Voltage-gated potassium channel antibody limbic encephalitis: a case illustrating the neuropsychiatric and PET/CT features with clinical and imaging follow-up

Abstract

Voltage-gated potassium channel limbic encephalitis characteristically presents with neuropsychiatric symptoms and temporal lobe seizures. Positron-emission tomography-computed tomography can be a useful adjunct to the clinical and biochemical work-up.

Autoantibodies in patients with obsessive-compulsive disorder: a systematic review

“…Scheid et al 2003 [ 50 ] Anti-Ma2 Ab Paraneoplastic encephalitis with initial OCD (checking) M, 39 years Ab identification in CSF and serum Physical examination MRI EEG CSF Thoracic CT Serum: Anti-Ma2 Ab CSF: Anti-Ma2 Ab EEG: Inconstant left temporal sharp slow-wave activity MRI: T2-hyperintense signal change in the left hippocampus Physical examination: Progressing of severe neurological deficits Histologic examination: Differentiated teratoma and seminoma-in-situ Thoracic CT: Metastasis of teratoma IV immunoglobulins and lamotrigine → improvement of memory function and OCS Non-well characterized anti-neuronal autoantibodies 4. Celliers et al 2016 [ 46 ] Anti-VGKC Ab VGKC-Ab associated limbic encephalitis with OCS and faciobrachial seizures M, 64 years Ab identification in CSF FDG-PET EEG CSF: Increased VGKC Ab FDG-PET: Increased symmetrical uptake in the caudate and lentiform nuclei EEG: No associated EEG-changes with seizures detected Levetiracetam + IV methylprednisolone + mycophenolate mofetil → full remission of seizures and OCS; CSF: inconspicuous levels of VGKC Ab; FDG-PET: follow up showed significant glucose uptake reduction in the basal ganglia bilaterally 5. Zhu et al 2014 [ 52 ] IgG “ANAb” Antibody associated OCS (checking, washing) after pineal germinoma M, 23 years Ab identification in serum Physical examination MRI Brain biopsy Serum: 43-45kDA, positive staining with Hep2 epithelial cells Physical examination: Severe neurological symptoms MRI: Enlarged pineal gland Brain biopsy: Germinoma Cranial irradiation → OCS and Ab detection in serum (3 month later) Autoantibodies associated with systemic autoimmune diseases 6.…”

“…Metabolic brain imaging with 18F-Fluorodeoxyglucose positron-emission tomography (FDG-PET) revealed increased symmetrical uptake in the caudate and lentiform nuclei while no association between seizures and EEG alterations were detected. After treatment with cytostatics and prednisolone, complete remission of OCS and seizure symptoms was observed, along with normalization of anti-VGKC autoantibody levels and reduced FDG uptake in the basal ganglia [ 46 ].…”

“…A total of five patients with OCS described as case reports had anti-CNS autoantibodies [ 44 , 46 , 48 , 50 , 52 ]; out of those, three patients had well-characterized anti-neuronal autoantibodies (against NMDA-R, CV2 and Ma2), and two patients had autoantibodies against non-well-characterized neuronal antigens (VGKC and “anti-brain”). The patient with anti-NMDA-R autoantibodies was autoantibody positive in CSF and responded well to immunotherapy [ 44 ], suggesting a causal role of these autoantibodies in this patient [ 64 ].…”

“…Anti-VGKC autoantibodies are increasingly considered non-specific, and a determination of anti-leucine-rich, glioma inactivated 1 (anti-LGI1) and contactin-associated protein-2 (CASPR2) autoantibodies is suggested [ 70 ]. However, the OCD patient with anti-VGKC autoantibodies showed typical findings of limbic encephalitis with anti-VGKC autoantibody detection in the CSF and additional faciobrachial dystonic seizures [ 46 , 70 ]. Thus, this patient might have had functional autoantibodies as well, which is also supported by the response to immunotherapy.…”

Neuronal surface antibody-mediated encephalopathy as manifestation of chronic graft-versus-host disease after allogeneic hematopoietic stem cell transplantation

“…In our case, 18F-FDG brain PET-CT demonstrated diffuse cortical and subcortical hypometabolism that completely normalized following immunosuppressive therapy. Functional imaging with 18F-FDG brain PET-CT recently emerged as a useful tool for improving the diagnosis of some auto-immune encephalitis (Celliers et al, 2016;Dong et al, 2016;Lagarde and Guedj, 2015;Morbelli et al, 2017). Whether it could also bring relevant complementary information to integrate in the diagnostic algorithm of CNS-GVHD, especially in patients with normal MRI, is not known and has to be explored in the future.…”