Neuroimaging and CSF Findings in Patients with Autoimmune Encephalitis: A Report of Eight Cases in a Single Academic Center

Abstract

Autoimmune Encephalitis (AIE) is a rare and complex group of disorders wherein the body's immune system attacks and causes inflammatory changes in the central nervous system (CNS). It presents with altered mental status and a diverse range of typical and atypical symptoms and neuroimaging and cerebrospinal fluid (CSF) findings. The objective of this article is to highlight the importance of early identification of neurological symptoms, prompt diagnosis with neuroimaging and CSF findings, and timely management for early and complete resolution of the disease and long-term benefits. We report eight AIE cases from a single academic center confirmed by the presence of specific serum and CSF autoantibodies. The patients were mostly women, with imaging findings showing T2-weighted (T2), fluid-attenuated inversion recovery (FLAIR), hyperintensities/changes in cortical/mesio-temporal regions on a magnetic resonance imaging (MRI), and delta brush wave patterns or epileptogenic patterns on an electroencephalogram (EEG). Among the antibodies, the N-methyl-D-aspartate receptor (NMDA-R) antibody (AB) was most frequently identified, and CSF lymphocytosis and elevated CSF glucose were found in majority of the cases, CSF pleocytosis and elevated protein only in a minority of patients, and oligoclonal bands (OCBs) only in NMDA-R encephalitis. Early treatment with intravenous immune globulin (IVIG), steroids, plasmapheresis (PLEX), and rituximab was started in most cases, and all of them responded well and survived, but some had residual symptoms or relapses.

Keywords: Autoimmune Encephalitis; N-methyl-d-aspartate encephalitis; cerebrospinal fluid; magnetic resonance imaging.

Figure 1

CASE 1: Axial FLAIR (1a), Coronal T2 (1b), and post contrast coronal T1 RAGE (1c) sequences. Multifocal areas of confluent subcortical T2/FLAIR hyperintensity (orange) with overlying gyriform cortical enhancement (red) involving the right frontal, parietal, and occipital lobes. CASE 2: Coronal FLAIR (2a) and T2 (2b) sequences. Symmetric T2 (blue) and FLAIR (yellow) hyperintensity with mild swelling in the mesial temporal lobes involving the amygdala and hippocampi. CASE 3: Coronal CT of the pelvis with IV and oral contrast (3). Left ovarian mass containing fat and calcification consistent with a teratoma (green).

Figure 2

CASE 4: PET/CT of the chest (4a,4b), breast (4c), and axilla (4d) ultrasonography. Left breast subareolar hypermetabolic mass (4a) with hypermetabolic left axillary lymphadenopathy (4b) corresponding to suspicious left breast mass (4c) and left axillary lymph node (4d) on ultrasound. Coronal FLAIR (5a) sequence. Focal FLAIR hyperintensity in the right inferomedial cerebellum. Pelvic MRI with axial T1 fat suppressed post contrast (5b) sequences. Non-enhancing intrinsically T1 hyperintense right ovarian mass demonstrating fat suppression consistent with a teratoma.

Figure 3

CASE 6: Axial FLAIR (6a,6b) sequences. Moderate to advanced generalized parenchymal volume loss without focal signal abnormality involving the mesial temporal lobes. There was also advanced white matter chronic microvascular ischemic changes. CASE 7: Coronal FLAIR (7a) and axial T2 sequence. Normal appearance of the mesial temporal lobes. The rest of the examination was also normal. CASE 8: Coronal & Axial FLAIR/T2 (8a,8b) sequence. Normal examination without any mesial temporal or other focal signal abnormalities.