DefinitionAmebic liver abscess is a collection of pus in the liver in response to an intestinal parasite.
Alternative NamesHepatic amebiasis; Extraintestinal amebiasis; Abscess - amebic liver
Causes, incidence, and risk factorsAmebic liver abscess is caused by Entamoeba histolytica, the same parasite that causes amebiasis, an intestinal infection that is also called amebic dysentery. After an infection has occurred, the parasite may be carried by the blood from the intestines to the liver.The disease spreads from eating food or water that has been contaminated with feces (sometimes due to the use of human waste as fertilizer), and through person-to-person contact.The infection occurs worldwide, but is most common in tropical areas where crowded living conditions and poor sanitation exist. Africa, Latin America, Southeast Asia, and India have significant health problems from this disease.Risk factors for amebic liver abscess include:AlcoholismCancerImmunosuppressionMalnutritionOld agePregnancyRecent travel to a tropical regionSteroid use
SymptomsThere are usually no symptoms of intestinal infection. If symptoms do occur, they may include:Abdominal pain
Particularly in the right, upper part of the abdomenIntense, continuous, or stabbing painChillsDiarrhea (in only one-third of patients)FeverGeneral discomfort, uneasiness, or ill feeling (malaise)JaundiceJoint painLoss of appetiteSweatingWeight loss
Signs and testsTests that may be done include:Abdominal ultrasoundAbdominal CT scan or MRIComplete blood countLiver abscess aspiration -- to check for bacterial infection in the liver abscessLiver scanLiver function testsSerology for amebiasisStool testing for amebiasis
TreatmentAntibiotics such as metronidazole (Flagyl) or tinidazole (Tindamax) are the usual treatment for liver abscess. A medication such as paromomycin or diloxanide must also be taken to get rid of all the amoebas in the intestine, to prevent the disease from coming back. This treatment can usually be delayed until after the abscess has been treated.In rare cases, the abscess may need to be drained to relieve some of the abdominal pain.
Expectations (prognosis)Without treatment, the abscess may break open (rupture) and spread into other organs, leading to death. People who are treated have a very high chance of a complete cure or only minor complications.
ComplicationsThe abscess may rupture into the abdominal cavity, the lining of the lungs, the lungs, or the sac around the heart. The infection can also spread to the brain.
Calling your health care providerCall your health care provider if you develop symptoms of this disease, especially if you've recently traveled to an area where the disease is known to occur.
PreventionWhen traveling in tropical countries with poor sanitation, drink purified water and do not eat uncooked vegetables or unpeeled fruit.
ReferencesDonnelly JP, Blijlevens NMA, DePauw BE. Entamoeba species including amebiasis. In: Mandell GL, Bennett JE, Dolin R, eds. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Disease. 7th ed. Philadelphia, Pa: Saunders Elsevier; 2009:chap 273.Neuschwander-Tetri BA. Bacterial, parasitic, fungal, and granulomatous liver disease. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 155.