Pre-mesencephalic subarachnoid hemorrhage: rupture of tiny aneurysms of the basilar artery perforator

PURPOSE

Subarachnoid hemorrhage (SAH) around the midbrain without evidence of aneurysm, a so-called perimesencephalic SAH, has been considered a typical nonaneurysmal SAH. Recently, we have encountered several patients with SAHs that could have been classified as having perimesencephalic SAH, but a common cause of the bleeding was demonstrated. In this article, we describe clinical and radiologic characteristics of these patients.

METHODS

Clinical and radiologic data from patients with spontaneous SAH (total number 339) who were treated at Seoul National University Bundang Hospital between May 2003 and December 2007 were reviewed.

RESULTS

Of the 13 patients that could be classified as having perimesencephalic SAH, three had common radiologic features that were distinct from others. On computed tomography, the main hemorrhage (hematoma) was found localized in front of the midbrain (interpeduncular and/or peduncular cistern). Angiographically, the cause of the bleeding was not seen on conventional views and rotational angiograms. In three-dimensional reconstructed angiographic images, very small-sized (tiny) aneurysmal lesions were visible at the origin of mesencephalic perforators from the basilar artery. All the aneurysms were positioned at the exact site corresponding to the pre-mesencephalic clots. Follow-up angiography was performed on the three patients and all showed complete disappearance of the lesions at 1 month, 15 months, and 16 months follow-up, respectively.

CONCLUSIONS

Based on our experience, we suggest a subtype of spontaneous SAH that has unique hemorrhage localization (pre-mesencephalic cistern), specific cause (tiny aneurysms at the origin of the mesencephalic perforator), and a common benign clinical course.

[Dilation of subarachnoid space around the optic nerve in a patient with subdural effusion: a case report]

A fifty-year-old man who had a history of minor head injury a month previously presented with headache, visual disturbance and papilloedema. Brain MR imaging showed bilateral subdural effusion and fat saturated orbital MR imaging demonstrated dilated subarachnoid space around the optic nerve. The diameter of the subarachnoid space behind the globe was 7.0 mm and that of the optic nerve was 3.5 mm. Bilateral simple drainage was performed to prevent deterioration of the visual disturbance. Light bloody fluid with a subdural pressure of 10.5 cmH2O was drained from the burr hole at the left side, and colorless fluid was drained from the right. Orbital MR imaging during continuous drainage revealed shrinkage of the subarachnoid space around the optic nerve. However, follow-up MR imaging 5 months after drainage showed disappearance of the subdural effusion and the reappearance of the subarachnoid space around the optic nerve, even though the size was smaller than before surgery. These findings suggest that the diameter of the optic subarachnoid space co-relates with the intracranial pressure, and may be an indication for increased intracranial pressure.

Bone wax can cause foreign body granuloma in the medulla oblongata

Bone wax is commonly used in neurosurgical practice as a haemostatic and sealing agent. It is a safe agent, but may lead to adverse effects such as infection, epistaxsis, allergic reaction or foreign body granuloma. There are very few reported cases of the neurological complications of remnant bone wax in the subdural or subarachnoid space. The authors report the case of a foreign body granuloma infiltration through the medulla oblongata due to remnant bone wax in the subarachnoid space after posterior fossa decompressive surgery.

[Enlarged perivascular spaces associated with hydrocephalus: a case report]

We report a case of enlarged perivascular spaces (EPVS) in the mesencephalothalamic region associated with hydrocephalus. EPVS are extensions of the subarachnoid space that accompany penetrating arteries and may cause mass effects. A 56-year-old woman with EPVS-associated hydrocephalus underwent third ventriculostomy and biopsy. We compared pre-and postoperative images by magnetoencephalography (MEG) and tractography, and evaluated the effects of EPVS. These images were useful to determine the patient' s condition.

A case of ecchordosis physaliphora presenting with an intratumoral hemorrhage

Ecchordosis physaliphora is a rare congenital, benign, hamartomatous, retroclival mass derived from notochordal tissue that is typically located intradurally in the prepontine cistern. Ecchordosis physaliphora is usually asymptomatic. In rare cases, ecchordosis physaliphora can be symptomatic due to tumor expansion and compression of the surrounding structures and extratumoral hemorrhage. To our knowledge, ecchordosis physaliphora associated with intratumoral hemorrhage and vasogenic edema has not been previously described. We present a case of 22-year-old man who presented with headache and confusion. MR imaging and CT revealed intracranial ecchordosis physaliphora associated with intratumoral hemorrhage and vasogenic edema. The neurological findings resolved completely after medical therapy.

Aggressive leptomeningeal hemangioblastomatosis of the central nervous system in a patient with von Hippel-Lindau disease

Hemangioblastomas of the central nervous system are the most common tumors seen in patients with von Hippel-Lindau (VHL) disease. A very rare case of diffuse leptomeningeal hemangioblastomatosis obliterating large areas of the subarachnoid space, both intracranial and within the spinal canal, which developed during a relatively short period, in a patient with VHL disease is presented.

B cells and multiple sclerosis

Clonal expansion of B cells and the production of oligoclonal IgG in the brain and cerebrospinal fluid (CSF) of patients with multiple sclerosis (MS) have long been interpreted as circumstantial evidence of the immune-mediated pathogenesis of the disease and suggest a possible infectious cause. Extensive work on intrathecally produced antibodies has not yet clarified whether they are pathogenetically relevant. Irrespective of antibody specificity, however, the processes of antibody synthesis in the CNS of patients with MS are becoming increasingly clear. Likewise, targeting B cells might be therapeutically relevant in MS and other autoimmune diseases that are deemed to be driven predominantly by T cells. Accumulating evidence indicates that in MS, similar to rheumatoid arthritis, B cells aggregate into lymphoid-like structures in the target organ. The process of aggregation is mediated through the expression of lymphoid-homing chemokines. In the brain of a patient with MS, ectopic B-cell follicles preferentially adjoin the pial membrane within the subarachnoid space. Recent findings indicate that substantial numbers of B cells that are infected with Epstein-Barr virus (EBV) accumulate in these intrameningeal follicles and in white matter lesions and are probably the target of a cytotoxic immune response. These findings, which await confirmation, could be an explanation for the continuous B-cell and T-cell activation in MS, but leave open concerns about the possible pathogenicity of autoantibodies. Going beyond the antimyelin-antibody dogma, the above data warrant further work on various B-cell-related mechanisms, including investigation of B-cell effector and regulatory functions, definition of the consistency of CNS colonisation by Epstein-Barr virus-infected B cells, and understanding of the mechanisms that underlie the formation and persistence of tertiary lymphoid tissues in patients with MS and other chronic autoimmune diseases (ectopic follicle syndromes). This work will stimulate new and unconventional ways of reasoning about MS pathogenesis.

Concomitant localization of a myxopapillary ependymoma at the middle thoracic part of the spinal cord and at the distal part of the filum terminale. Case report

Myxopapillary ependymomas represent the most frequent type of ependymomas found at the conus medullaris-cauda equina-terminal filum level. In this article the authors describe the clinical presentation, radiographic findings, operative details, and pathological features of a patient with a concomitant presentations of a thoracic spinal cord myxopapillary ependymoma and a filum terminale myxopapillary ependymoma. A 16-year-old man presented to the Neurosurgery Department of the S. Maria delle Grazie Hospital (Naples, Italy) with an increased weakness of both the legs with great difficulties with walking and with bowel and bladder dysfunction. In a few minutes he becomes paraplegic. Magnetic resonance (MR) imaging revealed two ependymomas: the first one was localized in the middle thoracic part of the spinal cord and, the second one was localized in the cauda at sacral level. Two operations were performed for gross total resection of the masses. The first operation was performed at thoracic level and the second one was performed at the sacral level after two months. The examination demonstrated in both cases a myxopapillary ependymoma. The patient experienced complete resolution of her preoperative symptoms. This article reports an unusual case of a concomitant presentations of a thoracic spinal cord myxopapillary ependymoma and a filum terminale myxopapillary ependymoma myxopapillary. To the best of the authors' knowledge, this association has not yet been reported. This raises the interesting question of a possible associative or causative relationship between these pathologies. The authors considered dissemination to be the spread of tumor along the neuraxis to a location separate from the primary site. They do not believe that the lesion at the cauda level was a drop metastase. As the entire spinal cord and the brain were imaged, and as the tumor in the thoracic spinal cord area was we well capsulated, a disseminated ependymoma was confidently excluded.

Cerebral subarachnoid blood migration consecutive to a lumbar haematoma after spinal anaesthesia

We report the case of a woman who received spinal anaesthesia for peripheral vascular surgery of the lower limbs and subsequently developed a spinal subarachnoid haematoma. Interestingly, low back pain was the only symptom of this spinal subarachnoid haemorrhage. During the following days, blood migrated from the spinal haematoma towards the cerebral subarachnoid spaces. The patient presented with stupor, nausea and vomiting that resolved within 2 weeks with conservative treatment.

Apoptosis in meningoencephalitis of Angiostrongylus cantonensis-infected mice

A hallmark of eosinophilic meningoencephalitis is infiltration of leukocytes into brain parenchyma and subarachnoid space infected by Angiostrongylus cantonensis. Apoptosis, a process that eliminates useless cells and counterbalances tissue homeostasis, is important for homeostasis of the immune system. In this study, we investigated the characteristics of cell death induced in BABL/c mice infected with A. cantonensis. We observed increased expression of the apoptotic proteins, caspase-3, caspase-8, caspase-9, and cytochrome c, and decreased expression of anti-apoptotic proteins, B-cell leukemia 2 and inhibitor of apoptosis protein 1. On immunohistochemistry, apoptotic proteins were localized within the leukocytes infiltrate. A terminal deoxynucleotidyl transferase-mediated deoxyuridine 5-triphosphate nick-end labeling assay to detect DNA fragmentation confirmed these observations. The infiltration of leukocytes present in the brain parenchyma and subarachnoid space in vivo may also express these apoptotic regulatory molecules, which demonstrates the capacity of these cells to undergo apoptosis.

[Adhesive lumbar arachnoiditis. Endoscopic subarachnoepidurostomy as a new treatment]

BACKGROUND

Adhesive lumbar arachnoiditis is essentially an unknown, unreported, and unrecognised disease. It was better known at a time when oil-based dye was used for myelography. The factors causing this pathogenesis remain unknown. In addition, diagnosis is hard to achieve and frequently attained only by an exclusion process. Only in severe cases, using high-resolution MRI, is evidence for the diagnosis obtainable.

METHOD/PATIENTS

Modern neuroendoscopic techniques allow diagnosis at a reasonable risk (comparable with lumbar tap) and enable us substantially to treat the pain. Taken together, this means a radical new method of treatment for adhesive arachnoiditis. The treatment of a 23-patient research group suffering from adhesive lumbar arachnoiditis is monitored and described.

RESULTS

Various endoscopic manoeuvres were carried out. Endoscopic reduction of adhesions and internal shunting for CSF flow between subarachnoidal and epidural space improved both the biomechanical abilities of rootlets and restoration of blocked CSF pathways. Its main result is the significant reduction of long-term pain registered by a visual analogue pain scale. No bad side effect other than temporary headache was found. No CSF leak syndrome was observed.

DISCUSSION

The success of the method was directly influenced by the interventional procedure on the disturbed CSF circulation and its partial restoration (subarachnoepidurostomy). In cases of severe lumbar adhesive arachnoiditis, it was found very beneficial to implant special gravity-controlled valve systems for subarachnoid-peritoneal shunts.

CONCLUSION

Adhesive lumbar arachnoiditis is no longer a devastating diagnosis. Due to a novel endoscopic treatment of the local CSF disturbances that restores physiologic pathways, the chance exists for long-lasting improvement of the clinical condition.

Clinics in diagnostic imaging (119). Post-traumatic intracerebral pneumatocele

A 36-year-old man presented with cerebrospinal fluid rhinorrhoea after head injury in a road traffic accident three weeks prior to presentation. Magnetic resonance (MR) imaging demonstrated a hypointense cavity in the left frontal lobe communicating with the frontal horn of the left lateral ventricle, consistent with an intracerebral pneumatocele. The fistulous track communicating with the frontal sinus was demonstrated on the sagittal and coronal images. The patient underwent surgical decompression of the cavity and repair of the dural defect and fracture of the frontal bone. Postoperatively, the patient made excellent recovery. An intracerebral pneumatocele should be recognised on MR imaging, as potential complications include tension pneumocephalus and meningitis, and surgical treatment is indicated in most of the cases.

Hyperintensity in the subarachnoid space on FLAIR MRI

OBJECTIVE

The purposes of this essay are to illustrate the causes of FLAIR hyperintensity in the subarachnoid space and to outline the mechanisms of the findings.

CONCLUSION

FLAIR subarachnoid space hyperintensity may be encountered with both pathological conditions and artifacts. Knowledge of these conditions and appearances coupled with any associated findings may suggest the cause of the FLAIR subarachnoid space hyperintensity. A diffuse distribution and a lack of ancillary findings often remain nonspecific and may require clinical correlation and CSF analysis.

Giant cystic widening of Virchow-Robin spaces: an anatomofunctional study

We describe 2 patients with unusual white matter cystic dilations, which could correspond to widening of the perivascular spaces. They underwent morphologic MR imaging with tractography, functional MR imaging (fMRI), and neuropsychological evaluation. fMRI examination showed no functional reorganization of cortical areas. Tractography showed an apparent decrease of white matter tract vectors into the regions of concern. Findings of the neuropsychological examination were normal. It seems that even an extensive cystic dilation of white matter does not deteriorate brain function.

Spinal angiolipoma with acute subarachnoid hemorrhage

Angiolipoma is a rare tumor of the spine commonly presenting with compressive myelopathy. We report a spinal angiolipoma in a 14-year-old patient with acute spinal subarachnoid hemorrhage (SAH). To our knowledge this is the first reported case of a spinal angiolipoma presenting with SAH, associated with post-subclavian coarctation with diffuse hypoplasia of the descending aorta. This association of coarctation of aorta, aortic hypoplasia and spinal angiolipoma has also not been reported previously.

Increased signal in the subarachnoid space on fluid-attenuated inversion recovery imaging associated with the clearance dynamics of gadolinium chelate: a potential diagnostic pitfall

BACKGROUND AND PURPOSE

Hyperintense CSF in the subarachnoid space (SAS) on fluid-attenuated inversion recovery (FLAIR) imaging has been reported in numerous pathologic conditions, including subarachnoid hemorrhage, meningitis, meningeal carcinomatosis, superior sagittal thrombosis, adjacent tumors, status epilepticus, and stroke. It has also been reported in otherwise healthy patients undergoing anesthesia with supplemental oxygen. We present a series of 11 patients with hyperintense CSF signal intensity in the SAS on FLAIR imaging after previous administration of gadolinium chelate.

MATERIALS AND METHODS

Head MR images of patients who had a prior gadolinium-enhanced body, spine, or brain MR imaging and who had increased signal intensity in the SAS on FLAIR images were prospectively and retrospectively reviewed. Correlation was made with the clinical and laboratory findings.

RESULTS

Eight of the 11 patients had negative findings on lumbar punctures. Seven patients had either chronic renal insufficiency or acute renal failure, but the remaining 4 had normal renal function. Nine patients had no other significant intracranial abnormalities, and 2 patients had acute infarcts remote from the CSF hyperintensity. One patient had follow-up studies at 24 and 48 hours, documenting resolution of the CSF hyperintensities.

CONCLUSION

Given the sharp rise in volume of contrast-enhanced MR imaging studies, it is inevitable that some patients will have undergone a contrast-enhanced MR imaging 24-48 hours before an MR imaging of the brain. The neuroradiologist should be aware that previous administration of gadolinium chelate can cause increased signal intensity in the SAS on FLAIR imaging in patients with or without a history of renal insufficiency and without abnormalities known to disrupt the blood-brain barrier.

Multiple extradural arachnoid cysts: report of two operated cousin cases

STUDY DESIGN

Report of 2 operated cousin cases of the multiple spinal extradural arachnoid cysts.

OBJECTIVE

To report the operative findings of cousin cases of the multiple spinal extradural arachnoid cysts and analyze a genetic etiology with the pedigree of all family members.

SUMMARY OF BACKGROUND DATA

Spinal extradural arachnoid cyst is a relatively rare condition that occupies the intraspinal space and sometimes causes neurologic disturbances. The exact etiology is unknown since most reported cases are sporadic. Minimally invasive treatments have been recently applied to a single extradural arachnoid cyst. However, it is still unknown which minimally invasive treatments can be applied to the multiple extradural arachnoid cysts.

METHODS

We experienced 2 cousin cases of multiple spinal extradural arachnoid cysts. Operative findings were described. The pedigree of all family members was made, and a genetic etiology was discussed.

RESULTS

Minimally invasive treatment was tried in Case 1. However, it failed to remove all cysts completely. Each cyst had each stalk communicating with subarachnoid space in both cases. Pedigree showed that the mode of inheritance was likely autosomal dominant.

CONCLUSION

When the cysts are multiple, it is necessary to identify a dural defect in each cyst. The etiology of the multiple extradural arachnoid cysts may be hereditary.

Tuberculous meningitis presenting as mesencephalic infarction and syringomyelia

Cerebral ischaemia is a serious complication of tuberculous meningitis (TBM) with the anterior circulation most commonly affected. Acute syringomyelia is a very rare complication of TBM. Here, we report an unusual presentation of TBM with a third nerve palsy as a result of posterior circulation stroke as well as a syringomyelia.

Diffusion-weighted magnetic resonance imaging of cerebrospinal fluid in patients with and without communicating hydrocephalus

BACKGROUND

Recent concepts about cerebrospinal fluid (CSF) circulation in communicating hydrocephalus (CoHy), which is also termed "restricted arterial pulsation hydrocephalus," suggest reduced arterial pulsations of subarachnoid vessels with a smaller amount of CSF shifted in subarachnoid spaces during the early systole. The postulated restriction of subarachnoid arterial pulsations in CoHy should induce a smaller motion artifact and reduced local stream effects in CSF in magnetic resonance (MR) diffusion-weighted imaging (DWI).

PURPOSE

To investigate the maximum diffusivity in CSF in patients with and without CoHy using DWI.

MATERIAL AND METHODS

12 patients without CSF circulation disturbances and six cases with proven CoHy were assessed. Diffusion was measured in six non-collinear directions without triggering the arterial pulse wave (scan time 6:45 min, voxel size 2x2x2 mm). Due to expected artifacts, the calculated maximum diffusivity was called apparent diffusivity. Regional high and low apparent diffusivity was assessed in CSF spaces on newly created 3D CSF motion maps.

RESULTS

Patients with regular CSF circulation exhibited high apparent diffusivity in CSF in basal subarachnoid spaces, whereas apparent diffusivity was low there in patients with CoHy.

CONCLUSION

DWI opens a feasible approach to study CSF motion in the neurocranium. Restricted arterial pulsations seem to be involved in CoHy.

Atypical growth pattern of a meningioma in an adult

A 49-year-old woman presented with a rare atypical growth pattern of meningioma without evidence of dural attachment manifesting as chronic headache associated with transient paresthesia and left motor disorders. On admission, neurological examination showed no abnormalities. Magnetic resonance (MR) imaging revealed a right temporo-parieto-occipital lesion, which appeared to involve the subdural space and filling the cortical sulci. The lesion caused peritumoral white matter edema. The tumor appeared hypointense on T(1)-weighted and hyperintense on T(2)-weighted MR images, with homogeneous enhancement after contrast administration. A biopsy of the lesion was performed. Histological examination indicated that the lesion was a meningioma. Intraparenchymal meningiomas should be considered in the differential diagnosis of intraaxial lesions in patients of any age.

"Migration" of traumatic subarachnoid hematoma? A case report

BACKGROUND

Traumatic spinal SAH with neurologic deficits is rare and easily misdiagnosed, especially after traumatic intracranial hemorrhage.

CASE DESCRIPTION

We report a case of spinal SAH with root compression occurring after a scooter accident.

CONCLUSIONS

Physicians should be aware of descending migration of intracranial SAH as a possible cause of spinal cord or root compression, especially in the patient with late onset spinal symptoms.

Atypical cervical astrocytoma manifesting as occipitalgia

A 23-year-old female presented with chronic occipitalgia without signs of increased intracranial pressure followed by worsening headache and slight gait unsteadiness. Cerebral magnetic resonance (MR) imaging showed no corresponding lesions. Cervical MR imaging revealed a cervical intramedullary tumor. Intraoperatively the subpial tumor was found to stretch the 3rd-5th dorsal nerve roots posteriorly, which was thought to cause the intolerable headache. Total tumor resection was achieved without requiring myelotomy using electrophysiological monitoring with somatosensory and motor evoked potentials. Histological examination identified diffuse astrocytoma. Postoperatively the headache had completely resolved. Cervical astrocytoma of subpial location is a very rare cause of headache in adults. The subpial location enables surgical extirpation because minimal or no myelotomy is needed.

Three-dimensional histomorphometry of the normal and early glaucomatous monkey optic nerve head: neural canal and subarachnoid space architecture

PURPOSE

To delineate three dimensionally the neural canal landmarks-Bruch's membrane opening (BMO), anterior sclera canal opening (ASCO), anterior laminar insertion (ALI), posterior laminar insertion (PLI), and posterior scleral canal opening (PSCO)-and the anterior-most aspect of the subarachnoid space (ASAS), within digital three-dimensional (3-D) reconstructions of the monkey optic nerve head (ONH).

METHODS

The trephinated ONH and peripapillary sclera from both eyes of three early glaucoma (EG) monkeys (one eye normal, one eye with laser-induced EG) were serial sectioned at 3-microm thickness, with the embedded tissue block face stained and imaged after each cut. The images were aligned and stacked in a 3-D volume, within which the BMO, ASCO, ALI, PLI, PSCO, and ASAS were delineated in 40 digital, radial, and sagittal sections. An ellipse was fitted to the 80 BMO points to establish a BMO zero reference plane, on which all other points were projected. The distance from each projected point to the BMO centroid (offset) and BMO zero reference plane (depth) were calculated and compared regionally between normal and EG eyes, both overall and within each monkey, by analysis of variance.

RESULTS

BMO was the clinically visible optic disc margin in all six eyes. The neural canal architecture was highly variable in the three normal eyes. Radial expansion of the neural canal was greatest posteriorly in the EG eyes. Axial elongation of the canal was less pronounced overall but was regionally present within all three EG eyes. ASAS was regionally radially expanded and anteriorly displaced within two of the three EG eyes.

CONCLUSIONS

Profound deformation of the neural canal and ASAS architecture are present in young adult monkey eyes at the onset of ONH surface change in early experimental glaucoma.

[Dilatation of Virchow-Robin perivascular spaces (types III cerebral lacunae): radio-clinical correlations]

BACKGROUND AND PURPOSE

Virchow-Robin spaces are pia-lined extensions of the subarachnoid space surrounding the path of brain vessels. When enlarged, such dilated perivascular spaces are often seen as foci of cerebrospinal fluid signal on MRI or CT scan. These foci are found in patients with miscellaneous clinical status. It is necessary to determine the radiological significance and clinical associations, if any, in such patients in order to give them the appropriate treatment.

METHODS

We describe the clinical and radiological findings of five patients and review the literature on perivascular Virchow-Robin spaces.

RESULTS

The mechanisms of dilated Virchow-Robin spaces are still not well understood. Such dilated perivascular spaces are found in two locations: typically in the high-convexity white matter of healthy elderly subjects, or surrounding the lenticulostriate vessels as they enter the basal ganglia. On MR images, they may be confused with lacunar infarcts. Most of the patients present with no symptoms: small dilatations located in the high convexity actually represent an anatomic variant, also called "état criblé". Sometimes, giant dilatations, or Poirier's type IIIb "expanding lacunae", found in the basal ganglia and midbrain may result in symptomatic hydrocephalus needing appropriate treatment. For other miscellaneous symptoms as headache, generalized epilepsy, dysmorphy, macrocephaly, there is no reliable correlation with enlarged perivascular spaces seen on MR images.

CONCLUSIONS

The real symptomatic dilated perivascular spaces need appropriate and quick treatment. Most of the other patients present with no symptoms and will remain asymptomatic.

Neuroendoscopically assisted cyst-cisternal shunting for a quadrigeminal arachnoid cyst causing typical trigeminal neuralgia

A quadrigeminal cistern arachnoid cyst is a very rare cause of typical trigeminal neuralgia. A 62-year-old woman presented with right facial pain of 8 years duration. Neuroradiological findings revealed a cystic mass in the quadrigeminal region that compressed the cerebellum downward and the brainstem anteriorly and was associated with hydrocephalus. She had neuroendoscopically-assisted cyst-cisternal shunting via a small craniotomy. Postoperatively, the trigeminal neuralgia disappeared. The origin of the trigeminal neuralgia may have either been a marked distortion of the pons that caused stretching of the trigeminal nerve and irregular demyelination within the root entry zone, or there was contact between the root entry zone and a vascular structure. Neuroendoscopy is useful for treating arachnoid cysts; however, in order to safely relieve symptoms, the procedure needs to be appropriately adapted depending on the pathogenesis. In this paper, we review the literature and discuss the pathophysiology and treatment of our case.

Magnetic resonance imaging and pathological findings in a case of canine idiopathic eosinophilic meningoencephalitis

A case of idiopathic eosinophilic meningoencephalitis in a six-month-old male Maremma shepherd dog is reported. The dog was referred with a four month history of progressive weakness and depression with loss of trained habits. Tendency to recumbency, disorientation, visual impairment, bilaterally decreased menace response and hindlimb conscious proprioception deficits were detected. Magnetic resonance imaging showed a diffuse hypointense signal involving the cerebral grey matter with enlargement of the cerebral sulci on T1-weighted and fast fluid-attenuated inversion recovery (FLAIR) sequences consistent with a diffuse necrosis or atrophy of the cortical grey matter. Histological examination revealed severe inflammatory infiltration mainly composed of eosinophils and macrophages in the subarachnoid space and in the superficial layer of the cerebral cortex where parenchymal rarefaction and necrosis of neurones were also evident. No parasites, cysts or fungi were detected, and an immunologically mediated disorder was suspected. Magnetic resonance imaging may represent a useful diagnostic tool to differentiate idiopathic eosinophilic meningoencephalitis from other inflammatory brain diseases of young dogs.

Symptomatic tension pneumocephalus: An unusual post-operative complication of posterior spinal surgery

Pneumocephalus is a rare, but serious complication of spinal surgery and its management and physiology is not widely recognized. Symptomatic tension pneumocephalus secondary to iatrogenic cerebrospinal fluid (CSF) leak after surgical intervention, and drainage with a vacuum suction device, has not been previously reported. We report a patient who underwent intervertebral disc surgery who developed pneumoencephalus after drainage with a vacuum suction device. Imaging showed significant pneumocephalus in the subarachnoid space of the frontal region and in the cisterns. The condition was resolved by discontinuation of the suction drainage, bed rest and hyperhydration. Thus, spinal drainage may predispose to entry of air intracranially and pneumocephalus. It is important to be aware of this serious post-operative complication in patients with a CSF fistula.

A detailed morphologic and functional magnetic resonance imaging study of the craniocervical junction in adolescent idiopathic scoliosis

STUDY DESIGN

Conventional and phase-contrast magnetic resonance (MR) imaging were used to evaluate the morphology and cerebrospinal fluid (CSF) flow dynamics at craniocervical junction in adolescent idiopathic scoliosis (AIS).

OBJECTIVES

To determine the morphology of cerebellar tonsil, foramen magnum, and dynamic flow of CSF at the craniocervical junction in AIS patients versus normal controls and their correlation with somatosensory cortical evoked potentials (SSEP).

SUMMARY OF BACKGROUND DATA

Previous studies have documented obstructed CSF flow in patients with Chiari I malformation. Low-lying cerebellar tonsils and syringomyelia are also observed in AIS patients. We sought to investigate whether disturbed CSF flow is also evident in AIS subjects at the foramen magnum level and its association with level of cerebellar tonsils and dimensions of foramen magnum.

METHODS

Conventional and phase-contrast MR were performed in 105 adolescent girls (69 AIS subjects and 36 age-matched controls). Measurements of cerebellar tonsillar level related to the basion-opsithion (BO) line, anteroposterior (AP), transverse (TS) diameter, and area of foramen magnum, and peak velocity of CSF flow in both the anterior and posterior subarachnoid space through foramen magnum were obtained. Correlations were made among different parameters and SSEP findings.

RESULTS

A total of 42% of subjects in the AIS group had the cerebellar tonsillar tip positioned 1 mm below the BO line. The cerebellar tonsillar level in AIS subjects was significantly lower than the median tonsillar level in normal controls (P < 0.01). The AP diameter and area of foramen magnum were significantly larger in AIS subjects when compared with normal controls (P < 0.05), but the peak CSF velocities through foramen magnum showed no significant difference (P > 0.05).

CONCLUSION

Peak CSF velocities through foramen magnum were not significantly different in AIS subjects despite the presence of low-lying cerebellar tonsils. This might be explained by the compensatory effect of larger foramen magnum in AIS subjects.

Chronic headache after cranio-cervical trauma--hypothetical pathomechanism based upon neuroanatomical considerations

BACKGROUND

Chronic headache after whiplash injury is common, but the underlying mechanisms have not yet been elucidated. On the basis of human neuroanatomy, we hypothesize that rear-end collision can cause leakage of the cerebrospinal fluid (CSF) into the epidural space most frequently at the lumbosacral level, inducing chronic headache.

METHODS

We considered that the following phenomena would be evident in patients with chronic headache after rear-end collision: (1) orthostatic headache with early onset and long duration, (2) low intracranial pressure (ICP =or< 60 mm H2O), (3) CSF leakage mainly in the lumbosacral region on radioisotope-myelocisternography, and (4) diffuse pachymeningeal enhancement (DPE) on gadolinium enhanced magnetic resonant image (Gd-MRI). The clinical signs and symptoms, ICP and neuroimaging findings were analyzed retrospectively in 20 patients who complained of chronic headache after rear-end collisions.

RESULTS

Headaches were orthostatic and started on the day of the accident in 14 patients. The headaches lasted more than 3 months in all patients. Mean ICP was 120 +/- 30 cm H2O. Only one patient showed low ICP. RI-myelocisternography revealed signs of CSF leakage at the lumbosacral level in 10 patients. Gd-MRI showed no abnormalities known to be characteristic of spontaneous intracranial hypotension (SIH). Chronic headache disappeared or was diminished in all patients by epidural blood patching in the lumbosacral region.

CONCLUSION

This clinical study partly supports the validity of our verifiable hypothetical mechanism. The ICP is not low and DPE is not observed on Gd-MRI. Therefore, CSF leakage into the epidural space may not occur, but spinal CSF absorption may be over-activated. This condition may represent a new clinical entity.

Ruptured cerebral aneurysm complicated with rebleeding following thrombolysis during endovascular embolization: two case reports

A 68-year-old woman and a 42-year-old woman presented with subarachnoid hemorrhage due to rupture of cerebral aneurysm. Both patients were treated with endovascular coil embolization. Thromboembolic complications occurred during the procedure and local thrombolysis was performed for recanalization. One patient developed massive rebleeding immediately after the procedure and the other suffered minor hemorrhage adjacent to the embolized aneurysm 2 days later. Local thrombolysis during treatment of ruptured aneurysm by coil embolization carries a significant risk of rebleeding. Prevention of thromboembolic complication by adequate heparinization is important.

Focal Chronic Inflammatory Epileptic Encephalopathy in a Patient with Malformations of Cortical Development, with a Review of the Spectrum of Chronic Inflammatory Epileptic Encephalopathy

PURPOSE

Chronic cellular inflammation closely associated with epilepsy without an active infection is a hallmark of Rasmussen encephalitis (RE). RE has typical and defining features lacking in other rare epilepsy patients who also have neocortical lymphocytes without an identifiable cause. A patient with malformations of cortical development had an abrupt change in frequency and epileptic focus after 22 years of a stable seizure disorder. Functional neurosurgery yielded a specimen showing a mixed cellular meningoencephalitis in the absence of a demonstrable infection.

METHODS

Historical, neurologic, electroencephalographic, pathologic, and literature data were correlated.

RESULTS

There was a subarachnoid mixed infiltrate including evidence of dendritic cells in our patient and also cytotoxic T lymphocytes adjacent to karyolytic neurons that corresponded to cells previously demonstrated to damage neurons in RE. Literature review disclosed 42 other cases similar to RE but with heterogeneous findings. The course was more protracted and often more benign than in RE. The inflammation that would have markedly decreased or disappeared in RE over that period was generally still well represented.

CONCLUSIONS

Our patient has heterogeneous features similar to, yet with differences from, RE. Literature review of chronic cellular inflammatory epileptic encephalopathy cases also similar to RE discloses important differences that may reflect idiosyncratic reactions and pace of the disease rather than a different disease. Comorbidity factors, genetic population traits, and secondary effects of the seizure disorder may lead to an expansion of the initial site of damage by an autoimmune reaction. These cases might best be grouped, probably along with RE, as secondary autoimmune diseases.

Anterior sacral meningocele. A case report

A case of anterior sacral meningocele in a 6-year-old girl is reported. The laminotomies of L5, S1, and S2 vertebrae were performed through a median posterior approach. The communication between the subarachnoid space and the meningocele was closed using dural fibrin patch, which has not yet been described in the literature. The relevant literature is reviewed.

Intracranial dissemination of primary spinal cord anaplastic oligodendroglioma

We report the first case of a 22-year-old man, with a previously neurosurgically treated intramedullary anaplastic oligodendroglioma (World Health Organization grade III), who developed 19 months later two histologically proven intracranial metastases. We support a hypothesis whereby the anaplastic parts of tumors have spread along the spinal cord and brainstem via the cerebrospinal fluid pathways, a process that could be promoted by surgical manipulation, although the relative contribution of the two factors remains speculative.

Deafferentation Pain Resulting from Cervical Posterior Rhizotomy is Alleviated by Chromaffin Cell Transplants into the Rat Spinal Subarachnoid Space

OBJECTIVE

Deafferentation pain is common after posttraumatic brachial plexus avulsion in humans. Alleviation of such pain is poorly achieved by most therapeutic interventions; the only efficient neurosurgical procedure currently available is lesioning of the dorsal root entry zone. Previous work has demonstrated that adrenal medullary transplants into the lumbar spinal subarachnoid space can alleviate neuropathic pain behavior resulting from peripheral nerve or spinal cord injury. The purpose of this study was to evaluate the potential effects of adrenal medullary transplants on brachial plexus deafferentation pain.

METHODS

The cervical posterior rhizotomy model was selected as an upper segmental deafferentation model because it mimics the pathological situation after traumatic brachial plexus avulsion in humans. Animals underwent a right posterior cervical rhizotomy extending from C5 to T1 and received either adrenal medullary transplants or control striated muscle transplants into the cervical subarachnoid space. The clinical evolution was evaluated daily for self-directed behaviors indicative of ongoing pain, including onset, dermatomal extent, and severity.

RESULTS

In animals with muscle control transplants, self-directed behaviors appeared in 83.3% of the group, with a mean delay between rhizotomy and onset of self-directed behaviors of 8 days. In contrast, only 30.8% of the animals implanted with chromaffin cells exhibited any signs of self-directed behaviors, and these had a mean onset delay of 14 days.

CONCLUSION

The suppression of self-directed behaviors by adrenal medullary transplants is similar to that observed after dorsal root entry zone lesioning and suggests that this approach may offer a nonablative alternative in the management of deafferentation pain resulting from dorsal root avulsion.

Presumed recurrence of intracranial Rosai-Dorfman disease as a cervical spine tumor

Sinus histiocytosis with massive lymphadenopathy, Rosai-Dorfman disease (RDD) rarely involves the central nervous system. Previously reported lesions in the spine were primary occurrences. We report a patient who developed presumed secondary symptomatic involvement of the spine five years following therapy for a primary intracranial RDD.

Posttraumatic intratumoural haemorrhage: an unusual presentation of spinal ependymoma

Ependymomas presenting with intratumoural and/or subarachnoid haemorrhages are seen rarely. These haemorrhages are mostly due to anticoagulation, epidural analgesia or pregnancy. A 62-year-old male farmer with cauda equina syndrome after a work-related trauma is presented. He was admitted to our hospital with paraparesis, faecal incontinence and sensory loss below the level of the lumbar-2 dermatome. Magnetic resonance imaging of the spine displayed an intradural mass lesion at the level of the first lumbar vertebrae. The lesion was excised totally via dorsal midline approach. Histopathologic examination revealed grade-3 ependymoma with intratumoural haemorrhage. The patient's symptoms were relieved completely on postoperative day 7. The patient was given information about periodical examination for recurrence and discharged on the third postoperative week. Asymptomatic spinal lesions should be considered for operation whenever detected because of unpredicted complications.

Multiple schwannomas: report of two cases

In this paper authors present two cases of multiple schwannomas without the features of neurofibromatosis (NF). The authors retrospectively reviewed the hospital charts, radiology films, operative notes and pathology slides of these two patients. There was no family history of neurofibromatosis. The two patients had contrast enhanced MRI, which was negative for vestibular schwannomas. Both underwent surgical excision of symptomatic lesions. Histopathology confirmed these lesions as schwannomas. Molecular genetic analysis in case 1 demonstrated two distinct mutations of the NF2 gene in two different schwannomas, with concomitant loss of heterozygosity in both tumours. In contrast peripheral blood lymphocytes did not reveal mutations of NF2. The authors recommend surgery for symptomatic lesions. Asymptomatic tumours can be monitored. Regular follow up is essential as they may develop fresh lesions at any time. The relevant literature is discussed.

Perimesencephalic Non-aneurysmal Subarachnoid Hemorrhage Caused by Cavernous Sinus Thrombosis-Case Report-

A 37-year-old man presented with perimesencephalic non-aneurysmal subarachnoid hemorrhage associated with cavernous sinus thrombosis. Anticoagulant therapy was administered to treat the cavernous sinus thrombosis, but provoked severe intracranial hemorrhage, severely disabling the patient. Perimesencephalic non-aneurysmal subarachnoid hemorrhage is a benign clinical entity with generally good prognosis, but the association with cavernous sinus thrombosis requires careful investigation prior to treatment.

Gyriform differentiation in medulloblastoma - a radiological predictor of histology

Medulloblastoma with extensive nodularity (MBEN) is a variant with an apparently favorable outcome. The authors describe a 2-month-old child with MBEN who had a characteristic gyriform morphology on MR imaging preoperatively and was found to have local metastasis into the adjoining cerebellum on histopathological examination. This case illustrates that histological subtyping may be possible based on the imaging morphology in selected tumors, which may have a bearing on the management of these tumors.