OMG, I Can't C

A repeat ophthalmic exam two days after presentation showed vision to be hand motion OU. CSF analysis showed 1 RBC, 21 WBC, lymph 80%, glucose 90 (serum 164), protein 44 and negative cytology as well as no organisms or host cells on gram stain. The decision was made to start IV solumedrol to salvage vision. Other CSF studies that were negative included: CMV PCR, CMV IgG/IgM, crypto Ag, HSV, RPR and FTA-ABS. Chest-Xray was normal, PPD was negative. The patient also reported scrotal pain and a rash on his legs. Biopsy of the rash and a scrotal ultrasound were non-revealing. MRI T- and C-Spine were normal as well. Four days after initiation of IV methylprednisolone the patient's vision improved to 20/20 OU. On exam he still had a trace APD OS and his color plates were 1/8 OU. More CSF studies returned showing an elevated IgG synthesis rate (31.1mg/24hr), a high IgG index (1.09) and normal albumin (20.9). A dural biopsy showed pachymeningitis with increased IgG4 plasma cells. The patient was discharged on PO prednisone 60 mg with follow up. IgG4 pachymeningitis appears to be one of the manifestations in the newly recognized IgG4-related disease spectrum. This disease was first recognized in 2001 in sclerosing pancreatitis and in 2003 as a systemic condition. At this point in time there are only a few papers describing reports on the rare presentation of involvement of the CNS, with little information being available about clinical presentation, diagnostic criteria and optimal treatment. The treatment modalities available are based on Class IV evidence. Most of the information is currently being extrapolated from the more common presentation of autoimmune pancreatitis and include initial treatment with IV steroids, followed by glucocorticoid sparing agents and/or rituximab in the case of refractory disease.