Cryptogenic HACEK CNS Abscess in Otherwise Healthy Patient with Patent Foramen Ovale
Ai Ohno1, Matthew Cappiello2, Lu Pu2, Daniel Rogstad2
1Neurology, 2Infectious Disease, Loma Linda University
Objective:
To describe a case of a young, immunocompetent male who presented with intractable headaches. He was found to have a cryptogenic brain abscess with uncommon organisms on culture (HACEK spectrum and Actinomyces). Aside from patent foramen ovale, no evidence of endocarditis was found, nor other predisposing cardiac or dental disease.
Background:
Actinomycosis and HACEK organisms are part of the oral microbiome and rarely affect the central nervous system (CNS). Infections can be caused by contiguous or hematogenous spread.
Results:
A 25-year-old immunocompetent male presented with 1 week of progressively worsening generalized headaches, photophobia, nausea, and vomiting. Vital signs were stable without leukocytosis or focal deficits on exam. He had good dentition. Head imaging revealed a 4.0 cm right frontal lobe abscess with 7 mm midline shift. Patient was started empirically on vancomycin, ceftriaxone, and metronidazole. Evacuation and washout were performed. Small satellite abscesses were noted posterior to the main abscess. The cultures grew organisms from the HACEK spectrum (Aggregatibacter, Eikenella), Gemella morbillorum, Streptococcus constellatus, and Actinomycoses georgiae. Serial repeat imaging showed rapid increase in size of the residual abscess. The patient underwent re-operation on POD 5, with a thickened posterior capsular wall that was evacuated again. While the patient was found to have a small patent foramen ovale, there was no evidence of bacteremia nor valvular vegetation on transesophageal echocardiogram. No evidence of dental or sinus disease was seen on imaging. Based on sensitivities, the patient was discharged on an 8-week post-operative course of IV ceftriaxone followed by oral amoxicillin for a total of 12 months of antibiotic therapy.
Conclusions:
Cryptogenic CNS abscess can occur in patients with underlying patent foramen ovale - even in the absence of bacteremia, endocarditis, or frank odontogenic or sinus infection.