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 increased cellularity of the lamina propria. The parasite interferes the function of the enterocytes in the small bowel. Infested cells sh decrease in the disaccharidase levels.

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.

 

  

Comments

Popular posts from this blog

Management of Severe Malnutrition / MedUrgent

VIRAL HAEMORRHAGIC FEVERS / MedUrgent

TETANUS / MedUrgent