Correspondence

Amebiasis

N Engl J Med 2003; 349:307-308July 17, 2003

Article

To the Editor:

Haque et al. (April 17 issue)1 mention that amebic liver abscesses are usually solitary lesions in the right lobe. We believe that the classic description of amebic liver abscess needs to be modified, however, since many variants exist. In a sonographic evaluation of 212 patients, 34 (16 percent) had multiple abscesses, 75 (35 percent) had an abscess in the left lobe, and the remaining 103 (49 percent) had a solitary abscess in the right lobe.2

We also do not agree with Haque et al. that a liver abscess greater than 5 cm in diameter is an indication for drainage. In a randomized trial involving 37 patients,3 metronidazole at a dose of 2.4 g per day was given to all the patients for 10 days. Needle aspiration of the abscess was performed in 19 of the patients. The mean diameter of the liver abscess was 54 mm in the aspiration group and 72 mm in the metronidazole-only group. The clinical and biochemical improvement was similar in both groups. The indications for drainage should be the presence of left-lobe abscess, impending rupture, multiple abscesses, or abscess that does not respond to medical therapy within three to five days. There is no evidence that aspiration, even of large abscesses (up to 10 cm in diameter), accelerates healing.4

Mahesh P. Sharma, M.D., D.M.
Vineet Ahuja, M.D., D.M.
All India Institute of Medical Sciences, New Delhi 110029, India
mpsharma_s@hotmail.com

4 References

1. 1

   Haque R, Huston CD, Hughes M, Houpt E, Petri WA Jr. Amebiasis. N Engl J Med 2003;348:1565-1573
   Full Text | Web of Science | Medline

2. 2

   Sharma MP, Dasarathy S, Sushma S, Verma N. Variants of amebic liver abscess. Arch Med Res 1997;28:272-273
   Medline

3. 3

   Sharma MP, Rai RR, Acharya SK, Ray JC, Tandon BN. Needle aspiration in amoebic liver abscess. BMJ 1989;299:1308-1309
   CrossRef | Web of Science | Medline

4. 4

   Reed SL. Amebiasis and infection with free-living amebas. In: Braunwald E, Fauci AS, Kasper DL, Hauser SL, Longo DL, Jameson JL, eds. Harrison's principles of internal medicine. 15th ed. Vol. 1. New York: McGraw-Hill, 2001:1199-203.
   

To the Editor:

In their excellent review of amebiasis, Haque et al. do not mention alternatives to metronidazole that may be considered in cases in which metronidazole is not available or causes intolerable side effects. Erythromycin and tetracycline have been used in the treatment of amebic colitis,1,2 but they are not effective therapies for hepatic amebiasis. Alternatives for eradicating trophozoites in the liver include chloroquine (600 mg daily for two days, followed by 300 mg daily for three weeks) with or without dehydroemetine,3 although the latter is associated with serious side effects, including toxic cardiac effects, and should therefore be given only in a hospital setting.

Petros Kopterides, M.D.
Laiko General Hospital, Athens 14233, Greece

3 References

1. 1

   Badalamenti S, Jameson JE, Reddy KR. Amebiasis. Curr Treat Options Gastroenterol 1999;2:97-103
   CrossRef | Medline

2. 2

   Ravdin JI, Skilogiannis J. In vitro susceptibilities of Entamoeba histolytica to azithromycin, CP-63,956, erythromycin, and metronidazole. Antimicrob Agents Chemother 1989;33:960-962
   Web of Science | Medline

3. 3

   Georgopoulos A, Linnau KF, Buxbaum A, et al. Efficacy of macrolides vs. metronidazole against Entamoeba histolytica clinical isolates. Wien Klin Wochenschr 2001;113:593-596
   Web of Science | Medline

Author/Editor Response

It is well recognized that there are variants in the intrahepatic location of amebic liver abscesses and in their number. Although the most common amebic liver abscess is a solitary lesion in the right lobe, we agree with Drs. Sharma and Ahuja that in a substantial percentage of cases there are multiple abscesses in both lobes or there is a single lesion in the left lobe.1 The number and location of abscesses are not pathognomonic for amebic liver abscess and cannot be used to rule out other possible diagnoses, such as pyogenic abscess or cancer. With regard to needle aspiration of amebic liver abscesses, we presented guidelines for situations in which to consider aspiration. These guidelines are supported by published data and are meant to be used in conjunction with the physician's clinical judgment and information on the patient's response to initial antiamebic therapy.1,2

Chloroquine is an alternative therapy for amebic liver abscess if metronidazole or another nitroimidazole (such as secnidazole or tinidazole) is not available, but it is less effective.1,3,4 Chloroquine is suboptimal for treating intestinal amebiasis because of its absorption in the small intestine and hence low concentrations in the large intestine. Treatment of amebiasis with chloroquine (or metronidazole for the same reason) should therefore be followed with paromomycin or diloxanide furoate.1,3 Dehydroemetine is not recommended because of its potential toxic cardiac and gastrointestinal effects.3 Although, as Dr. Kopterides mentions, promising data have been published on the in vitro susceptibility of Entamoeba histolytica to a number of macrolides, correlation with in vivo studies is needed before these drugs can be recommended for the treatment of amebiasis.5

Molly A. Hughes, M.D., Ph.D.
University of Virginia, Charlottesville, VA 22908

Rashidul Haque, M.B., Ph.D.
International Centre for Diarrhoeal Disease Research, Dhaka, Bangladesh

William A. Petri, Jr., M.D., Ph.D.
University of Virginia, Charlottesville, VA 22908
wap3g@virginia.edu

5 References

1. 1

   Hughes MA, Petri WA Jr. Amebic liver abscess. Infect Dis Clin North Am 2000;14:565-582
   CrossRef | Web of Science | Medline

2. 2

   Sharma MP, Rai RR, Acharya SK, Ray JC, Tandon BN. Needle aspiration in amoebic live abscess. BMJ 1989;299:1308-1309
   CrossRef | Web of Science | Medline

3. 3

   Tracy JW, Webster LT Jr. Drugs used in the chemotherapy of protozoal infections. In: Hardman JG, Limbird LE, eds. Goodman & Gilman's the pharmacological basis of therapeutics. 10th ed. New York: McGraw-Hill, 2001:1097-120.
   

4. 4

   Maltz G, Knauer CM. Amebic liver abscess: a 15-year experience. Am J Gastroenterol 1991;86:704-710
   Web of Science | Medline

5. 5

   Ravdin JI, Skilogiannis J. In vitro susceptibilities of Entamoeba histolytica to azithromycin, CP-63,956, erythromycin, and metronidazole. Antimicrob Agents Chemother 1989;33:960-962
   Web of Science | Medline