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<Case>
A 40 year-old man was admitted due to bloody diarrhea for 5
days.
This man was healthy until 5 days before admission, he
began to suffer from frequent bloody diarrhea. Meanwhile
fever, vomiting and persistent right lower quadrant pain
accompanied and he lost 5 kg within 5 days. He is heterosexual
without fixed sexual partners. He had traveled to Philippine
one month ago. Physical examination showed that the blood
pressure was 120/56mmHg, the pulse rate was 102 per minute and
a low grade fever (37.8°C). Abdominal palpation demonstrated
diffuse tenderness with rebound tenderness at right lower
quadrant. Initial laboratory revealed leukocytosis with
neutrophilia (WBC: 18920, neutrophil: 81.1%). Stool
examination showed 4+ occult blood with numerous pus cells. No
parasite or parasite ova was detected. The serum anti-HIV
antibody was negative. Other examination including serum
biochemistry study, urine analysis and plain abdominal x ray
were all within normal range. Under the impression of
infectious diarrhea, empirical antibiotic was given. However,
the symptoms persisted. Image studies including abdominal
ultrasonography and CT revealed diffuse colitis. One week
after admission, a warm saline fresh stool sent for protozoa
detection showed a positive result. The serum indirect
hemagglutination (IHA) was also strong positive (2048:1) and
the diagnosis of amebic colitis was made. Intravenous
metronidazole was given and the bloody diarrhea dramatically
improved. The intravenous metronidazole was shifted to oral
form 4 days later and the patient was discharged.
<Discussion>
Amebiasis is an infection caused by the protozoal organism
Entamoeba histolytica and includes amebic colitis and liver
abscess. In developed countries, infection occurs primarily
among travelers to endemic regions, homosexual males,
immunosuppressed persons, and institutionalized individuals. E
histolytica probably is second only to malaria as a protozoal
cause of death. Transmission usually occurs by food-borne
exposure. Less common means of transmission include
contaminated water, oral and anal sexual practices. Amebic
colitis develops 2 to 6 weeks after ingestion of contaminated
food or water, and is characterized by mild to severe
abdominal pain, diarrhea, malaise, weight loss, and diffuse
lower abdominal or back pain. Stools consist mainly of blood
and mucus. In contrast to bacterial colitis, almost half of
all patients with amebic colitis are afebrile. Fulminant
infection produces severe abdominal pain and diarrhea with
high fever, but is rare and occurs predominantly in children.
Some patients may develop chronic amebic colitis, which may be
easily confused with inflammatory bowel disease. In as much as
steroid therapy exacerbatesamebiasis, it is important to rule
out amebiasis before treating inflammatory bowel disease with
glucocorticoids. Case fatality rates of amebic colitis range
from 1.9-9.1%. Amebic colitis is complicated by
intraperitoneal rupture in 2-7% of patients, with sudden
perforation causing a high mortality rate. Amebic liver
abscess is 7-12 times more common in men than in women,
although the sex distribution is equal in children. Amebic
colitis affects both sexes equally. The definitive diagnosis
is to demonstrate the hematophagous trophozoites of E.
histolytica in fresh stool. At least 3 fresh stool specimens
in wet mounts should be sent and examined within 20 minutes.
IHA also is a good serological test which carries a
sensitivity of 82% to
98%.
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Case Discussion
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