Cerebral hemodynamic alterations in patients with Covid-19

Cerebral Vasomotor Reactivity in COVID-19: A Narrative Review

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) primarily affects the respiratory system but can also lead to neurological complications. Among COVID-19 patients, the endothelium is considered the Achilles heel. A variety of endothelial dysfunctions may result from SARS-CoV-2 infection and subsequent endotheliitis, such as altered vascular tone, oxidative stress, and cytokine storms. The cerebral hemodynamic impairment that is caused is associated with a higher probability of severe disease and poor outcomes in patients with COVID-19. This review summarizes the most relevant literature on the role of vasomotor reactivity (VMR) in COVID-19 patients. An overview of the research articles is presented. Most of the studies have supported the hypothesis that endothelial dysfunction and cerebral VMR impairment occur in COVID-19 patients. Researchers believe these alterations may be due to direct viral invasion of the brain or indirect effects, such as inflammation and cytokines. Recently, researchers have concluded that viruses such as the Human Herpes Virus 8 and the Hantavirus predominantly affect endothelial cells and, therefore, affect cerebral hemodynamics. Especially in COVID-19 patients, impaired VMR is associated with a higher risk of severe disease and poor outcomes. Using VMR, one can gain valuable insight into a patient's disease progression and make more informed decisions regarding appropriate treatment options. A new pandemic may develop with the COVID-19 virus or other viruses, making it essential that healthcare providers and researchers remain focused on developing new strategies for improving survival in such patients, particularly those with cerebrovascular risk factors.

The Clinical Neurophysiology of COVID-19- Direct Infection, Long-Term Sequelae and Para-Immunization responses: A literature review

The COVID-19 pandemic resulting from the SARS-CoV-2 virus is in its third year. There is continuously evolving information regarding its pathophysiology and its effects on the nervous system. Clinical neurophysiology techniques are commonly employed to assess for neuroanatomical localization and/or defining the spectrum of neurological illness. There is an evolving body of literature delineating the effects of the SARS-CoV-2 virus on the nervous system as well as para-immunization responses to vaccination against this virus. This review focuses on the use of neurophysiological diagnostic modalities in the evaluation of potential acute and long-term neurological complications in patients that experience direct infection with SARS-CoV-2 and analyzes those reports of para-immunization responses to vaccination against the SARS-CoV-2 virus. The neurophysiological modalities to be discussed include electroencephalography (EEG), evoked potentials (EPs), nerve conduction studies and electromyography (EMG/NCV), autonomic function tests, transcranial magnetic stimulation (TMS) and Transcranial Doppler ultrasound (TCD).

Database and AI Diagnostic Tools Improve Understanding of Lung Damage, Correlation of Pulmonary Disease and Brain Damage in COVID-19

The COVID-19 pandemic caused a sharp increase in the interest in artificial intelligence (AI) as a tool supporting the work of doctors in difficult conditions and providing early detection of the implications of the disease. Recent studies have shown that AI has been successfully applied in the healthcare sector. The objective of this paper is to perform a systematic review to summarize the electroencephalogram (EEG) findings in patients with coronavirus disease (COVID-19) and databases and tools used in artificial intelligence algorithms, supporting the diagnosis and correlation between lung disease and brain damage, and lung damage. Available search tools containing scientific publications, such as PubMed and Google Scholar, were comprehensively evaluated and searched with open databases and tools used in AI algorithms. This work aimed to collect papers from the period of January 2019-May 2022 including in their resources the database from which data necessary for further development of algorithms supporting the diagnosis of the respiratory system can be downloaded and the correlation between lung disease and brain damage can be evaluated. The 10 articles which show the most interesting AI algorithms, trained by using open databases and associated with lung diseases, were included for review with 12 articles related to EEGs, which have/or may be related with lung diseases.

Non-Invasive Multimodal Neuromonitoring in Non-Critically Ill Hospitalized Adult Patients With COVID-19: A Systematic Review and Meta-Analysis

Introduction

Neurological complications are frequent in patients with coronavirus disease-2019 (COVID-19). The use of non-invasive neuromonitoring in subjects without primary brain injury but with potential neurological derangement is gaining attention outside the intensive care unit (ICU). This systematic review and meta-analysis investigates the use of non-invasive multimodal neuromonitoring of the brain in non-critically ill patients with COVID-19 outside the ICU and quantifies the prevalence of abnormal neuromonitoring findings in this population.

Methods

A structured literature search was performed in MEDLINE/PubMed, Scopus, Cochrane, and EMBASE to investigate the use of non-invasive neuromonitoring tools, including transcranial doppler (TCD); optic nerve sheath diameter (ONSD); near-infrared spectroscopy (NIRS); pupillometry; and electroencephalography (EEG) inpatients with COVID-19 outside the ICU. The proportion of non-ICU patients with CVOID-19 and a particular neurological feature at neuromonitoring at the study time was defined as prevalence.

Results

A total of 6,593 records were identified through literature searching. Twenty-one studies were finally selected, comprising 368 non-ICU patients, of whom 97 were considered for the prevalence of meta-analysis. The pooled prevalence of electroencephalographic seizures, periodic and rhythmic patterns, slow background abnormalities, and abnormal background on EEG was.17 (95% CI 0.04-0.29), 0.42 (95% CI 0.01-0.82), 0.92 (95% CI 0.83-1.01), and.95 (95% CI 0.088-1.09), respectively. No studies investigating NIRS and ONSD outside the ICU were found. The pooled prevalence for abnormal neuromonitoring findings detected using the TCD and pupillometry were incomputable due to insufficient data.

Conclusions

Neuromonitoring tools are non-invasive, less expensive, safe, and bedside available tools with a great potential for both diagnosis and monitoring of patients with COVID-19 at risk of brain derangements. However, extensive literature searching reveals that they are rarely used outside critical care settings.Systematic Review Registration: www.crd.york.ac.uk/prospero/display_record.php?RecordID=265617, identifier: CRD42021265617.

Evaluation of neurological disorders that develop concurrently with COVID-19 pneumonia: a retrospective analysis

BACKGROUND

During the pandemic, many neurological symptoms have been evaluated as complications of COVID-19 pneumonia.

OBJECTIVE

To investigate the frequency and characteristics of neurological findings, and their effects on the prognosis of patients with COVID-19 pneumonia who consulted with the Neurology department.

METHODS

Data on 2329 patients who were hospitalized with the diagnosis of COVID-19 pneumonia in our hospital were scanned. The clinical, laboratory and radiological findings relating to treatment of 154 patients who required neurological consultation were retrospectively evaluated by reviewing the clinical notes.

RESULTS

The number of COVID-19 pneumonia patients who required neurological consultations while hospitalized in the ICU was 94 (61.0%). The most common symptom among these patients was hyperactive delirium. Mean age, ferritin levels and CRP values ​​of those with delirium were higher, while the mean lymphocyte percentage were lower, than those of the patients without delirium. Epileptic seizures were observed in eight patients without an epilepsy diagnosis. Two patients were diagnosed with GBS and one patient with ICU neuropathy. The D-dimer levels of patients with acute hemorrhagic CVD and the thrombocyte levels of patients with acute ischemic CVD were found to be higher than in patients without acute ischemic CVD.

CONCLUSION

The proportion of patients who required neurological consultations was higher in the ICUs. We observed neurological symptoms more frequently in the advanced age group. There were no significant increases in the incidence of other neurological conditions except delirium, in COVID-19 patients. We think that further studies are needed to support our data.

Treating the body to prevent brain injury: lessons learned from the coronavirus disease 2019 pandemic

PURPOSE OF REVIEW

We aim to provide the current evidence on utility and application of neuromonitoring tools including electroencephalography (EEG), transcranial Doppler (TCD), pupillometry, optic nerve sheath diameter (ONSD), cerebral near-infrared spectroscopy (cNIRS), somatosensory-evoked potentials (SSEPs), and invasive intracranial monitoring in COVID-19. We also provide recent evidence on management strategy of COVID-19-associated neurological complications.

RECENT FINDINGS

Despite the common occurrence of neurological complications, we found limited use of standard neurologic monitoring in patients with COVID-19. No specific EEG pattern was identified in COVID-19. Frontal epileptic discharge was proposed to be a potential marker of COVID-19 encephalopathy. TCD, ONSD, and pupillometry can provide real-time data on intracranial pressure. Additionally, TCD may be useful for detection of acute large vessel occlusions, abnormal cerebral hemodynamics, cerebral emboli, and evolving cerebral edema at bedside. cNIRS was under-utilized in COVID-19 population and there are ongoing studies to investigate whether cerebral oxygenation could be a more useful parameter than peripheral oxygen saturation to guide clinical titration of permissive hypoxemia. Limited data exists on SSEPs and invasive intracranial monitoring.

SUMMARY

Early recognition using standardized neuromonitoring and timely intervention is important to reduce morbidity and mortality. The management strategy for neurological complications is similar to those without COVID-19.

ACE2 expression in rat brain: Implications for COVID-19 associated neurological manifestations

We examined cell type-specific expression and distribution of rat brain angiotensin-converting enzyme 2 (ACE2), the receptor for SARS-CoV-2, in the rodent brain. ACE2 is ubiquitously present in brain vasculature, with the highest density of ACE2 expressing capillaries found in the olfactory bulb, the hypothalamic paraventricular, supraoptic, and mammillary nuclei, the midbrain substantia nigra and ventral tegmental area, and the hindbrain pontine nucleus, the pre-Bötzinger complex, and nucleus of tractus solitarius. ACE2 was expressed in astrocytes and astrocytic foot processes, pericytes and endothelial cells, key components of the blood-brain barrier. We found discrete neuronal groups immunopositive for ACE2 in brainstem respiratory rhythm generating centers, including the pontine nucleus, the parafascicular/retrotrapezoid nucleus, the parabrachial nucleus, the Bötzinger, and pre-Bötzinger complexes and the nucleus of tractus solitarius; in the arousal-related pontine reticular nucleus and gigantocellular reticular nuclei; in brainstem aminergic nuclei, including substantia nigra, ventral tegmental area, dorsal raphe, and locus coeruleus; in the epithalamic habenula, hypothalamic paraventricular and supramammillary nuclei; and in the hippocampus. Identification of ACE2-expressing neurons in rat brain within well-established functional circuits facilitates prediction of possible neurological manifestations of brain ACE2 dysregulation during and after COVID-19 infection.

Cerebral Hemodynamics and Intracranial Compliance Impairment in Critically Ill COVID-19 Patients: A Pilot Study

Introduction: One of the possible mechanisms by which the new coronavirus (SARS-Cov2) could induce brain damage is the impairment of cerebrovascular hemodynamics (CVH) and intracranial compliance (ICC) due to the elevation of intracranial pressure (ICP). The main objective of this study was to assess the presence of CVH and ICC alterations in patients with COVID-19 and evaluate their association with short-term clinical outcomes. Methods: Fifty consecutive critically ill COVID-19 patients were studied with transcranial Doppler (TCD) and non-invasive monitoring of ICC. Subjects were included upon ICU admission; CVH was evaluated using mean flow velocities in the middle cerebral arteries (mCBFV), pulsatility index (PI), and estimated cerebral perfusion pressure (eCPP), while ICC was assessed by using the P2/P1 ratio of the non-invasive ICP curve. A CVH/ICC score was computed using all these variables. The primary composite outcome was unsuccessful in weaning from respiratory support or death on day 7 (defined as UO). Results: At the first assessment (n = 50), only the P2/P1 ratio (median 1.20 [IQRs 1.00-1.28] vs. 1.00 [0.88-1.16]; p = 0.03) and eICP (14 [11-25] vs. 11 [7-15] mmHg; p = 0.01) were significantly higher among patients with an unfavorable outcome (UO) than others. Patients with UO had a significantly higher CVH/ICC score (9 [8-12] vs. 6 [5-7]; p < 0.001) than those with a favorable outcome; the area under the receiver operating curve (AUROC) for CVH/ICC score to predict UO was 0.86 (95% CIs 0.75-0.97); a score > 8.5 had 63 (46-77)% sensitivity and 87 (62-97)% specificity to predict UO. For those patients undergoing a second assessment (n = 29), after a median of 11 (5-31) days, all measured variables were similar between the two time-points. No differences in the measured variables between ICU non-survivors (n = 30) and survivors were observed. Conclusions: ICC impairment and CVH disturbances are often present in COVID-19 severe illness and could accurately predict an early poor outcome.

Latent class cluster analysis identified hidden headache phenotypes in COVID-19: impact of pulmonary infiltration and IL-6

Background and objective

Clinical studies on COVID-19 headache are limited. This prospective study aimed to define headache characteristics, associated clinical and laboratory factors, and treatment response in COVID-19.

Methods

Cross-sectional study enrolled 287 patients diagnosed with COVID-19 and hospitalized on a regular ward during the pandemic. All patients were examined face to face and followed by a neurologist during their stay in the hospital. The characteristics, concomitant symptoms, treatment responses, and laboratory findings of COVID-19-associated headaches were recorded.

Results

Eighty-three COVID-19 patients reported headache (28.9%), in which 85.5% had no prior headaches. Mean age was 48.40 ± 15.90 and 58% was men. Compared to COVID-19 patients without headache (n = 204), patients with headache showed significantly higher frequency of pulmonary involvement (76%) and increased D-dimer levels. Fifty-nine percent of headaches responded iv paracetamol 1000 mg, and 85% of the paracetamol unresponsive headaches were relieved by greater occipital nerve (GON) blocks. Latent class cluster analysis identified 2 distinct class of bilateral, frontal, throbbing headaches: severe (VAS > 84), longer (> 14 h), frequent (> 7 headache days), paracetamol unresponsive-GON responsive headaches (85%), with pulmonary involvement (100%), and higher IL-6 levels (> 90 pg/mL) were classified in cluster 1. Cluster 2 included moderately affected patients (VAS > 54, > 6 h, > 4 days, 60% pulmonary involvement, > 20 pg/mL IL-6) and paracetamol responsive headaches (96%). VAS scores showed positive linear correlation with IL-6 levels (p < 0.001; r = 0.567).

Conclusion

The intensity, duration, frequency, bilateral frontal location, and treatment response of COVID-19 headache was related to pulmonary involvement and IL-6 levels, which indicated a role of inflammation in determining the headache manifestations in moderately affected hospitalized patients. ROC curve cutoff values pointed that VAS > 70 severity, > 9 h duration, > 5 headache days, and IL-6 > 43 pg/mL levels can be diagnostic for COVID-19 headache. GON blocks can effectively abort headache when patients are unresponsive to paracetamol, and other NSAIDs are avoided during the SARS-CoV-2 infection.