Anti-MOG encephalitis mimicking small vessel CNS vasculitis

Abstract

ObjectiveTo report 2 patients with anti–myelin oligodendrocyte glycoprotein (MOG)-associated encephalitis who were initially misdiagnosed with small vessel primary CNS vasculitis.MethodsReview of symptoms, MRI and neuropathologic features, and response to treatment. MOG antibodies were determined in serum and CSF using a cell-based assay.ResultsSymptoms included fever, headache, and progressive mental status changes and focal neurologic deficits. CSF studies revealed lymphocytic pleocytosis, and both patients had abnormal brain MRIs. Brain biopsy samples showed prominent lymphocytic infiltration of the wall of small vessels; these findings initially suggested small vessel CNS vasculitis, and both patients were treated accordingly. Although 1 patient had a relapsing-remitting course not responsive to cyclophosphamide, the other one (also treated with cyclophosphamide) did not relapse. Retrospective assessment of serum and CSF demonstrated MOG antibodies in both cases, and review of biopsy specimens showed absence of fibrinoid necrosis (a pathologic requirement for small vessel CNS vasculitis).ConclusionsAnti–MOG-associated encephalitis can be mistaken for small vessel CNS vasculitis. This is important because the diagnosis of anti–MOG-associated encephalitis does not require brain biopsy and can be established with a serologic test.

Clinical approach to the diagnosis of autoimmune encephalitis in the pediatric patient

“…44 Children with MOG antibodies are also less likely to have oligoclonal bands than those with MS. 42,44 However, the spectrum of brain disease associated with MOG antibodies in adults and children has broadened to include ADEM, meningoencephalitis, cortical encephalitis with seizures, brainstem encephalitis, and mimics of vasculitis. [45][46][47] Some of these patients will evolve into more typical demyelinating phenotypes, such as ADEM; therefore, MOG antibodies should be considered in pediatric AE presentations beyond ADEM. [45][46][47] MOG autoantibodies are typically transient in monophasic ADEM, but remain positive in relapsing phenotypes.…”

“…[45][46][47] Some of these patients will evolve into more typical demyelinating phenotypes, such as ADEM; therefore, MOG antibodies should be considered in pediatric AE presentations beyond ADEM. [45][46][47] MOG autoantibodies are typically transient in monophasic ADEM, but remain positive in relapsing phenotypes. 8,9,42 Limbic encephalitis The clinical, EEG, and radiologic features of limbic encephalitis are uncommon in children.…”

The Expanding Clinical Spectrum of Myelin Oligodendrocyte Glycoprotein (MOG) Antibody Associated Disease in Children and Adults

“…All three cases underwent brain biopsy, which showed small vessel perivascular inflammation, consistent with CNS vasculitis. However, fibrinoid necrosis, a pathologic requirement for small vessel CNS vasculitis, was absent in two of the cases (66,67). Whether vasculitis should be regarded as a primary or secondary manifestation of MOGAD, or MOG-Ab is unrelated to vasculitis diagnosis, is difficult to determine given rarity of the association.…”

“…Finally, mention should be made of rare cases when MOG-Ab was found in patients with pathologically-proven CNS vasculitis ( 65 , 66 ). Two patients presented with fever, headache, confusion, and focal neurologic deficits ( 66 ), and the third had 9 months of progressive cognitive and behavioral decline ( 65 ). MRI showed multifocal lesions in both the gray and white matter in two cases, one of whom also had open-ring contrast-enhancing lesions.…”

N2 year in review

“…In the March issue of N2, 2 groups described cases of patients with additional clinical conditions associated with MOG antibodies. 77,78 In 1 study, Patterson et al 77 reported on 2 patients exhibiting signs of small vessel CNS vasculitis. Both patients presented with fever, headaches, and mental status changes, and 1 had cranial nerve palsies.…”