TAKAYOSHI SHIMOHATA1, Akira Takekoshi1, Kimihiko Kaneko2, Juichi Fujimori2, Tetsuya Ioku3, Keisuke Imai3, Akio Kimura1
1Department of Neurology, Gifu University Graduate School of Medicine, 2Department of Neurology, Tohoku Medical and Pharmaceutical University Hospital, 3Department of Neurology and Stroke Treatment, Kyoto First Red Cross Hospital
Objective:
To determine clinical features and biomarkers of acute encephalitis with claustrum sign on brain MRI and to clarify the pathogenetic mechanism.
Background:
The claustrum sign has been described as reversible bilateral claustrum MRI hyperintensity on a T2-weighted MRI image. This finding has been reported in acute encephalitis, including acute necrotizing encephalopathy, febrile infection–related epilepsy syndrome, a subcategory of new-onset refractory status epilepticus.
Design/Methods:
We retrospectively analyzed the clinical features and cerebrospinal fluid (CSF) findings of three patients with acute encephalitis with claustrum sign.
Results:
All patients had prior symptoms suspected of infection, including fever, cough, and general fatigue. Two patients had meningeal signs and refractory status epilepticus. One patient had pyramidal signs and tremor. Claustrum sign was noted at 8, 28, and 52 days after the onset. In CSF, a glial fibrillary acidic protein (GFAP) antibody was detected in one patient with pyramidal signs and tremor. The other two patients had no antineuronal antibodies detected by tissue-based immunofluorescence assay using frozen rat brain sections. Compared with GFAP antibody-negative patients, GFAP antibody-positive patients had increased levels of CSF cell counts (antibody-positive vs antibody-negative; 127/μL vs 13 and 32/μL), protein concentrations (157 mg/dL vs 39 and 58 mg/dL), and tumor necrosis factor α (25.3 pg/mL vs 2.82 and 2.95 pg/mL). Interleukin 6 (IL-6) in CSF with GFAP antibody-negative patients was significantly higher than those with antibody-positive patients (195 and 609 pg/mL vs. 19.2 pg/mL). All patients required ventilator management and received immunotherapies. Two GFAP antibody-negative patients had improved, but a GFAP antibody-positive patient had died due to pneumonia.
Conclusions:
Acute encephalitis with claustrum sign is associated with at least increased levels of IL6 and GFAP antibody (i.e., GFAP astrocytopathy). In addition to CSF cytokine measurements, it is considered that GFAP antibody measurements should be performed in this disorder.