Fusobacterium Nucleatum: Atypical Organism of Pyogenic Liver Abscess Might be Related to Sigmoid Diverticulitis

CONTEXT: Pyogenic liver abscesses (PLAs) are the most common form of liver abscesses in the United States. Most cases are caused by enteric bacteria and anaerobes. We report a case of PLA caused by a rare pathogen, Fusobacterium nucleatum, from an unusual primary site of infection. CASE REPORT: A 60-year-old male presented with subacute fever. Initial work-up revealed leukocytosis and elevated alkaline phosphatase (ALP). Dental examination and Panorex x-ray were normal. Imaging of the liver with abdominal computed tomography demonstrated a 5.5 cm abscess in the right lobe of the liver. Culture of the aspirate grew Fusobacterium nucleatum. He improved with abscess drainage and antibiotic therapy with moxifloxacin and metronidazole. Colonoscopy performed a few weeks later, demonstrated sigmoid ulceration most likely from the previous diverticulitis. CONCLUSION: PLAs can be a complication of sigmoid diverticulitis and as a result of occult dental disease as well. The clinical presentation of Fusobacterium infection is diverse and can be fatal if diagnosis is delayed. Therefore, early diagnosis and treatment are the keys to preventing serious complications.