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PubMed1985

Spinal cord aspergillus invasion--complication of an aspergilloma.

Acute paraplegia developed in a 53-year-old man with pulmonary aspergilloma because of contiguous extension of Aspergillus infection to the epidural and subdural spaces and spinal cord. Histopathologic findings of the spinal cord showed Aspergillus hyphae penetrating the myelin sheath and myelomalacia, predominantly in the anterior and lateral columns. To the authors' knowledge, there have been no previous descriptions or illustrations of spinal cord involvement and the pathologic changes caused by Aspergillus infection.

Abscess↗
PubMed1990

Spinal opiate administration: a case of catheter misplacement.

Continuous spinal opiate administration via permanently implantable drug delivery devices has been proven to provide profound analgesia for chronic pain conditions. We present a case in which the catheter of an implantable subarachnoid device was misplaced into the subdural/extra-arachnoid space despite the free flow of cerebrospinal fluid. This was verified by x-ray dye studies. It is postulated that this misplacement of the catheter likely occurred as a result of recent lumbar punctures the patient had undergone. Extravasation of cerebrospinal fluid created a false space and contributed to the misplacement and ultimate failure of the device to provide analgesia.

Adult↗
PubMedDate not supplied

Dural carcinomatosis: MR demonstration.

A case of pachymeningeal carcinomatosis is presented in which CT evaluation revealed an extraaxial, heterogeneous density over the left cerebral convexity. The finding was believed to be consistent with subdural hematoma, empyema, or meningeal thickening. Magnetic resonance evaluation demonstrated a similar crescentic lesion that was of intermediate signal intensity on both T1- and T2-weighted images. This was thought to be uncharacteristic of either subdural hematoma or empyema. The T2-weighted image showed CSF interposed between the cerebrum and the lesion, limiting the abnormality to the dura or subdural space.

Biopsy↗
PubMedDate not supplied

Gadolinium-DTPA enhanced MR imaging of spinal dural arteriovenous fistulas.

To evaluate the role of magnetic resonance (MR) in the diagnosis of dural arteriovenous (AV) fistulas and the resulting myelopathy, the MR examinations of 11 patients with symptoms and signs of slowly progressive myelopathy of the lower spinal cord have been reviewed. Patients with intradural or extradural AV malformations were excluded. Six patients have been examined without the use of a contrast agent. The other five patients were studied prior and after intravenous administration of gadolinium-diethylenetriamine pentaacetic acid (DTPA). Serpentine linear areas of low signal due to flow void effects within the subdural space have been detected in seven patients. The T1-weighted sagittal images and T2-weighted sagittal and axial images demonstrated signal intensity changes within the center of the cord due to prolongation of T1 and T2 relaxation times. In addition, a relatively abrupt increase of the sagittal and transverse diameters of the lower thoracic cord was found in all cases. In nine patients T1-weighted, proton-density and T2-weighted sagittal images presented "blurred" margins of the lower thoracic cord. After intravenous administration of Gd-DTPA (0.1 mmol/kg), contrast enhancement was present not only within these vessels but also within the lower spinal cord. There was only slight enhancement of the cord immediately after injection of the contrast agent, but significant enhancement was observed 40-45 min later.

Adult↗
PubMedDate not supplied

An unusual malformation of the forebrain and concomitant destructive encephalopathy with calcifications.

A 9-year old boy with profound mental retardation and severe neurologic deficit presented an unusual malformation of the forebrain distinguished by the following features: 1) microtelencephalon, alobulation, afissuration, and abnormal convolutional pattern; 2) persistence of hippocampal formation at its embryonic site in the dorsomedial wall of the telencephalon; 3) hypoplasia and abnormal configuration of ventricles; 4) agenesis of cerebral commissures; and 5) abnormal location and orientation of gray structures. Important concomitant findings characterized by severe destructive lesions, massive calcification, granular ependymitis, and low grade inflammation were suggestive of late sequelae of an infectious process, possibly congenital. Transplacental transmission of an unidentified pathogen with teratogenic properties was hypothesized as the probable cause. The teratogenic insult started in an early embryonic period and affected primarily the development of the neopallium in the telencephalic wall. The arrested development of the neopallium disrupted the chain of interdependent developmental events; consequently characteristic morphological modifications normally induced by the continuous growth and differentiation of the neopallium failed to occur or took an abnormal course. The name architelencephalon (Greek: arche, beginning; telencephalon, cerebral hemispheres) proposed for this particular malformation of the forebrain indicates its resemblance both to the human brain at early stages of development and also to mammalian brains on a lower level of phylogeny. Associated anomalies included an unilateral microphthalmia with cataract, severe stenosis of the aqueduct of Sylvius and macrocephaly. The microphthalmia was either a developmental anomaly or was infectious in origin. The stenosis of the aqueduct was attributed to granular ependymitis. Tearing of the thin dorsal diencephalic plate and arachnoid membrane and escape of the cerebrospinal fluid into the subdural space probably accounted for the macrocephaly.

Brain↗
PubMed1979

Fine structure of arachnoid cysts.

Recent studies of the fine structure of the cranial meninges of laboratory animals and man have shown that there is no subdural space. The latter is formed artificially by the tendency of meningeal tissues to cleave along a collagen-free zone, the dura-arachnoid interface layer. This layer is composed of an outer zone of dural border cells and an inner arachnoid barrier layer. The fine structure of nine arachnoid cysts was studied to determine the derivation of the cyst's wall from the various components of normal human meninges. A cleaved dura-arachnoid interface layer covered only the dome of the cyst where the latter had abutted the dura mater. The interface layer did not partake in forming the cyst's wall. The dominant phenomenon of the cyst's wall was an absence of the normal trabeculation of the subarachnoid space, the trabecules being replaced by tightly packed collagen fibrils and a few scattered cells in between. Some cells were layered discontinuously at the inner face of the cyst wall, but there was no organized inner lining. No evidence was found for either a tight sealing of the extracellular spaces in the cyst's wall, nor for the existence of an active transcellular fluid movement.

Aged↗
PubMed1994

Changes in hemodynamic and metabolic parameters following induced brain death in the pig.

Changes in hemodynamic and metabolic parameters (systemic oxygen delivery, [DO2], oxygen consumption [VO2], arterial lactate content) in brain-dead and control pigs in the absence of any inotropic or fluid support were studied. Brain death was induced by the inflation of a Foley catheter balloon placed into the subdural space of the animals. Serial atrial natriuretic peptide (ANP) determinations were performed to evaluate concomitant changes occurring in the endocrine function of the heart. Experiments were completed by a volume expansion protocol to provide a dynamic evaluation of these parameters. A significant increase in heart rate (from 113 +/- 5 to 176 +/- 11 beats/min), pulmonary capillary wedge pressure (from 7 +/- 1 to 12 +/- 3 mmHg), dP/dt (from 2040 +/- 340 to 4200 +/- 660 mmHg/sec-1), cardiac output (from 2.4 +/- 0.2 to 3.3 +/- 0.4 L/min), mean arterial pressure (from 66 +/- 8 to 93 +/- 14 mmHg), and systemic oxygen delivery (from 360 +/- 30 to 530 +/- 90 ml/min-1), was observed following brain death induction. These parameters returned below basal values within 60 min. On the contrary, serum lactate and VO2 remained unchanged. Following volume expansion, brain-dead pigs exhibited impaired hemodynamic response, with a significant decrease in dP/dt, MAP, and DO2. These changes were accompanied by a significant decrease in VO2 and a significant increase in lactate plasma levels. At the same time, a similar increase in ANP release was observed in both groups in response to volume expansion, suggesting that despite impaired myocardial contractility, endocrine function of the heart was preserved following brain death. We conclude that brain death leads to early impaired left ventricular contractility, which could be responsible for the changes observed in aerobic to anaerobic metabolism in response to rapid volume infusion. These results suggest that the use of fluid infusion to reduce the need in inotropic support in conventional therapeutic modalities should be used with care in the management of a brain-dead potential organ donor.

Animals↗
PubMed1993

Development of a subdural motor blockade.

We report an unusual development of motor blockade following the subdural injection of local anaesthetic during attempted continuous lumbar epidural anaesthesia. Four characteristic features of subdural block, extensive spread, segmental distribution, delayed onset, and short duration of motor blockade were all features of the case. The patient had gradual development of complete motor blockade in the left upper extremity, incomplete in the right upper extremity, but absence of motor blockade in the lower extremities. The duration of complete motor blockade was 10 min in the hand and 35 min in the arm. The spread of contrast medium in the subdural space revealed the extent and degree of motor blockade.

Aged↗
PubMed2005

Mechanisms behind postspinal headache and brain stem compression following lumbar dural puncture--a physiological approach.

BACKGROUND: The cause of postspinal headache and its specific characteristics are unknown, and whether lumbar dural puncture (LP) triggers brain-stem compression in patients with brain oedema is still controversial. METHODS: Hydrostatic effects of distal opening of the dural sac towards the atmosphere are described and applied to the normal brain and the brain with disrupted BBB. Analogue analyses from previous results using an isolated skeletal muscle enclosed in a rigid shell were applied to the brain in an attempt to simulate and verify the haemodynamic effects of distal opening of the spinal canal. RESULTS: The theoretical considerations and the experimental results are compatible with the hypothesis that hydrostatic effects of distal opening of the fluid-filled spinal canal may obliterate the normal subdural venous collapse after a change from the horizontal to vertical position, which may be compatible with postural postspinal headache as occurring close to pain-sensitive meningeal regions. The hydrostatic forces may also initiate transcapillary filtration and aggravate oedema when permeability is increased, which may cause a narrower situation in the brain stem region, perhaps aggravated by venous stasis and a Cushing reflex-induced increase in blood pressure. An magnetic resonance imaging (MRI) picture illustrates how this scenario may separate the subdural space into an upper high- and a lower low-pressure cavity, pressing the brain downwards with sagging of the brain. A life-threatening positive feedback situation for brain-stem compression may develop. CONCLUSION: The present study strongly suggests that postspinal headache and brain-stem compression and other LP-related effects are predictable following LP, without involving CSF leakage, and can be explained by hydrostatic effects triggered by distal opening of the normally closed dural space to the atmosphere.

Adolescent↗
PubMed1998

Primary ductal adenocarcinoma of the lacrimal gland.

The morphological similarity of salivary and lacrimal gland tumors is known. Many clinicopathological studies and characteristics of salivary duct carcinoma, which bears histological similarities to mammary duct carcinoma, have been recently reported; however, only one case of lacrimal duct carcinoma is reported. A second case of lacrimal duct carcinoma is presented. A 67-year-old male with a painless mass in the right upper eyelid underwent total removal of the tumor mass. Microscopic examination of the tumor mass revealed ductal adenocarcinoma of the lacrimal gland, which was the equivalent of salivary duct carcinoma. The immunohistological studies of the lacrimal duct carcinoma showed similar results to those reported for salivary duct carcinoma. The recurrent tumor in the subdural spaces was removed 2 years after the initial surgery and the patient is followed as an outpatient.

Adenocarcinoma↗
PubMed1994

Cerebral vasodilation capacity: acute intracranial hypertension and supra- and infra-tentorial artery velocity recording.

This experiment is the first to compare cerebral vasomotor reactivity in the supra- and infra-tentorial regions in baseline conditions and during progressive acute intracranial hypertension. The increase in intracranial pressure was performed using liquid pressure transmission in two groups of 16 rabbits by elevating a saline infusion bottle connected to the subdural space. Cerebral microvessel dilation capacity was studied using acetazolamide arterial infusion during three stages of 20 min: at baseline conditions, with an intracranial pressure value equal to half the diastolic arterial pressure and with an intracranial pressure equal to the diastolic arterial pressure. The effects of acetazolamide in the basilar artery and in the carotid siphon were simultaneously monitored by transcranial Doppler sonography during all the experiments. The changes in cerebral vasomotor reactivity occurred with the same intensity and latency in both vascular compartments in baseline conditions. The maximum amplitude of changes happened 30 s later in the basilar artery than in the carotid siphon. When intracranial pressure was above half the diastolic arterial pressure, the vasomotor tone began to decrease in the carotid siphon which supplies a small region of the rabbit brain, whereas it was maintained in the basilar artery. This effect could be explained by brain tissue hypertension. Vasomotor reactivity had nearly disappeared in all the cerebral arteries investigated when intracranial hypertension was equal to the diastolic arterial pressure. These results show evidence of a direct and late effect of acute elevation of intracranial pressure on cerebral microvascular tone. This begins in the supra-tentorial region but there is an early local effect on the carotid siphon due to the brain tissue pressure.

Animals↗
PubMed2001

Human brain temperature in vivo: lack of heating during color transcranial Doppler ultrasonography.

This study was undertaken to assess the effect of ultrasound on human brain temperature in vivo. The investigation consisted of direct recording of intracranial temperature during color transcranial Doppler (TCD) sonography in a neurosurgical patient. The temperature was recorded from 3 thermocouples. One was implanted together with an intracranial pressure sensor into a surgically reduced intraparenchymal hematoma, the second was placed within the subdural space close to the temporal acoustic window, and the third was located extracranially at the outer surface of the temporal bone. Tympanic temperatures were also measured to give an approximation of global brain temperature. A 2.5-MHz transducer was used, and the system settings were as follows: spatial peak temporal average intensity = 234 mW/cm2 in B-mode at a maximum power of 32.3 mW and 2132 mW/cm2 in Doppler mode at a maximum power of 149.3 mW. Neither increase in the intraparenchymal brain temperature nor increase in the temperature at the bone/soft tissue interface was observed during 30 minutes of insonation. The ipsilateral tympanic temperature increased by only 0.06 degree C, and this value may be regarded as a measure of the overall increase in brain temperature. Passive cooling effect produced by the transducer, which was at ambient temperature, was found to reach the brain surface and to surpass any possible heating caused by the ultrasound. The results indicate that no noticeable increases in human brain temperature occur in response to ultrasound emitted by a color TCD device at high transmitter power settings within the diagnostic range.

Body Temperature↗
PubMed1971

Subdural spread of medulloblastoma: case report.

A case of widespread intracranial subdural invasion by medulloblastoma is presented. The origin of the metastases would seem to be a large subfrontal tumour mass, with dissemination through the subdural space. This appears to be the first report of intracranial spread of tumour by this route.

Brain↗
PubMed1974

Raised intracranial pressure and cerebral blood flow. 4. Intracranial pressure gradients and regional cerebral blood flow.

Intracranial pressure was raised by expansion of a supratentorial subdural ballon in anaesthetized baboons. Pressures were measured at several sites, both supratentorial and infratentorial, and cerebral blood flow was measured in each cerebral hemisphere separately. Pressures recorded from the right and left lateral ventricles corresponded closely throughout. Highly significant correlations were also obtained between the pressures in the right and left subdural spaces and the mean intraventricular pressure. There was, thus, no evidence of intracompartmental pressure gradients within the supratentorial space. Pressure gradients did, however, develop between the supratentorial and infratentorial compartments in the majority of experiments, although the level of supratentorial pressure at which this occurred, varied. Despite the presence of a large mass lesion over the right cerebral hemisphere, no significant differences developed between levels of cerebral blood flow in the two hemispheres, although flow in the right hemisphere remained consistently slightly lower than that in the left after the ballon was inserted.

Animals↗
PubMed1996

Inhibition of brain P-450 arachidonic acid epoxygenase decreases baseline cerebral blood flow.

Arachidonic acid (AA) is metabolized by the cytochrome P-450 (P-450) epoxygenase pathway to epoxyeicosatrienoic acids (EETs) in the brain parenchymal tissue and perivascular astrocytes. EETs dilate cerebral microvessels and enhance K+ current in cerebrovascular smooth muscle cells. In the current study, the effect of a subdural administration of miconazole, an inhibitor of P-450 epoxygenase, on microvascular perfusion of rat cerebral cortex was evaluated using laser-Doppler flowmetry (LDF) Baseline cerebral blood flow (CBF) decreased by 29.7 +/- 7.3% (n = 5) after administration of 20 microM miconazole into the subdural space for 30 min. Responses of CBF to sodium nitroprusside and 5-hydroxytryptamine were unaltered by miconazole treatment. Administration of vehicle alone in time-control experiments had no effect on CBF. In other experiments, the effects of miconazole on the metabolism of [14C]AA by cultured rat astrocytes and on nitric oxide synthase activity in homogenates of rat brain were examined. Miconazole inhibited conversion of AA to EETs by cultured astrocytes but had no effect on the conversion of L-arginine to L-citrulline by homogenates of rat brain. These results implicate endogenous P-450 epoxides of AA in the regulation of basal blood flow in cerebral microcirculation.

Animals↗
PubMed1984

External hydrocephalus in infants.

External hydrocephalus means abnormal fluid accumulation in the subarachnoid space under increased pressure with no or slight widening of the ventricles. 9 children were investigated because of pathologically increasing head circumference and abnormal transillumination. PEG and/or CT showed widened sulci frontally, parietally and interhemispherically but no widening of the ventricles. 7 patients were subjected to exploratory craniotomy which disclosed a deep arachnoid space. 2 patients were shunted. All follow-up CT examinations showed normal conditions. We suggest that infants with clinical signs of hydrocephalus and CT picture of external hydrocephalus should not be treated with shunt. The widening of the subarachnoidal space will normalize. The rate of headgrowth will also normalize.

Brain Neoplasms↗
PubMedDate not supplied

Dynamic response of the intracranial system in the conscious dog to papaverine hydrochloride.

The influence of papaverine on the intracranial system of the dog was studied by measuring the pressure-depth-time response for the intact intracranial system, i.e., for the subarachnoid and subpial compartments. This was accomplished by a measurement system which provided an accurate pressure-depth determination and a uniform rate of transducer insertion. Distinct regions of the intracranial system (subarachnoid, transitional, and subpial) were identified from inflections in the pressure response curve. The test parameter, brain relative stiffness (BRS), was obtained by determining the slope of the pressure response values within the subpial region. This parameter is a measure of the "stiffness" or elasticity of bring tissue within the test configuration. A bolus injection of papaverine (1 mg per kilogram, i.v.) caused an increase in the transitional region, a compensatory reduction in the subarachnoid space, and an increase in BRS. It is postulated that at normotensive arterial blood pressure, cerebrovascular expansion caused by papaverine resulted in increased brain tissue elasticity, i.e., an increase in the pressure-depth response for the subpial region. Possible implications for this increase are discussed. Experiments should be conducted in which local blood flow studies are coupled with measurements of brain elastic response.

Animals↗