Immunoglobulin G4-related spinal pachymeningitis: A case report.

Background: Immunoglobulin G4-related disease (IgG4-RD) is a complex immune-mediated condition that causes fibrotic inflammation in several organs. A significant clinical feature of IgG4-RD is hypertrophic pachymeningitis, which manifests as inflammation of the dura mater in intracranial or spinal regions. Although IgG4-RD can affect multiple areas, the spine is a relatively rare site compared to the more frequent involvement of intracranial structures.

Case summary: A 70-year-old male presented to our hospital with a two-day history of fever, altered mental status, and generalized weakness. The initial brain magnetic resonance imaging (MRI) revealed multiple small infarcts across various cerebral regions. On the second day after admission, a physical examination revealed motor weakness in both lower extremities and diminished sensation in the right lower extremity. Electromyographic evaluation revealed findings consistent with acute motor sensory neuropathy. Despite initial management with intravenous immunoglobulin for presumed Guillain-Barré syndrome, the patient exhibited progressive worsening of motor deficits. On the 45^th day of hospitalization, an enhanced MRI of the entire spine, focusing specifically on the thoracic 9 to lumbar 1 vertebral level, raised the suspicion of IgG4-related spinal pachymeningitis. Subsequently, the patient was administered oral prednisolone and participated in a comprehensive rehabilitation program that included gait training and lower extremity strengthening exercises.

Conclusion: IgG4-related spinal pachymeningitis, diagnosed on MRI, was treated with corticosteroids and a structured rehabilitation regimen, leading to significant improvement.