Colon non tumor
Infectious colitis
Trichuriasis

Author: Elliot Weisenberg, M.D. (see Authors page)

Revised: 24 October 2016, last major update October 2016

Copyright: (c) 2003-2016, PathologyOutlines.com, Inc.

PubMed Search: Trichuriasis colitis

Cite this page: Trichuriasis of colon. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/colontrichuriasis.html. Accessed December 10th, 2016.
Definition / General
  • Colonic infection with the nematode Trichuris trichiura (whipworm)
Essential Features
  • Infection via the fecal oral route
  • More common in children
  • Symptoms vary from none / mild to abdominal pain, diarrhea, growth retardation, anemia and others in children
ICD-10 coding
  • B79
Epidemiology
  • The CDC estimates that 604 to 795 million people are infected worldwide
  • Disease more common in children
  • Infection via the fecal oral route and correlates with poor sanitation and poverty
  • Infection most common in the tropics where human feces is used as fertilizer or where open defecation occurs
  • May also be common in temperate zones during warm and humid weather
  • Infection may occur via ingesting eggs in contaminated soil via hands, as commonly occurs in children or eating contaminated, inadequately cleaned fruits or vegetables
  • Genetic factors likely impact susceptibility to infection
  • Disease is uncommon in the United States but is found occasionally in the Southeast
  • Incidence of infection is decreasing with globally improved sanitation
Sites
  • Worms usually reside in the cecum and ascending colon
  • More distal colon may be involved with more severe infection
  • No migratory phase through the lungs
Pathophysiology
  • Excreted eggs become embryonated and infective in 15 to 30 days after passing through a 2 cell stage
  • Embryonated eggs are ingested and the larvae hatch in the small intestine
  • Larvae migrate to the cecum and ascending colon and penetrate crypts
  • Worms molt several times and embed their whip-like anterior into mucosal crypts
  • Females oviposit after two to three months
  • Female egg output is high, 3000 to 20,000 eggs per day or about 200 eggs per gram of stool
  • Worms live one to three years
  • Worms do not invade but infection may lead to mucosal production of anti-inflammatory cytokines; this property has led to the controversial use of Trichuris suis to treat inflammatory bowel disease, although most authorities do not recommend this treatment
Diagrams / Tables
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Life cycle


Clinical Features
  • Majority of carriers are asymptomatic or minimally symptomatic
  • Peripheral blood eosinophilia may occur
  • More severe disease tends to occur in children who often have higher parasite burdens and lesser immunity
  • Heavy infections may be associated with chronic abdominal pain, diarrhea, tenesmus, chronic anemia, nocturnal incontinence, growth retardation that may be due in part to vitamin A deficiency and rectal prolapse
  • Patients may also suffer from other parasitic infections
Diagnosis
  • Diagnosis is made by seeing worms on mucosal surfaces or by identifying the characteristic lemon shaped eggs in stool
  • Stool examination has a very high yield due to high egg output
Laboratory
  • Eggs are 50 - 55 × 20 - 25 micrometers and have a characteristic barrel shape with thick shells and polar plugs at each end
Prognostic Factors
  • Disease is more severe in children
  • Infection clears in essentially all patients with appropriate treatment
Case Reports
Treatment
  • Three to seven day courses of albendazole, mebendazole or ivermectin, depending on the severity of the infection
Clinical Images
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Endoscopic image
of adult worm

Gross Description
  • Worms display a characteristic shape with a slender whip-like anterior that embeds in the colonic mucosa and a thicker posterior that is visible during endoscopy or on the surface of prolapsed rectal mucosa
  • Adult worms are about 4 cm in length
Gross Images
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Adult T. trichiura removed during a colonoscopy

Infestation with mucosal hemorrhage

Micro Description
  • Mucosa in the vicinity of embedded worms is edematous and friable with increased histiocytes within the laminal propria
Micro Images
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Ova stained with iodine

Differential Diagnosis