Discussion:
Autoimmune glial fibrillary acidic protein (GFAP) astrocytopathy, is a recently described clinical entity presenting with aseptic meningitis and a variety of neurological manifestations. It is a relatively new addition to an ever-increasing list of autoimmune cerebellar ataxia syndromes. it is defined by the presence of GFAP IgG in serum and CSF which shows a similar pattern of immuno-florescence like AQP4 antibody binding to pial and subpial astrocytes. (1)
Autoimmune glial fibrillary acidic protein (GFAP) astrocytopathy can appear with other autoimmune diseases, systemic infections or as a para-neoplastic disorder. (3,4,6) Many other antibodies including NMDAR-IgG, AQP4-IgG, antinuclear, anti -endothelial cell, anti -cardiolipin, anti -neutrophil cytoplasmic and anti -double -stranded DNA can be found in serum of patients with GFAP astrocytopathy.(7) 30–40% of patients may have symptoms of systemic infection before the onset of CNS manifestations. (3) Some patients develop the disorders after Herpes Simplex type 1 or Varicella zoster viral infections.(8,9) Our case also had a history of long-standing rheumatoid arthritis. In a previously published case series of 22 patients with GFAP associated syndrome, three subjects had coexisting rheumatoid arthritis. GFAP has also been identified as an auto-antigen in the synovial fluid of patients with RA. (10) Pachymeningitis in GFAP astrocytopathy has never been reported before but can rarely be seen in long standing rheumatoid arthritis.
Clinical symptoms in our case responded very well to oral steroids. Most of the cases show rapid clinical and radiological improvements upon starting corticosteroids with 20–50% of patients having relapsing course requiring more prolonged therapy. (3,7,8,11,12) Prognosis varies but is good with appropriate treatment in most of the cases. (2,13)