COVID-19-related encephalopathy: a case series with brain FDG-positron-emission tomography/computed tomography findings

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.