- Biliary tract disease is the most common cause
- No cause identified in the majority of patients
- Nonspecific clinical findings - high degree of suspicion required for diagnosis
- Most often single, rather than multiple foci
- Hyperbilirubinemia and elevated alkaline phosphatase in the majority of patients, but low specificity.
- E. coli the most prevalent organism, followed by Klebsiella, Streptococcus, and Bacteroides species.
- Rare cause is bowel perforation following foreign body ingestion
- Therapy for solitary liver abscess from causes other than bowel perforation is intravenous antibiotics and percutaneous US- or CT-guided drainage
- Therapy for liver abscess caused by bowel perforation or foreign body is open surgical drainage
- Amoebic liver abscess occurs in 94% of cases of amoebiasis
- Liver abscess is a relatively infrequent (1.7% according to Cho, D. et. al.), although possible, complication of percutaneous radiofrequency ablation of hepatic tumors.
 Imaging Findings
- Right pleural effusion, elevated right hemidiaphragm, and subsegmental atelectasis on chest radiography
- Findings on abdominal radiography nonspecific in 87% of cases
- US and CT are critical imaging tools
- US may demonstrate a peripheral echo-free halo, distal acoustic enhancement, and progressive change over a short period of time.
- On CT, abscesses may be single or multipe, round or oval, have an enhancing rim, complete or incomplete rim of edema, have smooth or nodular margins, intraabscess hemorrhage, peripheral biliary ductal dilatation, and may contain internal septations. Patterns are variable.
- Pretreatment amebic liver abscess appears as a heterogeneously low-signal intensity mass with sharp borders on T1 and as a hyperintense region with hyperintensity extending to the liver surface, corresponding to edematous hepatic parenchyma.
- Progression of edema is followed with T2-weighted imaging.
- Posttreatment amebic liver abscess becomes homogeneously hypointense on T1-weighted images.
- Maturation of the abscess wall during and after treatment is characterized by the appearance of concentric rings.
- Differential for MR findings for amebic liver abscess also includes bacterial abscess, hematoma and necrotic tumor.
Patient #1: CT images demonstrate a large abscess in the right hepatic lobe
 See Also
 External Links
- Dongil Choi, Hyo K. Lim, Min Ju Kim, Suk Jung Kim, Seung Hoon Kim, Won Jae Lee, Jae Hoon Lim, Seung Woon Paik, Byung Chul Yoo, Moon Seok Choi, and Seonwoo Kim. Liver Abscess After Percutaneous Radiofrequency Ablation for Hepatocellular Carcinomas: Frequency and Risk Factors. Am. J. Roentgenol., Jun 2005; 184: 1860 - 1867.
- Dewbury, K.C., Joseph, A.E., Millward Sadler, G.H., and Birch, S.J. Ultrasound in the diagnosis of the early liver abscess. Brit. J. of Radiol. 1980;53, 635: 1160-1165.
- Drnovsek, V., Fontanez-Garcia, D., Wakabayashi, M.N., Plavsic, B.M. Gastrointestinal Case of the Day, Radiographics, 1999;19:820-822.
- Elizondo, G., Weissleder, R., Stark, D.D., Todd, L.E., Compton, C., Wittenberg, J., and Ferrucci, J.T. Amebic Liver Abscess: Diagnosis and Treatment Evaluation with MR Imaging. Radiology, 1987; 165:795-800.
- Radin, D.R., Ralls, P.W., Colletti, P.M., and Halls, J.N. CT of amebic liver abscess. Am. J. Roentgen. 1988; 150, 6: 1297-1301.