Clinical and Radiological Features in the Cases with Cryptogenic Brain Abscess in Association with Patent Foramen Ovale: A Case Report and Review of the Literature

Brain abscesses are commonly associated with cranial trauma, a contiguous focus of infection, or hematogenous spread from a distant focus. However, no predisposing factors are identified in approximately 4% of the cases, being recognized as a cryptogenic brain abscess (CBA). Here we report a patient with a CBA in the left occipital lobe presumably caused by a periodontal disease. The patient displayed a patent foramen ovale (PFO), through which a spontaneous right-to-left shunt was revealed with transesophageal echocardiography. A literature review indicated that in contrast to cases of general brain abscesses, patients with CBA were older and mostly had dental disorders represented by periodontal diseases and a large PFO. In these patients, the abscess was located predominantly in the posterior circulation area, and their prognosis was worse than that of general cases. Consequently, we emphasize the significance of screening for PFO in cases of advanced age with CBA in the posterior circulation region. Furthermore, to avoid neurological sequelae, we suggest immediate surgical drainage with antibiotic administration and maintenance of oral hygiene.