Gastroenteritis Flashcards
1
Q
What is Gastroentertitis?
A
It is the inflammation of the stomach and intestine
Most common cause of acute GI infection
caused by viral,bacterial and parasitic infection
2
Q
What are the main symptoms of Gastroenteritis?
A
Diarrhoea (+/-) vomiting ( main)
abdominal pain and fever
3
Q
What is acute diarrhea?
A
more than 3 or more episodes of unformed stools a day for less than 2 weeks
4
Q
What is dysentery?
A
Infectious gastroenteritis with blood/mucus diarrhoea
5
Q
What is traveller’s diarrhoea?
A
passage of three or more unformed stools per day during ,or shortly after foreign travel
Mainly occurs in young people and from those in developed countries travelling in developing countries
6
Q
What’s the difference between type 1 and type 7 stools on the bristol stool chart?
A
Type 1 - separate hard lumps
Type 7- watery no solid pieces
7
Q
Large volume of diarrhea suggest?
A
its origin is from small bowel
8
Q
What is persistent diarrhoea?
A
acutely started diarrhoea lasting more than 2 weeks
9
Q
What are 2 common bacteria which cause gastroenteritis and have short incubation periods?
ii. what type of bacteria are they?
A
Bacillus cereus- gram positive
Staphylococcus aureus- gram positive
10
Q
What is the most common cause of gastroenteritis?
A
Viral infection
11
Q
Give examples of Infective causes of gastroenteritis?
diarrhoea without blood
A
main viruses
Norovirus
Rotavirus
Main Bacteria
Bacillus cereus
staphylococcus aureus
cholera
Enterotoxigenic/enteropathogenic E coli
Clostridium perfringens
Main parasites
Giardia
cryptospordium
12
Q
What are the main infective causes of dysentery?
A
common Virus
CMV
common bacteria
Shigella
salmonella
campylobacter
E coli O 157 (EHEC)
costridium difficile
common parasites
Whipworm ( trichuriasis)
amoeba Entamoebic histolytica ( amoebic dysentery)
13
Q
What type of virus is Norovirus?
A
single stranded RNA virus
14
Q
How does norovirus transmitt?
A
Faecal oral transmission
aerosol transmission
transmission allows for people to people
common sources: food,water and fomites (objects- little kids put them in there mouth)
15
Q
What are the signs and symptoms of norovirus?
A
Vomiting ( explosive and sudden! may be only symptom)
watery diarrhoea ( explosive and sudden!)
abdominal cramps
Nausea
headaches
short incubation ( less than 24 hours)
Vomiting more prevalent in children
diarrhoea more prevalent in adults
16
Q
You can shed norovirus even if asymptomatic true or false?
A
true
17
Q
How do you diagnose norovirus?
A
Stool sample or vomit swab for reverse transcriptase PCR
18
Q
How do you treat Norovirus?
A
Usually is self limiting 2-4 days
oral rehydration solution
prevention: good hygiene and food preparation
Isolation may be required
19
Q
What type of virus is rotavirus?
A
Double stranded RNA virus
20
Q
Which age group does it mainly affect?
A
kids under age of 5 - most common cause in the world for gastroenteritis in this age group
21
Q
What are the signs and symptoms of Rotavirus?
A
Watery diarrhoea
vomiting
fever
abdominal pain
symptoms are usually mild or absent in adults
bottle fed babies more likely to be symptomatic than breast fed
severe in immunocompromised children
22
Q
How does rotavirus transmitt?
A
person-person
faecal oral
23
Q
How do you diagnose rotavirus?
A
ELISA/PCR for stool antigens and vomit swab
histology
jejunal mucosa in children shows shortening of the villi with crypt hyperplasia
24
Q
How do you manage rotavirus?
A
usually self limiting - 1 week
Oral rehydration therapy and sometimes IV fluid
Vaccines are now used - both are live vaccines ( Rotarix and rotateq) routine rotarvirus vaccination
25
What time of year does it mainly become effective?
winter months in non tropical areas
26
What are the main risk factors for gastroenteritis?
```
Poor sanitation & hygiene
Commercialisation of food production
Import of food from other countries
Increase in day care/care home
International Travel
Acid suppression
immunosuppression
```
27
What are the three main forms of mechanisms for bacteria to cause diarrhoea?
mucosal adherence- sometimes is a prelude only to the other two forms
( watery diarrhoea)
enteropathogenic/aggregative E.coli
diffusely adhering E.coli
mucosal invasion- penetration of the intestinal mucosa invasins disrupt host cell cytoskeleton.
Shigella
campylobacter
(dysentery)
toxin production:
Enterotoxins: induce excessive fluid secretion into bowel lumen.
(watery diarrhoea)
salmonella
campylobacter
Bacillus cereus
cholera
cytotoxins- damage intestinal mucosa
(dysentery)
E coli O157
salmonella
campylobacter
28
What should all bacteria stools check for?
Shigella.
E Coli 0157.
Campylobacter
Cryptosporidium
29
How does B cereus transmitt?
mainly through spores which germinate in semi cooked rice which is stored in warm temperatures before eaten
30
What are the symptoms of B cereus?
vomiting diarrhoea
| nausea
31
Where does staphylococcus aureus originate from?
uncooked food
32
What are the symptoms of staphylococcus aureus?
violent vomiting (main)
profuse watery diarrhoea
rapid symptoms 2-4 hours
33
What type of bacteria is Enterotoxigenic E coli
gram negative anaerobic bacteria
34
what is the pathophysiology
Has heat labile and heat stable enterotoxins which stimulate secretion of fluid into the intestinal lumen
35
What types of diarrhoea does it cause?
Major cause of travellers' diarrhoea
also causes infective diarrhoea
36
What are the signs and symptoms of enterotoxigenic E.coli
watery diarrhoea
cramps and nausea
37
How does enterotoxigenic E.coli transmit?
Person to person via contaminated food and water
38
How do you diagnose Enterotoxigenic E.coli?
stool culture for PCR
39
How do you manage Enterotoxigenic E.coli?
self limiting- 1-4 days
oral rehydration therapy
antimotility agents (Loperamide)- avoid if severe pain or bloody diarrhoea as may indicate invasive colitis
40
What type of bacteria is cholera?
gram negative aerobic bacteria
41
How does cholera transmit?
faecal oral route
faecal contaminated water main factor
found in asia
42
What are the signs and symptoms of cholera?
watery diarrhoea (rice-water stool)
vomiting
dehydration ( sunken eyes, hollow cheeks and a diminished urine output)
metabolic acidosis
circulatory collapse
Hypovolaemic shock
most are mild symptoms
can be asymptomatic
43
How do you diagnose cholera
stool culture ( serovars 01 or 139 will be present)
rapid dipstick test
death due to dehydration from watery diarrhoea and under the age of 5
44
How do you manage cholera?
Oral rehydration therapy ( salts)
IV therapy if severe
Antibiotics: doxycycline or tetracycline to decrease diarrhoea or ciprofloxacin
prevention: mainly clean water
good hygiene
oral cholera vaccines
zinc shortens illness in children
45
What type of bacteria is shigella?
Gram negative anaerobic bacteria
46
How does shigella transmit?
poor hygiene
person to person
more common in developing world and in children
47
What are the signs and symptoms of shigella?
occur after 1-2 days since infection
Dysentery
Pain
tenesmus
fever
48
what are the species responsible for shigella?
S. dysenteriae
s. flexneri
s. boydii
s. sonnei
49
How do you diagnose shigella
stool culture
PCR/enzyme immunoassay
50
How do you manage shigella?
Usually self limiting
ORS
Antibiotics used only if systemically unwell or immunosuppressed due to resistance
Ciprofloxacin 500 mg twice daily or ampicillin and azithromycin
Nutrition:
Green bananas- increase short-chain fatty acids in colon
vitamin A
zinc if younger than 6
Avoid antidiarrheal agents- increase risk of toxic dilation
51
What are the complications of shigella?
bacteraemia
reactive arthritis
HUS
52
What type of bacteria is Shiga Toxin producing E.coli (STEC)
Gram negative anaerobe
53
give an example of STEC?
E.coli O157
54
What is the pathophysiology of E.coli O157?
produces verotoxins which are shigella which affects endothelial cells in the gut and kidney. Irreversibly inhibit protein synthesis
55
What age group is mainly affected by E coli O157?
children and elderly
and immunocompromised
56
How does E coli O157 transmit?
contaminated food and livestock
57
What are the signs and symptoms of E coli 0157
Diarrhoea ( bloody)
Hemorrhagic colitis
Abdominal pain
Nausea
HUS ( haemolytic uraemic syndrome)
thrombotic thrombocytopenic
58
How do you diagnose E coli O157
stool culture
PCR
59
How do you treat E coli O157
Supportive ( ORS and potentially IV fluid balance)
don't give antibiotics, NSAIDs or antimotility agents as increase risk of HUS
60
How do you diagnose Staphylococcus aureus?
Culture of organism in vomit or remaining food
61
How long does it take to recover from staphylococcus aureus?
less than 24 hours
62
How do you diagnose Bacillus cereus?
Culture of organism in faeces and food
Reheated rice!!!
63
How long does it take to recover from Bacillus cereus?
6-24 hours
can die from fulminant hepatic failure
64
What type of bacteria is salmonella enteritidis?
Bacillus gram negative anaerobe
65
How does salmonella transmit?
contaminated foodstuffs ( poultry,meat,raw eggs) and water
66
What are the signs and symptoms of salmonella?
diarrhoea (bloody)
Vomiting
fever
cramps
usually between 12-36 hours after
invasive infections of salmonella can cause:
sepsis
meningitis
osteomyelitis
children and elderly risk of dehydration
67
What are the antigens found on the lipopolysaccharide /body( LPS) of a bacteria?
O antigens
68
What are the antigens found on the flagellum of the bacteria?
H antigens
69
How do you diagnose salmonella?
Stool culture - can serogroup salmonella based on O antigens
PCR
70
How do you manage salmonella?
Supportive care
usually self limits after 3-6 days
may have stool issues for several weeks though
71
What type of bacteria is campylobacter
gram negative spiral shaped rod
72
What part of the body can salmonella and campylobacter both effect?
small and large bowel
73
salmonella is the most common cause of gastroenteritis true or false?
false- its campylobacter
74
How does campylobacter transmit?
comes from undercooked meat ( especially beef burgers and chicken)
contaminated milk and water
less likely to spread human to human
75
What are the signs and symptoms of campylobacter?
incubation 2-5 days
Bloody or watery diarrhoea
pain fever
headache
severe abdominal cramps
76
what diseases are associated with campylobacter?
Guillain Barre syndrome
Bacteraemia
hepatitis
pancreatitis
77
How do you diagnose campylobacter?
Stool culture
PCR/enzyme immunoassay
78
what is the main symptom of Guillain-Barre syndrome?
tingling of the feet leads to progressive paralysis of the arms, legs and rest of the body
79
How do you manage campylobacter jejuni?
self limiting 3-5 days
supportive care mainly
can give antibiotics (azithromycin)- if symptoms severe
80
what is clostridium difficile
Gram positive bacillus anaerobic
81
Where can clostridium difficile be found?
part of colonic flora
82
What is the pathophysiology of clostridium difficile?
Production of enterotoxins A and B cause symptoms
antibiotic exposure inhibits colonic flora allowing for it to grow rapidly
faecal oral spread
83
What are the signs and symptoms of clostridium difficile
watery diarrhoea
abdominal pain
mild to fulminant colitis ( pseudomembranous colitis)
ileus - lack of motility
toxic megacolon
84
What are the risk factors of clostridium difficile
Age
surgery
prolonged stay at hospital- considered hospital superbug
Drugs: mainly antibiotics- clindamycin, co amoxiclav and quinolones ( ciprofloxacin )
85
How do you diagnose c.difficile?
Markers of severity include:
Temperature higher than 38.5
raised white cell count >15x 10^9
raised serum creatine
raised serum lactate
severe abdominal pain
Detection of A or B toxins in stool culture with PCR
ELISA if stool antigen is positive
sigmoidoscopy for pseudomembranous colitis
Abdominal x ray for toxic megacolon
86
How do you manage c.difficile?
1. for mild or moderate disease: metronidazole 400 mg three times daily
for severe or relapsing cases: Oral vancomycin 125-500 mg four times daily or fidaxomicin
2. in relapsing cases faecal transplant can restore normal bowel
Prevention
Think 'SIGHT'
Suspect
Isolate within 2 hours
Gloves and aprons
Hygiene ( clean surfaces and wash hands etc)
Test immediately
87
What are the signs and symptoms of HUS?
haemolytic uraemic syndrome
Microangiopathic haemolytic anaemia
Acute kidney injury- caused by thrombosis of glomerular capillaries from microangiopathy
Bloody diarrhoea
Abdominal pain
fever
pallor
petechiae (tiny red spots on skin look like bruises)
oliguria
88
which age group is HUS mainly associated with?
children ( 85% of cases under age of 16)
89
How do you diagnose HUS?
Increase in LDH
high WBC
detection of RBC fragments in blood film
decrease in Platelets
decrease in haemoglobin
evidence of E coli O157 (STEC)
signs of AKI - proteinuria
90
How do you manage HUS
No NSAIDs, antibiotics or antimotility agents- all increase risk of precipitating HUS
mainly supportive care
91
what does thumb printing show on an abdominal xray?
inflammatory/infective bowel condition
92
what are the 3 classes of antidiarrhoeal agents?
antimotility agents
antisecretory agents
absorbents
93
when should you avoid antimotility agents such as opiates and loperamide?
```
dysenteric symptoms
(fever, bloody diarrhoea, abdominal pain)
```
94
when giving metronidazole for an intra-abdominal infection what organisms is this antibiotics targetting?
anaerobes
95
What is Giardis lamblia?
Flagellate protozoa which causes Giardiasis- a cause for parasitic Gastroenteritis in the small intestine
96
How does Giardiasis spread?
ii how does it exist?
faecal oral route
infected drinking water/food and fomites
ii.exists as either cyst or a trophozoite ( cyst form is how it transmits)
person to person may occur in nurseries and residential institutions
97
what are the signs and symptoms of giardisasis
mainly asymptomatic
symptoms form between 1-3 weeks after ingesting cysts
diarrhoea
malabsorption
Bloating
flatulence
abdominal discomfort
nausea
potentially weight loss
98
What is Giardiasis mainly associated with?
travellers diarrhoea- most common parasitic cause in travellers returning to UK
99
What can chronic giardiasis cause?
growth retardation in children- common in developing countries
100
How do you diagnose giardiasis?
stool microscopy for cysts and trophozoites- need more than 3 samples due to intermittent shedding allowing to increase sensitivity
Endoscope for giardiasis which is found in duodenal aspirate
or duodenal aspirate fluid analysis
101
How do you manage giardiasis?
1. Hygiene to prevent transmission
2. metronidazole- single dose on three successive days
or
tinidazole
or
albendazole-- less side effects while also treating other parasites
102
What is amoebiasis caused by?
entamoeba histolytica
103
How does amoebiasis spread?
faecal oral pathway
source: water
form: cysts and trophozoites
104
What are the signs and symptoms
asymptomatic in luminal amoebiasis (90%)
intestinal - dysentery ,headache, nausea,pain,colitis, appendicitis, toxic megacolon formation of ameboma (inflammatory abdominal mass)
extra intestinal- high swinging Fever, liver abscess (rare) , RUQ pain and hepatomegaly
105
How do you diagnose Amoebiasis?
stool microscopy of cysts and trophozoites via sigmoidoscopy
biopsy sample
amoebic antibody detection in extraintestinal disease (especially with liver abscess)
PCR can distinguish E. histolytica
AXR for toxic mega colon
potentially abnormal LFT
106
How do you manage amoebiasis?
Metronidazole or tinidazole
luminal agent such as diloxanide furoate should be used
107
What is enteric fever?
primarily a tropical disease it is. an acute systemic illness
108
What are the two main types of enteric fever
typhoid- salmonella typhi
paratyphoid- salmonella paratyphi
109
How does typhoid spread?
faecal oral
from contaminated food or water
110
What are the signs and symptoms of typhoid?
diarrhoea
fever
headache
abdominal pain
abdominal tenderness
hepatosplenomegaly
maculopapular rash ( rose spots)
111
What are the complications of typhoid?
intestinal haemorrhage
meningitis
lobar pneumonia
112
How do you diagnose enteric fever?
blood culture is usually positive in first two weeks of both bacteria
113
How do you manage typhoid?
quinolones ( ciprofloxacin)
if resistant to quinolone then ceftriaxone
114
How do you diagnose acute traveller's diarrhoea?
Stool culture
check stool for amoebic trophozoites( mainly) and cysts
115
How do you treat acute traveller's diarrhoea?
Supportive- fluid rehydration
treat systemic issues
fluoroquinolone ( ciprofloxacine) if travelling
116
When examining a returned traveller what should you look for?
fever ( could be anything from pneumonia to arboviruses) - not just traveller's diarrhoea
rash
hepatosplenomegaly
lymphadenopathy
insect bites
wounds
117
where are helminth infections associated with?
eosinophilia
118
give example of Helminths.
Nematodes (roundworms)
trematodes (flukes)
cestodes. ( tapeworm)
119
How are Helminths often diagnosed?
eggs in stool culture or adult worm passed
120
What are the complication of flukes?
schistosomiasis- from fresh water
chronic infection can cause hepatomegaly, liver fibrosis and portal hypertension
121
What are the complications of tapeworms?
From undercooked Pork or beef which contain their larval cysts
cause cysticercosis even neuro form which can lead to seizures
