Neuroinfectious Emergencies.

OBJECTIVE: This article describes nervous system infections and complications that lead to neurologic emergencies. LATEST DEVELOPMENTS: New research on the use of dexamethasone in viral and fungal infections is reviewed. The use of advanced MRI techniques to evaluate nervous system infections is discussed. ESSENTIAL POINTS: Neurologic infections become emergencies when they lead to a rapid decline in a patient's function. Emergent complications may result from neurologic infections that, if not identified promptly, can lead to permanent deficits or death. These complications include cerebral edema and herniation, spinal cord compression, hydrocephalus, vasculopathy resulting in ischemic stroke, venous thrombosis, intracerebral hemorrhage, status epilepticus, and neuromuscular respiratory weakness.

Neurovascular ultrasound in acute stroke: emergency department applications.

Acute stroke is one of the most common neurologic emergencies encountered by emergency clinicians. While point of care ultrasound has been a core part of emergency clinicians' training and practice for many years, the use of specialized ultrasound modalities in the care of acute ischemic stroke has not been as widely adopted. This review discusses the use of ultrasound in acute stroke, with a focus on applications of interest to emergency clinicians. Transcranial Doppler, carotid Doppler, microembolic signal detection, transthoracic echocardiography, evaluation for collateral circulation and optic nerve sheath diameter measurement are discussed in a case-based format, with a focus on practical applications for emergency clinicians.

Derivation, External Validation and Clinical Implications of a deep learning approach for intracranial pressure estimation using non-cranial waveform measurements.

Importance: Increased intracranial pressure (ICP) is associated with adverse neurological outcomes, but needs invasive monitoring. Objective: Development and validation of an AI approach for detecting increased ICP (aICP) using only non-invasive extracranial physiological waveform data. Design: Retrospective diagnostic study of AI-assisted detection of increased ICP. We developed an AI model using exclusively extracranial waveforms, externally validated it and assessed associations with clinical outcomes. Setting: MIMIC-III Waveform Database (2000-2013), a database derived from patients admitted to an ICU in an academic Boston hospital, was used for development of the aICP model, and to report association with neurologic outcomes. Data from Mount Sinai Hospital (2020-2022) in New York City was used for external validation. Participants: Patients were included if they were older than 18 years, and were monitored with electrocardiograms, arterial blood pressure, respiratory impedance plethysmography and pulse oximetry. Patients who additionally had intracranial pressure monitoring were used for development (N=157) and external validation (N=56). Patients without intracranial monitors were used for association with outcomes (N=1694). Exposures: Extracranial waveforms including electrocardiogram, arterial blood pressure, plethysmography and SpO2. Main Outcomes and Measures: Intracranial pressure > 15 mmHg. Measures were Area under receiver operating characteristic curves (AUROCs), sensitivity, specificity, and accuracy at threshold of 0.5. We calculated odds ratios and p-values for phenotype association. Results: The AUROC was 0.91 (95% CI, 0.90-0.91) on testing and 0.80 (95% CI, 0.80-0.80) on external validation. aICP had accuracy, sensitivity, and specificity of 73.8% (95% CI, 72.0%-75.6%), 99.5% (95% CI 99.3%-99.6%), and 76.9% (95% CI, 74.0-79.8%) on external validation. A ten-percentile increment was associated with stroke (OR=2.12; 95% CI, 1.27-3.13), brain malignancy (OR=1.68; 95% CI, 1.09-2.60), subdural hemorrhage (OR=1.66; 95% CI, 1.07-2.57), intracerebral hemorrhage (OR=1.18; 95% CI, 1.07-1.32), and procedures like percutaneous brain biopsy (OR=1.58; 95% CI, 1.15-2.18) and craniotomy (OR = 1.43; 95% CI, 1.12-1.84; P < 0.05 for all). Conclusions and Relevance: aICP provides accurate, non-invasive estimation of increased ICP, and is associated with neurological outcomes and neurosurgical procedures in patients without intracranial monitoring.

Transcranioplasty Ultrasonography Through a Sonolucent Prosthesis: A Review of Feasibility, Safety, and Benefits.

Data on the effectiveness of transcranioplasty ultrasonography through sonolucent cranioplasty (SC) are new and heterogeneous. We performed the first systematic literature review on SC. Ovid Embase, Ovid Medline, and Web of Science Core Collection were systematically searched and published full text articles detailing new use of SC for the purpose of neuroimaging were critically appraised and extracted. Of 16 eligible studies, 6 reported preclinical research and 12 reported clinical experiences encompassing 189 total patients with SC. The cohort age ranged from teens to 80s and was 60% (113/189) female. Sonolucent materials in clinical use are clear PMMA (polymethylmethacrylate), opaque PMMA, polyetheretherketone, and polyolefin. Overall indications included hydrocephalus (20%, 37/189), tumor (15%, 29/189), posterior fossa decompression (14%, 26/189), traumatic brain injury (11%, 20/189), bypass (27%, 52/189), intracerebral hemorrhage (4%, 7/189), ischemic stroke (3%, 5/189), aneurysm and subarachnoid hemorrhage (3%, 5/189), subdural hematoma (2%, 4/189), and vasculitis and other bone revisions (2%, 4/189). Complications described in the entire cohort included revision or delayed scalp healing (3%, 6/189), wound infection (3%, 5/189), epidural hematoma (2%, 3/189), cerebrospinal fluid leaks (1%, 2/189), new seizure (1%, 2/189), and oncologic relapse with subsequent prosthesis removal (<1%, 1/189). Most studies utilized linear or phased array ultrasound transducers at 3-12 MHz. Sources of artifact on sonographic imaging included prosthesis curvature, pneumocephalus, plating system, and dural sealant. Reported findings were mainly qualitative. We, therefore, suggest that future studies should collect quantitative measurement data during transcranioplasty ultrasonography to validate imaging techniques.

HSV Encephalomyelitis in an Immunocompetent Patient With Prior Splenectomy.

A 44-year-old male with history of asplenia, provoked PE, and hyperlipidemia presented with ascending paralysis, bowel and bladder incontinence and altered mental status, and progressively developed acute hypoxic respiratory failure. Initial workup including CT head, magnetic resonance imaging (MRI) brain, and lumbar puncture which was concerning for herpes simplex virus (HSV) meningoencephalitis; out of caution he was started on multiple antibiotics consequently resulting in the development of Clostridium difficile (C.diff). He also received two doses of IVIG. He was transferred to our institution and after interval re-imaging via MRI brain and spinal surveys and repeat lumbar punctures, he was found to have a high CSF HSV titer and positive GAD 65 antibody, the latter likely a false positive due to IVIG administration. IVIG was not continued from the outside hospital due to the development of deep vein thrombosis (DVT), and the risks of plasmapheresis outweighed the benefits. The patient gradually improved after a prolonged course of acyclovir and was downgraded out of the Neuroscience ICU (NSICU), however decompensated due to rectal bleeding, and subsequently went into cardiac arrest. Though this patient underwent a splenectomy, his relative immunocompetency towards non-encapsulated organisms should have been preserved. It has not been clearly described in the literature how and why HSV encephalomyelitis takes a fulminant course in immunocompetent patients, including our asplenic patient. Furthermore, definitive treatment and management of this condition remains unclear. Severity of HSV encephalomyelitis has not been clearly described in the literature, particularly in immunocompetent patients (such as this asplenic patient).

Cardiac index is associated with oxygenation in COVID-19 acute respiratory distress syndrome.

Eleven participants with COVID-19 acute respiratory distress syndrome requiring mechanical ventilation underwent pulmonary artery catheterization for clinical indications. Clinical interventions or events concurrent with hemodynamic were recorded. Increased cardiac index was associated with worse hypoxemia. Modulation of cardiac index may improve hypoxemia in patients with COVID-19 acute respiratory distress syndrome.

Severe Neurologic Complications of SARS-CoV-2.

PURPOSE OF REVIEW: This review presents an overview of the known neurocritical care complications of severe acute respiratory virus 2 (SARS-CoV-2). We present readers with a review of the literature of severe neurologic complications of SARS-CoV-2 and cases from our institution to illustrate these conditions. RECENT FINDINGS: Neurologic manifestations are being increasingly recognized in the literature. Some patients can have severe neurologic manifestations, though the true prevalence is unknown. SUMMARY: Severe neurologic complications of COVID-19 include large vessel occlusion ischemic stroke, intracranial hemorrhage, encephalitis, myelitis, Guillain-Barre syndrome, status epilepticus, posterior reversible encephalopathy syndrome, and hypoxic-ischemic encephalopathy. These conditions can manifest in COVID-19 patients even in the absence of risk factors and must be promptly identified as they can have a high mortality if left untreated.

Interhospital Transfer of Intracerebral Hemorrhage Patients Undergoing Minimally Invasive Surgery: The Experience of a New York City Hospital System.

OBJECTIVE: The impact of interhospital transfer (IHT) on outcomes of patients with intracerebral hemorrhage (ICH) has not been well studied. We seek to describe the protocolized IHT and systems of care approach of a New York City hospital system, where ICH patients undergoing minimally invasive surgery (MIS) are transferred to a dedicated ICH center. METHODS: We retrospectively reviewed 100 consecutively admitted patients with spontaneous ICH. We gathered information on demographics, variables related to IHT, clinical and radiographic characteristics, and details about the clinical course and outpatient follow-up. We grouped patients into 2 cohorts: those admitted through IHT and those directly admitted through the emergency department. Primary outcome was good functional outcome at 6 months, defined as modified Rankin Scale score 0-3. RESULTS: Of 100 patients, 89 underwent IHT and 11 were directly admitted. On multivariable analysis, there were no significant differences in 6-month functional outcome between the 2 cohorts. All transfers were managed by a system-wide transfer center and 24/7 hotline for neuroemergencies. An ICH-specific IHT protocol was followed, in which a neurointensivist provided recommendations for stabilizing patients for transfer. Average transfer time was 199.7 minutes and average distance travelled was 13.6 kilometers. CONCLUSIONS: In our hospital system, a centralized approach to ICH management and a dedicated ICH center increased access to specialist services, including MIS. Most patients undergoing MIS were transferred from outside hospitals, which highlights the need for additional studies and descriptions of experiences to further elucidate the impact of and best protocols for the IHT of ICH patients.

Fatal cerebral edema in patients with decompensated cirrhosis: A case series.

PURPOSE: Unlike patients with acute liver failure, patients with cirrhosis are not traditionally thought to be at risk for developing cerebral edema. In the largest case series to date, we document clinical characteristics of cirrhotic patients who develop cerebral edema. MATERIALS AND METHODS: In this retrospective case series, seventeen adult patients with acute-on-chronic liver failure (ACLF) were identified using Morbidity & Mortality data. Neurological decompensation was defined by focal neurological deficits or abnormal movements. Elevated ICP was diagnosed clinically by pupillary reflex change improving with hyperosmolar therapy, or by herniation on CT. Pulsatility indices >1.2 on transcranial Dopplers (TCDs) and/or optic nerve sheath diameter (ONSD) >0.5 cm were acceptable alternatives. RESULTS: Median MELD-Na was 36 (IQR 31.5,43) compared with 20 (IQR 19,23) prior to admission. Neurological decompensation was associated with abnormal pupil reactivity in 76% and abnormal movements in 65%. Cerebral edema was diagnosed by CT (n = 14). For those too ill to transport, elevated ICP was confirmed with TCDs for three patients and ONSD for two. Mortality was 100% a median of 3 days (IQR 1.5,5) from neurologic decompensation. CONCLUSIONS: ACLF patients with neurological decompensation exhibit distinct clinical changes. Noninvasive bedside techniques may serve as surrogate measures for ICP.

Neurologic infections during pregnancy.

Neurologic infections during pregnancy represent a significant cause of maternal and fetal morbidity and mortality. Immunologic alterations during pregnancy increase the susceptibility of the premature brain to damage. This chapter summarizes the epidemiology, pathophysiology, and clinical manifestations in the pregnant woman and the infant, and the diagnosis, treatment, and prevention of the major viral, parasitic, and bacterial infections known to affect pregnancy. These organisms include herpes virus, parvovirus, cytomegalovirus, varicella, rubella, Zika virus, toxoplasmosis, malaria, group B streptococcus, listeriosis, syphilis, and tuberculosis. There is an emphasis on the important differences in diagnosis, treatment, and fetal outcome between trimesters. An additional overview is provided on the spectrum of neurologic sequelae of an affected infant, which ranges from developmental delay to hydrocephalus and seizures.

Extensive Pneumorrhachis After Spontaneous Pneumomediastinum.

BACKGROUND: Pneumorrhachis is the presence of air within the spinal canal and is most often traumatic or iatrogenic in etiology. Rarely, a small amount of pneumorrhachis can be seen with spontaneous pneumomediastinum. Here we describe a case of asymptomatic longitudinally extensive pneumorrhachis associated with spontaneous pneumomediastinum. CASE DESCRIPTION: A man in his mid-20s presented to the hospital with subcutaneous emphysema after a choking episode. On imaging of his neck and chest he was noted to have extensive pneumorrhachis with anterior displacement of the spinal cord. Out of concern for further accumulation of air, he was monitored in an intensive care setting for 48 hours but remained asymptomatic. He was discharged home after ruling out esophageal rupture as a cause for his pneumomediastinum. On follow-up 1 month after discharge he was doing well without symptoms. CONCLUSIONS: In cases of spontaneous pneumomediastinum, air can be entrained within the spinal canal. Special attention should be paid to any patient with pneumomediastinum with neurologic symptoms, as this could be due to pneumorrhachis.

COVID-19 and Decompressive Hemicraniectomy for Acute Ischemic Stroke.

BACKGROUND AND PURPOSE: Young patients with malignant cerebral edema have been shown to benefit from early decompressive hemicraniectomy. The impact of concomitant infection with coronavirus disease 2019 (COVID-19) and how this should weigh in on the decision for surgery is unclear. METHODS: We retrospectively reviewed all COVID-19-positive patients admitted to the neuroscience intensive care unit for malignant edema monitoring. Patients with >50% of middle cerebral artery involvement on computed tomography imaging were considered at risk for malignant edema. RESULTS: Seven patients were admitted for monitoring of whom 4 died. Cause of death was related to COVID-19 complications, and these were either seen both very early and several days into the intensive care unit course after the typical window of malignant cerebral swelling. Three cases underwent surgery, and 1 patient died postoperatively from cardiac failure. A good outcome was attained in the other 2 cases. CONCLUSIONS: COVID-19-positive patients with large hemispheric stroke can have a good outcome with decompressive hemicraniectomy. A positive test for COVID-19 should not be used in isolation to exclude patients from a potentially lifesaving procedure.