Acute necrotizing encephalopathy (ANE) is a rare complication of coronavirus disease 2019 (COVID-19) secondary to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. The condition is typically diagnosed based on characteristic neuroimaging findings in the context of active viral respiratory symptoms. We present a rare case of COVID-19-associated ANE presenting with expressive aphasia and encephalopathy in the absence of active respiratory symptoms. Initial evaluation revealed bilateral thalamic lesions and a mild neutrophilic-predominant pleocytosis on cerebrospinal fluid analysis, the latter of which has not been described in previously published cases. Presence of these atypical features prompted extensive diagnostic evaluation. Metagenomic next-generation sequencing on cerebrospinal fluid did not detect the presence of pathogenic nucleic acids. Thalamic biopsy revealed perivascular neutrophilic inflammation suggestive of small vessel vasculitis with surrounding hemorrhage and necrosis. Ultimately, the diagnosis was made following detection of SARS-CoV-2 serologies and after exclusion of alternative etiologies. The patient was successfully treated with a short course of high-dose methylprednisolone with favorable outcome.

An 88-year-old man presented with a 1-month history of altered mental status and seizures. His electrographic and imaging findings were suggestive of herpes simplex encephalitis (HSE), for which he was empirically treated with acyclovir. He underwent two lumbar punctures 3 days apart; both cerebrospinal fluid analyses tested negative for herpes simplex virus (HSV) by polymerase chain reaction (PCR). These negative results and his continued deterioration after 9 days of acyclovir therapy prompted treatment with steroids for possible autoimmune encephalitis. Shortly after the change in management, the patient died from cardiac arrest. At autopsy, his brain showed both gross and microscopic evidence of encephalitis and was positive for HSV by immunohistochemistry. This fatal case of HSE emphasizes the limitations of HSV PCR and the importance of clinical suspicion in the diagnosis and management of this disease.

Myelopathy is a broad term used to describe a heterogeneous group of disorders that affects the spinal cord; the focus of this article will be a subgroup of these disorders with an autoimmune and inflammatory-based pathology. Symptoms typically develop over hours or days and then worsen over a matter of days to weeks, but sometimes can have a more insidious or subacute presentation, which can make the diagnosis more puzzling. Despite relatively low incidence rates, almost a third of affected patients are left with severely disabling symptoms. Prompt recognition of the underlying etiology is essential so that a specific targeted therapy can be implemented for optimal outcomes. The authors discuss a systematic approach to immune-mediated myelopathies, with a focus on the unique characteristics of each that may aid in diagnosis.

Background and ObjectivesCerebrovascular manifestations in neurosarcoidosis (NS) were previously considered rare but are being increasingly recognized. We report our preliminary experience in patients with NS who underwent high-resolution vessel wall imaging (VWI).MethodsA total of 13 consecutive patients with NS underwent VWI. Images were analyzed by 2 neuroradiologists in consensus. The assessment included segment-wise evaluation of larger- and medium-sized vessels (internal carotid artery, M1-M3 middle cerebral artery; A1-A3 anterior cerebral artery; V4 segments of vertebral arteries; basilar artery; and P1-P3 posterior cerebral artery), lenticulostriate perforator vessels, and medullary and deep cerebral veins. Cortical veins were not assessed due to flow-related artifacts. Brain biopsy findings were available in 6 cases and were also reviewed.ResultsMean patient age was 54.9 years (33–71 years) with an M:F of 8:5. Mean duration between initial diagnosis and VWI study was 18 months. Overall, 9/13 (69%) patients had vascular abnormalities. Circumferential large vessel enhancement was seen in 3/13 (23%) patients, whereas perforator vessel involvement was seen in 6/13 (46%) patients. Medullary and deep vein involvement was also seen in 6/13 patients. In addition, 7/13 (54%) patients had microhemorrhages in susceptibility-weighted imaging, and 4/13 (31%) had chronic infarcts. On biopsy, 5/6 cases showed perivascular granulomas with vessel wall involvement in all 5 cases.DiscussionOur preliminary findings suggest that involvement of intracranial vascular structures may be a common finding in patients with NS and should be routinely looked for. These findings appear concordant with previously reported autopsy literature and need to be validated on a larger scale.