Clinical and prognostic profiles in immune-mediated hypertrophic meningitis: a retrospective analysis of 92 cases.

OBJECTIVES

Immune-mediated hypertrophic pachymeningitis (HP) is an inflammatory disorder with diverse neurological manifestations. Considering its various etiology and rarity, HP remains a diagnostic challenge. Comparisons of clinical and prognostic profiles across different etiologies remain insufficiently explored. We analyzed the clinical characteristics, treatment approaches, and outcomes of immune-mediated HP patients from a single center in China.

METHOD: A retrospective study was conducted at Peking Union Medical College Hospital, analyzing immune-mediated HP cases from December 2003 to September 2021. We evaluated patients' neurological symptoms, systemic involvement, image findings, and baseline laboratory results, and compared these features among three predominant etiologies: antineutrophil cytoplasmic antibody (ANCA)-related HP, idiopathic HP, and IgG4-related disease (IgG4-RD). The treatment approaches and outcomes were also reviewed.

RESULTS

The study included 92 patients, 49 (53.3%) male and 43 (46.7%) female. ANCA-related HP was the leading cause of immune-mediated HP (n = 42, 45.6%), followed by idiopathic HP (n = 28, 30.4%), IgG4-RD (n = 12, 13.0%), and other underlying causes (n = 10, 10.9%). Despite different etiologies, similar patterns of cranial nerve and brain region involvement were observed. Large doses of glucocorticoids combined with immunosuppressants were the most common treatment across all etiologies. Kaplan-Meier analysis (mean follow-up time: 4.1 years) showed no significant differences in relapse-free survival rates among the three subgroups.

CONCLUSIONS

ANCA-related HP, idiopathic HP, and IgG4-RD HP were the three predominant causes of immune-mediated HP in this Chinese cohort. The three etiologies exhibited similar clinical manifestations, imaging findings, and long-term prognoses, indicating that a standardized management strategy may benefit HP patients regardless of etiology. Key Points • Immune-mediated hypertrophic pachymeningitis (HP) is a rare disorder with diverse etiologies, and research comparing clinical and prognostic profiles across different causes remains limited. • This study involved 92 immune-mediated HP patients, comparing clinical characteristics, imaging findings, treatment approaches, and outcomes among ANCA-related, idiopathic, and IgG4-related HP. • The three predominant etiologies of HP showed similar clinical features and similar relapse-free survival rates. • Regardless of the underlying etiology, HP patients may benefit from a uniform management approach.