Spectrum of Brain MRI Features in CASPR2 Associated Autoimmune Encephalitis: A Case Report With Parietal Lobe Involvement

Abstract

Objective Contactin-associated-protein-like 2 (CASPR2)-antibody-mediated autoimmune encephalitis (AE) is characterized by diverse clinical manifestations with involvement of both central and peripheral nerve systems. Background Furthermore, approximately 50-55% of the patients with this condition present with an abnormal brain MRI including bilateral/unilateral T2-hyperintensity in the mesial temporal lobes, thalami, basal ganglia, brainstem, or cerebellum and hippocampal atrophy/sclerosis. To our knowledge this is the first case of CASPR-Ab-related AE reporting concurrent parieto-occipital lobes enhancing and non-enhancing brain lesions. Design/Methods A 71-year-old male presented with 3-months of cognitive decline, generalized tonic-clonic seizures, and parasomnias. Initial neurological examination showed diminished attention with neuropsychology evaluation revealed episodic memory deficits and executive dysfunction, otherwise no focal abnormality. Results Brain MRI with and without contrast from showed subtle cortical enhancement in the anterior left parietal lobe, additionally T2 FLAIR hyperintensities in the bilateral hippocampi, left centrum semiovale and left dorsal pons. CSF analysis revealed 5 nucleated cells, protein and glucose were normal. Serum and CSF paraneoplastic panel was positive for CASPR-2 auto antibodies. His memory and executive function improved after plasma exchange and long-term steroids. One year later the patient developed ataxia and gait instability. Repeated examination revealed diminished vibration in bilateral lower extremities, prominent left upper extremity ataxia compared to the right and a wide based gait. Updated brain MRI demonstrated progression of T2 FLAIR hyperintensities in the cortical and subcortical areas of the left parieto-occipital fissure. IVIG was started with stabilization of the progression. Conclusions CASPR2-autoantibody is associated to a wide range of neurological manifestations and diagnosing this condition could be challenging. This case demonstrates the possible involvement of the parietal and occipital cortex as a target of the antibodies directed against this membrane protein. Recognition of this spectrum of symptoms and imaging findings are important for early diagnosis of this disorder and appropriate treatment.