Shistosomiasis Flashcards
name of organism
another name for disease
schistoma haematobium
bilharzia
type of organism
blood fluke parasite - trematode
areas
middle east
africa
southwest asia
presenting symptoms itch fever chronic 2 phases 2 urinary symptoms, when occur
swimmers itch 3-18 hours fever katayama fever at 3-9 weeks chronic active phase chronic inactive phase urinary symptoms haematuria, terminal dysuria at 12 weeks
life cycle schistosomiasis
20% of eggs produced by adult worms cross into bladder and bowel and shed in urine and faeces into fresh water
mature eggs contain miracidia
hatch releasing miracidia
go into host bulinus snail
successive generations of sporocysts - asexual reproductive phase
release cercariae, 200-400 from each sporocyst
with forked tail
penetrate human skin loses tail
into blood stream
portal circulation of liver, mature over 80-110 days
mature into adult worms
paired adult worms into mesenteric venules of bowel and bladder for oviposition to commence
release eggs 200-500 a day
eggs not crossing into bowel and bladder become calcified and form calcified eosinophillic granuloma
investigations
midday urine noon to 3pm terminal spinal eggs serology ELISA Cystoscopy sandy patches biopsy containing egs
treatment schisto
praziquantel 2 oral doses of 40mg/kg in 1 day
cure rate 83-100%
proportion of scc vs adeno in shisto
60-90% in schisto
5-15% adenocarincoma
histology
keratin at edge of tissue keratizing sq metaplasia conglomeration of eggs granuloma oval shaped eggs calcification terminal spikes
action of praziquantal
The drug’s mode of action is not exactly known at present, but experimental evidence indicates praziquantel increases the permeability of the membranes of schistosome cells towards calcium ions. The drug thereby induces contraction of the parasites’ muscle, resulting in paralysis in the contracted state.
complications schisto in bladder
cancer ulceration haematuria polyposis bladder contraction bladder calcification sandy patches
complications schisto ureter
ureteric stenosis upper tract obstruction vur usually bilateral affects distal ureter 25% incidence ureteric complications
complications shisto lower urinary tract
boo and retention
epididymitis
haematospermia
two disease stages
active and inactive
actie when laying eggs which trigger immune response
inactive when adults have died and there is a reaction to remaining eggs
chronic effects on bladder
calcified eggshell non compliant bladder and hydronephrosis high pressure system
