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CT appearance of shearing injuries of the brain.

Shearing injuries, also called diffuse axonal injuries, are a special kind of severe head trauma, usually caused by a motor vehicle accident, in which disruption of white matter axons takes place. Twelve cases of shearing injuries were diagnosed by computed tomography (CT). The typical CT findings were small hemorrhagic lesions in the cerebral white matter, most often in cerebral hemispheres and internal capsules. In most patients, hemorrhagic foci were multiple. Single lesions were found in only two patients. Features of brain edema were found in eight of ten early studies, and subarachnoidal hemorrhage only in three. Two patients also had subdural hematomas. CT appearance of the shearing injuries is characteristic, especially in connection with clinical data indicating a history of head trauma and severe state of the patient.

Accidents, Traffic↗

Diffuse axonal and tissue injury in patients with multiple sclerosis with low cerebral lesion load and no disability.

BACKGROUND: Although in situ pathological studies and in vivo magnetic resonance (MR) investigations have shown that axonal injury can be significant in the early stages of multiple sclerosis (MS), diffuse axonal injury is generally considered a secondary event. Cerebral axonal damage can be specifically assessed in vivo by measuring levels of brain N-acetylaspartate (NAA, a specific index of axonal integrity detected by MR spectroscopy). Other new MR measurements such as magnetization transfer ratio (MTr) or computed estimation of brain volume can provide less specific indexes of tissue damage. OBJECTIVE: To determine whether diffuse axonal and tissue injury is present in patients with definite MS who do not show clinically significant disability. METHODS: We measured brain NAA levels (normalized to creatine [Cr]), MTr values, and cerebral volumes in patients with definite MS who had low T2-weighted MR imaging lesion volumes and no clinical disability, and also in age-matched healthy control subjects. RESULTS: Values of central brain NAA/Cr and MTr in normal-appearing white matter were significantly lower in the MS patients than in controls (P<.001). In contrast, total brain volumes were not significantly different between these groups. Similar results were found for MS patients with early disease (duration, <3 years) and with a particularly low cerebral T2-weighted MR imaging lesion load (< or = 2 cm(3)). CONCLUSIONS: Cerebral NAA/Cr and MTr values are diffusely decreased in MS patients with early disease, low demyelinating lesion load, and no significant disability. This suggests that axonal and/or tissue injury begins very early in the course of MS and might be at least partially independent of cerebral demyelination.

Adolescent↗

Identification and characterization of heterogeneous neuronal injury and death in regions of diffuse brain injury: evidence for multiple independent injury phenotypes.

Diffuse brain injury (DBI) is a consequence of traumatic brain injury evoked via rapid acceleration-deceleration of the cranium, giving rise to subtle pathological changes appreciated best at the microscopic level. DBI is believed to be comprised by diffuse axonal injury and other forms of diffuse vascular change. The potential, however, that the same forces can also directly injure neuronal somata in vivo has not been considered. Recently, while investigating DBI-mediated perisomatic axonal injury, we identified scattered, rapid neuronal somatic necrosis occurring within the same domains. Moving on the premise that these cells sustained direct somatic injury as a result of DBI, we initiated the current study, in which rats were intracerebroventricularly infused with various high-molecular weight tracers (HMWTs) to identify injury-induced neuronal somatic plasmalemmal disruption. These studies revealed that DBI caused immediate, scattered neuronal somatic plasmalemmal injury to all of the extracellular HMWTs used. Through this approach, a spectrum of neuronal change was observed, ranging from rapid necrosis of the tracer-laden neurons to little or no pathological change at the light and electron microscopic level. Parallel double and triple studies using markers of neuronal degeneration, stress, and axonal injury identified additional injured neuronal phenotypes arising in close proximity to, but independent of, neurons demonstrating plasmalemmal disruption. These findings reveal that direct neuronal somatic injury is a component of DBI, and diffuse trauma elicits a heretofore-unrecognized multifaceted neuronal pathological change within the CNS, generating heterogeneous injury and reactive alteration within both axons and neuronal somata in the same domains.

Animals↗

Tissue lactate in pediatric head trauma: a clinical study using 1H NMR spectroscopy.

In order to define the metabolic abnormalities associated with different types of pediatric head injury, proton magnetic resonance spectroscopy was performed on 21 cerebral regions obtained from 17 patients. On the basis of MRI scans, the regions of interest were classified as normal (6 hemispheres), or showing diffuse axonal injury (3 hemispheres), contusion (4 hemispheres), or cerebral infarction (8 hemispheres). In comparison with normal brain there was no significant elevation in tissue lactate in the diffuse axonal injury patients, but a significant increase in the regions of contusion and infarction. It is concluded that treatment strategies using buffering agents are most likely to benefit these two groups of patients.

Acidosis↗

The significance of haematomas of the basal ganglia in closed head injury.

In a large series of patients with severe closed head injury, 26 (3.2%) had haematomas of the basal ganglia. It is suggested that such haematomas indicate primary brain damage, being part of the spectrum of lesions that may be seen in diffuse axonal injury. Clinical outcome was found to depend on the pattern of brain damage, notably on the additional presence of contusions or of other computed tomographic (CT) evidence of diffuse axonal injury.

Adult↗

[Bilateral sixth nerve and left third nerve palsy after head trauma].

CASE REPORT: To describe a case of combined bilateral cranial nerve palsy of traumatic origin. To determine the lesions that produce the symptoms is useful to define the final prognosis and the best treatment. DISCUSSION: We report the case of a patient who developed a bilateral sixth nerve and left third nerve palsy after head trauma. The underlying lesion was a diffuse axonal injury. After an observation period during which no spontaneous improvement occurred, we administered botulinum toxin with a successful clinical result. Bilateral combined traumatic cranial nerve palsies are rare. When a diffuse axonal injury is present, the chance of spontaneous resolution is poor.

Abducens Nerve Diseases↗

Cytochemical evidence for redistribution of membrane pump calcium-ATPase and ecto-Ca-ATPase activity, and calcium influx in myelinated nerve fibres of the optic nerve after stretch injury.

There has been controversy for some time as to whether a posttraumatic influx of calcium ions occurs in stretch/nondisruptively injured axons within the central nervous system in both human diffuse axonal injury and a variety of models of such injury. We have used the oxalate/pyroantimonate technique to provide cytochemical evidence in support of such an ionic influx after focal axonal injury to normoxic guinea pig optic nerve axons, a model for human diffuse axonal injury. We present evidence for morphological changes within 15 min of injury where aggregates of pyroantimonate precipitate occur in nodal blebs at nodes of Ranvier, in focal swellings within axonal mitochondria, and at localized sites of separation of myelin lamellae. In parallel with these studies, we have used cytochemical techniques for localization of membrane pump Ca(2+)-ATPase and ecto-Ca-ATPase activity. There is loss of labelling for membrane pump Ca(2+)-ATPase activity on the nodal axolemma, together with loss of ecto-Ca-ATPase from the external aspect of the myelin sheath at sites of focal separation of myelin lamellae. Disruption of myelin lamellae and loss of ecto-Ca-ATPase activity becomes widespread between 1 and 4 h after injury. This is correlated with both infolding and retraction of the axolemma from the internal aspect of the myelin sheath to form periaxonal spaces which are characterized by aggregates of pyroantimonate precipitate, and the development of myelin intrusions into invaginations of the axolemma such that the regular profile of the axon is lost. There is novel labelling of membrane pump Ca(2+)-ATPase on the cytoplasmic aspect of the internodal axolemma between 1 and 4 h after injury. There is loss of an organized axonal cytoskeleton in a proportion of nerve fibres by 4-6 h after injury. We suggest that these changes demonstrate a progressive pathology linked to calcium ion influx after stretch (non-disruptive) axonal injury to optic nerve myelinated fibres. We posit that calcium influx, linked to or correlated with changes in Ca(2+)-ATPase activities, results in dissolution of the axonal cytoskeleton and axotomy between 4 and 6 h after the initial insult to axons.

Adenosine Triphosphatases↗

Susceptibility weighted imaging: neuropsychologic outcome and pediatric head injury.

Traumatic brain injury is among the most frequent pediatric neurologic disorders in the United States, affecting multiple aspects of neuropsychologic functioning. This study assessed the efficacy of susceptibility weighted imaging as a predictor of long-term neuropsychologic functioning after pediatric brain injury compared with magnetic resonance spectroscopic imaging. Susceptibility weighted imaging is a relatively new method that is considered superior to traditional magnetic resonance imaging sequences for detecting hemorrhagic diffuse axonal injury. In this study, imaging and spectroscopy were acquired 6 +/- 4 days after injury. Measures of neuropsychologic functioning were administered to 18 children and adolescents 1-4 years post injury. Negative correlations between lesion number and volume with neuropsychologic functioning were demonstrated. Lesion volume explained over 32% of the variance in cognitive performance, explaining at least an additional 20% beyond injury severity and age at injury alone and 19% beyond magnetic resonance spectroscopic metabolite variables. Exploratory analyses resulted in notable trends, with lesions in deeper brain regions more strongly associated with poorer neuropsychologic performance. Improved detection of the extent of diffuse axonal injury following a brain injury will allow for a better understanding of its association with long-term outcome, which in turn can improve prognostic efficacy for effective treatment planning.

Adolescent↗

Anatomical correlations of intrinsic axon repair after partial optic nerve crush in rats.

About 15% of retinal ganglion cells survive diffuse axonal injury of the optic nerve in adult rats. Following initial blindness, discrimination of visual stimuli in behavioral tests recovers within three weeks. To investigate the mechanisms promoting this functional recovery the axonal transport and the neurofilaments were studied. Intraocularly applied MiniRuby is transported until the place of crush and accumulated in enlarged axon terminals. Three weeks after lesion the anterograde transport of MiniRuby recovers distal to the place of crush. At the same point in time the retrograde transport of surviving retinal ganglion cells is restored which was visualized by horseradish peroxidase injected into the superior colliculus. The heavy neurofilament was stained immunohistochemically and analyzed statistically up to three weeks after optic nerve crush. The stained filaments in the axon fibers of retinal ganglion cells appear wavelike and/or fragmented up to day 8, but first signs of heavy neurofilament restitution in the fibers of the optic nerve are seen at day 12 after axonal injury. Because these results cannot be explained by longlasting axon regeneration, the present results provide convincing evidence for intrinsic axon repair soon after diffuse axonal injury that correlates in time with recovery of vision.

Animals↗

Blood metallothionein, neuron specific enolase, and protein S100B in patients with traumatic brain injury.

OBJECTIVES: The aim of this study was to evaluate the correlation of neuron specific enolase (NSE), protein S100B and time-profile of Glasgow Coma Score (GCS) development with metallothionein (MT) blood levels in patients with traumatic brain injury (TBI) during 10 days of hospitalization. Patients were divided into 2 groups with respect to NSE and S100B levels - with (group I) and without (group II) GCS improvement. METHODS: Serum NSE and S100B concentrations were measured by immunochemical methods; serum metallothionein concentration by electrochemical technique. Cortical biopsies were investigated immunohistochemically and by electron microscope. A cDNA microarray containing 700 gene probes was used to study the changes in gene expression in the ipsilateral cortex. RESULTS: Values of MT in the blood of group I showed a non-significant decrease compared to group II during 1-3 days after admission. There was an increase of MT during 4-8 days in comparison with values of 1-3 days. The highest value of MT during hospitalization was found in a patient with diffuse axonal injury (group II). The data of cDNA microarray suggested an increase in expression of gene transcripts for oxygen free radical scavenger proteins corresponding with the increase of MT during 4-8 days in both groups. CONCLUSIONS: The experimental data indicate that monitoring the content of MT in patients with trauma brain injury would be a suitable approach to evaluate the degree of injury or duration of prolonging unconsciousness, particularly in diagnosis of diffuse axonal injury.

Brain Injuries↗

Cortical hypoxic-ischemic brain damage in shaken-baby (shaken impact) syndrome: value of diffusion-weighted MRI.

Shaken-baby syndrome (SBS) is a type of child abuse caused by violent shaking of an infant, with or without impact, and characterized by subdural hematomas, retinal hemorrhages, and occult bone fractures. Parenchymal brain lesions in SBS may be missed or underestimated on CT scans, but can be detected at an earlier stage with diffusion-weighted MRI (DW-MRI) as areas of restricted diffusion. We demonstrate the value of DW-MRI in a 2-month-old baby boy with suspected SBS. The pattern of diffusion abnormalities indicates that the neuropathology of parenchymal lesions in SBS is due to hypoxic-ischemic brain injuries, and not to diffuse axonal injury.

Brain↗

[Clinical application of three dimensional ultrafast MR imaging to intracerebral traumatic lesions].

We applied a T1-weighted three-dimensional (3D) magnetization-prepared rapid gradient-echo sequence (MPRAGE) for the detection of intracerebral lesions associated with closed head injuries. Thirty-four patients underwent brain MR imaging on a 1.5 Tesla superconducting MR unit. We applied an MPRAGE sequence, together with spin echo (SE) and gradient echo (GRE) sequences, and evaluated the detectability of lesions with each sequence. A total of 100 intracerebral traumatic lesions (33 cortical contusion, 56 diffuse axonal injury, 11 subcortical gray matter injury) were found. Ninety-seven percent of all lesions were detected on MPRAGE images, and 67% on SE and GRE images. The detectability of lesions in each category was 91%, 98%, and 100% on MPRAGE images, and 88%, 54%, and 73% on either SE or GRE images. 3D MPRAGE is a promising method to detect intracerebral traumatic lesions, particularly those associated with diffuse axonal injury, because of its high quality of contrast and spatial resolution and the capability of image reconstruction in any plane.

Adolescent↗

Technical aspects of an impact acceleration traumatic brain injury rat model with potential suitability for both microdialysis and PtiO2 monitoring.

This report describes technical adaptations of a traumatic brain injury (TBI) model-largely inspired by Marmarou-in order to monitor microdialysis data and PtiO2 (brain tissue oxygen) before, during and after injury. We particularly focalize on our model requirements which allows us to re-create some drastic pathological characteristics experienced by severely head-injured patients: impact on a closed skull, no ventilation immediately after impact, presence of diffuse axonal injuries and secondary brain insults from systemic origin... We notably give priority to minimize anaesthesia duration in order to tend to banish any neuroprotection. Our new model will henceforth allow a better understanding of neurochemical and biochemical alterations resulting from traumatic brain injury, using microdialysis and PtiO2 techniques already monitored in our Intensive Care Unit. Studies on efficiency and therapeutic window of neuroprotective pharmacological molecules are now conceivable to ameliorate severe head-injury treatment.

Acceleration↗

Classification of acquired lesions of the corpus callosum with MRI.

MRI has facilitated diagnostic assessment of the corpus callosum. Diagnostic classification of solitary or multiple lesions of the corpus callosum has not attracted much attention, although signal abnormalities are not uncommon. Our aim was to identify characteristic imaging features of lesions frequently encountered in practice. We reviewed the case histories of 59 patients with lesions shown on MRI. The nature of the lesions was based on clinical features and/or long term follow-up (ischaemic 20, Virchow-Robin spaces 3, diffuse axonal injury 7, multiple sclerosis 11, hydrocephalus 5, acute disseminated encephalomyelitis 5, Marchiafava-Bignami disease 4, lymphoma 2, glioblastoma hamartoma each 1). The location in the sagittal plane, the relationship to the borders of the corpus callosum and midline and the size were documented. The 20 ischaemic lesions were asymmetrical but adjacent to the midline; the latter was involved in new or large lesions. Diffuse axonal injury commonly resulted in large lesions, which tended to be asymmetrical; the midline and borders of the corpus callosum were always involved. Lesions in MS were small, at the lower border of the corpus callosum next to the septum pellucidum, and crossed the midline asymmetrically. Acute disseminated encephalomyelitis and the other perivenous inflammatory diseases caused relatively large, asymmetrical lesions. Hydrocephalus resulted in lesions of the upper part of the corpus callosum, and mostly in its posterior two thirds; they were found in the midline. Lesions in Marchiafava-Bignami disease were large, often symmetrically in the midline in the splenium and did not reach the edge of the corpus callosum.

Adolescent↗

[Bilateral traumatic hemorrhage in the basal ganglia: report of two cases].

Hematomas of the basal ganglia in head injury have long been recognized by pathologists with an interest in head injury but their mechanism has not been revealed clearly. We report two cases of bilateral traumatic hemorrhage in the basal ganglia. Case #1, a 17-year-old male was admitted to our hospital immediately after a traffic accident. Neurological examination revealed that the patient was comatose and had right hemiparesis. CT scan showed bilateral hemorrhage of the basal ganglia and subarachnoid hemorrhage in the perimesencephalic cistern. MRI showed high signal intensity areas in the bilateral basal ganglia, perimesencephalic cistern, cerebral white matter and corpus callosum. The patient was diagnosed as having diffuse axonal injury coinciding with bilateral hemorrhage of the basal ganglia. Stereotactic aspiration for the hematoma of the left basal ganglia was carried out. Case #2, a 75-year-old male was admitted immediately after falling from the roof of his house. Neurological examination revealed no neurological deficit except for headache and nausea. CT scan on the day of injury revealed no abnormality. But CT scan 12 hours following the injury showed bilateral hemorrhage of the basal ganglia. Blood pressure of the patient was within normal range and he was diagnosed as having traumatic bilateral intracerebral hematoma. Conservative treatment was carried out and the patient was discharged 7 days after injury with no neurological deficit. The mechanism of traumatic hemorrhage of the basal ganglia has not been clear. In case #1, diffuse axonal injury (DAI) may have played an important role in the bilateral hemorrhage. But in case #2, non-DAI factor such as vasoparalysis syndrome may have existed.(ABSTRACT TRUNCATED AT 250 WORDS)

Accidental Falls↗

The association between skull fracture, intracranial pathology and outcome in pediatric head injury.

We prospectively studied 653 consecutive head-injured children (less than or equal to 14 years old) treated over a 54-month period (1984-88) at the Department of Neurosurgery of the Rambam Medical Center (Haifa, Israel). Demographic and clinical data were collected, the patients were divided into five age groups (birth to 2 years, 169; 3-5 years, 194; 6-9 years, 164; 10-12 years, 77; and 13-14 years, 49), and the information relative to each was then compared. All patients (except three who died on the operating table) underwent computed tomography (CT) scans; 225 (34.6%) had intracranial pathology, e.g. focal mass lesions, diffuse axonal injury, and subarachnoid haemorrhage. The rate of detected pathology increased with age. Skull fracture was documented in 468 (72%) patients. Craniotomies were done on 114 (17.5%) patients. After 3 months, the patients were classified as having good recovery (84.8%), moderate disability (5.5%), or severe disability (2.3%); 0.9% were in a vegetative state. The mortality was 6.6% (43 patients); of these, 39 (90.7%) had admission Glasgow Coma Scale scores below 8. In our area the annual incidence of neurosurgical hospitalization due to head injury in the pediatric group was 37.6 per 100,000 inhabitants per year. This study substantiates the findings of other series on the effects of prognosis of factors such as associated trauma, admission Glasgow Coma Score, mass lesions with persistent intracranial pressure elevation, or diffuse axonal injury.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

Neuropathology in vegetative and severely disabled patients after head injury.

OBJECTIVE: To discover if the neuropathology differs in head-injured patients who were in a vegetative state (VS) or were severely disabled at time of death. METHODS: Review of 35 VS cases and 30 severely disabled cases treated in this institute in the acute stage, surviving at least a month; all brains were fixed for 3 weeks before full neuropathologic examination. RESULTS: The severely disabled cases were older, had a higher incidence of skull fracture and of evacuated intracranial hematoma, and they had more cortical contusions. Diffuse axonal injury (DAI) was less common in the severely disabled cases, particularly its most severe grade. Structural damage in the thalamus was much less common in severely disabled cases. Half of the severely disabled patients had neither grade 2 or 3 DAI nor thalamic damage and 10 of these 15 cases did not have ischemic brain damage either. These combinations did not occur in a single VS case. However, some severely disabled cases had similar lesions to VS cases, and this included some patients who were in a minimally conscious state as well as some who were out of bed and mobile. CONCLUSIONS: Half the severely disabled cases had only focal brain damage, a feature not found in any VS cases. In the severely disabled patients with lesions similar to those of VS cases it is likely that a greater quantitative amount of damage occurred in the VS cases.

Adolescent↗

Diffuse brain swelling after head injury: more often malignant in adults than children?

A series of 118 patients with diffuse traumatic brain swelling was studied retrospectively in order to compare the clinical findings in children with those in adults, and to determine the occurrence of neurological deterioration and outcome. The computerized tomography (CT) picture of absent third ventricle and basal cisterns was used to identify the cases. Although this condition has been associated with children, we found the same number of children and adults (59 cases each). Secondary deterioration (decline in consciousness, the development of new focal neurological signs, or an increase in intracranial pressure) occurred in 40% of cases and was more common in adults than children. Features that were significantly associated with deterioration were the presence of prolonged coma (> 1 hour) after the injury, CT signs of diffuse axonal injury or subarachnoid hemorrhage, or a recorded episode of hypotension. A moderate or good recovery at 6 months was achieved by 70 patients (59%), but 45 patients had a poor outcome (severe disability in nine, vegetative state in three, and death in 33) and this was often a consequence of secondary deterioration. In three patients, the outcome was not known. The combination of a severe initial injury, secondary insult, and diffuse swelling is associated with a poor outlook, particularly in adults. The CT appearance of diffuse swelling may develop more readily in children because of the lack of cerebrospinal fluid available for displacement. In children, diffuse swelling may have a relatively benign course unless there is a severe primary injury or a secondary hypotensive insult.

Adolescent↗