GIARDIASIS / MedUrgent
GIARDIASIS
Giardia is a flagellate protozoan
which has both a trophozoite and a cystic form. It inhabits the duodenum and
jejunum and it is one of the most common parasites in man worldwide. In endemic
situations children may suffer from malabsorption. It infests the upper small
bowel causing travelers' diarrhea'.
The parasite has a sucking disc by which it
attaches itself to the mucosa of the small intestine. It has 4 pairs of
flagellae and multiplies by binary fission. The cyst is oval and has 4 nuclei.
They are infectious as soon as they hatch and may ex-cyst in the upper
gastrointestinal tract when they can cause acute diarrhea.
Transmission
Man is the only source of infection. It is more common in children than adults, and the spread is by the oral-fecal route through contaminated food and water with cysts.
PATHOLOGY
Exposure to G. Lamblia is variable
depending upon variations in load of the parasite and host factors. The disease
may be asymptomatic or present with acute or chronic diarrhea.
The latter may result in malabsorption in some
individuals secondary to shortening of villi or flat mucosa and
The susceptibility to infection is increased
by -
1- Achlorhydria
2- Chronic pancreatitis
3- Immunodeficiency state 4- Malnutrition 5-
Hypogammaglobinaemia 6- AIDS
CLINICAL PICTURE
· Could be asymptomatic; however, almost 70%
of cases have symptoms which are:
• Diarrhea. The incubation period is 1-4 weeks
but could extend to several weeks.
• Symptoms and signs of which diarrhea is the
most important. The stools are pale, offensive, explosive, and bulky and
accompanied by flatus. It does not contain blood or pus.
• There is abdominal pain, nausea and anorexia
(more common in children). Tenesmus does not occur
• Dull epigastric pain associated with urgency
for passing motions
• Less than 10% develop malabsorption with
loss of weight and lethargy
• Features of malabsorption improve with
treatment.
DIAGNOSIS
• Examination of the stools for the cyst rm in
formed stools or the trophozoite form in loose stools:
• An important method if the stools are negative is the jejunal aspirate by the string test.
• Jejunal biopsy of the bowel by a Crosby
capsule and mucosa impression test (Always positive)
• Serological tests such as gel diffusion
which has not been always helpful in some centers.
• Therapeutic trial of Metronidazole or
tinidazole
TREATMENT (adults)
• Metronidazole 800mg tds for 3 to 5 days or 2
grams once daily for 3 days.
• Tinidazola 2 grams given initially and a
further 2 grams after a week are useful.
• The patient may need treatment for the
malabsorption in addition to folic acid, iron, and vitamin B complex.
Treatment of Giardiasis in children
Drugs of choice are: Metronidazole:
15mg/kg/day oral in 3 divided dose for 5 days.
Quinacrine: 6mg/kg/day in3
divided doses for 5 days Tinidazole: 50mg/kg in a single dose Furazolidine:
6-8mg/kg/day in 4 divided doses for 7-10 days Paromomycin: 25-30mg/kg/day in 3
divided doses for 7 days.
Control of infection
. Proper disposal of excreta.
. Appropriate cleaning of uncooked vegetables
e.g.green salads
. Washing hands after defecation, and when
preparing or eating food.
. Super-chlorination of water.
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