parasitic diseases of the GI Flashcards
(139 cards)
1
Q
protozoa
A
single celled organism that can multiply inside a human host
2
Q
what are the best known protozoans in the US
A
giardia intestinalis, duodenalis, cryptosporidium parvum
3
Q
what organism is the cause of intestinal amebiasis
A
entamoeba histolytica
4
Q
where is entamoeba histolytica most common
A
mexico, central america, south america, south asia, egypt, the middle east, parts of africa. where sanitation is poor and where the food and water supplies are contaminated with fecal matter
5
Q
is entamoeba histolytica common in the US
A
no. its rare
6
Q
helminths
A
multicellular organisms (worms) that cannot multiply in their adult form within the human body
7
Q
what is a cestode
A
flat worm with multiple segmented body consisting of rounded head, and a flat body with many segments.
8
Q
what is the rounded head of a cestode called
A
scolex
9
Q
what are the segments of a cestode called
A
proglottid
10
Q
what are the medically important cestodes
A
taenia solium, saginata; diphyllobothrium latum and echinococcus granulosus
11
Q
what is the common name of taenia solium
A
pork tape worm
12
Q
what is the common name of the taenia saginata
A
beef tape worm
13
Q
what is the common name of diphyllobothrium latum
A
fish tapeworm
14
Q
what is the common name of echinococcus granulosu
A
dog tape worm
15
Q
what are nematodes
A
round worms with a cylindrical body and a complete digestive tract with mouth and anus.
16
Q
what are the important nematodes
A
enterobius vermicularis, trichuris trichiuria, ascaris lumbricoides, necator americanus, ancylostoma duodenale, strongyloides atercoralis
17
Q
what is the common name of enterobius vermicularis
A
pin worm
18
Q
what is the common name of trichuris trichiuria
A
whipworm
19
Q
what is the common name of ascaris lumbricoides
A
giant round worm
20
Q
what is the common name of necator americanus
A
hook worm
21
Q
what is the common name ancylostoma duodenale
A
another hookworm
22
Q
what is the common name of strongyloides atercoralis
A
small round worm
23
Q
what symptoms do many of the multicellular organisms cause?
A
they can live their for many years and not cause any symptoms. if they do: abdominal pain, diarrhea, N/V, passing worm, gas/bloating, dysentery, rash or itching around anus, stomach pain/tenderness, feeling tired, weight loss.
24
Q
where does giardiasis occur?
A
worldwide.
25
who are the high-risk groups for giardiasis
infants and children. international adoptees, travelers, immunocompromised, hypochlorhydria, cystic fibrosis
26
where is giardiasis especially common?
poor sanitary conditions and insufficient water treatment plants.
27
what other animals are affected by giardiasis
beavers and raccoons
28
what are the two morphological forms of giardia lamblia
cysts and trophozoites
29
what are morphology is infectious for giardia lamblia
cysts. they can live in the environment for long periods.
30
how are the cysts of giardia lamblia transmitted
water, food, fecal material, between infected individuals.
31
what is the infectious dose of giardia lamblia
10-25 cysts
32
what happens after a giardia lamblia cyst is ingested
excystation occurs in the proximal small bowel with release of the trophozoites.
33
what percentage clear a giardia lamblia infection?
50%
34
what percentage of people shed the giardia lamblia cysts asymptomatically
5-15%
35
what percentage have a giardia lamblia symptomatic infection?
35-45%
36
how long does the asymptomatic shedding of giardia lamblia occur
6 months
37
why is it difficult to identify a water supply that is infected with giardia lamblia
because the shedding can occur for 6 months.
38
what are the symptoms of giardia lamblia infection
diarrhea, malaise, foul-smelling and fatty stools, abdominal cramps and bloating, flatulence, nausea, weight loss, vomiting (30), fever (low percentage)
39
what is average incubation period for giardia lamblia
7 to 14 days.
40
what is the range for giardia lamblia days to symptom
1-45 days.
41
how long with symptoms of giardia lamblia last
2-4 weeks
42
what percentage and how much weight is lost during giardia lamblia infection
10-20 percent in 50% of cases
43
how often is giardia lamblia chronic
sometimes as high as 50%. although studies suggest much less. the symptoms may wax and wane for many months.
44
what are the symptoms of chronic giardia lamblia
loose stools, steatorrhea, weight loss, malabsorption, malaise, abdominal cramping, borborygmi, flatulence, burping, fatigue, depression.
45
how do we diagnose giardia lamblia
stool microscopy. although immunoassays have a higher sensitivity
46
cryptosporidiosis (cryptosporidium parvum)
intracellular protozoan parasite associated with GI diseases found everywhere except Antartica
47
when do infections with cryptosporidium parvum peak in the US
july through september
48
how common is cryptosporidium parvum
one of the most common human GI pathogens.
49
where do cryptosporidium parvum infect and reproduce
in the respiratory tract and the GI epithelial cells
50
what are the cryptosporidium parvum infections cause patholgoically>
diarrhea and biliary disease
51
what is common link for cryptosporidium parvum infections
drinking water
52
are fecally passed cryptosporidium parvum oocysts infectious
yes immediately. this is how this is spread through fecal contamination
53
what common summer recreations are associated with cryptosporidium parvum infections?
swimming and animal contact. also drinking supplies and travel.
54
how many cryptosporidium parvum cause infection?
4
55
what is the asexual cycle of cryptosporidium parvum
oocyst > sporozoite > trophozoite > type 1 meront > back to trophozoite
56
what is the sexual cycle for cryptosporidium parvum
oocyst > sporozoite > trophozoite > type 1 meront > morozoite > type II meront > merozoites > undifferentiated gamont > microgamont/microgamont > zygote > oocyst
57
what are three presentations of cryptosporidium parvum
asymptomatic, mild dirrheal, severe enteritis w/wo/ biliary tract involvement.
58
what is the incubation period for cryptosporidium parvum
7-10 days. the number ingested is related to the time and duration of infection
59
what other symptoms do the cryptosporidium parvum diarrheal illness patients have?
malaise, nausea, anorexia, crampy abdominal pain, low grade fever
60
are there fecal blood or leulocytes for cryptosporidium parvum infection?
rarely unless there is coinfection
61
how long until the cryptosporidium parvum infections resovle
10-14 days. although it can progress or relapse
62
diagnosing cryptosporidium parvum
microscopy or immunoassays. organism present in stool, duodenal aspirates, bile secretions, biopsy or respiratory
63
entamoeba histolytica
mostm asymptomatic but can be amebic dysentery, extraintestinal disease. there are many cases of colitis and even death.
64
what are the extraintestinal manifestations of entamoeba histolytica
liver abscess, pulmonary, cardiac, brain involvement
65
what two forms does entamoeba histolytica have
cyst stage, trophozoite
66
what is the infectious form of entamoeba histolytica
cystic form.
67
what form of entamoeba histolytica causes the invasive disease
the trophozoite
68
how does infection of entamoeba histolytica occur
through ingestion of the cyst or through fecal-oral contact.
69
what happens to the entamoeba histolytica cysts once ingested>
they are viable for months. they pass through the stomach and the small intestine where they excyst to form trophozoites. trophozoites can invade and penetrate the mucous barrier of the colon causing damage or persistent secretion and thus bloody diarrhea
70
what is the infectious dose for entamoeba histolytica
a single cyst.
71
how common is entamoeba histolytica
third most
72
who is most at risk for entamoeba histolytica
travelers to and immigrants from endemic areas. also institutionalized individuals.
73
what is the most common presentation of entamoeba histolytica
diarrhea without dysentery.
74
what is entamoeba histolytica dysentery
amebic colitits. diarrhea with mucous or blood. occurs in 15-33%. 70% have a gradual onset.
75
what is the primary complaint of amebic dysentery
progressively worsening diarrhea and abdominal pain
76
what is the most common extraintestinal manifestation of entamoeba histolytica
hepatic abscess. they ascend the portal venous system,.
77
how long before the symptoms arise for entamoeba histolytica
8-20 weeks
78
how long before liver abscess with entamoeba histolytica
1-2 weeks and presents with RUQ pain and fever
79
RUQ pain in entamoeba histolytica infection
usually dull and aching epigastrum, right chest, right shoulder
80
other symptoms of entamoeba histolytica
coughing, sweating, malaise, weight loss, anorexia,
81
are humans definitive and intermediate hosts for cestodes?
can either or, not both
82
why is T. solium an exception to the cestodes?
because it can infect humans in two forms: the cysticercus and the worm or even both
83
T solium stage of infection
larvae in undercooked pork, eggs in food or water contaminated by human feces
84
T solium stage most associated with disease
adult tapeworm in intestine, cysticercus (esp. in brain)
85
T solium stages outside human
larvae in muscle of pig
86
taenia saginata stage of infection
larvae in undercoooked beef
87
taenia saginata stages associated with human disease
adult tapeworm in intestine
88
taenia saginata stages outside of human
larvae in the muscle of cow
89
diphyllobothrium latum stage for infection of human
larvae in undercooked fish
90
diphyllobothrium latum most associated with disease
adult tapeworm in the intestine can cause b12 def.
91
diphyllobothrium latum outside of human
larvae in the muscle of fresh water fish
92
E. granulosus stage that infects humans
eggs in food or water contaminated with dog feces
93
E. granulosus stage most associated with disease
hydatid cysts especially in the liver and lung
94
E. granulosus outside of human
larvae in the muscle of freshwater fish
95
cysticercosis
infection with T solium eggs -tissue infection of parasite cyst. the patient is the intermediate host for the parasite. eggs transmitted fecal-oral. there is autoinfection through this route.
96
who gets T solium
people that eat raw or undercooked pork.
97
what do the worms look like
they are 2-8m and live 10-20 years
98
what should you suspect if tapeworm of T solium is diagnosed
concomitant cysticercosis
99
how is t solium diagnosed
diagnosed by eggs in stool
100
neurocysticercosis
larval cysts infect the brain, muscle, other tissues, and are a major cause of adult onset seizures. can effect any part, but usually intracerebral lesions that cause seizure, mass effect or both. seizures occur in 70%.
101
how does one contract cysticercosis
by ingesting a t solium egg via fecal oral transmission
102
can you get cysticercosis from eating raw or undercooked pork?
NO. you get the intestinal tapeworm. if it consists of larval cysts.
103
tissue cysticerci occur when after eating stool
3-8 weeks. can occur in one or multiple sites, initially does not cause inflammation. n
104
when is there a lack of inflammation for the cysticercosis
upon the initial infection. this is the asymptomatic phase and can last a long time (years)
105
what is the intermediate host for T saginata
cattle
106
what dishes are associated with saginata infection
rare steak, or kababs, and steak tartare.
107
what are the other intermediate hosts of saginata
buffalo, llamas and giraffes
108
what do saginata worms look like?
they are long 10m and have 1000s of proglottids -each capable of producing thousands of eggs
109
what are the symptoms of saginata infections
most absent. although some have cramping. or malaise.
110
are the proglottids of saginata motile?
yes, they can move outside of the anus and be found on clthing or in the perineum.
111
D. Latum
acquired by eating freshwater fish containing the plerocercoid cysts. raw fish bars have increased the incidence
112
endemic areas for D latum
europe, siberia, north america, japan, chile
113
what do the D latum look like>
large. 25 m with 3000-4000 proglottids
114
how long until d latum matures and hoe long to live
3-6 weeks to mature and can live for 30 years
115
can a patient have multiple d latum worms?
yes, common
116
what are the symptoms of d latum
usually asymptomatic. but can be nonspecific: weakness, dizziness, salt-craving, diarrhea, abdominal discomfort.
117
what can prolonged d latum infection lead to.
vit b12 def. and thus megaloblastic anemia. can also lead to CNS malfunction
118
what are the mechanism of b12 def in d latum infections
use of the vitamin by the parasite, and dissociation of the vit-intrinsic factor complex.
119
ascaris lumbricoides
most common helminthic infection. white pinkish adult worms. 15-35 cm. live and mate in the jejunum. most people are asymptomatic.
120
what is a common symptom of ascaris lumbricoides
HSR to lung parenchymal infection around the second week. nonproductive cough, chest discomfort, fever, eosinophilia.
121
what are severe infections with ascaris lumbricoides
eosinophilic pneumonia (loffler syndrome) with transient patchy infiltrates
122
ascaris lumbricoides life cycle
adult worms in the lumen of small intestine > females produce 200,000 eggs/day in the feces > fertilized become infective after 18 days. > swallowed fertilized become imbedded in the mucosa carried by portal and systemic circulation to the lungs. > larvae mature in lungs and penetrate the alveolar walls > ascend to the bronhcial tree to the throat and are swallowed > develop into adults in the intestine.
123
are unfertilized ascaris lumbricoides eggs infective
NO
124
what are the complications of chronic ascaris lumbricoides
obstruction of the intestinal, bile, pancreatic, appendicitis, and intestinal perforation. entanglement of a large number of worms in the ileocecal region provokes spasmotic contractions and obstruction especially children. this can be partial or complete.
125
enterobius vermicularis (pin worm)
highly prevalent throughout the world. small white worm about 1 cm.
126
life cycle of enterobius vermicularis (pin worm)
inhabits the cecum, appendix and adjacent gut. > graivd females migrate out of the anus at night to the perianal regions and lay their eggs and die. > the eggs embryate for 6 hours and then are carried by air, clothes, hands.
127
clinical symptoms of enterobius vermicularis (pin worm) infections
most are asymptomatic, largely perianal pruritis. local itching and restless sleep
128
diagnosis of enterobius vermicularis (pin worm)
picked up from the perianal region in the moring
129
T trichiuria
very prevalent whipworm. children living in poverty in the tropics. many host coinfections with lumbricoides
130
symptoms of T trichiuria
recurrent rectal prolapse.
131
diagnose T trichiuria
lemon-shaped eggs in the stool. prolapsed rectum.
132
ancylostoma duodenale and necator americanus
hookworm, causes iron deficiency. inhabit only areas that have long standing warmth for several months and have minimum annual rainfall of 50-60 inches because the larva are susceptible to environment.
133
what increases the risk for transmission of ancylostoma duodenale and necator americanus
defecation and then people walking through it. children
134
what are the symptoms of ancylostoma duodenale and necator americanus
most harbor light infections and are asymp. iron deficiency and protein energy malnutrition. previously sensitized pepl might get a pruritic skin rash at the site of injury -ground itch. migration through the lungs causes transient pneumonitis.
135
strongloides stercoralis
tropics/subtropics, US and europe. endemic in appalacia southe eastern US, japan, europe, australia.
136
syndromes of strongloides stercoralis
more than 50% are asymp. greater than 75% have fluctuating eosinophilia. macropapular and urticaria on the buttocks, perineum and thighs.
137
hyperinfection of strongloides stercoralis
severe, complicated. this is increased generation of filariform larvae or accelerated auto infection typically occurs with an immunocompromised host.
138
disseminated strongloides stercoralis
found in the CNS, kidney, liver.
139
life cycle of strongloides stercoralis
poop > step in it > lungs > migrates to the intestines.
