Case Presentation: A 76-year-old male with past medical history of GERD, hypothyroidism, and pre-diabetes presented with fever, chills, lethargy and 5-pound unintentional weight loss for 2 weeks. He denied abdominal pain, nausea or vomiting. No history of recent travel or IV drug use was present. Physical exam was unremarkable. Labs were significant for neutrophil-predominant leukocytosis of 12.4 x10E+09/L, lactate of 3mMol/L, ALT 60unit(s)/L, AST 50unit(s)/L, alkaline phosphatase 424unit(s)/L and GTP 229unit(s)/L. Urinalysis was unremarkable. Chest x-ray showed non-specific bibasilar opacities. CT chest was negative for any infectious process in the lungs but incidentally showed a vague nonspecific area of hypo attenuation within the right hepatic lobe. Ultrasound abdomen revealed multiple solid-appearing hypo echoic lesions. A tri-phasic CT scan was then performed, demonstrating multi-lobulated, necrotic space-occupying lesion in the right lobe of the liver measuring approximately 6.7cm x 4.8cm in transverse dimension, with a fine rim of enhancement. A smaller similar appearing lesion was also seen in the periphery of the right hepatic lobe. Hepatic viral panel was negative. AFP and CA 19-9 were within normal limit. CEA was mildly elevated (4ng/ml). Blood cultures at this point showed growth of Fusobacterium. A liver biopsy was initially planned due to suspicion of malignancy, however, peripheral fine rim of enhancement and central hypo attenuation favored the diagnosis of abscess as opposed to a tumor; especially in the setting of bacteremia. CT maxillofacial later revealed untreated dental caries of the left mandibular lateral incisor – the probable source of Fusobacterium. Incision and drainage of abscess was technically difficult due to the risk of puncturing pleura. Treatment with a 6-week course of IV Zosyn was pursued. A follow-up contrast-enhanced CT abdomen showed interval decrease in the size of the hepatic mass, confirming the diagnosis of pyogenic liver abscess.
Discussion: Fusobacterium is a genus of anaerobic gram-negative bacilli, most commonly implicated in periodontal diseases and Lemierre’s Syndrome but rarely associated with visceral abscesses. In case of hepatic abscess secondary to Fusobacterium, incision and drainage might not always be necessary as Fusobacterium is highly sensitive to antibiotics. A 4-6 week-course of appropriate IV antibiotics and follow up contrast enhanced CT demonstrating interval decrease in the size of the abscess can be a management strategy. A colonoscopy is eventually recommended to look for gastrointestinal pathology and screen for colorectal carcinoma.
Conclusions: Hepatic abscess secondary to Fusobacterium is rare and only a few cases have been reported. The decision for incision and drainage can be individualized based on size, number and location of abscesses. Treatment with 4-6 week course of IV antibiotics can lead to complete resolution of the abscess.