Infectious Disease Flashcards
(146 cards)
1
Q
what are infectious diseases caused by?
A
cross contamination, undercooking, improper storage of food and reheating of food
2
Q
what is the general pathophysiology of organisms
A
attachment to GI mucosa > cellular invasion > production of exotoxins > changes in epithelial cell physiology > loss of brush border digestive enzymes > inc intestinal motility
3
Q
what are risk factors for pts becoming infected?
A
immunosuppression, genetics, bad hygiene, malnutrition, contamination
4
Q
what are the 6 bacterias responsible for GI infections?
A
C.Diff, campylobacter, salmonella, listeria monocytogenes, shigella, E.Coli
5
Q
C.diff epidemiology?
A
most common cause of diarrhoea
6
Q
what does c.diff produce and why is it bad?
A
produce spores that may be resistant to disinfectant
7
Q
true/false…
c.diff is transmittable
A
true
8
Q
some strains of c.diff are _______ of toxins
A
hyperproducers
9
Q
what are the 2 toxins that c.diff produce?
A
toxin A (enterotoxin) toxin B (cytotoxin)
10
Q
what exacerbates c.diff bacteria already in gut?
A
antibiotics that kill normal gut flora which allows c.diff to overgrow
11
Q
symptoms of c.diff infection
A
bloody diarrhoea, abdominal pain
12
Q
ix for c.diff?
A
GDH (if +ve then test for toxins) > if GDH +ve and toxin test -ve assess pt clinically and retest
13
Q
2 antibiotics given for c.diff
A
metronidazole & vancomycin
14
Q
prevention for c.diff?
A
use narrow spec antibiotics and avoid 4Cs, isolate pts
15
Q
what are the 4Cs
A
clindamycin, ciprofloxacin, co-amoxi, clarithromycin
16
Q
what are possible complications of C.diff?
A
pseudomembranous colitis and perforation
17
Q
campylobacter is a gram ___ ____
A
-ve bacilli
18
Q
how long is campylobacter’s intubation period?
A
3-10 days
19
Q
campylobacter is most common organism that causes…?
A
gastroenteritis
20
Q
source of campylobacter?
A
raw poultry
21
Q
symptoms of campylobacter?
A
abdo pain, fever, bloody diarrhoea
22
Q
what may campylobacter mimic?
A
appendicitis
23
Q
tx for campylobacter?
A
self-limiting, antibis (erythromycin or ciprofloxacin)
24
Q
complications of campylobacter?
A
bacteraemia, Guillain-Barre syndrome
25
what type of organism is salmonella?
colifrom (gram -ve)
26
is intubation for salmonella long or short?
short-24 to 48hr
27
why is salmonella dangerous?
produces toxin and is invasive
28
source of salmonella?
poultry, meat, raw egg
29
pathophysiology of salmonella?
born in animal gut and multiplies in food
30
symptoms of salmonella?
diarrhoea & vomit, bloody?, fever, abode pain
31
salmonella typhoic is a strain of salmonella- what is its common presentation?
rose spots on abdomen
32
tx for salmonella?
same as campylobacter ie. Antibes are erythromycin and ciprofloxacin
33
Listeria Monocytogenes is a gram __ bacterium
+ve
34
true/false...
| intubation of LM is long
false..
| it is short (9-48hrs)
35
listeria monocytogenes thrives in ...?
cold e.g. fridge
36
symptoms of listeria monocytogenes?
fever, muscle aches, diarrhoea
37
source of Listeria Monocytogenes?
unpasteurised milk, deli counter
38
transmission of listeria monocytogenes?
food Bourne, mother to child
39
shigella is gram __?
-ve
40
how long is Shigella's intubation?
1-9 days
41
what kind of toxin does shigella release?
shiga toxin
42
how does shiga toxin work?
binds to renal cell receptors (RBC etc) and inhibits protein synthesis causing cell death
43
which of the shiga toxins is more potent?
shiga toxin 2
44
who does e.coli usually affect more?
children
45
pathogenesis of e.coli?
adhere to epigastric cells and elaborate shiga toxin which inhibits proton synthesis resulting in death of enterocytes and endothelial cells > this activates inflammatory response causing fibrin deposits and clot formation > hameturia is caused
46
symptoms of e.coli?
bloody diarrhoea, high WBC, low Hb
47
tx for e.coli?
supportive
48
complications of e.coli?
renal failure
49
types of e.coli...
```
e.coli 0157
enterotoxigenic
enteropathogenic
enteroinvasive
enteroaggregative
```
50
intubation of e.coli 0157?
1-14 days
51
what toxin is produced with e.coli 0157?
verotoxin (kidney damage > HUS)
52
symptoms of 0157?
blood diarrhoea, fever pain
53
main complication of e.coli 0157?
Haemolytic Uraemic Syndrome (HUS)
54
epidemiology for HUS?
<16 yo, elderly
55
ix for HUS?
stool sample, bloods (high WBC, low platelets & Hb)
56
why is HUS an emergency?
can easily progress to acute renal failure, thrombocytopenia, haemolytic anaemia
57
which 2 e.coli's are mostly associated with travel?
enterotoxigenic and enteroaggregative
58
true/false...
| amoebas are responsible for outbreaks on cruise ships
false...
| usually viruses- rota & noro virus
59
rotovirus is no1 culprit for what presentation in young kids (<3)?
diarrhoea and vomiting
60
what type of spread does rotavirus have?
faecal-oral
61
how long does rotavirus last?
1 week
62
true/false...
| adults are affected more badly that kids by rotavirus
false...
| kids are more badly affected
63
symptoms of rotavirus?
diarrhoea with NO BLOOD
64
source of rotavirus?
contaminated drinking water, food, fomites
65
ix for rotavirus?
PCR
66
tx for rotavirus?
self-limiting, rehydration, vaccine
67
complications of rotavirus
post-infection malabsorption or repeat infections
68
what is norovirus presentation like
explosive vomiting
69
norovirus spread?
faecal-roal or droplets
70
how long is norovirus incubation?
2-4 days
71
what should be noted for fomites of norovirus?
asymptomatic shedding of virus for up to 48hrs post cessation of symptoms
72
true/false...
| like rotavirus, nor virus mainly affects kids
false...
| affects all ages
73
source of norovirus?
contaminated food or water
74
ix for norovirus?
faeces or vomit for PCR
75
tx for norovirus?
rehydration, self limiting
76
how to control infection in hospital setting?
standard infection control precautions, contact precautions, prudent antibiotic prescribing
77
spread of entamoeba histolytica?
faecal-oral
78
symptoms of entamoeba histolytica?
asymptomatic, abdominal pain, fever, acute, bloody diarrhoea, tenderness peritonism
79
ix for entamoeba histolytica?
stool for custs/ trophozoites, AXR (exclude toxic megacolon), endoscopy w biopsy
80
common complication of entamoeba histolytica?
amoebic liver abscess
81
epi for amoebic liver abscess?
intubation is 8-20 days, more common in men
82
s/s of amoebic liver abscess?
sub-acute: 2-4 weeks (fever, sweats, upper ab pain, GI upset, hepatomegaly, tenderness over right lower ribs)
83
ix for amoebic liver abscess
LFTs, CXR (opacity over right lung base), USS, CT
84
tx for amoebic liver abscess?
metronidazole/ tinidazole
85
4 types of protozoa
- giardiasis
- helminths
- chugs disease
- enterobius vermicularis
86
what is giardiasis causing organism?
flagellated protozoa
87
source of giardiasis?
contaminated water
88
sites of giardiasis infection?
duodenum and proximal jejunum
89
symptoms of giardiasis?
explosive watery diarrhoea, bloating, ab cramps, wt loss
90
ix for giardiasis?
stool microscopy-cysts seen, PCR, OGD (oesophagus-gastro- duodenoscopy)
91
tx for giardiasis?
metronidazole
92
helminth infection site?
in gut and tissue
93
signs of helminths infection?
eosinophilia, adult worm passed or eggs in stools
94
what are 3 types of helminths?
nematodes, trematodes, cestodes
95
nematodes are also known as?
intestinal roundworms
96
pathogenesis of nematode infection?
egg ingested > hatches in small intestine > invades gut walls and reaches venous system > breaks into lung and alveoli > goes into bronchial tree and then swallowed into gut where becomes worm
97
true/false...
| schistosomiasis is caused by nematodes
false...
| by trematodes
98
what is a complication of schistosomiasis
can lead to hepatomegaly, liver fibrosis or PHTension
99
where do cestodes originate in?
pork or beef that is undercooked and contains larval cysts
100
what are cestodes also known as?
tapeworms
101
a common complication of tapeworms is...
cysticercosis- tissue cysts in muscles and brain
102
what is the organism that causes chagas disease?
trypanasoma cruzi
103
transmission of chagas?
kissing bug (triatome)
104
what is chagas disease?
causes parasympathetic denervation affecting colon and oesophagus
105
what is Enterobius vermicularis?
threadwormss- tiny white worms in stool
106
classic epidemiology of threadworms?
children
107
s/s of threadworms?
perianal itch, worms in stool
108
pathogenesis of threadworms?
eggs ingested > hatch in intestine > live in caecum/colon > adult females exit onto perianal skin and lay eggs > itchy so scratch and then fingers in mouth again
109
how does enterobius vermicularis spread?
person to person- human only disease
110
tx for threadworms (enterobius vermicularis)?
oral mebendazole
111
what is gastroenteritis
infection of large intestine
112
what microbiomes are responsible for gastroenteritis
campylobacter, shigella, e.coli, entamoeba histolytica
113
what is the most common bacteria that causes gastroenteritis?
campylobacter
114
duration of gastroenteritis?
< 2 weeks
115
aetiology of gastroenteritis?
contaminated food, toxins, poisons
116
symptoms of gastroenteritis?
diarrhoea & vomiting, abdominal pain
117
important hx to take note of when pt presents with gastroenteritis?
travel, food hx e.g. reheating, contact tracing, antibiotics?
118
ix for gastroenteritis?
stool sample - takes 48hrs
119
complications of gastroenteritis?
many organisms that cause gastroenteritis invade other tissues and produce toxins
120
intubation for gastroenteritis?
very short- 1 to 6hrs
121
what type of organism thrives when reheating rice?
gram +ve bacillus e.g. bacillus cereus
122
what is main presentation of bacillus cereus?
profuse vomiting
123
what organisms thrive when food is left out at room temp e.g. milk, fish etc
gram +ve cocci e.g. staphylococcus aureus
124
3 factors that allows bacteria to multiply?
time, temp and moisture
125
what 2 micro organisms are responsible for viral gastroenteritis?
rotavirus & norovirus
126
ix for viral gastroenteritis?
stool sample- PCR, antigen detection, serology, immunoassay
127
if a returned traveler presents in A&E feeling unwell, what must you do straight away?
isolate, have a full comprehensive travel hx e.g. accommodation, since bites etc, s/s
128
what are some ddx's for returned traveler presenting with fever?
resp tract infection (pneumonia, influenza), traveller's diarrhoea, malaria, enteric fever (typhoid), arboviruses (Dengue, Zika)
129
what is the definition of acute traveller's diarrhoea?
3 loose stools in 24 hrs
130
micro organisms responsible for acute traveller's diarrhoea?
enterotoxigenic E.Coli, campylobacter, salmonella, shigella, viruses?
131
important acute traveler's diarrhoea's are...
cholera (watery diarrhoea, refugee camps)
| dysentery (bloody diarrhoea caused by e.coli 0157)
132
ix for acute traveller's diarrhoea?
stool culture
133
tx for acute traveller's diarrhoea?
supportive, rehydration therapy, macrolide
134
where is enteric fever most commonly found in?
india and SE asia
135
incubation for enteric fever?
7-18 days
136
types of enteric fevers?
typhoid and paratyphoid
137
symptoms of enteric fever?
fever and non-specific symptoms e.g. headache
138
main organism responsible for enteric fever?
salmonella
139
ix for enteric fever?
blood tests, stool, urine
140
tx for enteric fever?
ciprofloxacin, azthromycin, vaccines
141
complications of enteric fever?
GI bleed, GI perf, encephalopathy, other infections
142
main causes for pre-hepatic jaundice in returned travellers?
malaria, HUS, sickle cell crisis triggered by infection
143
main causes for hepatic jaundice in returned travellers?
hep A&E, leptospirosis, malaria, enteric fever
144
main causes for post- hepatic jaundice in returned travellers?
ascending cholangitis
145
ix for fever and jaundice in returned travellers
USS abdomen, bloods (FBC,LFT,coags, serology)
146
tx for fever and jaundice in returned travellers
supportive (dialysis?), liver transplant worst case scenario
