micro sheet #6 of Dr 7assan - Mais Smady

بسم الله الرحمن الرحيم
Helminth of the GIT
We have 2 families of helminth :
1. nematode
2 . platyhelminth

Today we will talk about some nematodes which are :
1. enterobius vermicularis
2. trichuris trichiura
3. ascaris lumbricoidses
4. hookworm
Now let's start :

1. enterobius vermicularis:
Its also called pinworm or threadworm bcs its thin #
Its length is up to 1 cm #
It doesn’t live long its only live for 6 weeks #
The condition of being infected by this worm is known as oxyuriasis #
Life cycle : #
-these worms live in the large intestine , there are male and female of these worms which copulated and produced the fertilized eggs which are still in the females body (I mean the female doesn't lay the eggs till now)
-then female come out from the anal canal and it crop all over the perianal skin so it infect the perianal skin and lay the eggs on it ,
- as the female go to the perianal skin and lay the eggs there patient will start having itching and this itching in the medical term known as pruritis and bcs it around anal opening we called it pruritis ani which is the main clinical manifestation for these worms
- of course when the infected children especially at night change their pajamas they will itch their bottoms and so they will pick up some eggs under their fingernails
-then they will either:1. suck their fingers so they eat these eggs again that’s why autoinfection with these worms is very common or 2. contaminate the foods and infect other people especially children at schools so you find that infection by this worm really a common disease of children at schools bcs they aren’t very hygienic ;they don’t wash their hands and they come in contact with each other and they might share foods so its very easy for the children to infect another especially children in the kindergarten and in the primary grades so again it’s a very common infection and indeed you find it mainly in children
-so the story is that usually child eating eggs from his friend at school then he comes home and he will have infection and start having pruritis ani so when he itch he will have eggs under his fingernails and start to autoinfect himself and infect his brothers and sisters and even his parents and of course child will autoinfect himself again and again and that’s why the disease can pass for months , but if the child doesn’t itch himself and pickup the eggs under his fingernails the disease will be self limited and the eggs will die and infection will be disappear but usually the child will itch and the infection will perpetuate bcs of self autoinfection
notes: it live for 6 weeks as we said before (6 week : it’s the time from which the patient eat the eggs- which will develop into males and females- until the female go to the perianal skin and lay the eggs) so the female after it lay the eggs on the perianal skin it will die
 as soon as the eggs layed on the skin they are matured and infective
#Clinical manifestations :
As we said the main clinical manifestation is the pruritis ani which can be sever and interfere with sleep otherwise there are no any other manifestations and even sometimes there is also no pruritis ani but in most cases there is
#diagnosis:
If you do not see the worms or if you don’t sure from the symptoms the diagnosis will be by look for the eggs by bring a tape and then you stick this tape to the perianal region so some eggs will stick to this tape and then you put the tape under microscope and you see eggs very nicely they are asymmetrical in shape one side is flat while the other side is convex it look like the bean of almond and inside the egg there is embryo you can see it very nicely
Treatment :#
the mother can observe these worm in the perianal skin of her child bcs its about 1cm as we said before especially if she look at the perianal region at morning before the child defecate and sometimes if the infection is very heavy the worms can actually seen in the feces bcs there are so many of them but otherwise it will be presented in the perianal skin and when the mother bring her child to the doctor saying that he is itching all the time and this also interfere with his sleep doctor will recognize that the child is infected with these worms and when he told the mother she will get upset and she put the responsibility on their relatives and neighbors to not allow people to say that this is a bad mother bcs it didn’t take care of her children so the doctor have to reassure the mother that this occur in all families although its really a disease of lower social class but that doesn’t mean that if you are from the high social class then your children wont be infected bcs as we said any child get infected can transmit the infection to all his friends at school , then doctor prescribe drug for the patient which usually vermox or albendazole ;these drugs given as one tablet and its recommended to give him another tablet after 10 or 14 days bcs the 1st tablet will kill all the worms in the intestine but the patient may still have alive eggs under his fingernails so he may autoinfect himself after few days so to prevent this autoinfection you can give him another tablet after 2 weeks ,and if the other members of the family are also infected you have to treat them as well even the parents they have to take the treatment for this worm if they are infected

2. trichuris trichiura:
#Its also called whipworm and this name refer to the shape of the worm which look like whip with wider handle at the posterior end ; the anterior 2/3 of it is thin and the posterior 1/3 is thick
#its about 5 cm in length
#this worm actually live few years it has a life span of 4 years
Life cycle:#
-its very thin anteriorly to anchor itself into the wall of the intestine bcs it must have a way to anchor itself inside the intestine otherwise they will be washed out or flushed away by the mean of the peristalsis and the movement of the intestinal fluids , so this worm has thin anterior end like the pin by which it stick itself to wall of the intestine
-they live mainly in the cecum(1st part of the large intestine ) but sometime if there are a lot of them they will migrate and colonize all the large intestine as well but mainly it live in the cecum
-for this worm to actually transmit the infection the eggs have to live a little period in the soil bcs the eggs as it come out with the feces they aren’t matured
-these worms layed the eggs on the cecum and the eggs pass in the feces
- now the eggs are not matured they have to pass into the soil
-how they will pass into the soil? by ex: somebody defecate on the soil ; so if everybody use toilet many of these worms will be disappear bcs if the eggs pass into the sewerage their life cycles wont by completed but usually you find that children or people who don’t have toilet defecate on the soil and they pass these eggs into the soil
- after these eggs pass into the soil it need about 4 weeks to be matured and develop an embryo inside it ; so after 4 weeks it will be mature so if anyone eat it at this time he will be infected but if anyone eat it from fresh feces he wont be infected
-so when the children play on the contaminated soil they will contaminate their fingers with soil that contaminated with the mature eggs then if they go and eat without washing their hands the eggs will go down to the small intestine and it will release the embryos which will develop into adult worm which will seat in the cecum and that's it so that's the life cycle which is a simple life cycle
#clinical manifestations:
-If there are few worms really there aren’t much of symptoms and the patient can go with no problems at all ,
- but if there are a huge numbers of these worm:
1.the patient will complain abdominal pain and if they penetrate the intestine it will cause pain especially if it transfer from one place to another
2.at the same time there is bld loss the patient will loss about 0.005ml per worm per day it seem a little amount but the patient may have a huge numbers of worms and these worms live for few years so the patient will have continuous bld loss and this may lead to iron deficiency anemia ,
3.in some cases in the children in sever conditions the worms may move to the rectum and it cause irritation in the rectum and produce diarrhea which is a streaky diarrhea ; it has a streaks of bld its different from the bloody diarrhea
4. prolapse of the rectum may occur in the children ;if you look to the children's rectum you find that the connective tissue around it doesn’t condense properly so its easy to find that they have prolapse of the rectum which mean that rectum will be inverted outside through the anal canal as in the case of herniation of the rectum this condition happen in the children bcs the connective tissue around their rectum isn’t well established to maintain intact in these cases
#diagnosis :
By examination of the feces under the microscope and you can see their eggs, the eggs of trichuris trichiura are look like bean of lemon or tea tray


3. ascaris lumbricoidses
#its also called roundworm
#its length is about 30cm
#it live only for few years
#its look like the earth worm
#its color usually gray or pink
#25% of the people in the world are infected by it
#life cycle:
-its a very muscular worm bcs usually it has no teeth or any thing to anchor itself into the wall of the small intestine so it bracing itself against the wall of the small intestine
-in the mucus membrane of the small intestine there are rugae and there are something like gaps in between them and this worm insert itself in these gaps by the mean of its muscle and if it doesn’t do that it will be flushed away by the peristalsis and the movement of the fluids in the intestine
-so this worm usually seated in the small intestine and it produce eggs which are passed into the soil
- these eggs need a period of maturation in the soil , when they passed with the feces they are not mature and they have to stay in the soil for about 4 weeks and then it become actually matured
- when they become matured as the trichuris trichiura you remember the story of children who play in the contaminated soil and contaminate their fingers and then they go to eat without washing their fingers and now the eggs will pass to their small intestine -when the eggs in the small intestine it will release larva then the larva penetrate the wall of the small intestine and it go to the bld stream to be carried to the liver through the portal circulation so it go to the liver and gain access to the systemic circulation and go to the lungs and in the lungs it will be squashed in the capillaries of the lungs bcs its size larger than the diameters of the capillaries so the larva stop there; they don’t travel any more they stay in the lungs then in the lungs the larvae will enter into 2 cycles of development then they go to the alveoli and from the alveoli they go with bronchial tree to the trachea and then it go to the pharynx then they are swallowed again(be careful the one which is swallowed isn’t the worm which is 30 cm it’s the larva which is about 200 micron ; so when we say this worm is 30 cm we mean when it in the small intestine not in the lungs ) and they will go down back to the small intestine and then they develop into an adult worm
-so there are 4 cycle of development for this worm the 1st in the small intestine then the 2nd and 3rd in the lungs and the 4th again in the small intestine then it become a worm so as you see its life cycle is a little bit complicated but it has to do all that to be infective
-Again : once the eggs enter the intestine they will release the larvae and the 1st cycle of development occur there then they will penetrate the wall of the small intestine and reach the bld stream through which they go to the liver then they gain access to the systemic circulation then they reach the lungs and the 2nd and 3rd cycle of their development will occur then they squashed in the alveoli then they go to the trachea to the pharynx then they will swallowed again then they go back to the small intestine where the 4th cycle of their development occur and they become worms
#clinical manifestations :
-If there are only few worms may be no manifestation occur at all
-The most frequent manifestation that child go to toilet early at morning then he call his mother and tell her that a snake come out from him ; it’s the ascaris lumbricoidses, actually when it come out the from the body its dead bcs as we said that it live for few years through which it enlarge and become very large then it will die then it go outside the body with feces through the anal canal ,there are other sites through which it go outside the body :
1.sometimes the worm by mistake go up from the intestine into the stomach and the patient will vomit it so it go outside through the mouth and when the patient wake up he will find it on the pad ,
2. in some very rare cases it may go outside the body through the umbilicus it come to the umbilicus through miracle diverticulum (its in the mid gut and sometimes it remain attach with the umbilicus through the umbilical cord ) so the worm may squeeze itself and go outside the body through the umbilicus ,
3. also some books said that it may go outside the body through the inguinal canal ;it will penetrate the wall of the intestine to go outside the intestine to the inguinal canal and then it go outside the body through the penetration of the skin so this one which penetrate the skin has miraculous power so this can be occur although its very very rare
-Also it may go from the intestine into the appendix and cause appendicitis but this is rare
-Or it may go up to the ampulla of vater (it’s the opening of the common bile duct and its located in the 2nd part of duodenum )and it enter the ampulla of vater and block this opening and cause Pancreatitis, jaundice but this is very rare to occur
-Also if there are a huge numbers of these worms they may gather with each other and form a huge mass block stream of the intestine so the patient may have intestinal obstruction but this is also very rare to occur
-Sometimes children who have ascaris they don’t thrive very well they have weight loss and they appear in poor health condition ; of course it doesn’t believe that ascaris eat the child's food but these worms produce some toxic metabolites that suppress the appetite and affect the child so the child doesn’t gain weight and doesn’t live very well
#diagnosis :
They look to the feces and look for the eggs and they can see the eggs which are look like pineapple and they are coarse and its color is brown to yellow bcs it will be stained by bile that pass into the small intestine and stain them so their eggs have a very special characteristic
#treatment :
By give the patient drug that paralysis the worms which is called ivermectin so if we paralysis the worm it cant anchor itself any more in the gaps between the rugae in the small intestine so it will be flushed out , so we give one tablet of this drug in one day and give other tablet in the 2nd day then you get rid of ascaris

4. hookworm
#anterior end of it is curved so it look like the hooks and that’s why its called hookworm
#its length is about 1cm
#this worm is live for few years
#it has a mouth opening and teeth inside it that are different in shape according to the species
#there are 2 species for it which are :
1.ancylostoma duodenale: from the old world
2.nector americanus: from the new world
Note : Dr said you don’t have to memorize the names of these 2 species , and actually these 2 species are very similar to each other may be one of them live more and they different in the shape of their teeth
#life cycle:
-they live in small intestine and they open their mouth and anchor themselves to the villi and suck the bld and they produce eggs which are matured as they layed out from the worms
- then they will release larvae which will go outside the body and stay free living in the soil for few days
- the larvae at this stage are thick so they called it rhabditoform stage larvae and they stay in the soil eat bacteria and waste in the soil for few days
- then they will change into filariform stage larva then they stick out from the soil -then if someone walk in the contaminated soil barefoot they will be attracted to the skin of his foot and this phenomena is know as thigmotaxis and if somebody is used to walking barefoot its very unlikely for these larva to penetrate through the sole of the his foot bcs his sole will be thick and difficult to be penetrated so in this case the worm will go up to the dorsum of his foot and they penetrate into his body through the webs (the skin btw the toes of the feet ) bcs its softer and easy to be penetrated
-once they come inside the body they go through the bld to the lungs and similar to the ascaris they go through the alveoli to the trachea then to the pharynx then will be swallowed and they will go to the intestine and they will develop into hookworms inside the intestine , so it has a complicated life cycle
Clinical manifestations : #
The main clinical manifestation is the anemia bcs they suck the bld and they move from one place to another and this may cause bleeding so they lead to iron deficiency anemia and they said that the world each day loss one million liter of bld to feed the hookworms inside the human body and this is very significant
Note : this worm should penetrate the skin to be infective not only through the skin of the foot so if someone lie on the contaminated soil the larvae will penetrate through the skin of the back or neck for example into the body and they cause infection , but if someone eat the larvae then it will go to the stomach and the acids in the stomach will kill them so they wont cause any infection at all if they are eaten .







Best wishes
Done by :mays smadi
Micro/ lecture #6 (1st one of Dr hassan after the quiz )

by mays,, thanx 4 her...

"correction for my sheet
hi , i just check from hand out and found that
in page 2 line 29 its not albendazole its mebendazole
in page 5 line 21 its not ivermectine its piperazine
thats it"

gd luck ppl

thanx dyala

ur welcome sweetie