Acute actinomycotic brain abscess in a patient with rheumatoid arthritis

Area of Science:

• Neuropathology
• Infectious Diseases
• Rheumatology

Background:

• Actinomycotic brain abscesses are rare, comprising only 0.6% of all brain abscesses.
• Central nervous system involvement occurs in less than 5% of actinomycosis cases.
• Typical actinomycotic brain abscesses present with protracted courses and well-formed pyogenic membranes.

Observation:

• An autopsy of a 72-year-old male with rheumatoid arthritis revealed an acute, non-encapsulated actinomycotic brain abscess.
• The abscess, in the late cerebritis stage, measured 2 cm and contained filamentous bacilli and sulfur granules.
• Pulmonary findings included fibrosis, bronchiectasis, emphysema, and sulfur granules in bronchi.

Findings:

• The brain abscess had ruptured into the lateral ventricle, causing ventriculitis and mild leptomeningitis.
• This case uniquely illustrates the very early pathological stage of cerebral abscess development.
• The presence of sulfur granules in both the brain and lungs suggests disseminated actinomycosis.

Implications:

• This case highlights the potential for acute presentations of actinomycotic brain abscesses, contrasting with typical protracted courses.
• Understanding early-stage pathology is crucial for diagnosing and treating rare central nervous system actinomycosis.
• The association with rheumatoid arthritis warrants further investigation into potential immune-related factors facilitating infection.