Arachnoid involved in idiopathic hypertrophic pachymeningitis

Hypertrophic pachymeningitis in ANCA-associated vasculitis: Clinical and immunopathological features and insights

Hypertrophic pachymeningitis (HP) is an inflammatory disorder characterized by intracranial and spinal thickened dura mater, leading to several neurological manifestations including headaches, cranial neuropathies, seizures, and sensorimotor disorders. Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a crucial disease that is implicated in the development of immune-mediated HP. HP is observed throughout the clinical course of AAV, and 3%-4% of patients with AAV experience HP as the initial clinical episode. However, patients with ANCA-related HP are unclassifiable in the classification criteria of AAV when HP is the only manifestation, suggesting that ANCA-related HP can be identified as a central nervous system-limited type of AAV. Among patients with AAV, those who develop HP have predominantly been classified as having granulomatosis with polyangiitis (GPA). Myeloperoxidase-ANCA positivity has been more frequently demonstrated than proteinase 3-ANCA positivity in patients with ANCA-related HP. The ear, nose, and throat manifestations, such as otitis media, sinusitis, and mastoiditis, as well as mucous membranes/eyes manifestations including sudden visual loss, are robustly associated with HP in AAV. The histology of thickened dura mater tissues includes fibrotic changes and infiltration of several immunocompetent cells, but the typical findings of GPA, such as granulomatous inflammation with necrotizing vasculitis, are not observed in all patients with ANCA-related HP. Corticosteroids are the first-line therapy for ANCA-related HP, while the concomitant use of immunosuppressive agents including cyclophosphamide, methotrexate, and mycophenolate mofetil, is an ideal strategy for achieving remission. Rituximab is a useful agent in refractory ANCA-related HP.

Difficulties of diagnosing idiopathic hypertrophic pachymeningitis in children: Case report and literature review

Hypertrophic pachymeningitis (HP) is a rare inflammatory disorder characterised by local or diffuse thickening of the cranial and spinal dura mater. HP occurs owing to idiopathic or secondary causes, including autoimmune disease, infection, and trauma. HP has mainly been reported in adults, with few reported cases in children. We encountered an 11-year-old boy with idiopathic HP who presented with chronic inflammation and daily occipital headache. Gadolinium (Gd)-enhanced magnetic resonance imaging (MRI) helped us to diagnose him with HP. He was successfully treated with corticosteroids and azathioprine with no recurrence. We also conducted a literature review of childhood-onset HP and found only 16 cases, including our patient. Seven patients had idiopathic HP, and the remaining nine had secondary HP, including two with rheumatic disease. The most common clinical symptoms were headache (68.8%) and cranial nerve-related symptoms (68.8%). Inflammatory laboratory markers were elevated in 60% of patients with available data. Fifteen cases were diagnosed using Gd-enhanced MRI. The main initial treatment was steroids and/or immunosuppressants, to which 87.5% of patients responded. However, two patients with HP associated with trauma and neuroblastoma (12.5%) died, and seven patients (43.8%) had left cranial nerve-related sequelae. As the prognosis for childhood HP is poor, early diagnosis and treatment are essential. Children with headache, cranial nerve symptoms, and elevated inflammatory marker levels should be suspected of having HP and Gd-enhanced MRI should be considered.

Idiopathic Hypertrophic Cranial Pachymeningitis With Chiari Type I Malformation: Case Report and Review of the Literature

Idiopathic hypertrophic cranial pachymeningitis (IHCP) is a rare chronic inflammatory disease characterized by diffuse thickening of the dura mater. Although IHCP mostly presents as a diffuse lesion, it may also occur as focal tumour-like lesions. Here we present the first reported case of IHCP associated with a Chiari type I malformation (CMI). A 65-year-old man presented with a one-year history of chronic headache and vertigo exacerbated by standing and neck flexion. The neurological examination was unremarkable except for tongue wasting and fasciculations. MRI demonstrated features of CMI and findings suggestive of IHCP.

Posterior fossa decompression resulted in significant symptomatic improvement and the diagnosis of IHCP was confirmed on histopathology. Though there is no consensus about the management of IHCP in this case, we advocate surgical decompression with prolonged steroid therapy.

Hypertrophic Pachymeningitis in a Southern Chinese Population: A Retrospective Study

Aims: To investigate the causes, clinical characteristics, imaging features, and therapeutic implications of hypertrophic pachymeningitis (HP) in a southern Chinese population.

Methods: We retrospectively analyzed 48 patients with HP with different causes from 1 January 2006 to 31 December 2018. Clinical manifestation, laboratory findings, and neuroimaging results were evaluated in all HP patients.

Results: The mean age at onset was 50 ± 12 years. The most common diagnosis was idiopathic HP (67%), followed by antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (15%), tuberculous meningitis (8%), viral meningitis (6%), and bacterial meningitis (4%). Headache was the most common symptom. The most frequently changed laboratory finding was elevated erythrocyte sedimentation rate (ESR). Imaging was characterized by cerebral or spinal dura mater enhancement in MRI scan with contrast. Enhancements were mainly located in the posterior fossa for idiopathic HP; frontal, parietal, and occipital lobes for ANCA-related HP; and posterior fossa for tuberculous-associated HP. Diffuse enhancement was found in most cases, except for tuberculous-associated HP. Glucocorticoid or immunosuppressive treatment was applied in most cases.

Conclusions: The etiology of HP varied among patients, with idiopathic HP being the most common. MRI showed enhancement of the dura mater, which differed according to different etiologies. Glucocorticoid or immunosuppressive agents were the primary drugs for treatment.

Hypertrophic Pachymeningitis in Chinese Patients: Presentation, Radiological Findings, and Clinical Course

Background

Hypertrophic pachymeningitis (HP) is generally regarded as a rare inflammatory disease, which results in a diffuse thickening of the dura mater. We retrospectively collected data from patients with HP.

Methods

A total of 16 patients with HP were included in our study. The clinical features, laboratory evaluation, imaging findings, treatment, and outcome were reviewed.

Results

Of the 16 cases, half were male, with a mean age of 52.6 ± 13.2 years. The mean duration from onset to diagnosis was 8.6 months. The most frequent presenting symptoms in HP cases were a recurrently chronic headache (81.3%) and multiple cranial nerve injury (50%). Antineutrophil cytoplasmic antibody- (ANCA-) related HP was found in 5 cases and IgG4-related HP in 1 case. The intracranial pressure was elevated in 4 cases. The cerebrospinal fluid (CSF) had lymphocytosis in 5 cases and increased protein in 12 cases. Immunoglobulins (IgG, IgA, and IgM) and protein showed linear relationships in the CSF. On magnetic resonance imaging (MRI), localized or diffuse dura maters were thickened in all cases. HP combined with subacute subdural hemorrhage or hypertrophic spinal pachymeningitis was also observed in individual cases. Biopsy of the dura mater in one case showed amounts of inflammatory cells infiltrating, with an increased percentage of IgG4-positive plasma cells. Of all cases referring to glucocorticoid treatment, the symptoms have improved significantly in 10 cases. In other 6 cases, mycophenolate mofetil or azathioprine was added. All patients showed clinical improvement at the follow-up visits.

Conclusion

The clinical characters of HP are chronic onset, recurrently chronic headache, and multiple cranial nerves paralysis. Inflammatory changes in CSF caused by intrathecal synthesis of immunoglobulin, characteristic dural enhancement on MRI, and pathologic biopsy are all helpful for diagnosis. The addition of immunosuppressant, especially mycophenolate mofetil, is a good choice for steroid-resistance HP.