Intestinal helminthic infections diagnosed by colonoscopy in a regional hospital during 2001-2008.
ABSTRACT The present study investigated characteristics of 24 parasite infection cases detected during colonoscopy in a regional hospital from January 2001 to December 2008. Sixteen patients were confirmed with Trichuris trichiura infection, 6 patients were with Ascaris lumbricoides infection, 1 patient with Enterobius vermicularis infection, and 1 patient with Anisakis infection. Among them, 7 patients (43.8%) were asymptomatic. Colonoscopy findings were normal in 18 patients (75.0%). Among the patients with T. trichiura infection, colonoscopy showed several erosions in 2 patients (8.3%) and non-specific inflammation of the affected segment of the colon in 3 patients (12.5%). In 1 patient with anisakiasis, colonoscopy revealed a markedly swollen colonic wall. Stool examinations were performed before treatment in 7 patients (29.2%) and were all negative for parasite eggs or worms. These results suggest that colonoscopy is a useful diagnostic approach for parasitic infections even for asymptomatic patients and for patients with negative stool examinations.
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ABSTRACT: Trichuriasis is an intestinal infection found in human beings which is caused by Trichuris trichiura, more commonly known as whipworm because of its whip-like appearance. It is characterized by the invasion of the colonic mucosa by the adult Trichuris and produces minor inflammatory changes at the sites of localization. It is prevalent throughout the world, especially in tropical areas. Its diagnosis is usually made by identification of the typical eggs in the stool; adult whipworm is rarely seen during colonoscopy. Colonoscopy can directly diagnose trichuriasis, confirming the threadlike form of worms with an attenuated end. The worms can be overlooked, particularly if colon preparation is imperfect. Attenuated whip-like ends of whipworms, which are embedded in the colonic mucosa, were removed with biopsy forceps. We report on 5 cases of whipworm infection that were diagnosed on total colonoscopy.Hepato-gastroenterology 01/1993; 45(24):2105-9. · 0.77 Impact Factor
- Journal of Clinical Gastroenterology 10/1998; 27(2):152-3. · 3.20 Impact Factor
- Gastrointestinal Endoscopy 10/1999; 50(3):435-6. · 5.21 Impact Factor
Until the 1970s, intestinal parasitic infections, mostly soil-
transmitted helminths, were prevalent in South Korea. Since
the South Korean government tried to establish parasite con-
trol projects in the 1960s, the helminth egg positive rate has
dramatically decreased from 84.3% in 1971 to 2.4% in 1997
. The egg positive rate in 2004 was 3.7% and has appeared
to have shown a small increase as compared to the survey con-
ducted in 1997 .
Colonoscopy is a preferred examination strategy for colorec-
tal cancer screening due to a greater sensitivity and specificity as
compared to the use of other modalities . Occasionally, colo-
noscopy can reveal unexpected findings, including the presence
of parasite infections, even if patients are asymptomatic. There
have been a number of case reports where colonoscopy identi-
fied the presence of adult worms by direct visualization [4-11].
The present study investigated the characteristics of parasitic infe-
ctions detected during colonoscopy in a regional hospital dur-
ing the past 8 years.
At Uijeongbu St. Mary’s hospital, colonoscopies performed to
identify cases of parasitic infections were reviewed during the pe-
riod from January 2001 to December 2008. Our records contain-
ed 24 reports that identified parasitic infections discovered dur-
ing colonoscopy. Corresponding patient records were evaluat-
ed to determine the age at the time of presentation, gender, pre-
senting symptoms, reasons for the colonoscopy, and histopath-
ological findings. All parasites identified after a colonoscopywere
removed using biopsy forceps or polypectomy snares. For para-
site examinations, specimens were sent to Department of Parasi-
tology, The Catholic University of Korea (Seoul, Korea).
The number of total colonoscopy examinations performed
within an 8-year period was 29,234. Twenty-four reports (0.08%)
of parasitic infections after a colonoscopy were identified (Table
1). Parasitic infections included 16 Trichuris tricihura infections
(66.7%), 6 Ascaris lumbricoides infections (25%), 1 Enterobius ver-
micularis infection (4.2%), and 1 Anisakis larval infection (4.2%).
The mean age at the time of diagnosis was 46.5 ± 14.2 years
(age range, 22-81 years). Twelve (50%) of 24 patients were men,
with a male:female ratio of 1 : 1. Among 16 patients with T. tri-
chiura infection, 4 patients (25%) were immigrants from South-
east Asia. The anatomic location of T. trichiura was identifiedas
the cecum for 8 patients (50%), the ascending colon for 6 pa-
tients (37.5%), at multiple sites in 1 patient (cecum and descen-
ding colon, 6.3%), and in the rectum for 1 patient (6.3%). Colo-
noscopy findings were normal in 18 patients (75%). Among
Intestinal Helminthic Infections Diagnosed by
Colonoscopy in a Regional Hospital during 2001-2008
Korean J Parasitol. Vol. 48, No. 1: 75-78, March 2010 DOI: 10.3347/kjp.2010.48.1.75
Kyong-Rock Do1, Young-Seok Cho1,�, Hyung-Keun Kim1, Byung-Hee Hwang1, Eun-Jung Shin1,
Hae-Bin Jeong1, Sung-Soo Kim1, Hiun-Suk Chae1and Myung-Gyu Choi2
1Department of Internal Medicine, Uijeongbu St. Mary’s Hospital, The Catholic University of Korea, Uijeongbu 480-717, Korea;
2Department of Internal Medicine, Seoul St. Mary’s Hospital, The Catholic University of Korea, Seoul 137-701, Korea
Abstract: The present study investigated characteristics of 24 parasite infection cases detected during colonoscopy in a
regional hospital from January 2001 to December 2008. Sixteen patients were confirmed with Trichuris trichiura infection,
6 patients were with Ascaris lumbricoides infection, 1 patient with Enterobius vermicularis infection, and 1 patient with Ani-
sakis infection. Among them, 7 patients (43.8%) were asymptomatic. Colonoscopy findings were normal in 18 patients
(75.0%). Among the patients with T. trichiura infection, colonoscopy showed several erosions in 2 patients (8.3%) and
non-specific inflammation of the affected segment of the colon in 3 patients (12.5%). In 1 patient with anisakiasis, colono-
scopy revealed a markedly swollen colonic wall. Stool examinations were performed before treatment in 7 patients (29.2%)
and were all negative for parasite eggs or worms. These results suggest that colonoscopy is a useful diagnostic approach
for parasitic infections even for asymptomatic patients and for patients with negative stool examinations.
Key words: Trichuris trichiura, Ascaris lumbricoides, Enterobius vermicularis, Anisakis, colonoscopy
●Received 15 December 2009, revised 17 January 2010, accepted 18 January
* Corresponding author (email@example.com)
patients with T. trichiurainfection, colonoscopy showed several
erosions in 2 patients (8.3%) and non-specific inflammations of
the affected segment of the colon in 3 patients (12.5%). The
anatomic location of A. lumbricoideswas identified as the termi-
nal ileum in 1 patient (16.7%),the cecum in 1 patient (16.7%),
theascending colon in 2 patients (33.3%), the descending colon
in 1 patient (16.7%), and the rectum in 1 patient (16.7%). In A.
lumbricoidesinfections, colonoscopic findings were normalexcept
for a live Ascaris (Fig. 1). These roundworms were captured with
polypectomysnares or biopsy forceps and retrieved alive. One pa-
tient with E. vermicularis had undergone colonoscopy for the
evaluation of anemia. E. vermicularis was detected in the ascen-
ding colon. One patient with colonic anisakiasis was asymptoma-
tic. The Anisakis worm was found and was extracted from the
ascending colon.Colonoscopy demonstrated a markedly swoll-
en colonic wall in 1 patient with colonic anisakiasis. Stool exami-
nations were performed before treatment in 7 patients (29.2%),
and all examinations were negative for both eggs and parasites.
All patients were treated with anthelmintic agents after colonosco-
pic removal of parasites.
In the present study, all parasites identified by the use of colo-
noscopy were nematodes, including T. trichiura, E. vermicularis,
A. lumbricoides, and Anisakis sp. Among the parasites, T. trichiura,
also known as the whipworm because of the whip-like shape of
the adult worms, was the most prevalent. The infection is mostly
Korean J Parasitol. Vol. 48, No. 1: 75-78, March 2010
Cecum & D-colon/ Hyperemia
Terminal ileum/Normal mucosa
Lower abdomen discomfort
Lower abdomen discomfort
Bleeding per rectum
Abdominal pain & constipation
Lower abdomen discomfort
Lower abdomen discomfort
Bleeding per rectum
Table 1.Intestinal parasitic infections found at colonoscopic examinations at Uijeongbu St. Mary’s Hospital during 2001-2008
PatientSpecies of parasite
Colonoscopic findings Symptoms
Fig. 1. Endoscopic observation of Ascaris lumbricoides infection in
mild and asymptomatic. In our study, almost all T. trichiura in-
fections were asymptomatic or mild. However, when the para-
site load increases, various symptoms, such as chronic lower ab-
dominal pain, diarrhea, anorexia, and weight loss can arise. Mo-
reover, colonic obstruction and perforation as well as lower gas-
trointestinal bleeding have been reported [12,13]. Among 16
patients with T. trichiura infection, 4 patients were immigrants
from endemic areas, suggesting that sporadic cases occur occa-
sionally due to immigration. In our study, the second most com-
mon parasitic infection determined was ascariasis. Most infections
are asymptomatic. Only a minority of patients had clinical pro-
blems, mostly caused by a mobile adult worm mechanically bloc-
king the lumen of the small intestine, main duodenal papilla,
and appendix . The A. lumbricodes infections seen in the
present study were also asymptomatic or mild. Almost all previ-
ous case reports have shown that A. lumbricoides have been fo-
und in the appendix, cecum, ascending colon, or transverse colon
[7,8]. However, our study demonstrated that A. lumbricoides co-
uld also be found in the descending colon or rectum. The pin-
worm, E. vermicularis has the broadest geographic distribution
range and is the most common intestinal parasite encountered
in the primary care setting . It has been shown that a number
of children with E. vermicularis infections could have endoscopic
and histopathological features of nonspecific colitis . How-
ever, we could not find abnormal colonoscopic findings in our
patient. The stomach wall and the small intestinal wall are fre-
quently involved sites for gastrointestinal anisakiasis. However,
colonic anisakiasis is a rare condition. Although Anisakis infec-
tions can be asymptomatic, as in our case, infection may cause
an acute onset of abdominal symptoms shortly after the inges-
tionof raw fish . Colonoscopy frequently shows the presence
of edematous mucosa, characterized by narrowing and multiple
smooth and round protrusions. Furthermore, a variety of cases mi-
ght be initially misdiagnosed as appendicitis, cancer, or inflam-
matorybowel disease, such as Crohn’s disease or intestinal tuber-
culosis [17,18]. In this study, stool examinations failed to show
thepresence of any fecal eggs or parasites in 7 patients. Although
stool testing is essential to determine the diagnosis of intestinal
parasite infections, some difficulties can arise when infestation
is caused by a limited number of male parasites . Moreover,
careful management, including sample collection, handling, and
storage is necessary for optimalfecal assessment.
In conclusion, a careful colonoscopic examination should be
performed for the identification and removal of parasites when
symptomatic patients have a negative stool examination. Colo-
noscopy can be useful for the diagnosis of parasitic infections,
even if patients are asymptomatic.
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