Temporal Evolution of PM2.5 Levels Related to COVID-19 Mortality in Europe for the Early-2020 to End-2022 Period (preprint)

Rationale: The possible effect of Particulate Matter (PM10 and PM2.5 of diameter 10 and 2.5 µm respectively) levels on Covid-19 mortality is now well established. However, time-evolution of Covid-19 mortality according to PM2.5 levels has been scarcely investigated. Aim: To understand this relationship at the European level for the period 2020 (beginning) - 2022 (end). Methods: 16 representative locations in Europe (81 million people) with heterogeneous levels of PM2.5 (µg.m-3), from low to high. PM2.5 levels were assessed by various methods, and Covid-19 mortality was reported by Johns Hopkins University. Results: The trend of Covid-19 mortality vs. PM2.5 levels varied among locations. Overall, the estimated mean value was of a 40±20% mortality increase per 1 µg.m-3 PM2.5 increase. The stronger the positive gradient of the PM peak, the stronger the positive gradient of the Covid-19 mortality. Exposure to several PM peaks during about a 2-month period was the main contributor to Covid-19 mortality increases. Conclusion: Our data confirm a temporal relation between PM2.5 exposure and Covid-19 mortality, considering a 2-month integration-time for pollution events. Number-concentrations of PM should be used in the future rather than the PM2.5 mass-concentrations (µg.m-3) with the consideration of PM composition to better explain this finding.

Assessment of Aerosol Persistence in ICUs via Low-cost Sensor Network and Zonal Models (preprint)

The COVID-19 pandemic heightened public awareness about airborne particulate matter (PM) due to the spread of infectious diseases via aerosols. The persistence of potentially infectious aerosols in public spaces, particularly medical settings, deserves immediate investigation; however, a systematic approach to characterize the fate of aerosols in most clinical environments has not been reported. This paper presents a methodology for mapping aerosol propagation using a low-cost PM sensor network in ICU and adjacent environments and the subsequent development of the data-driven zonal model. Mimicking aerosol generation by a patient, we generated trace NaCl aerosols and monitored their propagation in the environment. In positive (closed door) and neutral-pressure (open door) ICUs, up to 6% or 19% respectively of all PM escaped through the door gaps, however, the outside sensors did not register an aerosol spike in negative-pressure ICUs. The K-means clustering analysis of temporospatial aerosol concentration data suggests that ICU can be represented by three distinct zones: (1) near the aerosol source, (2) room periphery, and (3) the outside region. These zones inform two-phase aerosol plume behavior: dispersion of the original aerosol spike throughout the room and an evacuation phase where "well-mixed" aerosol concentration in the ICU decayed uniformly. Decay rates were calculated in positive, neutral, and negative modes, with negative-pressure rooms clearing out nearly twice as fast. The aerosol concentration decay followed the trends in the air exchange rates. This research demonstrates the methodology for aerosol persistence monitoring in medical settings; however, it is limited by a relatively small data set and is specific to small-size ICU rooms. Future studies need to evaluate medical settings with high risks of infectious disease transmission and optimize hospital infrastructure.

MRI of Cerebrovascular Injury Associated With COVID-19 and Non-COVID-19 Acute Respiratory Distress Syndrome: A Matched Case-Control Study.

OBJECTIVES: Cerebrovascular injury associated with COVID-19 has been recognized, but the mechanisms remain uncertain. Acute respiratory distress syndrome (ARDS) is a severe pulmonary injury, which is associated with both ischemic and hemorrhagic stroke. It remains unclear if cerebrovascular injuries associated with severe COVID-19 are unique to COVID-19 or a consequence of severe respiratory disease or its treatment. The frequency and patterns of cerebrovascular injury on brain MRI were compared among patients with COVID-19 ARDS and non-COVID-19 ARDS. DESIGN: A case-control study. SETTING: A tertiary academic hospital system. PATIENTS: Adult patients (>18 yr) with COVID-19 ARDS (March 2020 to July 2021) and non-COVID-19 ARDS (January 2010-October 2018) who underwent brain MRI during their index hospitalization. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Cerebrovascular injury on MRI included cerebral ischemia (ischemic infarct or hypoxic ischemic brain injury) and intracranial hemorrhage (intraparenchymal, subarachnoid, or subdural, and cerebral microbleed [CMB]).Twenty-six patients with COVID-19 ARDS and sixty-six patients with non-COVID ARDS underwent brain MRI during the index hospitalization, resulting in 23 age- and sex-matched pairs. The frequency of overall cerebrovascular injury (57% vs 61%), cerebral ischemia (35% vs 43%), intracranial hemorrhage (43% vs 48%), and CMB (52% vs 41%) between COVID-19 ARDS and non-COVID-19 ARDS patients was similar (all p values >0.05). However, four of 26 patients (15%) with COVID-19 and no patients with non-COVID-19 ARDS had disseminated leukoencephalopathy with underlying CMBs, an imaging pattern that has previously been reported in patients with COVID-19. CONCLUSIONS: In a case-control study of selected ARDS patients with brain MRI, the frequencies of ischemic and hemorrhagic cerebrovascular injuries were similar between COVID-19 versus non-COVID-19 ARDS patients. However, the MRI pattern of disseminated hemorrhagic leukoencephalopathy was unique to the COVID-19 ARDS patients in this cohort.

Coats plus in prematurity.

BACKGROUND: Coats plus syndrome or cerebroretinal microangiopathy with calcifications and cysts (CMCC) is an exceedingly rare autosomal recessive disorder that predominantly affects the microvasculature in the retina, brain, bones, and gastrointestinal system. Unlike Coats disease, CMCC is bilateral and affects multiple organ systems. MATERIALS AND METHODS: Case report. RESULTS: We report the case of two brothers with Coats Plus syndrome who presented with variable phenotypic expression. One sibling (Patient 1) was thought to have atypical retinopathy of prematurity and was only diagnosed with Coats plus after his older brother (Patient 2) presented with a seizure and a left upper extremity tremor at 4 years of age. The CTC1 mutation was confirmed in both patients. Aggressive treatment with laser photocoagulation and intravitreal bevacizumab dramatically improved the retinal vascular and exudative changes. CONCLUSION: Coats Plus syndrome can have a variable phenotypic presentation, including retinal vascular findings. This rare genetic disease should be in the differential diagnosis in patients who present with atypical retinal pathology, including Retinopathy of Prematurity, Familial Exudative Vitreoretinopathy, or Coats disease associated with non-specific multiorgan abnormalities.

Sensitivity of diffusion-tensor and correlated diffusion imaging to white-matter microstructural abnormalities: application in COVID-19 (preprint)

There has been growing attention on the effect of COVID-19 on white-matter microstructure, especially among those that self-isolated after being infected. There is also immense scientific interest and potential clinical utility to evaluate the sensitivity of single-shell diffusion MRI methods for detecting such effects. In this work, the sensitivities of three single-shell-compatible diffusion MRI modeling methods are compared for detecting the effect of COVID-19, including diffusion-tensor imaging, diffusion-tensor decomposition of orthogonal moments and correlated diffusion imaging. Imaging was performed on self-isolated patients at baseline and 3-month follow-up, along with age- and sex-matched controls. We demonstrate through simulations and experimental data that correlated diffusion imaging is associated with far greater sensitivity, being the only one of the three single-shell methods to demonstrate COVID-19-related brain effects. Results suggest less restricted diffusion in the frontal lobe in COVID-19 patients. Results also demonstrate, for the first time, more restricted diffusion in the cerebellar white matter, in agreement with several existing studies highlighting the vulnerability of the cerebellum to COVID-19 infection. Whereas correlated diffusion imaging can be successfully applied using single-shell diffusion data, different b-values also confer different sensitivities to these two opposing effects. No significant difference was observed in patients at the 3-month follow-up. To summarize, correlated diffusion imaging is shown to be a sensitive single-shell diffusion analysis approach that allowed us to uncovered opposing patterns of diffusion changes in the frontal and cerebellar regions of COVID-19 patients, suggesting the two regions react differently to viral infection.

Brain microstructural changes and fatigue after COVID-19 (preprint)

Background Fatigue and cognitive complaints are the most frequent persistent symptoms in patients after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. This study aimed to assess fatigue and neuropsychological performance and investigate changes in the thickness and volume of gray matter (GM) and microstructural abnormalities in the white matter (WM) in a group of patients with mild-to-moderate coronavirus disease 2019 (COVID-19). Methods We studied 56 COVID-19 patients and 37 matched controls using magnetic resonance imaging (MRI). Cognition was assessed using Montreal Cognitive Assessment and Cambridge Neuropsychological Test Automated Battery, and fatigue was assessed using Chalder Fatigue Scale (CFQ-11). T1-weighted MRI was used to assess GM thickness and volume. Fiber-specific apparent [fi]ber density (FD), free water index, and diffusion tensor imaging data were extracted using diffusion-weighted MRI (d-MRI). d-MRI data were correlated with clinical and cognitive measures using partial correlations and general linear modeling. Results COVID-19 patients had mild-to-moderate acute illness (95% non-hospitalized). The average period between real-time quantitative reverse transcription polymerase chain reaction-based diagnosis and clinical/MRI assessments was 93.3 ({+/-}26.4) days. The COVID-19 group had higher CFQ-11 scores than the control group (p < 0.001). There were no differences in neuropsychological performance between groups. The COVID-19 group had lower FD in the association, projection, and commissural tracts, but no change in GM. The corona radiata, corticospinal tract, corpus callosum, arcuate fasciculus, cingulate, fornix, inferior fronto-occipital fasciculus, inferior longitudinal fasciculus, superior longitudinal fasciculus, and uncinate fasciculus were involved. CFQ-11 scores correlated with microstructural changes in patients with COVID-19. Conclusions Quantitative d-MRI detected changes in the WM microstructure of patients recovering from COVID-19. This study suggests a possible brain substrate underlying the symptoms caused by SARS-CoV-2 during medium- to long-term recovery.

Acute Disseminated Encephalomyelitis After SARS-CoV-2 Vaccination.

BACKGROUND Acute disseminated encephalomyelitis (ADEM) is a disorder of the central nervous system which has been associated with preceding infection as well as vaccinations. We present a case of a 61-year-old woman with ADEM after receiving her initial vaccination for the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). This case highlights management of this acute condition. CASE REPORT A 61-year-old woman with history of hypertension and anxiety presented with progressive generalized weakness and difficulty with communication which began a few weeks ago, shortly after receiving the Pfizer vaccine for the novel coronavirus (COVID-19). On arrival, she was found to be encephalopathic and tachypneic, ultimately requiring emergent intubation. During her hospital course, an MRI of her brain was obtained which showed nonspecific acute versus subacute leukoencephalopathy involving the brainstem and deep white matter. Her cerebrospinal fluid showed elevated protein but was otherwise unremarkable. Further testing to rule out tick-borne illnesses, viral etiology, and multiple sclerosis were negative. Electroencephalography showed nonspecific diffuse cerebral dysfunction but no seizures or epileptiform discharges. She was treated with 5 doses of methylprednisolone 1 g and intravenous immunoglobulin (IVIG) 2 g/kg over 5 days. She had marked improvement in her neurologic status after treatment. CONCLUSIONS In conclusion, ADEM should be acknowledged as a rare but potential complication related to COVID-19 vaccination. A proper history and physical exam in addition to a thorough work-up are necessary for prompt recognition of this condition. Initial treatment should consist of steroids followed by IVIG versus plasmapheresis for those not responsive to steroids.

Case 303: Delayed Posthypoxic Leukoencephalopathy.

HISTORY: A 54-year-old man was found by paramedics in his home face-down at his computer desk with a substantially reduced level of consciousness. He had not contacted his family for more than 50 hours. The patient lived alone and was a heavy smoker with a history of alcohol abuse. His medical history was otherwise unremarkable, and there was no history of cancer, psoriasis, or rheumatoid arthritis, nor was there a history of methotrexate administration. At presentation to the emergency department, he was mildly hypotensive and was experiencing hypercapnic respiratory failure and acute renal failure with rhabdomyolysis. His toxicology screen was mildly positive for opiates. He received naloxone (Narcan; Emergent) with minimal effect. An unenhanced CT scan of the head was obtained. Of note, this patient's presentation predated the COVID-19 pandemic. He was admitted to the intensive care unit for decreased level of consciousness and respiratory failure. The decreased level of consciousness was thought to be secondary to seizure, as he developed seizurelike movements prior to intubation, probably in the context of intoxication or alcohol withdrawal. Electroencephalography revealed moderate bilateral cerebral dysfunction and encephalopathy, with no evidence of nonconvulsive seizures. He had a short course of intermittent hemodialysis and was discharged home 8 days later with an appointment for neurology follow-up. At discharge, he was at his cognitive and functional baseline. Approximately 3 weeks later, the patient was brought back to the emergency department for progressive confusion and decrease in balance. He became apathetic with reduced psychomotor activity and was no longer able to perform basic daily activities, such as cooking or bathing. He displayed bizarre behavior, such as staring at a wall for hours, and was somnolent, irritable, and inattentive. He eventually became incontinent of urine and stool. Results of a neurologic examination of the cranial nerves, motor function, sensation, and reflexes were normal. The results of blood work-up were grossly normal, and the results of an extensive toxicology work-up were negative. Repeat head CT was performed. MRI was ordered to further investigate the patient's encephalopathic presentation.

COVID-19-associated leukoencephalopathy in the absence of severe hypoxia with subsequent improvement: a case report.

BACKGROUND: Several cases of coronavirus disease 2019 (COVID-19)-associated leukoencephalopathy have been reported. Although most cases involve hypoxia, the pathophysiological mechanism and neurologic outcomes of COVID-19-associated leukoencephalopathy remain unclear. CASE PRESENTATION: We report a case of COVID-19-associated leukoencephalopathy without severe hypoxia in a 65-year-old woman diagnosed with pyelonephritis. After the initiation of intravenous ceftriaxone, her fever resolved, but she developed an altered state of consciousness with abnormal behavior and, subsequently, a relapse fever. She was diagnosed with COVID-19 pneumonia and was intubated. Lung-protective ventilation with deep sedation and neuromuscular blockade were used for treatment. After cessation of sedative administration, her mental status remained at a Glasgow Coma Scale score of 3. COVID-19 was assumed to have caused leukoencephalopathy due to the absence of severe hypoxia or other potential causes. She subsequently showed gradual neurologic improvement. Three months after the COVID-19 diagnosis, she regained alertness, with a Glasgow Coma Scale score of 15. CONCLUSION: Clinicians should consider leukoencephalopathy in the differential diagnosis of consciousness disorders in patients with severe COVID-19, even in the absence of severe hypoxia. Gradual neurologic improvement can be expected in such cases.

Is COVID-19 the culprit for critical illness-associated cerebral microbleeds and encephalopathies or a marker of severe disease: a case series (preprint)

Critical illness-associated cerebral microbleeds and leukoencephalopathy related to COVID-19 infection are increasingly being recognized in the literature. We report seven cases of COVID-19 with microbleeds in the juxtacortical white matter and corpus callosum and one case of leukoencephalopathy.

Zonal Model of Aerosol Persistence in ICUs: Utilization of Time and Space-resolved Sensor Network (preprint)

The COVID-19 pandemic heightened public awareness about airborne particulate matter (PM) due to the spread of infectious diseases via aerosols. The persistence of potentially infectious aerosol in public spaces, particularly medical settings, deserves close investigation; however, approaches for rapidly parameterizing the temporospatial distribution of particles released by an infected individual have not been reported in literature. This paper presents a methodology for mapping the movement of aerosol plumes using a network of low-cost PM sensors in ICUs. Mimicking aerosol generation by a patient, we tracked aerosolized NaCl particles functioning as tracers for potentially infectious aerosols. In positive (closed door) and neutral-pressure (open door) ICUs, an aerosol spike was detected outside the room, with up to 6% or 19% of all PM escaping through the door gaps, respectively. The outside sensors registered no aerosol spike in negative-pressure ICUs. The K-means clustering analysis of temporospatial data suggests three distinct zones: (1) near the aerosol source, (2) room periphery, and (3) immediately outside the room. These zones inform two-phase aerosol plume behavior: dispersion of the original aerosol spike throughout the room, and evacuation phase where "well-mixed" PM decayed uniformly. Decay rates were calculated for 4 ICUs in positive, neutral, and negative mode, with negative modes decaying the fastest. This research demonstrates the methodology for aerosol persistence monitoring in medical settings; however, it is limited by a relatively small data set. Future studies need to evaluate medical settings with high risks of infectious disease, assess risks of airborne disease transmission, and optimize hospital infrastructure.

Experience of Parents of Children with Genetically Determined Leukoencephalopathies Regarding the Adapted Health Care Services During the COVID-19 Pandemic.

Parents of children with genetically determined leukoencephalopathies play a major role in their children's health care. Because of the COVID-19 pandemic, many health care services were suspended, delayed or delivered remotely with telemedicine. We sought to explore the experience of parents of children with genetically determined leukoencephalopathies during the pandemic given the adapted health care services. We conducted semistructured interviews with 13 parents of 13 affected children. Three main themes were identified using thematic analysis: perceived impact of COVID-19 on health care services, benefits and challenges of telemedicine, and expectations of health care after the pandemic. Parents perceived a loss/delay in health care services while having a positive response to telemedicine. Parents wished telemedicine would remain in their care after the pandemic. This is the first study assessing the impact of COVID-19 on health care services in this population. Our results suggest that parents experience a higher level of stress owing to the shortage of services and the children's vulnerability.

White Matter Beta-Amyloid Precursor Protein Immunoreactivity in Autopsied Subjects With and Without COVID-19 (preprint)

The coronavirus SARS-CoV-2 causes COVID-19, a predominantly respiratory disease that has been reported to be associated with numerous neurological signs, symptoms and syndromes. More than 20 published studies have used RT-PCR methods to determine viral SARS-CoV-2 genomic presence in postmortem brain tissue and the overall impression is that viral brain invasion is relatively uncommon and occurs in low copy numbers, supporting indirect mechanisms as the cause of most neurological phenomena. Hypoxic-ischemic brain injury and stroke are one such possible indirect mechanism, as acute ischemia or stroke concurrence with COVID-19 has been reported as being 0.5% to 20%. Immunohistochemical stains for beta-amyloid precursor protein (APP) have been suggested to be a signature change of hypoxic leukoencephalopathy or COVID-19 brain disease, although prior reports have not had a non-COVID-19 control group. We therefore compared the prevalence and intensity of white matter APP staining in the brains of subjects dying with and without COVID-19. Clinical and neuropathological results, including semi-quantitative assessment of the density of white matter APP staining, were compared between 20 COVID-19 cases and 20 pre-COVID-19 autopsy cases, including 10 cases with autopsy-proven non-COVID-19 pneumonia and 10 cases without pneumonia. Positive APP white matter staining in at least one of the two brain regions (precentral gyrus and cingulate gyrus) studied was not significantly more common in COVID-19 vs controls (14/20 vs 12/20). Comparing density scores from both brain regions combined, the mean scores for COVID-19 cases were higher than those for controls of both types together but not significantly different when restricting to controls with pneumonia. Among control cases, cases with pneumonia had significantly higher scores. The presence or absence of a major neuropathologically-defined neurodegenerative disorder did not significantly affect the APP scores. The major finding is that while APP white matter staining cannot be regarded as a specific marker of COVID-19, as it does not occur with significantly greater probability in in COVID-19 brains as compared to non-COVID-19 brains, it is possible that white matter APP staining, representing acute or subacute axonal damage, may be a common occurrence in the perimortem period, and that it may be more intense in subjects dying with pneumonia, regardless of cause.

Long-term neuroimaging follow-up of COVID-19-related leukoencephalopathy.

More than a year after the start of the COVID-19 pandemic, long-term neurological manifestations of COVID-19 are increasingly being reported. The long-term sequelae of COVID-19-related leukoencephalopathy, however, remain unclear. Here, we present long-term neuroimaging follow-up in two cases of COVID-19-related leukoencephalopathy. The two cases demonstrate the utility of brain MRI for evaluating neurologic symptoms in critically ill patients with COVID-19, for diagnosis of underlying neural injury and prognostication of future recovery. The presence of leukoencephalopathy may result in chronic neurologic manifestations and may represent a poor prognosticator of neurologic recovery. The presence of leukoencephalomalacia on follow-up neuroimaging is potentially an indicator of irreversible white matter damage, which may be associated with more severe chronic deficits.

Acute COVID-19 Infection Associated With Necrotizing Disseminated Acute Leukoencephalopathy and Brain Microhemorrhages in a Pediatric Patient.

We present a case of a 14-year-old, previously healthy female, admitted with acute coronavirus disease 2019 infection and new-onset seizures secondary to virus-associated necrotizing disseminated acute leukoencephalopathy. Her symptoms resolved completely with intravenous immunoglobulin and steroids. Pathophysiology and prognosis of neurologic manifestations of coronavirus disease 2019 remain unclear.

Early reversible leukoencephalopathy and unilateral sixth cranial nerve palsy in mild COVID-19 infection.

OBJECTIVES: To provide new insights into neurological manifestations of COVID-19. We describe a patient with mild COVID-19 associated with diplopia from right sixth cranial nerve palsy and early diffuse leukoencephalopathy, successfully treated with intravenous methylprednisolone. METHODS: The patient was evaluated for diplopia that occurred 1 day after the onset of fever, myalgia, and headache. A complete neurological workup, including neurological examination, cerebrospinal fluid (CSF) analysis with viral polymerase chain reaction (PCR), serum autoimmune encephalitis, and anti-nerve antibodies and brain magnetic resonance imaging (MRI), was performed. RESULTS: Clinical examination revealed incomplete right sixth cranial nerve palsy. Brain MRI showed diffuse confluent fluid-attenuated inversion recovery (FLAIR) hyperintense white matter abnormalities, while CSF analysis showed mild hyperproteinorrachia (61 mg/dL) without pleocytosis. The patients were treated with high-dose intravenous methylprednisolone with rapid improvement of neurological symptoms and resolution of CSF and MRI abnormalities. DISCUSSION: Our report shows that COVID-19 may predominantly present with neurological symptoms; furthermore, it argues the notion of leukoencephalopathy as a typical feature of a severe case of the disease. Mechanisms underpinning neurological symptoms in COVID-19 still need to be elucidated; nonetheless, early recognition and prompt management may ensure their improvement or even complete recovery and are therefore recommended.

COVID-19-related diffuse leukoencephalopathy with microbleeds and persistent coma: a case report with good clinical outcome.

A 60-year-old patient presented with respiratory distress, after recently being tested COVID-19 positive and was mechanically ventilated for 15 days. After cessation of sedation, he remained in deep comatose state, without any reaction on pain stimuli (Glasgow Coma Score 3). MRI of the brain showed diffuse leukoencephalopathy and multiple (>50) microbleeds. Diffuse COVID-19-associated leukoencephalopathy with microhaemorrhages is associated with a poor prognosis. However, 3 months later, our patient showed a remarkable recovery and was able to walk independently. This case report shows COVID-related leukoencephalopathy and intracerebral microbleeds, even with persistent comatose state, may have a favourable clinical outcome and prolonged treatment should be considered in individual cases.