eMedicine Specialties > Pediatrics: General Medicine > Parasitology

Dientamoeba Fragilis Infection: Treatment & Medication

Author: David R Mack, MD, FRCPC, Professor, Departments of Pediatrics and Biochemistry, Microbiology, and Immunology, University of Ottawa Faculty of Medicine; Head, Division of Gastroenterology, Hepatology, and Nutrition, Department of Pediatrics, Children's Hospital of Eastern Ontario, Canada
Contributor Information and Disclosures

Updated: Jul 24, 2008

Treatment

Medical Care

The goal of therapy is eradication of the parasite (see Medication).

Medication

The goal of therapy is eradication of the parasite. The drugs used are considered investigational by the US Food and Drug Administration because of a lack of clinical trials. Response rates for a single course of therapy are 70-90% in the limited data published.

Anthelmintics

Parasite biochemical pathways are different from the human host; thus, toxicity is directed to the parasite, egg, or larvae. Mechanism of action varies within the drug class. Antiparasitic actions may include the following:

  1. Inhibition of microtubules, causing irreversible block of glucose uptake
  2. Tubulin polymerization inhibition
  3. Depolarizing neuromuscular blockade
  4. Cholinesterase inhibition
  5. Increased cell membrane permeability, resulting in intracellular calcium loss
  6. Vacuolization of the schistosome tegument
  7. Increased cell membrane permeability to chloride ions via chloride channels alteration


Metronidazole (Flagyl)

Imidazole ring-based antibiotic active against various anaerobic bacteria and protozoa.

Adult

500-750 mg PO tid for 10 d

Pediatric

20-40 mg/kg/d PO divided tid for 10 d; not to exceed 2 g/d

Cimetidine may increase toxicity of metronidazole; may increase effects of anticoagulants; may increase toxicity of lithium and phenytoin; disulfiramlike reaction may occur with PO ingested ethanol

Documented hypersensitivity; first trimester of pregnancy

Pregnancy

B - Fetal risk not confirmed in studies in humans but has been shown in some studies in animals

Precautions

Contraindicated in first trimester of pregnancy; adjust dose in hepatic disease; monitor for seizures and development of peripheral neuropathy


Tetracycline (Sumycin)

Inhibits bacterial protein synthesis by binding with 30S and, possibly, 50S ribosomal subunits.

Adult

500 mg PO qid for 10 d

Pediatric

40 mg/kg/d PO divided qid for 10 d; not to exceed 2 g/d

Bioavailability decreases with antacids containing aluminum, calcium, magnesium, iron, or bismuth subsalicylate; can decrease effects of PO contraceptives, causing breakthrough bleeding and increased risk of pregnancy; can increase hypoprothrombinemic effects of anticoagulants

Documented hypersensitivity; severe hepatic dysfunction

Pregnancy

D - Fetal risk shown in humans; use only if benefits outweigh risk to fetus

Precautions

Photosensitivity may occur with prolonged exposure to sunlight or tanning equipment; reduce dose in renal impairment; consider drug serum level determinations in prolonged therapy; use during tooth development (last one half of pregnancy through age 8 y) can cause permanent discoloration of teeth; Fanconilike syndrome may occur with outdated tetracyclines


Iodoquinol (Yodoxin)

Amebicide used in treatment of D fragilis.

Adult

650 mg PO tid for 20 d

Pediatric

30-40 mg/kg/d PO divided tid for 20 d; not to exceed 2 g/d

Documented hypersensitivity; hepatic damage

Pregnancy

C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus

Precautions

Avoid long-term use because optic neuritis, optic atrophy, and peripheral neuropathy have been reported; use caution in patients with thyroid disease


Paromomycin (Humatin)

Amebicidal and antibacterial aminoglycoside obtained from strain of Streptomyces rimosus; active in intestinal amebiasis.

Adult

25-35 mg/kg/d PO divided tid for 7 d

Pediatric

Administer as in adults

Nephrotoxic potential may increase with concurrent administration of other aminoglycosides, penicillins, cephalosporins, amphotericin B, and loop diuretics

Documented hypersensitivity; intestinal obstruction

Pregnancy

C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus

Precautions

Because of narrow therapeutic index and toxic hazards associated with extended administration, do not use for long-term therapy; caution in renal failure, hypocalcemia, myasthenia gravis, and conditions that depress neuromuscular transmission; adjust dose in renal impairment

More on Dientamoeba Fragilis Infection

Overview: Dientamoeba Fragilis Infection
Differential Diagnoses & Workup: Dientamoeba Fragilis Infection
Treatment & Medication: Dientamoeba Fragilis Infection
Follow-up: Dientamoeba Fragilis Infection
References
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References

  1. Cuffari C, Oligny L, Seidman EG. Dientamoeba fragilis masquerading as allergic colitis. J Pediatr Gastroenterol Nutr. Jan 1998;26(1):16-20. [Medline].

  2. Johnson EH, Windsor JJ, Clark CG. Emerging from obscurity: biological, clinical, and diagnostic aspects of Dientamoeba fragilis. Clin Microbiol Rev. Jul 2004;17(3):553-70, table of contents. [Medline].

  3. Verweij JJ, Mulder B, Poell B, van Middelkoop D, Brienen EA, van Lieshout L. Real-time PCR for the detection of Dientamoeba fragilis in fecal samples. Mol Cell Probes. Oct-Dec 2007;21(5-6):400-4. [Medline].

  4. Butler WP. Dientamoeba fragilis. An unusual intestinal pathogen. Dig Dis Sci. Sep 1996;41(9):1811-3. [Medline].

  5. Frenkel LM. Dientamoeba fragilis infection. In: Textbook of Pediatric Infectious Diseases. Vol 2. 4th ed. Elsevier Health Sciences; 1998:2403-6.

  6. Grendon JH, DiGiacomo RF, Frost FJ. Descriptive features of Dientamoeba fragilis infections. J Trop Med Hyg. Oct 1995;98(5):309-15. [Medline].

  7. Keystone JS, Yang J, Grisdale D, et al. Intestinal parasites in metropolitan Toronto day-care centres. Can Med Assoc J. Oct 1 1984;131(7):733-5. [Medline].

  8. Kurt O, Girginkardesler N, Balcioglu IC, Ozbilgin A, Ok UZ. A comparison of metronidazole and single-dose ornidazole for the treatment of dientamoebiasis. Clin Microbiol Infect. Jun 2008;14(6):601-4. [Medline].

  9. Medical Letter on Drugs and Therapeutics. Drugs for parasitic infections. Med Lett Drugs Ther. Mar 6 1992;34(865):17-26. [Medline].

  10. Norberg A, Nord CE, Evengard B. Dientamoeba fragilis--a protozoal infection which may cause severe bowel distress. Clin Microbiol Infect. Jan 2003;9(1):65-8. [Medline].

  11. Preiss U, Ockert G, Broemme S, Otto A. On the clinical importance of Dientamoeba fragilis infections in childhood. J Hyg Epidemiol Microbiol Immunol. 1991;35(1):27-34. [Medline].

  12. Shein R, Gelb A. Colitis due to Dientamoeba fragilis. Am J Gastroenterol. Oct 1983;78(10):634-6. [Medline].

  13. Spencer MJ, Garcia LS, Chapin MR. Dientamoeba fragilis. An intestinal pathogen in children?. Am J Dis Child. Apr 1979;133(4):390-3. [Medline].

  14. Spencer MJ, Millet VE, Garcia LS, et al. Parasitic infections in a pediatric population. Pediatr Infect Dis. Mar-Apr 1983;2(2):110-3. [Medline].

  15. Stark DJ, Beebe N, Marriott D, et al. Dientamoebiasis: clinical importance and recent advances. Trends Parasitol. Feb 2006;22(2):92-6. [Medline].

  16. Turner JA. Giardiasis and infections with Dientamoeba fragilis. Pediatr Clin North Am. Aug 1985;32(4):865-80. [Medline].

  17. Vandenberg O, Peek R, Souayah H, Dediste A, Buset M, Scheen R. Clinical and microbiological features of dientamoebiasis in patients suspected of suffering from a parasitic gastrointestinal illness: a comparison of Dientamoeba fragilis and Giardia lamblia infections. Int J Infect Dis. May 2006;10(3):255-61. [Medline].

  18. Vandenberg O, Souayah H, Mouchet F, Dediste A, van Gool T. Treatment of Dientamoeba fragilis infection with paromomycin. Pediatr Infect Dis J. Jan 2007;26(1):88-90. [Medline].

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Further Reading

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Keywords

Dientamoeba fragilis, D fragilis, Enterobius vermicularis, pinworm, trichomonad parasite, intestinal protozoa, large intestine parasite, Cyclospora cayetanensis, Giardia lamblia, Cryptosporidium parvum, diarrhea

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Contributor Information and Disclosures

Author

David R Mack, MD, FRCPC, Professor, Departments of Pediatrics and Biochemistry, Microbiology, and Immunology, University of Ottawa Faculty of Medicine; Head, Division of Gastroenterology, Hepatology, and Nutrition, Department of Pediatrics, Children's Hospital of Eastern Ontario, Canada
David R Mack, MD, FRCPC is a member of the following medical societies: American Gastroenterological Association, Canadian Association of Gastroenterology, and North American Society for Pediatric Gastroenterology and Nutrition
Disclosure: Nothing to disclose.

Medical Editor

Michael D Nissen, MBBS, BMedSc, FRACP, FRCPA, Associate Professor in Biomolecular, Biomedical Science & Health, Griffith University; Director of Infectious Diseases and Unit Head of Queensland Paediatric Infectious Laboratory, Sir Albert Sakzewski Viral Research Centre, Royal Children's Hospital
Michael D Nissen, MBBS, BMedSc, FRACP, FRCPA is a member of the following medical societies: American Academy of Pediatrics, American Society for Microbiology, Pediatric Infectious Diseases Society, Royal Australasian College of Physicians, and Royal College of Pathologists of Australasia
Disclosure: Nothing to disclose.

Pharmacy Editor

Mary L Windle, PharmD, Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy, Pharmacy Editor, eMedicine
Disclosure: Pfizer Inc Stock Investment from financial planner; Avanir Pharma Stock Investment from financial planner ; WebMD Salary and stock Employment and investment from financial planner

Managing Editor

Martin Weisse, MD, Program Director, Associate Professor, Department of Pediatrics, West Virginia University
Martin Weisse, MD is a member of the following medical societies: Ambulatory Pediatric Association, American Academy of Pediatrics, and Pediatric Infectious Diseases Society
Disclosure: Nothing to disclose.

CME Editor

Robert W Tolan Jr, MD, Chief, Division of Allergy, Immunology and Infectious Diseases, The Children's Hospital at Saint Peter's University Hospital; Clinical Associate Professor of Pediatrics, Drexel University College of Medicine
Robert W Tolan Jr, MD is a member of the following medical societies: American Academy of Pediatrics, American Medical Association, American Society for Microbiology, American Society of Tropical Medicine and Hygiene, Infectious Diseases Society of America, Pediatric Infectious Diseases Society, Phi Beta Kappa, and Physicians for Social Responsibility
Disclosure: GlaxoSmithKline Honoraria Speaking and teaching; MedImmune Honoraria Speaking and teaching; Merck Honoraria Speaking and teaching; sanofi pasteur Honoraria Speaking and teaching; Baxter Healthcare Honoraria Speaking and teaching

Chief Editor

Russell W Steele, MD, Head, Division of Pediatric Infectious Diseases, Ochsner Children's Health Center; Clinical Professor, Department of Pediatrics, Tulane University School of Medicine
Russell W Steele, MD is a member of the following medical societies: American Academy of Pediatrics, American Association of Immunologists, American Pediatric Society, American Society for Microbiology, Infectious Diseases Society of America, Louisiana State Medical Society, Pediatric Infectious Diseases Society, Society for Pediatric Research, and Southern Medical Association
Disclosure: None None None

 
 
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