Mastoiditis and Tegmen Tympani Defect Leading to Intracranial Abscess with Actinomyces odontolyticus

Abstract

Introduction: Central nervous system (CNS) actinomycosis typically presents from the local spread of infection via the ear, sinus, or cervicofacial region, resulting most commonly in abscesses. Only one other case report reports on cerebral abscess with Actinomyces odontolyticus. Presentation of Case: A 60-year-old male presented with cognitive impairment and speech difficulties. Imaging revealed a cerebral abscess in the left temporal lobe causing significant mass effect and uncal herniation. Bony erosion was noted along the middle cranial fossa with fluid attenuation of the middle ear and mastoid. An emergent surgery was performed with neurosurgery and otolaryngology. Initially, a left craniotomy was performed in order to obtain access to the left temporal lobe. A vascularized flap was harvested from the fascia of the temporalis in order to repair any defects along the middle cranial fossa. The abscess was drained using ultrasound guidance. A mastoidectomy was then performed for source control. Cultures revealed Actinomyces odontolyticus for which intravenous antibiotics were administered. The patient developed postoperative seizures requiring monitoring and anti-epileptic medication. Follow-up revealed continued improvement in the patient’s cognition. Discussion: Cerebral abscess in the temporal lobe along the floor of the middle cranial fossa can be due to direct extension of infection from the middle ear or mastoid which requires a multidisciplinary approach to surgical treatment. Actinomycosis is a rare pathogen for CNS infection with only one other case report of CNS Actinomyces odontolyticus. Postoperative care in regards to antibiotic treatment and follow-up are also reviewed. Conclusion: The case highlights the urgency of treatment and surgical decision making made intraoperatively by both neurosurgery and otolaryngology in regards to drainage, repair of the defect, and treatment of infectious source.