Abstracts

Rationale: IgG4-related disease is a rare, systemic, heterogeneous, and immune-mediated disease characterized by lymphoplasmacytic infiltration of IgG4-related plasma cells and “storiform” fibrosis of affected tissue. Major neurological manifestations include headache, ophthalmoplegia, visual field defects, and hypo-pituitarism. Although IgG4-related disease can lead to pachymeningitis, isolated seizure has never been reported as the only presenting clinical symptom. Here we discuss a unique case of a healthy woman who presented to hospital after an isolated seizure and who was eventually diagnosed with IgG4-related disease. Methods: Case report. Results: A 41 year old left-handed female was brought to hospital after being found at home with decreased level of consciousness and a bitten tongue. She had been healthy aside from several weeks of a vague bilateral pressure-type headache. Her neurological exam demonstrated only mild somnolence but unexpected bilateral optic disc edema with peripapillary hemorrhage. MRI then revealed left frontal, temporal, and falcine pachymeningeal enhancement. Lumbar puncture revealed an opening pressure of 49cm H20 and 49 nucleated cells. The patient was started on antiepileptic medication and admitted for empiric broad spectrum anti-microbials. Extensive serological and cerebrospinal fluid investigations were unrevealing. She was discharged home in stable condition with a presumed diagnosis of aseptic meningitis. Repeat MRI revealed worsening pachymeningeal enhancement. She then underwent meningeal biopsy, which revealed dural perivascular lymphoplasmacytic infiltrate surrounded by stromal fibrosis, consistent with IgG4-related disease. Unfortunately, the patient became lost to follow-up before presenting again one month later with recurrent focal aphasic seizures culminating in convulsive status epilepticus. EEG performed on intravenous sedation demonstrated ill-formed right frontal interictal epileptiform discharges. Another MRI demonstrated disease progression and suggested cerebral venous sinus thrombosis (CVST), which was then confirmed on MRV. Acetazolamide resolved papilledema by normalizing intracranial pressure, antiepileptic medications were adjusted, she was started on immunotherapy for IgG4-related disease, and anticoagulation was started for CVST, all of which have rendered her seizure-free. Conclusions: This case demonstrates a novel link between IgG4-related disease and seizure. Although IgG4-related disease typically affects basal brain structures, it can also cause pachymeningitis, which can lead to direct cortical irritation and seizures. Our case also highlights another novel pathophysiologic link through an autoimmune-induced and pro-inflammatory hypercoagulable state leading to CVST and then seizures. We believe that clinicians should be aware of the differential diagnosis of IgG4-related disease in anyone who presents with a seizure, especially in patients with seemingly idiopathic pachymeningitis. Funding: None.