Hypertrophic Pachymeningitis - Differential Diagnosis Framework Pachymeningitis is a rare condition that causes areas of a layer of tissue that surrounds the spinal cord and brain (dura mater) to thicken and become inflamed. This thickening can cause different symptoms based on its location. Some people may have vision changes, headaches, or hearing loss. Idiopathic Infective • Neurosyphilis • CNS tuberculosis: tuberculous pachymeningitis • CNS cryptococcosis • Bacterial meningitis Inflammatory • IgG4-related hypertrophic pachymeningitis • GPA • Neurosarcoidosis • Polyarteritis nodosa • Rheumatoid arthritis • Relapsing polychondritis • Behçet disease Other • Rosai-Dorfman disease • Hemodialysis • Mucopolysaccharidoses Tumors • Dural metastases CT Imaging: • Subdural collection • Acquired tonsillar ectopia • Dural venous sinus distention • Layer cake skull: diffuse layered calvarial hyperostosis seen in 14-32% of patients MRI Imaging: • The most common qualitative finding is pachymeningeal thickening and enhancement • dural venous engorgement • tonsillar herniation • Subdural collection Changes in Perfusion/Pressure • Intracranial hypotension - Primary: spontaneous intracranial hypotension - Secondary: iatrogenic (lumbar puncture or surgery) - Frontotemporal brain sagging syndrome (FBSS) - type 1: dural tear - type 2: lateral leak - type 3: CSF-venous fistula - type 4: distal nerve root sleeve leaks • Cerebral venous thrombosis CT • Subdural collection • Acquired tonsillar ectopia • Dural venous sinus distention • Layer cake skull: diffuse layered calvarial hyperostosis seen in 14-32% of patients MRI • The most common qualitative finding is pachymeningeal thickening and enhancement • dural venous engorgement • tonsillar herniation • Subdural collection #Hypertrophic #Pachymeningitis #HP #Neurology #differential #diagnosis
