Giardiasis Complications

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Giardiasis has been associated with several gastrointestinal disorders such as irritable bowel syndrome (IBS) and, in rare cases, inflammatory bowel disease and biliary tract dysfunction. There have also been rare occurrences of reactive arthritis and various reports of dermatologic and ocular manifestations.

Gastrointestinal Disorders

In a study by Bolin, there was a 9% prevalence rate of giardiasis among 100 consecutive patients with chronic diarrhea. Fifteen patients without a definitive diagnosis responded to empiric metronidazole or tinidazole therapy.1 Patients initially diagnosed with severe irritable bowel syndrome (IBS) were treated for Giardia with metronidazole, resolving all symptoms.2 In another case, a patient with biliary tract dysfunction was treated for giardiasis; all the patient's symptoms disappeared and gallbladder visualization returned to normal.3

Extraintestinal Manifestations

Although infrequently reported in literature, there have been several extraintestinal manifestations associated with giardiasis. Other infections of the gastrointestinal tract (Campylobacter and Shigella) have also produced these extraintestinal manifestations.

Arthritis

Among 66 children with arthritis, Giardia was confirmed in 64 of the patients. Subsequent treatment with metronidazole or quinacrine resolved both conditions in 90% of cases.4 There have been numerous case reports (in both children and adults) of reactive arthritis associated with confirmed giardiasis following metronidazole treatment.5-8

Dermatologic Manifestations

A number of case reports of pruritis and urticaria have been associated with confirmed giardiasis. Patients have experienced resolution of both conditions following therapy with metronidazole or tinidazole.9-11 Among 434 Romanian patients with chronic urticaria, angioedema or both, Giardia was detected in 62% of the cases.12 In a study by Veronesi, Giardia was detected in 6 out of 50 patients diagnosed with chronic urticaria. Upon treatment for Giardia with metronidazole, both Giardia and urticaria were resolved in these patients.13

Ocular Manifestations

In 90 children with confirmed giardiasis, 11% presented with "salt and pepper" retinal changes, while no children did in either of two control groups of 200 children each.14 In another study of 141 children diagnosed with giardiasis, 28 (20%) displayed "salt and pepper" retinal changes vs. 0 in control group of 300 Giardia negative children.15 Case reports of uveitis, retinal arteritis, and giardiasis treated with metronidazole or quinacrine showed resolution of ocular conditions.16-19

There are several rationales as to why Giardia leads to other disorders. One possible mechanism is an immune or allergic response to the organism. Another possibility is the release of toxin from Giardia initiating an inflammatory response. Some patients may have a genetic predisposition related to HLA-B27+ status. The introduction of the Giardia antigen into the blood and synovial fluid may result in T-cell proliferation. A final possible mechanism is an altered intraluminal intestinal state, causing a synergy between gastrointestinal disorders such as IBD or IBS and Giardia growth.

  1. Bolin TD, Davis AE, Duncombe VM. A prospective study of persistent diarrhoea. Aust N Z J Med. 1982 Feb;12(1):22-6.
  2. Gunasekaran TS, Hassall E. Giardiasis mimicking inflammatory bowel disease. J Pediatr. 1992 Mar;120(3):424-6.
  3. Goldstein F, Thornton JJ, Szydlowski T. Biliary tract dysfunction in giardiasis. Am J Dig Dis. 1978 Jun;23(6):559-60.
  4. Goobar JP. Joint symptoms in giardiasis. Lancet. 1977 May 7;1(8019):1010-1.
  5. Tupchong M, Simor A, Dewar C. Beaver fever--a rare cause of reactive arthritis. J Rheumatol. 1999 Dec;26(12):2701-2.
  6. LeBlanc CM, Birdi N. Giardia lamblia associated arthritis in a 19-month-old child. J Rheumatol. 1999 Sep;26(9):2066-7.
  7. Letts M, Davidson D, Lalonde F. Synovitis secondary to giardiasis in children. Am J Orthop. 1998 Jun;27(6):451-4.
  8. Shaw RA, Stevens MB. The reactive arthritis of giardiasis. A case report. JAMA. 1987 Nov 20;258(19):2734-5.
  9. Sanchez-Carpintero I, Vazquez-Doval FJ. Cutaneous lesions in giardiasis. Report of two cases. Br J Dermatol. 1998 Jul;139(1):152-3.
  10. Spaulding HS Jr. Pruritus without urticaria in acute giardiasis. Ann Allergy. 1990 Aug;65(2):161.
  11. Clyne CA, Eliopoulos GM. Fever and urticaria in acute giardiasis. Arch Intern Med. 1989 Apr;149(4):939-40.
  12. Chirila M, Panaitescu D, Capraru T. Frequency of Giardia lamblia in certain allergic syndromes. Med Interne. 1981 Oct-Dec;19(4):367-72.
  13. Veronesi S, Palmerio B, Negosanti M, Tosti A. Urticaria and giardiasis. Dermatologica. 1983;166(1):42-3.
  14. Pettoello Mantovani M, Giardino I, Magli A, di Martino L, Guandalini S. Intestinal giardiasis associated with ophthalmologic changes. J Pediatr Gastroenterol Nutr. 1990 Aug;11(2):196-200.
  15. Corsi A, Nucci C, Knafelz D, Bulgarini D, Di Iorio L, Polito A, De Risi F, Ardenti Morini F, Paone FM. Ocular changes associated with Giardia lamblia infection in children. Br J Ophthalmol. 1998 Jan;82(1):59-62.
  16. Anderson ML, Griffith DG. Intestinal giardiasis associated with ocular inflammation. J Clin Gastroenterol. 1985 Apr;7(2):169-72.
  17. Horton RO, Bartlett JD. Presumed ocular vitelliform macular giardiasis and lesions. J Am Optom Assoc. 1983 Jan;54(1):23-7.
  18. Carroll ME, Anast BP, Birch CL. Giardiasis and uveitis. Arch Ophthalmol. 1961 Jun;65:775-8.
  19. Knox DL, King J Jr. Retinal arteritis, iridocyclitis, and giardiasis. Ophthalmology. 1982 Dec;89(12):1303-8.