Childhood autoimmune glial fibrillary acidic protein astrocytopathy with spinal cord FDG accumulation on 18F-FDG-PET imaging

Abstract

Background

Glial fibrillary acidic protein astrocytopathy (GFAP-A) is an autoimmune central nervous system disease associated with auto-antibodies against GFAP, an intermediate filament protein in astrocytes. GFAP-A typically presents as middle-age-onset subacute meningoencephalitis or meningoencephalomyelitis; however, we present a childhood-onset case of meningomyelitis with persistent fever and malaise.

Case presentation

A fourteen-year-old girl presented with persistent high-grade fever, head and body aches, nausea, neck rigidity, weakness in the extremities, and dysuria. An initial diagnosis of aseptic meningitis was made based on increased cells and proteins in her spinal fluid; however, fever and malaise persisted, and no pathogenic antigens or antibodies could be detected. Subsequently, 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) showed extensive longitudinal FDG accumulation along the spinal cord. Ophthalmological examination revealed papilledema. Magnetic resonance imaging of the brain and spine revealed no abnormalities. Based on a suspicion of autoimmune meningomyelitis, we started immunotherapy on day 27. Intravenous methylprednisolone, followed by prednisolone administration relieved the fever and accompanying symptoms that had persisted for a month. A definitive diagnosis of GFAP-A was confirmed by detecting cerebrospinal fluid GFAP-immunoglobulin G in a cell-based assay. Prednisolone was tapered off, with no relapse or significant sequelae.

Discussion/conclusion

In children with persistent fever and neurological symptoms, autoimmune central nervous system disorders such as GFAP-A should be considered in the differential diagnosis; further, if infectious pathogens are excluded, immunotherapy should be initiated early. The clinical presentation of GFAP-A is diverse, including cases with no symptoms of encephalopathy. FDG-PET findings in the spinal cord can be a valuable diagnostic aid.