S5650 An Unusual Presentation of Klebsiella pneumoniae Primary Hepatic Abscess in an Immunocompetent Immigrant

Introduction: Klebsiella pneumoniae primary liver abscesses (KLA) are predominantly reported in immunocompromised patients, particularly in Southeast Asia. However, cases in immunocompetent individuals are becoming increasingly recognized, even in non-endemic areas such as the United States. This case of a 40-year-old male immigrant from Mauritania underscores the importance of considering KLA in febrile patients, even in the absence of traditional risk factors. Case Description/Methods: A 40-year-old man without significant past medical history presented with a 4-day history of fevers and fatigue. He had been residing in Michigan for 5 months and reported occasional consumption of unclean tap water. He denied any alcohol, tobacco, illicit drug use, recent antibiotics, or weight loss. On admission, the patient was febrile and tachycardic. Laboratory studies were remarkable for leukopenia (white blood cell count 2.1 K/µL), elevated liver enzymes (aspartate aminotransferase 125 U/L, alanine aminotransferase 100 U/L), and a lactic acidosis of 2.3 mmol/L. HbA1c was within normal limits. Stool studies, amoebic serologies and viral hepatitis serologies were negative. HIV-1/HIV-2 were non-reactive. Computed tomography (CT) scan of the abdomen with contrast revealed a large, gas-containing lesion in the right hepatic lobe. MRCP demonstrated a 5.3 × 3.3 × 4.1 cm non-enhancing lesion. Subsequently, patient was started on empiric antibiotics with ceftriaxone and metronidazole, and a CT-guided abscess drainage was performed. Blood and abscess cultures grew Klebsiella pneumoniae, susceptible to cephalosporins. Colonoscopy was performed revealing unremarkable results. Lung and brain imaging were negative for metastatic complications. The patient showed marked clinical improvement with antibiotics. Follow-up appointments with hepatology and infectious diseases were scheduled. Discussion: This case highlights the importance of maintaining a broad differential when evaluating febrile patients with abnormal liver function tests. Klebsiella pneumoniae primary liver abscesses are more commonly seen in immunocompromised individuals, including those with diabetes and chronic liver disease. This case is unusual because the patient is immunocompetent and lacked typical risk factors for KLA, such as diabetes or alcoholism. KLA is often monomicrobial and can lead to metastatic infections, including septic emboli to the lungs or brain. Therefore, early imaging and initiating appropriate antibiotics in a timely manner are crucial in preventing complications and ensuring a favorable outcome.