a progression-free survival rate approaching that achieved with gross total resection. A comparison of cognitive evaluations obtained at base line and after one year of chemotherapy revealed no evidence of deterioration in cognitive function.

CONCLUSIONS

Chemotherapy appears to be an effective primary postoperative treatment for many malignant brain tumors in young children. Disease control for one or two years in a large minority of patients permitted a delay in the delivery of radiation and, on the basis of preliminary results, a reduction in neurotoxicity. For patients who had undergone total surgical resection or who had a complete response to chemotherapy, the results are sufficiently encouraging to suggest that radiation therapy may not be needed in this subgroup of children after at least one year of chemotherapy.

The third dimension in pediatric neurosurgery. A preliminary report

Three-dimensional computerized imaging with current advanced software (Cemax) has resulted in superior visual ergonomics and rapid data acquisition utilizing standard computed tomography (CT) or magnetic resonance imaging. Consequently, within 15-20 min of a standard CT scan, the information is available to be employed for operative planning, allowing this useful tool to be practical in emergency situations, such as trauma. The advanced lifelike imaging permits excellent preoperative planning due to correct demonstration of the surgical anatomy. We present three patients to illustrate the applications of this technology: one with a skull base tumor, another with a complex ethmoidal encephalocele, and a third with severe craniofacial trauma. We have found this technique to have a significant impact on the management of pediatric neurosurgery patients with complex pathology.

Effects of acute isotonic saline administration on serum osmolality, serum electrolytes, brain water content and intracranial pressure

Albino rabbits who had undergone a cryogenic insult over the left parieto-occipital cortex 24 hours previously were analyzed for serum osmolality, serum electrolytes, brain water content, intracranial pressure (ICP), following a 3 hour baseline intravenous infusion of above maintenance isotonic saline, and compared to sham operated controls. In the acute setting there was no difference in the serum osmolality and electrolytes between the subgroups. There was a significant increase in the water content of the white matter of the left hemisphere in the cold lesion group when compared to sham operated controls. Despite the intravenous fluid challenge, the ICP did not rise during the 3 hour experimental trial when compared to pre-trial values. It is concluded that in the acute setting an isotonic fluid load is compensated without significant disturbances of the above measured parameters, and should not alter therefore intracranial dynamics per se, in acute resuscitation measures following brain insults.

Paraplegia and congenital contractures as a consequence of intrauterine trauma

We present a newborn infant with paraplegia and contractures of the lower limbs, consistent with neurologic injury rather than malformation. The mother was involved in a severe motor vehicle accident during the sixth month of pregnancy. We propose that this infant's injuries are a result of that accident.

Hydrocephalus in infancy and childhood

Hydrocephalus is marked by the excessive accumulation of cerebrospinal fluid within the ventricles. The disorder is characterized by an imbalance in the production and reabsorption of cerebrospinal fluid. Congenital hydrocephalus is usually the result of an intrauterine infection or maldevelopment of the aqueduct of Sylvius. Acquired hydrocephalus can be caused by infection, neoplasm or hemorrhage. In infants, hydrocephalus usually presents as progressive head enlargement. The presenting symptoms in children are irritability, headache, nausea, vomiting and lethargy. Diagnosis is made with ultrasonography, computed tomography or magnetic resonance imaging. The majority of patients are treated with cerebrospinal fluid shunt procedures, most commonly the placement of ventriculoperitoneal or lumboperitoneal shunts. The outcome of hydrocephalus is determined by the etiology, the presence or absence of associated anomalies, and the timeliness of diagnosis and treatment.

The Vater association and spinal dysraphia

We here present a hereto previously undescribed association of occult spinal disorders of the distal spinal cord/filum in the Vater association. We present 6 patients who were diagnosed as having the Vater association who subsequently presented with occult spinal disorders, primarily lipomas of the filum/conus complex with or without subcutaneous lipomas. Uniformly the spinal cord was tethered to the lipoma/filum complex. Progressive neurological dysfunction was noted in those in whom the diagnosis was made late in the disease. The importance of neuroimaging of the distal spinal canal, in children in whom the diagnosis of the Vater association has been made, is emphasized to prevent insidious neurological damage if not already present.

Clinical course and diagnosis of migraine headaches in hydrocephalic children

Headaches, vomiting and altered sensorium can be seen in patients with migraines as well as in patients with shunt malfunctions. This is a report of 10 patients with hydrocephalus and CSF shunts who presented with headache, vomiting, varying degrees of impairment of consciousness, and coma. Various diagnostic considerations were made: shunt malfunction, slit ventricle syndrome and low pressure (overshunting). Repeated operative procedures were performed in all. 7 of 10 patients had a family history of migraines when the diagnosis of migraine was entertained, 8 patients improved on propranolol therapy, 1 failed with this therapy but responded to verapamil. In the remaining 2 patients, after a transient response to propranolol, compartmentalized hydrocephalus became obvious and improvement followed with shunt procedures. It is concluded that in those patients with hydrocephalus and small ventricles on neuroimaging and a family history of migraines, and in the face of documented adequate shunt function, the diagnosis of migraines be entertained before further operative interventions.

Prenatal diagnosis of a craniopharyngioma using ultrasonography and magnetic resonance imaging

We report an infant with a craniopharyngioma which was detected in utero. Maternal uterine ultrasonography, done at 27 weeks because of polyhydramnios, revealed a 4 cm midline mass near the base of the fetal skull. At 31 weeks, magnetic resonance imaging of the maternal abdomen confirmed the presence of a mass in the region of the third ventricle and revealed hydrocephalus. Two days post-partum a computed tomography (CT)-guided needle biopsy of the mass was performed and recovered tissue which was histologically consistent with a craniopharyngioma. The infant's postnatal period was complicated by seizures, which were treated with phenobarbital, and by progressive hydrocephalus, necessitating placement of a ventriculo-peritoneal shunt. He also received therapy for central hypothyroidism and diabetes insipidus. The infant's parents refused permission for attempted resection of the tumour and he died at 8 weeks of age. This represents the second reported case of an antenatally detected craniopharyngioma. Four other cases of different intracranial tumours have been detected in utero using ultrasound, with no reported survivors past 3 days of age. There is a uniformly poor prognosis of such infants, but earlier diagnosis and intervention may change this result.

Cryogenic brain oedema: loss of cerebrovascular autoregulation as a cause of intracranial hypertension. Implications for treatment

Experimental cryogenic brain oedema was created in albino rabbits, and intracranial pressure (ICP), cerebral blood flow (CBF), EEG, blood pressure, central venous pressure, were subsequently studied at a constant PaCO2. Upon completion the brain water content of the gray and white matter was analyzed by gravimetry. The findings were compared to controls and sham-operated. Two subsets of elevated ICP following cryogenic injury were identified: one with a mean of 6.2 +/- 3.3 torr (n = 7) and the other of 19.3 +/- 9 (n = 5) (p less than 0.005). Both these subsets had similar white and gray matter gravimetry values indicating that the magnitude of cerebral oedema was comparable and could not explain the difference in ICP. There was however a significant difference in the CBF of the left hemisphere between these subsets, with Subset A at 49.1 +/- 9 ml/100 g/min and Subset B with 70 +/- 9.1 (p less than 0.001). We conclude that the ICP elevation in the cryogenic oedema model may be due to not only increased brain water of the injured hemisphere, but also to increased cerebral blood volume due to increased CBF.

Spectrum of the syndrome of the isolated fourth ventricle in posthemorrhagic hydrocephalus of the premature infant

Ten patients who were premature born and had intracranial/intraventricular hemorrhage and developed hydrocephalus in early life were treated with ventriculoperitoneal shunts because of progression of the hydrocephalus. The hydrocephalus remained well controlled but in a follow-up period of 2 months to 7 years after shunt placement the patients developed an isolated fourth ventricle that required treatment. The presenting symptoms varied: increasing head size, fontanelle fullness, irritability difficulty with swallowing, vomiting, hypoactivity, headaches and lethargy. One patient presented with full cardiorespiratory arrest and expired. The remainder on neuroimaging studies revealed an extremely large fourth ventricle creating a mass effect and very small (slit-like) lateral ventricles, indicating a functioning lateral ventricle-peritoneal shunt. These patients were treated with the placement of a fourth ventricle shunt catheter and connection to the existing shunt, with resolution of symptoms. Premature infants with hydrocephalus need to be followed and assessed for findings of the syndrome of the isolated fourth ventricle in an attempt to prevent sudden neurological deterioration.

The reaction specificities of the thylakoidal processing peptidase and Escherichia coli leader peptidase are identical

Proteins which are transported across the bacterial plasma membrane, endoplasmic reticulum and thylakoid membrane are usually synthesized as larger precursors containing amino-terminal targeting signals. Removal of the signals is carried out by specific, membrane-bound processing peptidases. In this report we show that the reaction specificities of these three peptidases are essentially identical. Precursors of two higher plant thylakoid lumen proteins are efficiently processed by purified Escherichia coli leader peptidase. Processing of one precursor, that of the 23 kd photosystem II protein, by both the thylakoidal and E. coli enzymes generates the correct mature amino terminus. Similarly, leader (signal) peptides of both eukaryotic and prokaryotic origin are cleaved by partially purified thylakoidal processing peptidase. No evidence of incorrect processing was obtained. Both leader peptidase and thylakoidal peptidase are inhibited by a synthetic leader peptide.

Transport of proteins into chloroplasts. Import and maturation of precursors to the 33-, 23-, and 16-kDa proteins of the photosynthetic oxygen-evolving complex

The 33-, 23-, and 16-kDa proteins of the photosynthetic oxygen-evolving complex are synthesized as precursors in the cytoplasm and transported into the thylakoid lumen of higher plant chloroplasts. In this report we have analyzed the import and maturation of these precursors, using reconstituted protein import assays and partially purified preparations of the processing peptidases involved. Precursors of the 33- and 23-kDa proteins from Spinacia and Triticum aestivum are processed by a stromal peptidase to intermediate forms; polypeptides of similar size are observed during the transport of these precursors and possibly that of the 16-kDa protein, into isolated chloroplasts. Complete maturation of the 33- and 23-kDa proteins is carried out by a thylakoidal peptidase shown previously to be involved in plastocyanin biogenesis. The data support an import mechanism involving successive cleavages by the stromal and thylakoidal processing peptidases.

Migraine headaches in hydrocephalic children: a diagnostic dilemma

Headaches, vomiting, and altered sensorium can be seen in patients with shunt malfunction as well as in those with migraines. We report five cases in which children with hydrocephalus and CSF shunts presented with a variety of recurring symptoms, including headache, vomiting, impairment of consciousness to the point of coma, and, in one patient, decerebrate posturing. Various diagnoses were entertained: shunt malfunction, slit ventricle syndrome, and low pressure (overshunting). Repeated procedures were carried out in all patients, including shunt taps, multiple shunt revisions, and a subtemporal decompression. When the diagnosis of migraine was considered, four patients improved on propranolol therapy; one failed this therapy but responded to verapamil. We conclude that in patients with hydrocephalus and repeated bouts of symptoms such as headaches, vomiting, and impairment of consciousness and in the case of documented, adequate shunt function, the diagnosis of migraine be entertained before further operative intervention is undertaken.

Sudden infant apnea and insidious hydrocephalus

Hydrocephalus secondary to intracranial-intraventricular hemorrhage is a common complication in the clinical course of the high-risk preterm newborn. Hydrocephalus in this population may be insidious without obvious intracranial hypertension. Apnea and respiratory arrest continue to cause concern following nursery discharge of the high-risk preterm newborn. We report a child who presented to the neonatology service with episodes compatible with serious sudden cardiorespiratory arrest. Insidious "non-hypertensive" hydrocephalus was documented as being responsible for these episodes, which resolved with treatment of the hydrocephalus. The perinatal neurosurgical consultant should be aware of this syndrome and instruct the parents and the pediatricians of these infants, who at the time of discharge are asymptomatic but have ventricular enlargement on neuro-imaging studies. The information presented here is of current importance, since most neonatologists are unaware of the syndrome of insidious hydrocephalus.

Experimental carbon dioxide laser brain lesions and intracranial dynamics: Part 3. Effect on cerebral blood flow

Experimental carbon dioxide brain lesions were created over the intact dura mater of the left parietooccipital region of the anesthetized albino rabbit (40-watt impacts of 0.5-second duration, for a total of 4 seconds, with 0.5-second intervals between impacts), and cerebral blood flow (CBF) studies were performed with the hydrogen clearance technique. The animals were mechanically ventilated to maintain a constant PaCO2. Blood pressure, central venous pressure, electroencephalogram, and intracranial pressure were continuously monitored. The control CBF before lesion was 64.1 +/- 15.8 and 70.9 +/- 13.4 ml/100 g/minute for the left and the right hemispheres, respectively. CBF studies at 2, 4, 6, 8, and 24 hours after the lesion did not significantly change from the control values, save for a trend to increase over the right hemisphere only at 2 hours (range 106.0 +/- 55.4 to 41.6 +/- 9.3). It is concluded that in this model the changes in intracranial pressure and brain edema that are seen and have been previously reported are not due to change in cerebral circulation. The brain edema that results probably has characteristics similar to those seen in the cryogenic lesion (vasogenic) model, and this could account for the rise in intracranial pressure.

Severe intracranial hemorrhage and hydrocephalus in low-birthweight infants treated with CSF shunts

The high-risk low-birth-weight newborn not uncommonly develops intracranial hemorrhage and intraventricular hemorrhage (ICH/IVH) from the immature state of the germinal matrix. Posthemorrhagic hydrocephalus may develop. Infants with small hemorrhages (grades I, II of Papile), with or without hydrocephalus have been shown to develop normally in 80%-90% of cases. There is limited information in the literature about the management and outcome of infants with more severe hemorrhages (grades III, IV of Papile), due to the dismal outlook as to their outcome in most centers. The current status and concerns as to the management of these infants is reviewed, and the aspects of neurosurgical and neonatal follow-up and outcome are described. A significant number of these infants have severe handicaps, which are primarily motor. However, a group of infants is noted who have normal intellectual performance despite varying degrees of motor handicaps: 18% have normal intellectual and motor development. In the current series predictors of poorest outcome are the presence of grade IV hemorrhage and/or seizures. The vast majority of the grades III and IV hemorrhages develop hydrocephalus that is a complex management issue for the neurosurgeon.

Insidious hydrocephalus in the preterm newborn following discharge from the nursery

Posthemorrhagic ventriculomegaly may be due to perinatal brain damage and consequent cerebral atrophy, or represent progressive hydrocephalus due to impairment of CSF flow and reabsorption. 'Arrested' hydrocephalus occurs when the CSF pathways are adequate and, hence, intracranial hypertension no longer exists. The differential diagnosis is often difficult and insidious progressive hydrocephalus should always be a concern in the high-risk preterm newborn. We report 10 preterm infants who were discharged with the diagnosis of arrested hydrocephalus (7) or cerebral atrophy (3), and who later developed progressive severe hydrocephalus 1.5-15 months after the discharge. Five had been treated with intermittent lumbar punctures, while 4 had not received any treatment prior to nursery discharge. One infant died prior to the shunt procedure. Progressive insidious hydrocephalus should be suspected in preterm infants with intracranial hemorrhage following discharge from the nursery.

An experimental study on the effects of DMSO and indomethacin on cerebral circulation and intracranial pressure

Albino rabbits with a cryogenic lesion to the left parieto-occipital cortex had cerebral blood flow studies (CBF) with the hydrogen clearance technique 24 hours after the insult. Similar subgroups were treated with DMSO (1 g/kg) bolus, DMSO (2 g/kg) infusion, indomethacin (20 mg/kg) bolus, and indomethacin followed by DMSO. Following DMSO bolus administration there was an immediate rise in CBF over both hemispheres, with a significant paradoxical decrease at 30 minutes, followed by a second smaller rise at 60 minutes. With DMSO infusion, the rise in CBF was sustained throughout the infusion period with no paradoxical decrease. With indomethacin there was an initial decrease immediately following the drug, and at 60 minutes there was a rise in the insulted left hemisphere, more than the right one. Indomethacin administration 15 minutes prior to DMSO failed to halt the immediate increase in CBF noted following DMSO bolus injection. These results, together with the changes that occurred in intracranial pressure and brain water content, are analyzed.

Central nervous system anomalies associated with meningomyelocele, hydrocephalus, and the Arnold-Chiari malformation: reappraisal of theories regarding the pathogenesis of posterior neural tube closure defects

Complete gross and microscopic neuropathological examinations of 25 children who died with meningomyelocele, the Arnold-Chiari malformation, and hydrocephalus revealed a wide range and frequency of associated central nervous system malformations. The most remarkable of these anomalies were hypoplasia or aplasia of cranial nerve nuclei (20%), demonstrable obstruction of cerebrospinal fluid flow within the ventricular system (92%), cerebellar dysplasia (72%), a disorder of migration of cortical neurons (92%), fusion of the thalami (16%), agenesis of the corpus callosum (12%), and complete or partial agenesis of the olfactory tract and bulb (8%). The anomalies associated with posterior neural tube closure defects can no longer be considered secondary, but rather must be considered part of a spectrum of malformations caused by an unidentified primary insult to the central nervous system. The frequency and pattern of brain malformations associated with neural tube defects of some children with meningomyelocele suggest that such malformations may seriously affect intellectual outcome.

The effects of acute high dose fentanyl administration on experimental brain edema: analysis of intracranial pressure, systemic arterial pressure, central venous pressure and brain water content

In rabbits who had brain edema and intracranial hypertension induced by a combined cold lesion (over the left hemisphere) and a metabolic blocker (6-aminonicotinamide), the authors analyzed the response of multiple parameters following the administration of 6 mcg/kg/dose of fentanyl every 5 minutes for 1 hour (12 doses), combined with nitrous oxide anesthesia. All animals were mechanically ventilated and the PaCO2 was maintained at 37-43 torr. Gross pathology and extent of Evans Blue extravasation was no different from pretreatment control animals. The systolic arterial pressure and the central venous pressure showed no change during the experiment. The intracranial pressure remained elevated despite fentanyl, but did not increase or decrease throughout the administration of the agent. The brain water content remained unchanged in the right hemisphere, but revealed a significant increase following fentanyl in the cold-lesioned left hemisphere for the gray (p less than 0.005) and white matter (p less than 0.05).

Ventriculoperitoneal shunts in low birth weight infants with intracranial hemorrhage: neurodevelopmental outcome

Fifty preterm infants (mean birth weight, 1266 +/- 303 g; mean gestational age, 30 +/- 2 weeks) who required a ventriculoperitoneal (VP) shunt for posthemorrhagic hydrocephalus (92% with Grade III or IV hemorrhage) were followed for neurodevelopmental problems. VP shunts were placed at a median age of 29 days (range, 18 to 87 days) after serial lumbar punctures failed to control progressive and symptomatic ventriculomegaly. A total of 34 infants (68%) required one shunt revision or more, and the overall infection rate per patient was 50%. Seven infants died, 2 from shunt infections. The infants were evaluated with audiological, ophthalmological, and neurodevelopmental examinations. Of the survivors, 11 (28%) have severe visual loss and 10 (24%) have hearing impairment. Of the infants, 21 (49%) have severe motor handicaps and 19 (38%) have seizure disorders. Developmental and motor scores were obtained using the Bayley or Knobloch-Gesell scales. Seven infants (18%) have normal developmental outcomes; 26 (60%) have multiple handicaps. Grade IV hemorrhage or the occurrence of seizures was a predictor of poor neurodevelopmental outcome. We conclude that progressive posthemorrhagic hydrocephalus in low birth weight infants is associated with multiple handicaps despite early VP shunt placement.

The effect of carbon dioxide laser irradiation on cranial bone healing. An experimental study

An experimental study on the effects of carbon dioxide laser irradiation osteotomy of the calvarium of 4-week old rabbits was compared with tht of an osteotomy performed with a high speed drill. Histological studies of calvarium cross sections were performed at 2, 4 and 6 weeks following the osteotomies. As early as 2 weeks following high speed drill osteotomy connective tissue bridged the bone edges. By 4 weeks this bridge was thickened and endowed with numerous vessels. At 6 weeks numerous osteoblasts lined the bone edge and connective tissue bridge. Following laser osteotomy the carbonized edges interrupted the connective tissue from bridging the bone edges at 2, 4 and 6 weeks. By 6 weeks following the laser osteotomy connective tissue had grown past the carbonized residue and the healing process proceeded with osteoblast proliferation from points beyond the carbonized residue. The significance of these findings in reference to the reossification process following osteotomies for craniosynostosis and craniofacial surgery, is discussed.