Transient Episodes Research Articles

Bow Hunter Syndrome Involving Rare PICA Variant (P3-5.032)

<h3>Objective:</h3> NA <h3>Background:</h3> Rotational vertebrobasilar insufficiency, also known as bow hunter’s syndrome (BHS), is a rare cause of dynamic vertebral artery stenosis or occlusion during rotation of the head resulting in posterior circulation ischemia. It is potentially a reversible condition which can remain undetected and cause multiple ischemic strokes in the posterior fossa leading to significant disabilities. A 78-year-old male presented with a two-year history of transient episodes of dysarthria, vertigo, and gait disturbance lasting several minutes. These symptoms occurred after exercise or upon turning his head to the left. Dynamic transcranial doppler (TCD) revealed a significant decline in PCA flow velocities with leftward head turn followed by a hyperemic response after moving his head to a neutral position. Dynamic cerebral angiogram showed the presence of a congenitally anomalous origin of the right posterior inferior cerebellar artery (PICA) which originated at the level of C1 transverse foramen and extended under the C1 lamina. Upon neck rotation, there was near occlusion of the vertebral artery at the PICA origin. Hemilaminectomy of C1 was performed with near resolution of the patient’s symptoms. A follow up TCD confirmed improvement in blood flow parameters post-operatively. <h3>Design/Methods:</h3> NA <h3>Results:</h3> NA <h3>Conclusions:</h3> This case report describes a rare presentation of BHS involving an anomalous cervical origin of right PICA. The patient underwent multiple diagnostic studies including MRIs, inner ear physiology tests, and EEGs without any formal diagnosis. The TCD provided an effective and noninvasive diagnostic modality for position related transient neurological symptoms. Frequent use of such test can help diagnose patients with BHS and improve their quality of life. <b>Disclosure:</b> Miss Trujillo has nothing to disclose. Miss Otero-Bell has nothing to disclose. Dr. Girotra has nothing to disclose.

Marine picocyanobacterial PhnD1 shows specificity for various phosphorus sources but likely represents a constitutive inorganic phosphate transporter

Despite being fundamental to multiple biological processes, phosphorus (P) availability in marine environments is often growth-limiting, with generally low surface concentrations. Picocyanobacteria strains encode a putative ABC-type phosphite/phosphate/phosphonate transporter, phnDCE, thought to provide access to an alternative phosphorus pool. This, however, is paradoxical given most picocyanobacterial strains lack known phosphite degradation or carbon-phosphate lyase pathway to utilise alternate phosphorus pools. To understand the function of the PhnDCE transport system and its ecological consequences, we characterised the PhnD1 binding proteins from four distinct marine Synechococcus isolates (CC9311, CC9605, MITS9220, and WH8102). We show the Synechococcus PhnD1 proteins selectively bind phosphorus compounds with a stronger affinity for phosphite than for phosphate or methyl phosphonate. However, based on our comprehensive ligand screening and growth experiments showing Synechococcus strains WH8102 and MITS9220 cannot utilise phosphite or methylphosphonate as a sole phosphorus source, we hypothesise that the picocyanobacterial PhnDCE transporter is a constitutively expressed, medium-affinity phosphate transporter, and the measured affinity of PhnD1 to phosphite or methyl phosphonate is fortuitous. Our MITS9220_PhnD1 structure explains the comparatively lower affinity of picocyanobacterial PhnD1 for phosphate, resulting from a more limited H-bond network. We propose two possible physiological roles for PhnD1. First, it could function in phospholipid recycling, working together with the predicted phospholipase, TesA, and alkaline phosphatase. Second, by having multiple transporters for P (PhnDCE and Pst), picocyanobacteria could balance the need for rapid transport during transient episodes of higher P availability in the environment, with the need for efficient P utilisation in typical phosphate-deplete conditions.

A superficial siderosis-related transient focal neurological episode in a patient with Marfan syndrome.

Sagittal computed tomography of lumbal spine showing dural ectasia and Tarlow Cyst (red arrows) (A). Magnetic resonance imaging (MRI) axial slice, susceptibility-weighted imaging (SWI) sequences showing siderosis in cerebellar sulci (red arrows) and in the inset uncharacteristic iron deposition in dental nuclei, more pronounced on the left side (red arrows) (B, inset). MRI, SWI, axial slice, showing numerous foci of superficial siderosis (C).

Iatrogenic Cerebral Amyloid Angiopathy Post Neurosurgery: Frequency, Clinical Profile, Radiological Features, and Outcome.

Prion-like transmission of amyloid-ß through cadaveric dura, decades after neurosurgical procedures, has been hypothesized as an iatrogenic cause of cerebral amyloid angiopathy (CAA). We investigated new and previously described patients to assess the clinical profile, radiological features, and outcome of this presumed iatrogenic CAA-subtype (iCAA). Patients were collected from our prospective lobar hemorrhage and CAA database (n=251) with patients presenting to our hospital between 2008 and 2022. In addition, we identified patients with iCAA from 2 other Dutch CAA-expertise hospitals and performed a systematic literature-search for previously described patients. We classified patients according to the previously proposed diagnostic criteria for iCAA, assessed clinical and radiological disease features, and calculated intracerebral hemorrhage (ICH)-recurrence rates. We evaluated the spatial colocalization of cadaveric dura placement and CAA-associated magnetic resonance imaging markers. We included 49 patients (74% men, mean age 43 years [range, 27-84]); 15 from our database (6% [95% CI, 3%-10%]; 45% of patients <55 years), 3 from the 2 other CAA-expertise hospitals, and 31 from the literature. We classified 43% (n=21; 1 newly identified patient) as probable and 57% (n=28) as possible iCAA. Patients presented with lobar ICH (57%), transient focal neurological episodes (12%), or seizures (8%). ICH-recurrence rate in the new patients (16/100 person-years [95% CI, 7-32], median follow-up 18 months) was lower than in the previously described patients (77/100 person-years [95% CI, 59-99], median follow-up 18 months). One patient had a 10 year interlude without ICH-recurrence. We identified no clear spatial relationship between dura placement and CAA-associated magnetic resonance imaging markers. During follow-up (median, 18 months), 20% of the patients developed transient focal neurological episodes and 20% cognitively declined. iCAA seems common in patients presenting with nonhereditary CAA under the age of 55. Clinical and radiological features are comparable with sCAA. After diagnosis, multiple ICH-recurrences but also long symptom-free intervals can occur. Harmonized registries are necessary to identify and understand this potentially underrecognized CAA-subtype.

School Examination Stress Precipitating Hematohidrosis in a Girl

Background: Hematohidrosis is a rare clinical disorder characterized by transient, self-limited bleeding from the eccrine sweat glands through intact skin in the absence of an underlying bleeding disorder. Clinical Description: We report a 10-year-old girl who presented with a history of bleeding from the dorsum of her right hand. The child has had recurrent episodes in the past. Many of the episodes were temporally related to her school examination. She did not have any other bleeding manifestations or susceptibility to bruising. Her general condition and systemic examination were unremarkable, and the skin underlying the bleeding site was normal and healthy. All investigations related to bleeding and coagulation parameters were within normal limits. Skin biopsy showed normal histology. Having ruled out all organic causes of bleeding, the typical history of transient episodes of bloody secretions from the skin, triggered by examination stress and normal skin histology, was consistent with a diagnosis of hematohidrosis. Management: The child responded dramatically to oral propranolol with a subsequent reduction in the frequency of the bloody sweating episodes, even during stressful times. Psychological counseling was also provided. Conclusion: In a child presenting with oozing of blood from the skin, a possibility of hematohidrosis may be considered, when all causes of bleeding diathesis have been ruled out by a thorough workup. Pediatricians need to counsel both parents and the child regarding the benign nature of the condition.

Weathering the storm: a single-institution experience with paroxysmal sympathetic hyperactivity after brain tumor resection in pediatric patients.

Paroxysmal sympathetic hyperactivity (PSH) is a complication of severe traumatic or hypoxic brain injury characterized by transient episodes of tachycardia, tachypnea, hypertension, hyperthermia, diaphoresis, and/or dystonic posturing. Posttraumatic "sympathetic storms" are associated with poor outcomes. PSH rarely occurs after brain tumor resection in pediatric patients; only 4 cases have been published since 1929. Thus, the authors sought to report their experience with postcraniotomy PSH in pediatric brain tumor patients. A retrospective study of patients younger than 18 years of age who underwent craniotomy for brain tumor resection at a single center by a single surgeon over a 7-year period was performed. A clinical diagnosis of postoperative PSH was recorded. Recorded outcomes included the interval between surgery and initiation of cytotoxic therapy, need for long-term CSF diversion, length of hospital stay, and survival. Of the 150 patients who were included for analysis, 4 patients were diagnosed with postoperative PSH for an overall occurrence of 2.7%. PSH patients were younger than non-PSH patients (1.8 ± 0.4 years vs 9.2 ± 5.3 years, p = 0.010) and tended to have intraventricular tumors close to the thalamus, basal ganglia, and/or brainstem. PSH patients experienced longer hospital admissions (44.3 ± 23.4 days vs 6.8 ± 9.4 days, p = 0.001), a shorter interval between surgery and initiation of cytotoxic cancer-directed therapy (14.3 ± 8.0 days vs 90.7 days ± 232.9 days, p = 0.011), and increased need for long-term CSF diversion compared with non-PSH patients (75% vs 25%, p = 0.005). At the last follow-up, 50% of PSH patients had died compared with 13% of non-PSH patients (p = 0.094). PSH is a rare postoperative complication that may affect young children with periventricular tumors and is associated with poorer clinical outcomes. Increasing awareness of this condition is vital to improving patient outcomes.

Headache after transcatheter closure of atrial septal defect: An attempt to explain its origin in the pediatric population.

Transcatheter closure of atrial septal defect (ASD) has become the treatment of choice for most patients. About 5% of them suffer from transient headache episodes (THE) after the procedure, whose etiology is unclear. To evaluate risk factors for THE occurrence after transcatheter closure of ASD in the pediatric population. Eight hundred and forty patients, after transcatheter ASD closure with nitinol devices, from a single center, were included in retrospective analysis. THE was defined as occurring up to 24 hours after the procedure. A logistic regression model including age, weight, ASD diameter, device size, presence of nitinol coating on the device, fluoroscopy time, application of balloon calibration, device oversizing, and residual shunt after 24 hours was created to evaluate risk factors for THE occurrence. There were 40 patients with THE (4.8%), 70% female and 30% male. The median age was 13 (7.35-16) years. In patients with headache, balloon calibration (BC) was performed more frequently (82.5% vs. 43.3%; P <0.001). The balloon waist median (interquartile range [IQR]), 19 (16-22) mm vs. 15 mm (12-18) mm (P <0.001), and device size median (IQR), 18 (13.5-22) mm vs. 14 (11-17) mm (P <0.001) were larger, and residual shunt after 24 hours (12.5% vs. 4.9%; P = 0.03) and a year (7.5 vs. 1.0%; P <0.001) were more frequent. ASD size and the prevalence of double/multiple ASD were similar in both groups. Age, BC application, no nickel release protection, duration of fluoroscopy, and device oversizing were predictors of THE (P <0.001). BC during percutaneous ASD closure and the lack of a protective layer against nickel release on the device are risk factors for headache occurrence in the early postprocedural period.

7T MRI in transient ischemic attacks: Have we only seen the tip of the iceberg?

Transient ischemic attack (TIA) has gained significant attention recently due to the increased incidence of subsequent stroke. However, there are many nonvascular clinical mimics of TIA, creating a need for improved biomarkers to identify a vascular origin. Following the recent approval of ultra-high field (UHF) 7T MRI in clinical practice, several clinical studies have highlighted its added utility in neuroimaging compared to lower-field 1.5T and 3T MRI, particularly in epilepsy and multiple sclerosis. Our case series of three patients with TIA illustrates that 7T MRI can depict small areas of intracortical microhemorrhages and microinfarctions, which could not be resolved with 3T or 1.5T MRI. There are currently no reports of intracortical localization of microhemorrhages in patients with TIA. This discovery may enhance our understanding and characterization of cerebrovascular abnormalities in TIAs. In addition, UHF imaging could potentially be utilized to distinguish transient neurological episodes secondary to cerebrovascular events from other differential considerations. Our cases highlight the underestimation of imaging abnormalities in cases of TIA and support the potential expanded application of clinical 7T to assess patients with TIA. Future studies are necessary at 7T redundant to determine the true incidence of such lesions in TIA and to examine the correlation between cortical microhemorrhages and subsequent ischemic stroke, hemorrhagic events, and neurocognitive impairment.

Magmatic addition rates differentiate periods of steady-state versus flare-up magmatism in the Central Andean arc

Cordilleran arcs are built by long periods of steady-state magmatism punctuated by transient high-flux magmatic episodes or flare-ups. Such flare-ups, manifested as periods of prodigious silicic volcanism and magmatism, result from geodynamic perturbations that cause elevated rates of magma addition to the crust. Questions remain, however, about how magmatic addition rates quantitatively compare between steady-state and flare-up modes of arc magmatism, and how long after the major geodynamic perturbation the flare-up begins. Here, we compute new estimates of erupted volumes over the last 35 Myr for the 22.5–29°S segment of the Central Andes based on a new volcanic geospatial database. These yield magmatic addition rates at least an order of magnitude higher during flare-up compared to steady-state conditions. A lag time of ~8–12 Myr between ocean ridge subduction (the major geodynamic perturbation in the Central Andean arc) and the onset of flare-up conditions is estimated.

Cerebral amyloid angiopathy and atrial fibrillation: anticoagulant dilemma

Cerebral amyloid angiopathy and atrial fibrillation are two frequent comorbidities in older patients, leading to a therapeutic dilemmaon the risk-benefit ratio of long-term anticoagulation. These patients both have a risk of cardioembolic complications due to atrial fibrillation, and a risk of cerebral haemorrhage from cerebral amyloid angiopathy. Since there is no therapeutic consensus, the best therapeutic strategy should be discussed during a multidisciplinary staff, based on four risk estimations: 1) the baseline risk of intracerebral haemorrhage without anticoagulation; 2) the risk of ischaemic stroke without anticoagulation; 3) the expected increase of intracerebral haemorrhage with anticoagulation; 4) the expected reduction in ischaemic stroke risk with anticoagulation. The risk of intracerebral haemorrhage varies according to the cerebral amyloid angiopathy phenotype. Patients with transient neurological episode or cortical superficial siderosis have the highest risk of intracerebral haemorrhage. Direct oral anticoagulant should be preferred to vitaminK antagonists, as the risk of intracerebral haemorrhage is lower with direct oral anticoagulants. If anticoagulation is introduced, a close clinical and radiological monitoring should be performed every 6-12months minimum. If it has been decided not to anticoagulate, left atrial appendage occlusion should be proposed. In all situations, close blood pressure control is essential to reduce the risk of intracerebral haemorrhage.

The 2013 Slab‐Wide Kamchatka Earthquake Sequence

AbstractStudies of initiation of large earthquakes are usually focused on frictional instabilities occurring in the near vicinity of the future rupture. Possible contributions of long‐distance interactions with large‐scale tectonic instabilities remain unknown. Here we analyze seismic catalogs and geodetic time series during a few months preceding the 2013 M = 8.3 deep‐focus Okhotsk earthquake. This deep‐focus event is preceded by four intense seismic clusters in the seismogenic zone. GNSS time series in Kamchatka revealed a transient landward motion episode 1 month prior to the mainshock, consistent with an increase of seismogenic zone loading. This transient loading episode is accompanied by a doubling of the intermediate depth seismicity rate suggesting a transient slab pull as the origin. These observations question the constant subducting velocity hypotheses and may have implications in the understanding of the long‐distance along‐slab stress interactions and in their contribution to initiation of large deep‐focus earthquakes.

Acute stroke in familial Mediterranean fever: An analysis of 23 new cases and systematic review of the literature.

The nature of neurovascular involvement in cases of familial Mediterranean fever (FMF) has not been adequately clarified. Clinical features, infarct topography, vascular status, and stroke etiology were prospectively determined in 35 acute neurovascular events that occurred in 23 FMF patients. Clinicoradiological features were compared with an age- and gender-matched control group of 115 acute stroke patients. Characteristics of additional FMF and acute stroke cases (6 episodes in 6 patients) identified from a systematic literature review (PROSPERO registration no: CRD420212264820) were also analyzed. There were 27 acute ischemic stroke episodes in 19 patients, 7 transient ischemic attack episodes in 3 patients, and 1 patient with a single episode of parietal hematoma in our cohort. Twenty (74%) ischemic stroke episodes in 12 patients were cryptogenic. Ten of these 12 cases had a previous FMF diagnosis and were taking colchicine. There was no significant difference in the FMF group in terms of the presence of vascular risk factors and angiography-documented disease in comparison to controls. Cerebral distal artery involvement was significantly prevalent in FMF (78% vs 45%, P= .002). Especially, midbrain central deep perforating territory involvement was higher (30% vs 1%, P< .001). The long-term prognosis (median 8.5 years) under antiplatelet agents and colchicine is favorable. The acute stroke phenotype in FMF cases is herein described for the first time. Several clinicoradiological features such as thrombotic lacunar infarcts located in the central mesencephalon seem so typical that we recommend searching for FMF mutations in geographic regions where FMF is common.

Cognitive functions and epilepsy-related characteristics in patients with generalized tonic–clonic epilepsy: a cross-sectional study

BackgroundEpilepsy is a brain disorder affecting nearly 65 million people worldwide. It is characterized by sudden, transient, and uncontrolled episodes of brain dysfunction secondary to hypersynchronous abnormal discharge of cortical neuronal cells resulting in motor, sensory, and behavioral manifestations. Cognitive deterioration can occur in approximately 70–80% of epileptic patients with a variety of epilepsy-related characteristics being implicated. This study aimed to assess cognitive functions in a sample of patients with generalized tonic–clonic epilepsy and determine its relation to different epilepsy-related characteristics. It was designed as a case–control cross-sectional study in which 106 participants were enrolled and divided into two groups: a case group of fifty-three patients diagnosed with generalized tonic–clonic epilepsy and a control group including fifty-three healthy subjects. Sociodemographic and epilepsy-related characteristics and a variety of cognitive functions were assessed for both groups.ResultsEpileptic patients were significantly suffering from impairment in attention, memory, visuospatial (P = 0.001), and language functions (P = 0.018) compared to the healthy control group.ConclusionsEpileptic patients are significantly suffering from cognitive impairment with a variety of contributing epilepsy-related characteristics.

The Pathogenesis of Paroxysmal Kinesigenic Dyskinesia: Current Concepts.

Paroxysmal kinesigenic dyskinesia (PKD) is a movement disorder characterized by recurrent and transient episodes of involuntary movements, including dystonia, chorea, ballism, or a combination of these, which are typically triggered by sudden voluntary movement. Disturbance of the basal ganglia-thalamo-cortical circuit has long been considered the cause of involuntary movements. Impairment of the gating function of the basal ganglia can cause an aberrant output toward the thalamus, which in turn leads to excessive activation of the cerebral cortex. Structural and functional abnormalities in the basal ganglia, thalamus, and cortex and abnormal connections between these brain regions have been found in patients with PKD. Recent studies have highlighted the role of the cerebellum in PKD. Insufficient suppression from the cerebellar cortex to the deep cerebellar nuclei could lead to overexcitation of the thalamocortical pathway. Therefore, this literature review aims to provide a comprehensive overview of the current research progress to explore the neural circuits and pathogenesis of PKD and promote further understanding and outlook on the pathophysiological mechanism of movement disorders. © 2023 International Parkinson and Movement Disorder Society.

Marine biogenic emissions of benzene and toluene and their contribution to secondary organic aerosols over the polar oceans

Reactive trace gas emissions from the polar oceans are poorly characterized, even though their effects on atmospheric chemistry and aerosol formation are crucial for assessing current and preindustrial aerosol forcing on climate. Here, we present seawater and atmospheric measurements of benzene and toluene, two gases typically associated with pollution, in the remote Southern Ocean and the Arctic marginal ice zone. Their distribution suggests a marine biogenic source. Calculated emission fluxes were 0.023±0.030 (benzene) and 0.039±0.036 (toluene) and 0.023±0.028 (benzene) and 0.034±0.041 (toluene) μmol m-2 day-1 for the Southern Ocean and the Arctic, respectively. Including these average emissions in a chemistry-climate model increased secondary organic aerosol mass concentrations only by 0.1% over the Arctic but by 7.7% over the Southern Ocean, with transient episodes of up to 77.3%. Climate models should consider the hitherto overlooked emissions of benzene and toluene from the polar oceans.

Schumpeterian competition in a Lucas economy

We model a rent-seeking game where agents experiment with a new technology and compete for claims to a consumption stream. We characterize how creative destruction affects risk, wealth, and asset prices. Competition not only imposes excessive disruption risk on existing assets and higher technological uncertainty, it also increases the wealth duration (the weighted-average maturity of wealth). Because of hedging motives, a complementarity between wealth duration and technological uncertainty decreases systematic risk. If competition is sufficiently intense, a negative risk premium may arise. The model generates price paths consistent with boom-bust patterns and transient episodes of negative expected excess returns. We show that Schumpeterian competition may worsen income inequality.

Takotsubo Syndrome: The Secret Crosstalk between Heart and Brain.

An acute, transient episode of left ventricular dysfunction characterizes Takotsubo syndrome. It represents about 2% of all cases of acute coronary syndrome (ACS), and occurs predominantly in postmenopausal women, generally following a significant physical or emotional stressor. It can be diagnosed based on clinical symptoms and the absence of coronary artery disease on angiography. Ventriculography remains the gold standard for the diagnosis. Despite its transitory characteristic Takotsubo syndrome should not be considered a benign condition since complications occur in almost half of the patients, and the mortality rate reaches 4-5%. Lately, it has been revealed that Takotsubo syndrome can also lead to permanent myocardial damage due to the massive release of catecholamines that leads to myocardial dysfunction. Different mechanisms have been advanced to explain this fascinating syndrome, such as plaque rupture and thrombosis, coronary spasm, microcirculatory dysfunction, catecholamine toxicity, and activation of myocardial survival pathways. Here are still several issues with Takotsubo syndrome that need to be investigated: the complex relationship between the heart and the brain, the risk of permanent myocardial damage, and the impairment of cardiomyocyte. Our review aims to elucidate the pathophysiology and the mechanisms underlying this complex disease to manage the diagnostic and therapeutic algorithms to create a functional synergy between physicians and patients.

Cortical Superficial Siderosis and Transient Focal Neurological Episode Preceding Lobar Hemorrhage in Cerebral Amyloid Angiopathy.

Cortical Superficial Siderosis and Transient Focal Neurological Episode Preceding Lobar Hemorrhage in Cerebral Amyloid Angiopathy.

The role of surface processes in basin inversion and breakup unconformity

In the context of continental extension, transient compressional episodes (stress inversion) and phases of uplift (depth inversion) are commonly recorded with no corresponding change in plate motion. Changes in gravitational potential energy during the rifting process have been invoked as a possible source of compressional stresses, but their magnitude, timing, and relationship with depth inversions remain unclear. Using high-resolution two-dimensional numerical experiments of the full rifting process, we track the dynamic interplay between the far-field tectonic forces, loading and unloading of the surface via surface processes, and gravitational body forces. Our results show that rift basins tend to localize compressive stresses; they record transient phases of compressional stresses as high as 30 MPa and experience a profound depth inversion, 2 km in magnitude, when sediment supply ceases, providing an additional driver for the breakup unconformity, a well-documented phase of regional uplift typically associated with continental breakup.

The role of surface processes in basin inversion and breakup unconformity

Abstract In the context of continental extension, transient compressional episodes (stress inversion) and phases of uplift (depth inversion) are commonly recorded with no corresponding change in plate motion. Changes in gravitational potential energy during the rifting process have been invoked as a possible source of compressional stresses, but their magnitude, timing, and relationship with depth inversions remain unclear. Using high-resolution two-dimensional numerical experiments of the full rifting process, we track the dynamic interplay between the far-field tectonic forces, loading and unloading of the surface via surface processes, and gravitational body forces. Our results show that rift basins tend to localize compressive stresses; they record transient phases of compressional stresses as high as 30 MPa and experience a profound depth inversion, 2 km in magnitude, when sediment supply ceases, providing an additional driver for the breakup unconformity, a well-documented phase of regional uplift typically associated with continental breakup.