"Typical features include one or more well‑defined, low‑attenuation lesions, most often in the right hepatic lobe. The central cavity generally has attenuation values compatible with complex fluid, often around 10-20 HU 1,6,10. A peripheral enhancing wall is usually present, sometimes with an incomplete rim of surrounding oedema. Internal septations and fluid–debris levels may be seen, and focal intrahepatic biliary dilatation peripheral to the abscess has been described. A “double target” or “halo” appearance with an inner enhancing rim and outer low‑attenuation oedema may be present but is not specific 6,10."
"poor clinical response after several days (often 5–7) of appropriate medical therapy"
"T1: generally homogeneous low signal intensity (signal homogeneity within the abscess can be present more often on T1- than on T2-weighted images)"
"T2: generally homogeneous high signal intensity; perilesional oedema may be seen in half of the cases"
"DWI: typically restricted diffusion within the abscess cavity"
"Amoebic hepatic abscesses are hepatic abscesses caused by invasive infection with Entamoeba histolytica. They are the most common extra‑intestinal manifestation of amebiasis and an important cause of liver abscess in endemic areas 6,10."
"Amebiasis due to Entamoeba histolytica remains a major global health problem, with the highest burden in developing countries in the tropics and subtropics where sanitation and access to clean water are limited. Millions of people are infected worldwide, and amebic colitis is a leading cause of severe diarrhoea, estimated to result in more than 55,000 deaths each year. 12."
"Amoebic hepatic abscess occurs when invasive trophozoites of Entamoeba histolytica reach the liver via the portal circulation following intestinal infection. The organism is transmitted through ingestion of mature cysts in fecally contaminated food or water 8,10."
"Serologic testing for E. histolytica antibodies is highly sensitive in non‑endemic settings, although it may be negative early in the course of disease. Stool microscopy has limited sensitivity and cannot reliably distinguish pathogenic E. histolytica from non‑pathogenic species; stool antigen detection or nucleic acid amplification tests, where available, improve diagnostic accuracy 10."
"Aspiration is usually reserved for selected cases (e.g. uncertain diagnosis, lack of response to therapy, or high‑risk lesions) rather than for routine microbiologic confirmation 10."
Expected headings
"Pathophysiology"
"Diagnostic workup"
"Serologic testing for E. histolytica antibodies is highly sensitive in non‑endemic settings, although it may be negative early in the course of disease. Stool microscopy has limited sensitivity and cannot reliably distinguish pathogenic E. histolytica from non‑pathogenic species; stool antigen detection or nucleic acid amplification tests, where available, improve diagnostic accuracy 10."
"On ultrasound, amoebic hepatic abscesses typically appear as round or oval hypoechoic lesions with low‑level internal echoes. A definable wall may be thin or inapparent, and posterior acoustic enhancement is common. Echotexture can evolve from more homogeneous to heterogeneous as the lesion organises; internal septations or debris may be seen 10."
"T2: generally homogeneous high signal intensity; perilesional oedema may be seen in half of the cases"
"Prognosis is excellent in most treated patients, with rapid symptomatic improvement and decreasing inflammatory markers. Radiologic resolution lags behind clinical recovery, and abscess cavities may persist or involute slowly over many months; residual cavities can be seen on imaging for up to 2 years despite clinical cure. Rupture into the peritoneal, pleural, or pericardial spaces is an important cause of morbidity and mortality and requires prompt recognition and management 2,6,8,10."