Unexpected infectious complication following AVM embolization: E. coli brain abscess.

BACKGROUND

Brain arteriovenous malformations (AVMs) are rare vascular anomalies managed with surgery, radiosurgery, or endovascular embolization. Post-embolization intracranial infections are extremely uncommon, especially Escherichia coli abscesses in immunocompetent adults.

CASE PRESENTATION: We report a 37-year-old man with a giant left frontal AVM treated with staged Onyx® embolization. One month after the final session, he developed a left frontal brain abscess with motor aphasia and right-sided hemiparesis. Cultures grew hemolytic E. coli sensitive to multiple antibiotics. Recurrence after initial drainage necessitated complete AVM and nidus resection, followed by prolonged targeted antibiotic therapy, leading to resolution and neurological recovery.

LITERATURE REVIEW: Intracranial E. coli infections and post-AVM embolization abscesses are rare, typically associated with systemic or local immunosuppression. Our case is among the first describing hemolytic E. coli abscess after Onyx® embolization in a healthy adult.

CONCLUSION

Retained embolic material, local inflammation, and blood-brain barrier disruption may facilitate infection. Early recognition and total removal, and prolonged targeted antibiotics are crucial to prevent recurrence and ensure favorable outcomes.