Brain MRI findings in severe COVID-19 patients: a meta-analysis

Need for awareness and surveillance of long-term post-COVID neurodegenerative disorders. A position paper from the neuroCOVID-19 task force of the European Academy of Neurology

BACKGROUND

Neuropathological and clinical studies suggest that infection with SARS-CoV-2 may increase the long-term risk of neurodegeneration.

METHODS

We provide a narrative overview of pathological and clinical observations justifying the implementation of a surveillance program to monitor changes in the incidence of neurodegenerative disorders in the years after COVID-19.

RESULTS

Autopsy studies revealed diverse changes in the brain, including loss of vascular integrity, microthromboses, gliosis, demyelination, and neuronal- and glial injury and cell death, in both unvaccinated and vaccinated individuals irrespective of the severity of COVID-19. Recent data suggest that microglia play an important role in sustained COVID-19-related inflammation, which contributes to the etiology initiating a neurodegenerative cascade, to the worsening of pre-existing neurodegenerative disease or to the acceleration of neurodegenerative processes. Histopathological data have been supported by neuroimaging, and epidemiological studies also suggested a higher risk for neurodegenerative diseases after COVID-19.

CONCLUSIONS

Due to the high prevalence of COVID-19 during the pandemic, healthcare systems should be aware of, and be prepared for a potential increase in the incidence of neurodegenerative diseases in the upcoming years. Strategies may include follow-up of well-described cohorts, analyses of outcomes in COVID-19-registries, nationwide surveillance programs using record-linkage of ICD-10 diagnoses, and comparing the incidence of neurodegenerative disorders in the post-pandemic periods to values of the pre-pandemic years. Awareness and active surveillance are particularly needed, because diverse clinical manifestations due to earlier SARS-CoV-2 infections may no longer be quoted as post-COVID-19 symptoms, and hence, increasing incidence of neurodegenerative pathologies at the community level may remain unnoticed.

Diffusion tensor imaging after COVID-19 infection: A systematic review

BACKGROUND

Most COVID-19 neuroimaging research focuses on clinically evident lesions occurring during the acute period after infection. Chronic effects on brain structure, especially at a microstructural level, are less well defined. Existing advanced neuroimaging studies report inconsistent differences in white matter integrity after COVID-19 infection. Our aim was to systematically evaluate the advanced neuroimaging literature with a specific focus on examining diffusion MRI (dMRI) abnormalities observable after the resolution of the acute phase of COVID-19 illness.

METHODS

A search of the literature was conducted on PubMed, Embase, and Scopus on May 27th, 2023, and an updated search was performed September 20th, 2024. Inclusion criteria were a quantitative comparison of dMRI metrics between COVID-19 patients and non-COVID-19 volunteers with MRI acquired >6 weeks after COVID-19. Studies that included only subgroups of COVID-19 patients with specific symptoms, case reports, and post-mortem studies were excluded. Forwards and backwards citation chasing were performed.

RESULTS

The initial search identified 1709 unique records, and 11 met inclusion criteria. Most studies included hospitalized COVID-19 patients, with brain MRI acquired between 2 and 6 months after COVID-19 infection. The majority of studies reported lower fractional anisotropy and higher mean diffusivity in the post-COVID-19 cohort, compared to non-COVID-19 controls. However, there were inconsistent findings, with one study reporting higher fractional anisotropy after COVID-19 infection. Cohorts with a more severe acute COVID-19 illness tended to have lower fractional anisotropy and higher mean diffusivity than cohorts with a milder illness course. Compared to shorter follow-up periods, a longer time between COVID-19 and MRI was associated with fewer differences between COVID-19 patients and non-COVID-19 volunteers.

CONCLUSION

A review of the literature indicates that the heterogeneity of findings regarding dMRI metrics after the resolution of the acute phase of COVID-19 illness may be due in part to the severity of COVID-19 illness and the time between COVID-19 and MRI. Future studies should also consider how different SARS-CoV-2 variants differentially affect the structural brain differences after COVID-19.

Altered brain glucose metabolism in COVID-19 disease: an activation likelihood estimation meta-analysis of PET studies

COVID-19 disease, caused by the SARS-CoV-2 virus, has significantly altered modern society and lifestyles. We investigated its impact on brain glucose metabolism by meta-analyzing existing studies that utilized 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) scans of the brain. We conducted a systematic search of MEDLINE and EMBASE databases from inception to August 2024 for English-language publications using the keywords "positron emission tomography", and "COVID-19". We included original research articles that reported changes in brain glucose metabolism following COVID-19 disease. ALE values from these studies were aggregated and tested against a null hypothesis that anticipated a random distribution of ALE values, which proved to be significantly higher than chance. We identified nine papers that met our inclusion criteria. Significant increases in brain glucose metabolism were noted in the left anterior cingulate gyrus, right thalamus, and brainstem. In children with COVID-19 disease, decreased glucose metabolism was observed in the right and left cerebellum, left amygdala/hippocampus, left anterior cingulate gyrus, and right amygdala. In adults with COVID-19 disease, decreased metabolism was seen in the right temporal lobe, brainstem (acute phase), left occipital lobe, left and right temporal lobe (chronic phase). In conclusion, COVID-19 disease impacts brain glucose metabolism, typically manifesting as areas of decreased metabolism in 18F-FDG PET scans, though increases are also observed. These changes in metabolism vary with the patient's age and the time elapsed between the diagnosis of COVID-19 disease and the PET scan.

Long-Term Outcomes of Patients with Pre-Existing Essential Tremor After SARS-CoV-2 Infection

BACKGROUND/OBJECTIVES

Although COVID-19 has been linked to worse outcomes in patients with neurological disorders, its impact on those with essential tremor (ET) remains unclear. To investigate clinical outcomes of ET patients with and without COVID-19 three and a half years post-pandemic.

METHODS

1074 ET patients were evaluated in this retrospective study in the Montefiore Health System from January 2016 to July 2023. Comparisons between ET patients with and without a positive SARS-CoV-2 polymerase chain reaction test were made. Outcomes included post-index date major adverse cardiovascular events (MACEs), new-onset sleep disturbances, fatigue, dyspnea, first-time fall, new-onset anxiety, new-onset depression, headache, new-onset imbalance, new-onset mild cognitive impairment, and all-cause mortality, adjusted hazard ratios (aHR) adjusting for covariates were calculated.

RESULTS

ET patients with COVID-19 had higher prevalence of pre-existing type-2 diabetes, depression, and anxiety compared to ET patients without COVID-19. COVID-19 was significantly associated with higher risk of MACEs, (aHR = 2.39 [1.49, 3.82]), new-onset sleep disturbance, (aHR = 2.12 [1.44, 3.13]), fatigue, (aHR = 1.83 [1.27, 2.65]), dyspnea, (aHR = 1.98 [1.40, 2.80]), first-time fall, (aHR = 4.76 [2.24, 10.14]), new-onset anxiety, (aHR = 3.66 [2.02, 6.64]), and new-onset depression, (aHR = 2.38 [1.20, 4.70]). COVID-19 was not associated with all-cause mortality.

CONCLUSIONS

In patients with ET, COVID-19 significantly increases the risk of several long-term adverse health outcomes, but not mortality.

Differences in brain structure and cognitive performance between patients with long-COVID and those with normal recovery

BACKGROUND

The pathophysiology of protracted symptoms after COVID-19 is unclear. This study aimed to determine if long-COVID is associated with differences in baseline characteristics, markers of white matter diffusivity in the brain, and lower scores on objective cognitive testing.

METHODS

Individuals who experienced COVID-19 symptoms for more than 60 days post-infection (long-COVID) (n = 56) were compared to individuals who recovered from COVID-19 within 60 days of infection (normal recovery) (n = 35). Information regarding physical and mental health, and COVID-19 illness was collected. The National Institute of Health Toolbox Cognition Battery was administered. Participants underwent magnetic resonance imaging (MRI) with diffusion tensor imaging (DTI). Tract-based spatial statistics were used to perform a whole-brain voxel-wise analysis on standard DTI metrics (fractional anisotropy, axial diffusivity, mean diffusivity, radial diffusivity), controlling for age and sex. NIH Toolbox Age-Adjusted Fluid Cognition Scores were used to compare long-COVID and normal recovery groups, covarying for Age-Adjusted Crystallized Cognition Scores and years of education. False discovery rate correction was applied for multiple comparisons.

RESULTS

There were no significant differences in age, sex, or history of neurovascular risk factors between the groups. The long-COVID group had significantly (p < 0.05) lower mean diffusivity than the normal recovery group across multiple white matter regions, including the internal capsule, anterior and superior corona radiata, corpus callosum, superior fronto-occiptal fasciculus, and posterior thalamic radiation. However, the effect sizes of these differences were small (all β<|0.3|) and no significant differences were found for the other DTI metrics. Fluid cognition composite scores did not differ significantly between the long-COVID and normal recovery groups (p > 0.05).

CONCLUSIONS

Differences in diffusivity between long-COVID and normal recovery groups were found on only one DTI metric. This could represent subtle areas of pathology such as gliosis or edema, but the small effect sizes and non-specific nature of the diffusion indices make pathological inference difficult. Although long-COVID patients reported many neuropsychiatric symptoms, significant differences in objective cognitive performance were not found.

Cerebral microbleeds in patients with COVID-19: is there an inevitable connection?

The COVID-19 pandemic has underscored the critical interplay between systemic infections and neurological complications, notably cerebral microbleeds. This comprehensive review meticulously aggregates and analyses current evidence on cerebral microbleeds' prevalence, pathophysiological underpinnings and clinical implications within COVID-19 cohorts. Our findings reveal a pronounced correlation between cerebral microbleeds and increased severity of COVID-19, emphasizing the role of direct viral effects, inflammatory responses and coagulation disturbances. The documented association between cerebral microbleeds and elevated risks of morbidity and mortality necessitates enhanced neurological surveillance in managing COVID-19 patients. Although variability in study methodologies presents challenges, the cumulative evidence substantiates cerebral microbleeds as a critical illness manifestation rather than mere coincidence. This review calls for harmonization in research methodologies to refine our understanding and guide targeted interventions. Prioritizing the detection and study of neurological outcomes, such as cerebral microbleeds, is imperative for bolstering pandemic response strategies and mitigating the long-term neurological impact on survivors.

SARS-CoV-2 infection increases long-term multiple sclerosis disease activity and all-cause mortality in an underserved inner-city population

BACKGROUND

Although certain subsets patients with multiple sclerosis (MS), an immune-mediated disorder, are at higher risk of worse acute COVID-19 outcomes compared to the general population, it is not clear whether SARS-CoV-2 infection impacts long-term outcomes compared with MS patients without COVID-19 infection.

OBJECTIVES

This study investigated MS disease activity and mortality 3.5 years post SARS-CoV-2 infection and compared with MS patients without COVID-19.

METHODS

This retrospective study evaluated 1,633 patients with MS in the Montefiore Health System in the Bronx from January 2016 to July 2023. This health system serves a large minority population and was an epicenter for the early pandemic and subsequent surges of infection. Positive SARS-CoV-2 infection was determined by a positive polymerase-chain-reaction test. Primary outcomes were all-cause mortality, and optic neuritis post SARS-CoV-2 infection. Secondary outcomes included change in disease-modifying therapy (DMT), treatment with high-dose methylprednisolone, cerebellar deficits, relapse, and all-cause hospitalization post-infection.

RESULTS

MS patients with COVID-19 had similar demographics but higher prevalence of pre-existing major comorbidities (hypertension, type-2 diabetes, chronic obstructive pulmonary disease, congestive heart failure, chronic kidney disease, and coronary artery disease), optic neuritis, and history of high dose steroid treatment for relapses compared to MS patients without COVID-19. MS patients with COVID-19 had greater risk of mortality (adjusted HR=4.34[1.67, 11.30], p < 0.005), greater risk of post infection optic neuritis (adjusted HR=2.97[1.58, 5.58], p < 0.005), higher incidence of methylprednisolone treatment for post infection acute relapse (12.65% vs. 2.54 %, p < 0.001), and more hospitalization (78.92% vs. 66.81 %, p < 0.01), compared to MS patients without COVID-19.

CONCLUSIONS

MS patients who survived COVID-19 infection experienced worse long-term outcomes, as measured by treatment for relapse, hospitalization and mortality. Identifying risk factors for worse long-term outcomes may draw clinical attention to the need for careful follow-up of at-risk individuals post-SARS-CoV-2 infection.

Patients with unmet social needs are at higher risks of developing severe long COVID-19 symptoms and neuropsychiatric sequela

This study investigated long COVID of patients in the Montefiore Health System COVID-19 (CORE) Clinics in the Bronx with an emphasis on identifying health related social needs (HRSNs). We analyzed a cohort of 643 CORE patients (6/26/2020-2/24/2023) and 52,089 non-CORE COVID-19 patients. Outcomes included symptoms, physical, emotional, and cognitive function test scores obtained at least three months post-infection. Socioeconomic variables included median incomes, insurance status, and HRSNs. The CORE cohort was older age (53.38 ± 14.50 vs. 45.91 ± 23.79 years old, p < 0.001), more female (72.47% vs. 56.86%, p < 0.001), had higher prevalence of hypertension (45.88% vs. 23.28%, p < 0.001), diabetes (22.86% vs. 13.83%, p < 0.001), COPD (7.15% vs. 2.28%, p < 0.001), asthma (25.51% vs. 12.66%, p < 0.001), lower incomes (53.81% vs. 43.67%, 1st quintile, p < 0.001), and more unmet social needs (29.81% vs. 18.49%, p < 0.001) compared to non-CORE COVID-19 survivors. CORE patients reported a wide range of severe long-COVID symptoms. CORE patients with unmet HRSNs experienced more severe symptoms, worse ESAS-r scores (tiredness, wellbeing, shortness of breath, and pain), PHQ-9 scores (12.5 (6, 17.75) vs. 7 (2, 12), p < 0.001), and GAD-7 scores (8.5 (3, 15) vs. 4 (0, 9), p < 0.001) compared to CORE patients without. Patients with unmet HRSNs experienced worse long-COVID outcomes compared to those without.

Long-term outcomes of hospitalized patients with SARS-CoV-2/COVID-19 with and without neurological involvement: 3-year follow-up assessment

BACKGROUND

Acute neurological manifestation is a common complication of acute Coronavirus Disease 2019 (COVID-19) disease. This retrospective cohort study investigated the 3-year outcomes of patients with and without significant neurological manifestations during initial COVID-19 hospitalization.

METHODS AND FINDINGS

Patients hospitalized for Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection between 03/01/2020 and 4/16/2020 in the Montefiore Health System in the Bronx, an epicenter of the early pandemic, were included. Follow-up data was captured up to 01/23/2023 (3 years post-COVID-19). This cohort consisted of 414 patients with COVID-19 with significant neurological manifestations and 1,199 propensity-matched patients (for age and COVID-19 severity score) with COVID-19 without neurological manifestations. Neurological involvement during the acute phase included acute stroke, new or recrudescent seizures, anatomic brain lesions, presence of altered mentation with evidence for impaired cognition or arousal, and neuro-COVID-19 complex (headache, anosmia, ageusia, chemesthesis, vertigo, presyncope, paresthesias, cranial nerve abnormalities, ataxia, dysautonomia, and skeletal muscle injury with normal orientation and arousal signs). There were no significant group differences in female sex composition (44.93% versus 48.21%, p = 0.249), ICU and IMV status, white, not Hispanic (6.52% versus 7.84%, p = 0.380), and Hispanic (33.57% versus 38.20%, p = 0.093), except black non-Hispanic (42.51% versus 36.03%, p = 0.019). Primary outcomes were mortality, stroke, heart attack, major adverse cardiovascular events (MACE), reinfection, and hospital readmission post-discharge. Secondary outcomes were neuroimaging findings (hemorrhage, active and prior stroke, mass effect, microhemorrhages, white matter changes, microvascular disease (MVD), and volume loss). More patients in the neurological cohort were discharged to acute rehabilitation (10.39% versus 3.34%, p < 0.001) or skilled nursing facilities (35.75% versus 25.35%, p < 0.001) and fewer to home (50.24% versus 66.64%, p < 0.001) than matched controls. Incidence of readmission for any reason (65.70% versus 60.72%, p = 0.036), stroke (6.28% versus 2.34%, p < 0.001), and MACE (20.53% versus 16.51%, p = 0.032) was higher in the neurological cohort post-discharge. Per Kaplan-Meier univariate survival curve analysis, such patients in the neurological cohort were more likely to die post-discharge compared to controls (hazard ratio: 2.346, (95% confidence interval (CI) [1.586, 3.470]; p < 0.001)). Across both cohorts, the major causes of death post-discharge were heart disease (13.79% neurological, 15.38% control), sepsis (8.63%, 17.58%), influenza and pneumonia (13.79%, 9.89%), COVID-19 (10.34%, 7.69%), and acute respiratory distress syndrome (ARDS) (10.34%, 6.59%). Factors associated with mortality after leaving the hospital involved the neurological cohort (odds ratio (OR): 1.802 (95% CI [1.237, 2.608]; p = 0.002)), discharge disposition (OR: 1.508 (95% CI [1.276, 1.775]; p < 0.001)), congestive heart failure (OR: 2.281 (95% CI [1.429, 3.593]; p < 0.001)), higher COVID-19 severity score (OR: 1.177 (95% CI [1.062, 1.304]; p = 0.002)), and older age (OR: 1.027 (95% CI [1.010, 1.044]; p = 0.002)). There were no group differences in radiological findings, except that the neurological cohort showed significantly more age-adjusted brain volume loss (p = 0.045) than controls. The study's patient cohort was limited to patients infected with COVID-19 during the first wave of the pandemic, when hospitals were overburdened, vaccines were not yet available, and treatments were limited. Patient profiles might differ when interrogating subsequent waves.

CONCLUSIONS

Patients with COVID-19 with neurological manifestations had worse long-term outcomes compared to matched controls. These findings raise awareness and the need for closer monitoring and timely interventions for patients with COVID-19 with neurological manifestations, as their disease course involving initial neurological manifestations is associated with enhanced morbidity and mortality.