Features of Giardiasis -
Giardiasis Infection with Giardia lamblia is found worldwide and is common in the tropics. It paicularly affects children, tourists and immunosuppressed individuals, and is the parasite most commonly impoed into the UK. In cystic form, it remains ble in water for up to 3 months and infection usually occurs by ingesting contaminated water. Its flagellar trophozoite form attaches to the duodenal and jejunal mucosa, causing inflammation. Clinical features and investigations After an incubation period of 1-3 weeks, there is diarrhoea, abdominal pain, weakness, anorexia, nausea and vomiting. On examination, there may be abdominal distension and tenderness. Chronic diarrhoea and malabsorption may occur, with bulky stools that float.Stools obtained at 2-3-day intervals should be examined for cysts. Duodenal or jejunal aspiration by endoscopy gives a higher diagnostic yield. The 'string test' may be used, in which one end of a piece of string is passed into the duodenum by swallowing and retrieved after an overnight fast; expressed fluid is then examined for the presence of G. lamblia trophozoites. A number of stool antigen detection tests are available. Jejunal biopsy specimens may show G. lamblia on the epithelial surface. Management Treatment is with a single dose of tinidazole 2 g, metronidazole 400 mg 3 times daily for 10 days, or nitazoxanide 500 mg orally twice daily for 3 days. Ref Harrison20th edition pg v1137
Mal absorption
Cyst with 4 nuclei
Trophozoite with four nuclei
Common in hypogammaglobulinemia
Infection