Aim The aim of this paper is to describe the clinical features of COVID‐19‐related encephalopathy and their metabolic correlates using brain 2‐desoxy‐2‐fluoro‐D‐glucose (FDG)‐positron‐emission tomography (PET)/computed tomography (CT) imaging. Background and purpose A variety of neurological manifestations have been reported in association with COVID‐19. COVID‐19‐related encephalopathy has seldom been reported and studied. Methods We report four cases of COVID‐19‐related encephalopathy. The diagnosis was made in patients with confirmed COVID‐19 who presented with new‐onset cognitive disturbances, central focal neurological signs, or seizures. All patients underwent cognitive screening, brain magnetic resonance imaging (MRI), lumbar puncture, and brain 2‐desoxy‐2‐fluoro‐D‐glucose (FDG)‐positron‐emission tomography (PET)/computed tomography (CT) (FDG‐PET/CT). Results The four patients were aged 60 years or older, and presented with various degrees of cognitive impairment, with predominant frontal lobe impairment. Two patients presented with cerebellar syndrome, one patient had myoclonus, one had psychiatric manifestations, and one had status epilepticus. The delay between first COVID‐19 symptoms and onset of neurological symptoms was between 0 and 12 days. None of the patients had MRI features of encephalitis nor significant cerebrospinal fluid (CSF) abnormalities. SARS‐CoV‐2 RT‐PCR in the CSF was negative for all patients. All patients presented with a consistent brain FDG‐PET/CT pattern of abnormalities, namely frontal hypometabolism and cerebellar hypermetabolism. All patients improved after immunotherapy. Conclusions Despite varied clinical presentations, all patients presented with a consistent FDG‐PET pattern, which may reflect an immune mechanism.

Purpose Little is known about the neuronal substrates of neuropsychiatric symptoms associated with COVID-19 and their evolution during the course of the disease. We aimed at describing the longitudinal brain metabolic pattern in COVID-19related encephalopathy using 18F-FDG-PET/CT. Methods Seven patients with variable clinical presentations of COVID-19-related encephalopathy were explored thrice with brain 18F-FDG-PET/CT, once in the acute phase, 1 month later and 6 months after COVID-19 onset. PET images were analysed with voxel-wise and regions-of-interest approaches in comparison with 32 healthy controls. Results Patients' neurological manifestations during acute encephalopathy were heterogeneous. However, all of them presented with predominant cognitive and behavioural frontal disorders. SARS-CoV-2 RT-PCR in the CSF was negative for all patients. MRI revealed no specific abnormalities for most of the subjects. All patients had a consistent pattern of hypometabolism in a widespread cerebral network including the frontal cortex, anterior cingulate, insula and caudate nucleus. Six months after COVID-19 onset, the majority of patients clinically had improved but cognitive and emotional disorders of varying severity remained with attention/executive disabilities and anxio-depressive symptoms, and lasting prefrontal, insular and subcortical 18F-FDG-PET/CT abnormalities. Conclusion The implication of this widespread network could be the neural substrate of clinical features observed in patients with COVID-19, such as frontal lobe syndrome, emotional disturbances and deregulation of respiratory failure perception. This study suggests that this network remains mildly to severely impaired 6 months after disease onset.

No abstract

Background and Purpose-Intensive insulin therapy (IIT) has not yet proven its efficacy on stroke prognosis or in the reduction of MRI infarct growth. The INSULINFARCT study aims at determining in patients with hyperacute stroke whether IIT, with a better control of poststroke hyperglycemia, would reduce subsequent MRI infarct growth than usual care with subcutaneous insulin. Methods-One hundred eighty patients with MRI-proven ischemic stroke and with National Institutes of Health StrokeScale from 5 to 25 at admission (Ͻ6 hours) were randomized to receive IIT or usual subcutaneous insulin for 24 hours. Admission hyperglycemia was not required for recruitment. Control MRI and 3-month follow-up (with functional outcome and serious adverse events) were planned. The primary objective was to detect a difference in the proportion of patients with mean capillary glucose test Ͻ7 mmol/L during 24 hours. The secondary objective was to investigate whether IIT would reduce infarct growth. The analysis was planned in intention-to-treat. Patients with Ͼ3 missing capillary glucose test were excluded (nϭ4 Key Words: acute stroke Ⅲ clinical trials Ⅲ hyperglycemia Ⅲ magnetic resonance imaging P oststroke hyperglycemia is an independent predictor of poor functional outcome and death in the acute phase of stroke 1-4 but this statistical relationship does not prove causality. Indeed, there is still controversy about whether stroke-related hyperglycemia is a cause or effect of the more severe damage found in patients with stroke with elevated blood sugars. However, the hyperglycemia "toxicity" has been suggested by animal studies that reported accelerated penumbra-into-infarction conversion and no-reflow phenomenon. 5 Recent MRI and transcranial Doppler studies have suggested that a similar phenomenon may occur in humans. 6 -10 In these studies, evidence has accumulated to define that the glucose toxicity threshold was low (approximately 7 mmol/L, between 6 and 8 mmol/L). 11 These data explain why hyperglycemia is increasingly considered to be a potential therapeutic target in acute stroke and is of growing interest for intensive insulin treatment (IIT). 11,12 Currently published randomized trials do not conclude on the clinical efficacy of IIT in patients with stroke. [13][14][15][16][17][18][19][20] The UK Glucose Insulin in Stroke Trial (GIST), 14 which has enrolled 933 patients with stroke in the first 24 hours of stroke onset, is one such example. It has been criticized because of the heterogeneous population included in the study, its slow recruitment rate, late treatment initiation, and inefficient glucose control. Seven other small studies did not have the statistical power to detect clinical efficiency. 13,[15][16][17][18][19][20] They all showed that IIT carries a high risk of hypoglycemia (4%-76%). One of these studies 18 found that IIT was associated with greater infarct growth (IG) on MRI in patients with persistent arterial occlusion. However, the median delay of treatment initiation was 20 hours after stroke onset, ...