Amebic liver abscess

Definition

Amebic liver abscess is a collection of pus in the liver caused by the intestinal parasite Entamoeba histolytica.

Causes, incidence, and risk factors

Amebic liver abscess is caused by Entamoeba histolytica, the same organism that causes amebiasis, an intestinal infection. The organism is carried through the blood to the liver.

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 associated with this disease. Transmission occurs through ingestion of cysts in fecally-contaminated food or water, use of human waste as fertilizer, and person-to-person contact.

Risk factors for amebic liver abscess include:

• Malnutrition
• Old age
• Pregnancy
• Steroid use
• Cancer
• Immunosuppression  
• Alcoholism
• Recent travel to a tropical region 
• Homosexuality, particularly in males

Symptoms

Patients may or may not have symptoms of intestinal infection. Symptoms that may be present include:

• Fever
• Abdominal pain, particularly in the right, upper region. Pain may be intense, continuous, or stabbing.
• General discomfort, uneasiness, or ill feeling (malaise )
• Sweating
• Chills
• Loss of appetite
• Weight loss
• Diarrhea
• Jaundice
• Joint pain

Signs and tests

These tests detect abscess in the liver:

• Abdominal ultrasound
• Abdominal CT scan or MRI
• Liver biopsy - rarely done due to high risk of complications
• Liver scan
• Liver function tests may show abnormalities
• A CBC shows elevated white blood cell count, indicating infection.
• A serology for amebiasis is positive

Treatment

Antimicrobial therapy with 750 mg of metronidazole (Flagyl) taken 3 times a day for 10 days is the usual treatment for liver abscess. 

In rare cases, the abscess may need to be drained to help relieve some of the abdominal pain associated with the abscess.

Medication such as paromomycin must also be taken to eliminate intestinal amebiasis to prevent recurrence of the disease.

Expectations (prognosis)

Without treatment, the abscess may rupture and spread into other organs, and death may occur as a result. With treatment, the chance of complete cure or only only minor problems is high, at least 80-90%.

Complications

The 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 provider

Call your health care provider if symptoms develop after travel to an area where the disease is known to occur.

Prevention

When traveling in tropical countries where poor sanitation exists, drink purified water and do not eat uncooked vegetables or unpeeled fruit. Public health measures include improved water purification and waste treatment for underdeveloped countries.

References

Wells CD, Arguedas M. Amebic liver abscess. South Med J. 2004 Jul;97(7):673-82.

Lingvay I, Aung, K. Amebic liver abscess. eMedicine. 2004 Nov; 2662. Available online at: http://www.emedicine.com/med/topic2662.htm. Accessed June 23, 2005.

Torre A, Kershenobich D. Amebic liver abscess. Ann Hepa tol. 2002 Jan-Mar;1(1):45-7.

Feldman M, Friedman LS, Sleisenger MH, eds. Amebic Liver Abscess. In: Sleisenger & Fordtran’s Gastrointestinal and Liver Disease. 7th Ed. Philadelphia, PA: Saunders; 2002:1345-1346.

Illustrations

Liver cell death

Page Content:

Hepatic amebiasis; Extraintestinal amebiasis; Abscess - amebic liver ; amebic liver abscess