Peripheral facial nerve palsy in severe systemic hypertension: a systematic review

Signs of nervous system dysfunction such as headache or convulsions often occur in severe systemic hypertension. Less recognized is the association between severe hypertension and peripheral facial nerve palsy. The aim of this study was to systematically review the literature on the association of peripheral facial palsy with severe hypertension.

A clinical approach to arterial ischemic childhood stroke: increasing knowledge over the last decade

Childhood stroke is increasingly being recognized as an important burden not only for affected children and families, but also for socioeconomic reasons. A primary problem is delayed diagnosis, due to the many mimics of childhood stroke, and the variety of manifesting symptoms. The most important is hemiparesis (with/without dysphasia or facial palsy), but ataxia, seizures, and many more are also possible. Suspicion of stroke has to be ascertained by neuroimaging, gold standard being (diffusion weighted) magnetic resonance. Risk factors are multiple, but their presence might help to increase the suspicion of stroke. The most important factors are infectious/parainfectious etiologies, frequently possibly manifesting by transient focal cerebral arteriopathy (FCA). Cardiological underlying problems are the second most important. Arteriopathies can be detected in about half of the children, besides FCA and dissection and MoyaMoya disease are the most important. Hereditary coagulopathies increase the risk of stroke. There is still a controversy on best treatment in children: platelet antiaggregation and heparinization are used about equally. Thrombolysis is being discussed increasingly. Severity of symptoms at manifestation and on follow-up are not less significant in children than in young adults. About two-third of the children have significant residual neurological problems and a majority cognitive and behavior problems.

Cerebral formation in situ of S-carboxymethylcysteine after ifosfamide administration to mice: a further clue to the mechanism of ifosfamide encephalopathy

The clinical use of the alkylating oxazaphosphorine ifosfamide is hampered by a potentially severe encephalopathy. S-carboxymethylcysteine (SCMC), a metabolite of ifosfamide (IF), activates the alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)/kainate receptor, causes neuronal acidification, and could thus be responsible for the encephalopathy. Since the presence of SCMC in brain has not been documented following administration of IF, SCMC was measured in the brain of mice following both the individual i.p. administration of IF and SCMC. SCMC was found in a concentration of 108.2 +/- 29.7 nmol/g following IF, but was detectable at much lower levels following the administration of SCMC (21.1 +/- 21.2 nmol/g). Together with the observation that the concentration of SCMC was 10-fold higher in liver than in brain 1h after administration of SCMC, these findings suggest that the SCMC found after IF was formed in the brain in situ. The concentration of glutamic acid was similar in IF and SCMC treated animals. Methylene blue, which is used clinically to treat and to prevent IF encephalopathy, did not decrease the formation of SCMC in brain. By inhibiting monoamine oxidase activity it did, however, markedly increase the concentration of serotonin in brain which could modulate the effects of SCMC on AMPA/kainate receptors. Thus, SCMC is present in brain following the administration of IF and could contribute to the IF-associated encephalopathy by activation of AMPA/kainate receptors.

Lateralized and frequency-dependent effects of prefrontal rTMS on regional cerebral blood flow

Repetitive transcranial magnetic stimulation (rTMS) is a means to study the function and connectivity of brain areas. The present study addressed the question of hemispheric asymmetry of frontal regions and aimed to further understand the acute effects of high- and low-frequency rTMS on regional cerebral blood flow (rCBF). Sixteen healthy right-handed men were imaged using H(2)(15)O positron emission tomography (PET) immediately after stimulation. High (10 Hz)- and low (1 Hz)-frequency suprathreshold short-duration rTMS was applied over either the left or right dorsolateral prefrontal cortex (DLPFC). Slow and fast rTMS applied over the left DLPFC significantly increased CBF in the stimulated area. Compared to baseline, slow rTMS induced a significant increase in CBF contralateral to the stimulation site, in the right caudate body and in the anterior cingulum. Furthermore, slow rTMS decreased CBF in the orbitofrontal cortex (OFC, ipsilateral to stimulation side). Fast rTMS applied over the right DLPFC was associated with increased activity at the stimulation site, in the bilateral orbitofrontal cortex and in the left medial thalamus compared to 1-Hz rTMS. These results show that rCBF changes induced by prefrontal rTMS differ upon hemisphere stimulated and vary with stimulation frequency. These differential neurophysiological effects of short-train rTMS with respect to side and frequency suggest hemisphere-dependent functional circuits of frontal cortico-subcortical areas.

Orofacial/cerebral injuries and the use of mouthguards by professional athletes in Switzerland

The objective of the present study was to measure the occurrence of orofacial and cerebral injuries in different sports and to survey the awareness of athletes and officials concerning the use of mouthguards during sport activities. Two hundred and sixty-seven professional athletes and 63 officials participating in soccer, handball, basketball and ice hockey were interviewed. The frequency of orofacial and cerebral trauma during sport practice was recorded and the reason for using and not using mouthguards was assessed. A great difference in orofacial and cerebral injuries was found when comparing the different kinds of sports and comparing athletes with or without mouthguards. 45% of the players had suffered injuries when not wearing mouthguards. Most injuries were found in ice hockey, (59%), whereas only 24% of the soccer players suffered injuries when not wearing mouthguards. Sixty-eight percentage of the players wearing mouthguards had never suffered any orofacial and cerebral injuries. Two hundred and twenty-four athletes (84%) did not use a mouthguard despite general acceptance by 150 athletes (56%). Although the awareness of mouthguards among officials was very high (59%), only 25% of them would support the funding of mouthguards and 5% would enforce regulations. Athletes as well as coaches should be informed about the high risk of oral injuries when performing contact sports. Doctors and dentists need to recommend a more intensive education of students in sports medicine and sports dentistry, and to increase their willingness to become a team dentist.

Initiation of high-frequency oscillatory ventilation and its effects upon cerebral circulation in pigs: an experimental study

BACKGROUND: Current practice at high-frequency oscillatory ventilation (HFOV) initiation is a stepwise increase of the constant applied airway pressure to achieve lung recruitment. We hypothesized that HFOV would lead to more adverse cerebral haemodynamics than does pressure controlled ventilation (PCV) in the presence of experimental intracranial hypertension (IH) and acute lung injury (ALI) in pigs with similar mean airway pressure settings. METHODS: In 12 anesthetized pigs (24-27 kg) with IH and ALI, mean airway pressure (P(mean)) was increased (to 20, 25, 30 cm H(2)O every 30 min), either with HFOV or with PCV. The order of the two ventilatory modes (cross-over) was randomized. Mean arterial pressure (MAP), intracranial pressure (ICP), cerebral perfusion pressure (CPP), cerebral blood flow (CBF) (fluorescent microspheres), cerebral metabolism, transpulmonary pressures (P(T)), and blood gases were determined at each P(mean) setting. Our end-points of interest related to the cerebral circulation were ICP, CPP and CBF. RESULTS: CBF and cerebral metabolism were unaffected but there were no differences between the values for HFOV and PCV. ICP increased slightly (HFOV median +1 mm Hg, P<0.05; PCV median +2 mm Hg, P<0.05). At P(mean) setting of 30 cm H(2)O, CPP decreased during HFOV (median -13 mm Hg, P<0.05) and PCV (median -17 mm Hg, P<0.05) paralleled by a decrease of MAP (HFOV median -11 mm Hg, P<0.05; PCV median -13 mm Hg, P<0.05). P(T) increased (HFOV median +8 cm H(2)O, P<0.05; PCV median +8 cm H(2)O, P<0.05). Oxygenation improved and normocapnia maintained by HFOV and PCV. There were no differences between both ventilatory modes. CONCLUSIONS: In animals with elevated ICP and ALI, both ventilatory modes had effects upon cerebral haemodynamics. The effects upon cerebral haemodynamics were dependent of the P(T) level without differences between both ventilatory modes at similar P(mean) settings. HFOV seems to be a possible alternative ventilatory strategy when MAP deterioration can be avoided.

Decreased infarct size after focal cerebral ischemia in mice chronically infected with Toxoplasma gondii

To determine whether Toxoplasma gondii infection could modify biological phenomena associated with brain ischemia, we investigated the effect of permanent middle cerebral artery occlusion (MCAO) on neuronal survival, inflammation and redox state in chronically infected mice. Infected animals showed a 40% to 50% decrease of infarct size compared with non-infected littermates 1, 4 and 14 days after MCAO. The resistance of infected mice may be associated with increased basal levels of anti-inflammatory cytokines and/or a marked reduction of the MCAO-related brain induction of two pro-inflammatory cytokines, tumor necrosis factor-alpha and interferon-gamma (IFNgamma). In addition, potential anti-inflammatory/neuroprotective factors such as nerve growth factor, suppressor of cytokine signaling-3, superoxide dismutase activity, uncoupling protein-2 and glutathione (GSH) were upregulated in the brain of infected mice. Consistent with a role of GSH in central cytokine regulation, GSH depletion by diethyl maleate inhibited Toxoplasma gondii lesion resistance by increasing the proinflammatory cytokine IFNgamma brain levels. Overall, these findings indicate that chronic toxoplasmosis decisively influences both the inflammatory molecular events and outcome of cerebral ischemia.

Comparison of intraarterial and intravenous thrombolysis for ischemic stroke with hyperdense middle cerebral artery sign

BACKGROUND AND PURPOSE: It is unclear whether intraarterial (IAT) or intravenous (IVT) thrombolysis is more effective for ischemic stroke with hyperdense middle cerebral artery sign (HMCAS) on computed tomography (CT). The aim of this study was to compare IAT and IVT in stroke patients with HMCAS. METHODS: Comparison of data from 2 stroke units with similar management of stroke associated with HMCAS, except that 1 unit performed IAT with urokinase and the other IVT with plasminogen activator. Time to treatment was up to 6 hours for IAT and up to 3 hours for IVT. Outcome was measured by mortality and the modified Rankin Scale (mRS), dichotomized at 3 months into favorable (mRS 0 to 2) and unfavorable (mRS 3 to 6). RESULTS: One hundred twelve patients exhibited a HMCAS, 55 of 268 patients treated with IAT and 57 of 249 patients who underwent IVT. Stroke severity at baseline and patient age were similar in both groups. Mean time to treatment was longer in the IAT group (244+/-63 minutes) than in the IVT group (156+/-21 minutes; P=0.0001). However, favorable outcome was more frequent after IAT (n=29, 53%) than after IVT (n=13, 23%; P=0.001), and mortality was lower after IAT (n=4, 7%) than after IVT (n=13, 23%; P=0.022). After multiple regression analysis IAT was associated with a more favorable outcome than IVT (P=0.003) but similar mortality (P=0.192). CONCLUSIONS: In this observational study intraarterial thrombolysis was more beneficial than IVT in the specific group of stroke patients presenting with HMCAS on CT, even though IAT was started later. Our results indicate that a randomized trial comparing both thrombolytic treatments in patients with middle cerebral artery occlusion is warranted.

Pattern of regional cerebral blood-flow changes induced by acute heroin administration--a perfusion MRI study

Although both the subjective and physiological effects of abused psychotropic substances have been characterized, less is known about their effects on brain function. We examined the actions of intravenous diacetylmorphine (heroin), the most widely abused opioid, on regional cerebral blood flow (rCBF), as assessed by perfusion-weighted MR imaging (PWI) in a double-blind and placebo-controlled setting.

Cerebral correlates of muscle tone fluctuations in restless legs syndrome: A pilot study with combined functional magnetic resonance imaging and anterior tibial muscle electromyography

BACKGROUND: The pathology of restless legs syndrome (RLS) is still not understood. To investigate the pathomechanism of the disorder further we recorded a surface electromyogram (EMG) of the anterior tibial muscle during functional magnetic resonance imaging (fMRI) in patients with idiopathic RLS. METHODS: Seven subjects with moderate to severe RLS were investigated in the present pilot study. Patients were lying supine in the scanner for over 50min and were instructed not to move voluntarily. Sensory leg discomfort (SLD) was evaluated on a 10-point Likert scale. For brain image analysis, an algorithm for the calculation of tonic EMG values was developed. RESULTS: We found a negative correlation of tonic EMG and SLD (p <0.01). This finding provides evidence for the clinical experience that RLS-related subjective leg discomfort increases during muscle relaxation at rest. In the fMRI analysis, the tonic EMG was associated with activation in motor and somatosensory pathways and also in some regions that are not primarily related to motor or somatosensory functions. CONCLUSIONS: By using a newly developed algorithm for the investigation of muscle tone-related changes in cerebral activity, we identified structures that are potentially involved in RLS pathology. Our method, with some modification, may also be suitable for the investigation of phasic muscle activity that occurs during periodic leg movements.

Neuro-imaging of cerebral ischemic stroke

Major progress has recently been made in the neuro-imaging of stroke as a result of improvements in imaging hardware and software. Imaging may be based on either magnetic resonance imaging (MRI) or computed tomography (CT) techniques. Imaging should provide information on the entire vascular cervical and intracranial network, from the aortic arch to the circle of Willis. Equally, it should also give information on the viability of brain tissue and brain hemodynamics. CT has the advantage in the detection of acute hemorrhage whereas MRI offers more accurate pathophysiological information in the follow-up of patients.

Cerebral connectivity and psychotic personality traits : A diffusion tensor imaging study

This study aims to investigate the relationship between regional connectivity in the brain white matter and the presence of psychotic personality traits, in healthy subjects with psychotic traits. Thirteen healthy controls were administered the MMPI-2, to assess psychotic traits and, according to MMPI results, a dichotomization into a group of "high-psychotic" and "low-psychotic" was performed. Diffusion tensor imaging (DTI) was used as a non-invasive measure, in order to obtain information about the fractional anisotropy (FA), an intravoxel index of local connectivity and, by means of a voxelwise approach, the between-group differences of the FA values were calculated. The "high-psychotic" group showed higher FA in the left arcuate fasciculus. Subjects with low scores for psychotic traits had significantly higher FA in the corpus callosum, right arcuate fasciculus, and fronto-parietal fibers. In line with previous brain imaging studies of schizophrenia spectrum disorders, our results suggest that psychotic personality traits are related to altered connectivity and brain asymmetry.

Neonatal macrocephaly: cerebral primitive neuroectodermal tumor or neuroblastoma as an infrequent cause--a case report and review of the literature

We report a male term newborn presenting with a congenital macrocephaly 3.5 standard deviations above the median, with a wide and tense anterior fontanel, splayed calvarial sutures, and muscular hypotonia. Antenatal head circumferences were repeatedly below the median. A postnatal head ultrasound showed a large right intracerebral mass with right lateral ventricle compression, right temporal horn dilation, and right frontal horn enlargement with lateral displacement. Additional imaging by computed tomography scan and magnetic resonance imaging was performed. A decompression was performed and histology, immunohistochemistry, and molecular biology supported the diagnosis of a primitive neuroectodermal tumor. A MYCN gene amplification assay remained negative. The incidence of neonatal brain tumors is between 1.4 and 4.1/100,000 live births. Their most common presentation is macrocephaly, hydrocephalus, stillbirth, or diagnosis by pre- or postnatal imaging. Although hydrocephaly and intra- or extracranial hemorrhage are the most frequent causes of congenital macrocephaly, this should be initially investigated by head ultrasound. A suspected malignancy will be confirmed by histopathology, immunohistochemistry, and molecular biology.