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Amebic Hepatic Abscesses Treatment & Management

  • Author: Daniel Matei Brailita, MD; Chief Editor: BS Anand, MD  more...
Updated: Apr 15, 2015

Medical Care

Most uncomplicated amebic liver abscesses can be treated successfully with amebicidal drug therapy alone. Use tissue amebicides to eradicate the invasive trophozoite forms in the liver. After completion of treatment with tissue amebicides, administer luminal amebicides for eradication of the asymptomatic colonization state. Failure to use luminal agents can lead to relapse of infection in approximately 10% of patients.

In general, metronidazole, tinidazole, emetine, and dehydroemetine are active in invaded tissues; chloroquine is active only in the liver; tetracycline acts on the bowel wall; and diloxanide furoate, paromomycin, and iodoquinol are luminal agents only. The details on tissue and luminal amebicidal agents are discussed in Medication.


Metronidazole remains the drug of choice for amebic liver abscess. Metronidazole enters the protozoa by passive diffusion and is converted to reactive cytotoxic nitroradicals by reduced ferredoxin or flavodoxin. Tinidazole, another nitroimidazole closely related to metronidazole, was approved for the treatment of amebic liver abscess and invasive amebiasis. Tinidazole is well tolerated by patients. Tinidazole may be administered once daily and appears to be at least as effective as metronidazole, with a clinical cure rate of more than 90%.

Metronidazole, 750 mg 3 times a day orally for 10 days, was reported to be curative in 90% of patients with amebic liver abscess. The drug also is available for intravenous administration for those patients who are unable to take medication by the oral route.

Resolution of symptoms is fairly rapid and is observed within 3 days in most patients in the United States. In endemic areas outside the United States, it takes relatively longer to resolve symptoms because the abscesses are quite large or multiple by the time patients seek medical attention.

In vivo resistance to metronidazole by E histolytica has not been reported. Nevertheless, in vitro studies have shown an association between metronidazole resistance and decreased expression of ferredoxin 1 and flavodoxin and increased expression of iron-containing superoxide dismutase and peroxiredoxin in E histolytica.

Usual adverse effects of metronidazole include nausea, headache, and metallic taste. Abdominal cramps, vomiting, diarrhea, and dizziness also may occur. Dark urine may occur from a metabolite of the drug.

Other items to consider

Other considerations include the following:

  • No randomized controlled trials exist that demonstrate the benefits of combination therapy over monotherapy.
  • Outside the United States, other closely related amebicidal agents, such as secnidazole or ornidazole, can be substituted in appropriate dosages. These drugs are not available in the United States.
  • Chloroquine phosphate may be substituted or added in the event of failure of resolution of clinical symptoms with metronidazole or another nitroimidazole within 5 days or intolerance to metronidazole or a nitroimidazole. Chloroquine has the disadvantage of being associated with higher relapse rates than nitroimidazoles. Adverse effects include gastrointestinal upset, headache, dizziness, and blurred vision. Retinopathy does not occur at the dose used for amebic liver abscess.
  • Emetine or dehydroemetine has a direct lethal action on the trophozoites of E histolytica. These agents are very toxic and, therefore, should be used only as a second-line therapy. Their toxicity includes cardiac arrhythmias, precordial pain, muscle weakness, vomiting, and diarrhea. Dehydroemetine is less toxic than emetine.

Administer a luminal amebicidal agent to eradicate the intestinal carriage after the amebic liver abscess has been treated with one of the above tissue amebicides. Failure to use luminal agents can lead to relapse of infection in approximately 10% of patients. Luminal agents with proven efficacy include diloxanide furoate, iodoquinol, and paromomycin. Note the following:

  • Diloxanide furoate is free of major adverse effects. The most common adverse effect is flatulence and occasional gastrointestinal upset.
  • Iodoquinol (diiodohydroxyquin) rarely causes abdominal pain, diarrhea, or rash. A structurally related diiodohydroxyquin caused subacute myelopticoneuropathy and is obsolete now.
  • Although paromomycin may occasionally cause nausea, abdominal cramps, or diarrhea, it is the preferred luminal amebicidal.
  • The details on the luminal amebicides are discussed in Medication.


Consult with an interventional radiologist for imaging-guided aspiration of the abscess.

Consult with a general surgeon for open surgical drainage of the abscess under rare circumstances (see Surgical Care).

Diet and activity

No specific diet change or modification is required. However, discuss food hygiene with patients because amebiasis is associated with suboptimal personal or food hygiene (see Deterrence/Prevention).

No restriction of activity is needed, except during the first few days of acute illness with pain.

If emetine or dehydroemetine is used, the patient should remain sedentary for approximately 4 weeks after completing therapy because of their toxicity.


Surgical Care

Consider therapeutic aspiration of amebic liver abscess in the following situations: (1) high risk of abscess rupture, as defined by cavity size greater than 5 cm; (2) left lobe liver abscess, which is associated with higher mortality and frequency of peritoneal leak or rupture into the pericardium; (3) failure to observe a clinical medical response to therapy within 5-7 days; and (4) cannot differentiate from a pyogenic liver abscess.

The following are predictive of the need for aspiration: (1) age older than 55 years, (2) abscess greater than 5 cm in diameter, and (3) failure of medical therapy after 7 days.[25] In endemic areas, because of the late presentation and the existence of multiple abscesses, as many as 50% of patients may require aspiration.[26] However, routine needle aspiration offers only minimal benefit over medical care alone for uncomplicated amebic liver abscess and, unless one of the above indications exists, should be avoided.[27] Prompt medical care decreases the need for aspiration.[28]

Imaging-guided needle aspiration and catheter drainage are the procedures of choice. Generally, surgical drainage is not necessary and should be avoided; however, consider open surgical drainage when the abscess is inaccessible to needle drainage or a response to therapy has not occurred in 5-7 days.

Simple needle aspiration is less invasive, is less expensive, and has the advantage of being able to drain multiple abscesses in the same session. Simple needle aspiration avoids problems related to catheter care (see Procedures).

Although catheter drainage may be more effective than needle aspiration, in a study by Rajak et al,[29] the average time for clinical improvement, mean hospital stay, and time to resolution were similar among the patients who were successfully treated in the 2 treatment groups.

Contributor Information and Disclosures

Daniel Matei Brailita, MD Infectious Disease Specialist, Mary Lanning Healthcare and Central Nebraska Infectious Diseases

Daniel Matei Brailita, MD is a member of the following medical societies: American Medical Association, Infectious Diseases Society of America, HIV Medicine Association

Disclosure: Nothing to disclose.


KoKo Aung, MD, MPH, FACP Chief, Division of General Internal Medicine, O Roger Hollan Professor of Internal Medicine, Director, Office of Educational Programs, Department of Medicine, University of Texas Health Science Center at San Antonio

KoKo Aung, MD, MPH, FACP is a member of the following medical societies: American College of Physicians, Society of General Internal Medicine

Disclosure: Nothing to disclose.

Ildiko Lingvay, MD, MPH, MSc Assistant Professor, Department of Internal Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Texas Southwestern Medical Center at Dallas

Ildiko Lingvay, MD, MPH, MSc is a member of the following medical societies: Endocrine Society, Texas Medical Association

Disclosure: Received consulting fee from GI Dynamics for consulting; Received honoraria from NovoNordisk, Inc for board membership.

Ambrish Ojha, MBBS 

Ambrish Ojha, MBBS is a member of the following medical societies: American College of Physicians, American Medical Association

Disclosure: Nothing to disclose.

Specialty Editor Board

Francisco Talavera, PharmD, PhD Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Received salary from Medscape for employment. for: Medscape.

Chief Editor

BS Anand, MD Professor, Department of Internal Medicine, Division of Gastroenterology, Baylor College of Medicine

BS Anand, MD is a member of the following medical societies: American Association for the Study of Liver Diseases, American College of Gastroenterology, American Gastroenterological Association, American Society for Gastrointestinal Endoscopy

Disclosure: Nothing to disclose.

Additional Contributors

Robert J Fingerote, MD, MSc, FRCPC Consultant, Clinical Evaluation Division, Biologic and Gene Therapies, Directorate Health Canada; Consulting Staff, Department of Medicine, Division of Gastroenterology, York Central Hospital, Ontario

Robert J Fingerote, MD, MSc, FRCPC is a member of the following medical societies: American Association for the Study of Liver Diseases, American Gastroenterological Association, Ontario Medical Association, Royal College of Physicians and Surgeons of Canada, Canadian Medical Association

Disclosure: Nothing to disclose.


Harvey Kantor, MD Chief, Professor, Department of Internal Medicine, Division of Infectious Diseases, Texas Tech University Health Science Center

Harvey Kantor, MD is a member of the following medical societies: American College of Physicians, American Medical Association, American Society for Microbiology, Illinois State Medical Society, Infectious Diseases Society of America, New York Academy of Sciences, Royal Society of Medicine, and Sigma Xi

Disclosure: Nothing to disclose.

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CT scan of the abdomen with IV and oral contrast is shown. Note the thick-walled cavity with low attenuation center and contrast-enhanced periphery.
CT scan of the abdomen with contrast showing large amebic abscess with multiloculated appearance and atypical left liver lobe location. CT scan cannot differentiate amebic liver abscess from pyogenic liver abscess.
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