gastrointestinal parasitic infections Flashcards
protozoa
developed and developing world
important in immunocompromised
helminths worms
roundworms
tapeworms
large 0.75cm >1m
pathogenesis of gut parasites
intestinal mucosal injury
spectrum normal mucosa to sub total villus atrophy
microvillus damage throughout spectrum
damage correlates to functional impairment
luminal factors
nutritional competition
b12 theft-ascaris
barrier to adsoprtion
parasite and bacterial overgrowth
disruption of normal gut physiology
bile salt
deconjugation in giardiasis
obstruction
how is giardia transmitted
cysts and ova
resistant structures
may require period of development before becoming infective
release of next stage as aresult of environmental triggers e.g stomach ph
larval invasion
hookworm invasion
how is gut parasite transmitted
contamination of water supplies/environment
food sources
-cleaning
irrigation
inadequate cooking
giardiasis protozoa
direct life cycle
clinical symptoms
symptom free cyst passage
acute diarrhoea
chronic diarrhoea with intestinal malabsorption
significant morbidity in children and immunosupressed
giardia lamblia
transmission- water supplies
faecal oral route
incubation
amoebiasis
6 species common to humans
entameoba histolytica
worldwide distribution
lower small intestine and colon
clinical disease
invasion of intestinal mucosa
dissemination of other organs
cryptosporidium parvum
self limiting disease
oocyst-
protoza cryptosporidium parvum
incomplete life cycle in man
intracellular location
important in cattle as cattle is the resevoir
serious in old
young immunocompromised
helminths ascaris lumbricoides
world wide distribution
1 in 4 world population infected
200,000 eggs per day shed in faeces
contaminate soil
embryonate after 10 days
infective for months
helminths hookworms
anclystom dudodenale and necator americanus
warm moist environment
l1 larvae emerges
l3 filariform develop in 1 week
what are clinical manifestations
larvae pulmonary migration
cough fever wheezing
adults- gut
disruption and obstruction
malnutrition
b12 deficiency
what are clinical manifestations of hookwarm
at skin- itchy papules
migration through lungs
mild of ascaris
in gut- iron and protein loss
necator-0.5ml/worm/day
ancylostoma 2.5ml/worm/day
helminths- trichuris trichuria
bowel infection
warm humid climates
usually only symptomatic in children
clinical manifestations
bloody diarrhea no fever
rectal prolapse
anaemia
wasting
eosinophilia
helminths enterobius vermicularis
pinworm- found in environments where people are living together
ceacum and perianal region
pruritus ani
transmission by contamination
treatment- mebendazole single dose
treat other family members
helminths- strongyloides stercoralis
largely trivial symptoms until patient is immunosupressed
clinical features-
as hookworm
upper abdominal pain and diarrhoea (steatorrhoea)
weight loss
established disease
larva curens
iregular diarrhoea
hyperinfection syndrome
helminths tapeworms
taeni saginata beef or solium pig
small intestine
5-20 metres
60 million cases worldwide
hymenoplepsis nana
40mm
more than 2000 worms infection
institutions
disease associated with migration of larval stages- significant cause of epilepsy
