Propionibacterium acnes-associated chronic hypertrophic pachymeningitis followed by refractory otitis media: a case report

Abstract

Background: Hypertrophic pachymeningitis (HP) is a rare disorder that involves localized or diffuse thickening of the dura mater. HP is associated with various inflammatory, infectious, and malignant diseases, such as rheumatic arthritis, sarcoidosis, anti-neutrophil cytoplasmic antibody-associated vasculitis, IgG4-related disorders, syphilis, tuberculosis, bacterial and fungal infections, cancer, and idiopathic diseases, when evaluation fails to reveal a cause. Among them, chronic infection with Propionibacterium acnes is a rare etiology of HP, and its pathology remains unclear. Case presentation: An 80-year-old man having refractory otitis media with effusion of the right ear presented with progressive right-sided headache and nausea. Post-contrast brain magnetic resonance imaging revealed right mastoiditis and remarkable thickening of the dura mater and enhancement of pia mater extending from the right middle cranial fossa to the temporal lobe. HP secondary to middle ear infection was suspected, and a biopsy of the right mastoid was performed. An anaerobic culture of the biopsied right mastoid showed the growth of P. acnes, and histopathological examination using P. acnes-specific monoclonal antibody (PAB antibody) revealed the infiltration of inflammatory cells with P. acnes. Moreover, using PAB antibody, P. acnes was detected in the biopsy specimen of the thickening dura mater. No granulomas were identified in either specimen. HP was resolved with long-term administration of antibiotics and steroids. Conclusion: This is the first documentation of pathologically demonstrated chronic HP associated with P. acnes infection followed by refractory otitis media. This report showed that chronic latent P. acnes infection induces chronic inflammation.

Presença de Peptostreptococcus indolicus em bula timpânica de cão com otite média

“…Em medicina não há até o momento uma definição exata do papel que as bactérias anaeróbicas possam exercer na OM (Nwaokorie et al, 2017), porém as pesquisas indicam que estes microrganismos possivelmente mantêm a doença por períodos prolongados (mesmo após a instituição da terapia), conforme relatos de Paterson (2020). Há relatos demonstrando que essas bactérias anaeróbicas estão envolvidas com OM grave em seres humanos (Koneman et al, 1994;Amano et al, 2020), já que no ambiente da bula timpânica (baixa tensão de O 2 ), conseguem se desenvolver.…”