The Parasite Infections of the Digestive Tract in Children - Giardiasis - Part I

The Parasite Infections of the Digestive Tract in Children - Giardiasis - Part I

  Autor dr. Molfea Camelia Data: 10.01.2006

The Parasite Infections of the Digestive Tract in Children - Giardiasis -  Part I
The infection with intestinal parasite is still frequent in our country. The intestinal parasites may cause abdominal pains with recurrent character through the lesions which get infected later or allergically, produced on different parts of the intestine. The local and general disorders caused by the parasites are based on the following mechanism: 
  • a mechanical action of the parasite by phenomena such as occlusion, subocclusion, distension on the invaded intestinal part; 
  • toxic action of the parasite which helps the release of some metabolic products with harmful influence on the entire body; 
  • allergic symptoms such as skin lesions and mucosal lesions; 
  • predatory action of the parasite on the host body, causing many deficiencies and hypochromic anemia. 

GIARDIA lamblia is the most common parasite that colonizes the small intestine and it's spread worldwide. It lives in the small intestine especially in the duodenum, although it may also be found in the final part of the ileum. From the duodenum, the giardia is transmitted on the biliary ducts which it colonizes. This parasite appears under two special forms: trophozoites or vegetative flagellated form and cyst or resistance form. 
The human infection occurs through ingestion of the cysts in the contaminated water (the tap water was considered the mail infection source), in the food and in the beverages prepared with contaminated water. The hand to mouth transmission (oral-fecal contamination) is possible because the relatives of infected children are often infected. The infection rate in children in nurseries and kindergartens is very high. 

Clinical symptoms The symptoms appear after 9-15 days from the contamination and depends on the age of infection in the moment of establishing the diagnosis. They are polymorphic and have three clinical forms: 
  • gastrointestinal -characterized by dyspeptic disorders (nausea, vomiting, abdominal pains, diarrhea alternating with constipation); in some cases the symptoms are severe and lead to dysenteric symptoms 
  • biliary - with pains in the epigastrium and headaches, nausea and sometimes vomiting in the right hypochondrium. 
  • Toxic - with asthenia, weight loss, anxiety, anorexia, feverish state, paleness, headaches. 
In the acute stage of the disease, the bad smelling diarrhea is common, with watery, explosive stools, abdominal distension, belching, anorexia, nausea, vomiting, epigastric pains, fatigue. Fever (low or moderate), headaches and stools with pus might rarely occur. The acute phase lasts only for 3-4 days, without knowing the cause. It is possible for the acute phase to last for more months in children, leading to weight loss, a change of the general state and greasy stools. If the acute phase is not identified, the child is taken to the doctor with mild to moderate symptoms, recurrent or resistant. The chronic infection is associated with substernal, epigastric and periumbilical pains, with belching, anorexia and nausea. Children with chronic infection may be underdeveloped and with delayed growth. The eosinophilia is not common (when it really occurs, it has other causes). It is possible to get a rash. After different periods of time, the parasites and the symptoms might disappear, even if the disease is not treated. The diagnosis is established after the detection of the cysts in the feces when examined directly or when going through string testing with formalin- ether (3 samples are usually used). If you examined it again in two days, the chance to identify the parasite in the stool is greater. When the parasites are not found in the stools it is necessary to examine the duodenal fluid. The pear-like trophozoites are found in the duodenal biopsies, when examined directly. 
Some anti-acid antibiotics, most of them emetic and laxatives, may determine the temporary hiding or disappearance of the parasites in the stool; tests should be done in 5-10 days after taking them. For treating giardiasis you may use: metronidazole, trinidazole, quinacrine, furazolidone, ornidazole and albendazole according to "some studies". 
The metronidazole is the most used drug in our country. The recommended dose is of 15-20 mg/kg/day divided in 3 doses for 7 days, without exceeding 750mg/ day no matter the weight and age of the child. The cure rate is of 80-85 %. There are controversies regarding the use and the doses. Some 
authors contraindicate it for infants and babies; others only reduce the doses to 10 mg/kg/day for infants. The drug has a metallic taste and colors the urine. It is well tolerated and active in the treatment against this parasite. You may associate it with stamicin. Tinidazole (tablets with 500 mg of Fasigyn) has a similar or better action than metronidazole. This is taken in only one dose of 50mg/kg, without exceeding 2 g. the dose must be repeated in 7 days. Quinacrine (Atebrine) is not used in treating giardiasis anymore because of the severe side effects. Furazolidone is used by some American authors as a giardiasis detection treatment in infants and little baby. Take it in doses of 6mg/ kg/day 
divided into 4 doses, for 7-10 days. Ornidazole (tablet of 500g of Tiberal) is barely used in our country although it acts the same as metronidazole. There are no exact studies regarding the efficiency of the ornidazole in treating giardiasis. The dose for a child is of 40mg/kg- in only one dose. Also, there are no studies in the medical literature regarding the use of albendazole (Zentel drug product) in a dose of 400mg/day, for 5 days in a row, in treating this disease. It has been frequently used lately. From my own experience, this has a low cure rate. Regarding the prevention measures, they include the use of purified and treated water (use boiled and chilled water for infants). The food must be hygienically prepared, the fruits and vegetables must be washed, the hands also must be washed with water and soap after using the toilets. It is compulsory to do the biological tests (stool culture exam) for children who enter a community whenever necessary. 

Read the English version of this article: The Parasite Infections of the Digestive Tract in Children - Giardiasis - Part I