Pyogenic hepatic abscess (PHA) is a collection of pus in the liver caused by bacterial infection of the liver parenchyma. This potentially life-threatening condition has a mortality rate reported to be as high as 47%.1 The incidence of PHA is reported to be 2.3 per 100,000 individuals and is more common in immunosuppressed individuals and those with diabetes mellitus, cancer, and liver transplant.2,3 PHA infections are usually polymicrobial and most commonly include enteric organisms like Escherichia coli and Klebsiella pneumoniae.4
We present a rare cause of PHA with Fusobacterium nucleatum (F nucleatum) in an immunocompetent patient with poor oral health, history of diverticulitis, and recent COVID-19 infection whose only symptoms were chest pain and a 4-week history of fever and malaise.
Case Presentation
A 52-year-old man initially presented to the C.W. Bill Young Veterans Affairs Medical Center (CWBYVAMC) emergency department in Bay Pines, Florida, for fever, malaise, and right-sided chest pain on inspiration. The fever and malaise began while he was on vacation 4 weeks prior. He originally presented to an outside hospital where he tested positive for COVID-19 and was recommended ibuprofen and rest. His symptoms did not improve, and he returned a second time to the outside hospital 2 weeks later and was diagnosed with pneumonia and placed on outpatient antibiotics. The patient subsequently returned to CWBYVAMC 2 weeks after starting antibiotics when he began to develop right-sided inspiratory chest pain. He reported no other recent travel and no abdominal pain. The patient’s history was significant for diverticulitis 2 years before. A colonoscopy was performed during that time and showed no masses.
On presentation, the patient was febrile with a temperature of 100.8 °F; otherwise, his vital signs were stable. Physical examinations, including abdominal, respiratory, and cardiovascular, were unremarkable. The initial laboratory workup revealed a white blood cell (WBC) count of 18.7 K/μL (reference range, 5-10 K/μL) and microcytic anemia with a hemoglobin level of 8.8 g/dL. The comprehensive metabolic panel revealed normal aspartate transaminase, alanine transaminase, and total bilirubin levels and elevated alkaline phosphatase of 215 U/L (reference range, 44-147 U/L), revealing possible mild intrahepatic cholestasis. Urinalysis showed trace proteinuria and urobilinogen. Coagulation studies showed elevated D-dimer and procalcitonin levels at 1.9 ng/mL (reference range, < 0.1 ng/mL) and 1.21 ng/mL (reference range, < 0.5 ng/mL), respectively, with normal prothrombin and partial thromboplastin times. The patient had a normal troponin, fecal, and blood culture; entamoeba serology was negative.
A computed tomograph (CT) angiography of the chest was performed to rule out pulmonary embolism, revealing liver lesions suspicious for abscess or metastatic disease. Minimal pleural effusion was detected bilaterally. A subsequent CT confirmed the presence of hepatic lesions consistent with an abscess (Figure 1).
Following the procedure, the patient developed shaking chills, hypertension, fever, and acute hypoxic respiratory failure. He improved with oxygen and was transferred to the intensive care unit (ICU) where he had an increase in temperature and became septic without shock. A repeat blood culture was negative. An echocardiogram revealed no vegetation. Vancomycin was added for empiric coverage of potentially resistant organisms. The patient clinically improved and was able to leave the ICU 2 days later on hospital day 4.
The patient’s renal function worsened on day 5, and piperacillin-tazobactam and vancomycin were discontinued due to possible acute interstitial nephritis and renal toxicity. He started cefepime and continued metronidazole, and his renal function returned to normal 2 days later. Vancomycin was then re-administered. The results of the culture taken from the abscess came back positive for monomicrobial growth of F nucleatum on hospital day 9.
Due to the patient’s persisting fever and WBC count, a repeat CT of the abdomen on hospital day 10 revealed a partial decrease in the abscess with a persistent collection superior to the location of the initial pigtail catheter placement. A second pigtail catheter was then placed near the dome of the liver 1 day later on hospital day 11. Following the procedure, the patient improved significantly. The repeat CT after 1 week showed marked overall resolution of the abscess, and the repeat culture of the abscess did not reveal any organism growth. Vancomycin was discontinued on day 19, and the drains were removed on hospital day 20. He was discharged home in stable condition on metronidazole and cefdinir for 21 days with follow-up appointments for CT of the abdomen and with primary care, infectious disease, and a dental specialist.