Autoimmune GFAP astrocytopathy presenting with remarkable CNS hyperexcitability and oculogyric crises

Clinical and neuroimaging phenotypes of autoimmune glial fibrillary acidic protein astrocytopathy: A systematic review and meta-analysis

OBJECTIVE

This study was undertaken to provide a comprehensive review of neuroimaging characteristics and corresponding clinical phenotypes of autoimmune glial fibrillary acidic protein astrocytopathy (GFAP-A), a rare but severe neuroinflammatory disorder, to facilitate early diagnosis and appropriate treatment.

METHODS

A PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis)-conforming systematic review and meta-analysis was performed on all available data from January 2016 to June 2023. Clinical and neuroimaging phenotypes were extracted for both adult and paediatric forms.

RESULTS

A total of 93 studies with 681 cases (55% males; median age = 46, range = 1-103 years) were included. Of these, 13 studies with a total of 535 cases were eligible for the meta-analysis. Clinically, GFAP-A was often preceded by a viral prodromal state (45% of cases) and manifested as meningitis, encephalitis, and/or myelitis. The most common symptoms were headache, fever, and movement disturbances. Coexisting autoantibodies (45%) and neoplasms (18%) were relatively frequent. Corticosteroid treatment resulted in partial/complete remission in a majority of cases (83%). Neuroimaging often revealed T2/fluid-attenuated inversion recovery (FLAIR) hyperintensities (74%) as well as perivascular (45%) and/or leptomeningeal (30%) enhancement. Spinal cord abnormalities were also frequent (49%), most commonly manifesting as longitudinally extensive myelitis. There were 88 paediatric cases; they had less prominent neuroimaging findings with lower frequencies of both T2/FLAIR hyperintensities (38%) and contrast enhancement (19%).

CONCLUSIONS

This systematic review and meta-analysis provide high-level evidence for clinical and imaging phenotypes of GFAP-A, which will benefit the identification and clinical workup of suspected cases. Differential diagnostic cues to distinguish GFAP-A from common clinical and imaging mimics are provided as well as suitable magnetic resonance imaging protocol recommendations.

Case report: Autoimmune glial fibrillary acidic protein astrocytopathy misdiagnosed as tuberculous meningitis

Introduction

Autoimmune glial fibrillary acidic protein (GFAP) astrocytopathy is a new form of autoimmunity-mediated central nervous system disease. It is especially easy to misdiagnose when clinical symptoms and cerebrospinal fluid (CSF) indicators are similar to those observed in patients with tuberculous meningitis (TBM).

Methods

We retrospectively analyzed five cases of autoimmune GFAP astrocytopathy that were initially misdiagnosed as TBM.

Results

In the five reported cases, all but one patient had meningoencephalitis in the clinic, and all patients exhibited increased pressure, lymphocytosis, increased protein levels, and decreased glucose levels in their CSF results and did not have typical imaging findings of autoimmune GFAP astrocytopathy. TBM was the initial diagnosis in all five patients. However, we found no direct evidence of tuberculosis infection, and anti-tuberculosis treatment had inconclusive effects. Following a GFAP antibody test, the diagnosis of autoimmune GFAP astrocytopathy was made.

Conclusion

When there is a suspected diagnosis of TBM but TB-related tests are negative, the possibility of autoimmune GFAP astrocytopathy should be considered.

Delayed Appearance of Brain Magnetic Resonance Imaging Abnormalities in a Patient with Glial Fibrillary Acidic Protein Astrocytopathy

Recent studies have reported that autoantibodies against glial fibrillary acidic protein (GFAP), a major cytoskeletal protein expressed in astrocytes, can lead to GFAP astrocytopathy, an autoimmune central nervous system inflammatory disease. We herein report the unique case of a 59-year-old Japanese woman with GFAP astrocytopathy who presented with characteristic symptoms, including signs of meningeal irritation, cerebellar ataxia, and bladder/rectal dysfunction, in the absence of specific findings on initial brain magnetic resonance imaging (MRI). The patient exhibited new abnormal changes mainly in the brainstem on follow-up MRI, illustrating the need to recognize that MRI abnormalities may appear later in GFAP astrocytopathy.

Characteristics of Movement Disorders in Patients with Autoimmune GFAP Astrocytopathy

Autoimmune glial fibrillary acidic protein (GFAP) astrocytopathy (GFAP-A) is a type of autoimmune corticosteroid-responsive meningoencephalitis that occurs with or without myelitis. Movement disorders have been reported in GFAP-A patients but have not been characterized. In this study, we examined the characteristics of movement disorders in GFAP-A patients. We retrospectively reviewed clinical data from 87 consecutive patients with GFAP-A attending Gifu University Hospital in Japan. We compared the demographics, clinical features, cerebrospinal fluid characteristics, and neuroimaging findings from patients with and without movement disorders. Seventy-four patients (85%) had movement disorders, including ataxia (49%), tremor (45%), myoclonus (37%), dyskinesia (2%), opsoclonus (2%), rigidity (2%), myokymia (1%), and choreoathetosis (1%). GFAP-A patients with movement disorders were significantly older than those without. Movement disorders are therefore common in GFAP-A patients, and the main types of movement disorders observed in this population were ataxia, tremor, and myoclonus. These abnormal movements can serve as clinical features that facilitate the early diagnosis of GFAP-A. Elderly GFAP-A patients are more likely to have movement disorder complications than younger patients.