Gastroenteritis Flashcards
Define gastroenteritis
Syndrome of diarrhoea and vomiting that refers to non-inflammatory involvement of the upper small bowel or inflammation of the colon.
What is the most common cause of gastroenteritis?
Infection.
The vast majority is caused by a virus.
Bacteria - 20%
Parasites < 6%
What percentage of gastroenteritis cases are not infectious?
15%
Give some non-infectious diarrhoea examples
GI bleed Ischaemic gut Diverticulitis Endocrine disorders Numerous drugs Fish toxins WIthdrawal
What is the approach to any clinical infection syndrome?
What are the key clinical symptoms and signs that suggest the infection?
Differential diagnosis
Severity of Infection
Site and microbiological diagnosis: investigations
Antibiotic and supportive management
Infection Control
Public Health
What is another name for the norovirus?
Norwalk agent
Which pathogens cause toxin-mediated food poisoning?
Which of these pathogens pre form toxins and which are formed in vivo?
Preformed: Staph aureus Clostridium perfringens Bacillus cereus In vivo production: Vibrio Enterotoxigenic E. coli
What are the presenting clinical syndromes of food poisoning?
1. Acute enteritis (i.e. inflammation of the small intestine): Fever Diarrhoea Vomiting Abdominal pain 2. Acute colitis: Fever Pain Bloody diarrhoea 3. Enteric fever-like illness: Fever Rigors Pain Little diarrhoea
List infective and non-infective causes of bloody diarrhoea
Infection: bloody diarrhoea usually indicates colonic inflammation Campylobacter. spp Shigella. spp E. coli 0157 Amoebiasis
Non infective:
IBD
Malignancy
Ischaemia
Describe the symptoms of enteric fever-like illness
Fever
Systemically unwell
Abdominal pain
Constipation but possibly short history of diarrhoea
What is typhoid?
A bacterial infection that can spread throughout the body involving multiple organs.
Where does Typhoid come from?
It is almost always imported
From:
Indian subcontinant, South East Asia, Far east, middle east, Africa, central/south america, Increasing in Eastern Europe.
How is typhoid transmitted?
Food, water or carrier
How can typhoid present?
It can be asymptomatic
It can be mild
It can cause bacteraemia
it can cause enterocolitis
How is typhoid diagnosed?
Blood cultures are the key to diagnosis.
Stool and urine cultures also done.
How is typhoid treated?
Chloramphenicol and ciprofloxacin- some strains resistant to this
Ceftriaxone or azithromycin
How can typhoid be prevented?
There is an IV or oral vaccine.
It is not effective against paratyphoid.
What are key features in a gastroenteritis history?
Diarrhoea: frequency, nocturnal, constistency, colour, presence of blood
Associated symptoms: abdominal pain, vomiting, fever, urgency, incontinence
Anyone in family or work with similar symptoms
Occupation
Pets and animal contact
Travel abroad
History of medication- particularly recent Abx and PPIs
What are key features in a gastroenteritis examination?
Fever
Skin rashes, e.g. rose spots, erythema nodosum
Dehydration: pulse, mental state, dry tongue, skin turgor, blood pressure, postural drop
Abdominal tenderness
Abdominal distension
PR exam: stool, blood, tenderness
What investigations are carried out to help diagnosis a gastroenteritis?
Stool microscopy when appropriate (e.g. history of travel, for giardia, amoeba etc)
Stool culture: Salmonella, Camppylobacter, Shigella
Stool toxin for C diff (culture not routinely done), adn cytotoxin for E. coli
Blood cultures (salmonella)
PCR : .e.g norovirus
FBC- wcc key in severity of CDI
U, Es - renal function important
AXR
What are severity markers of CDI?
One or more of the following:
Suspicion of PMC or toxic megacolon or ileus or colonic dilatation in CT/AXR of >6cm
WCC > 15 cells/mm3
Creatinine > 1.5 x baseline
What are intestinal complications of bacterial enteritis?
Severe dehydration and renal failure
Acute colitis, toxic dilatation
Post infective irritable bowel
Transient secondary lactase intolerance
What are extra-intestinal complications of bacterial enteritis?
Septicaemia Metastatic infection: meningitis, aortitis, osteomyelitis, endocarditis Reactive arthritis Meningism Neurological- Guillian-Barre syndrome haemolytic uraemic syndrome
What is supportive treatment for gastroenteritis?
Oral rehydration IV fluids (saline important)
What is specific treatment for gastroenteritis?
Anti-spasmodics
Anti-motility agents
Antibiotics- only in specific situations
Name 2 antisecretory antidiarrhoeal agents
Chlorpromazine
Bismuth subsalycilate
Name 2 absorbant antidiarrhoeal agents
kaolin
charcoal
When are patients given empirical antibiotic therapy for gastroenteritis?
- They must have 3 or more unformed stools per day as well as one or more of: abdominal pain, nausea, vomiting, fever, blood in stool, tenesumus
- As well as 1, patients must either a) be high risk:
immunocomprimised
hypochlorhydria
inflammatory bowel disease
prosthetic intravascular device
or b) have dysenteric symptoms:
fever
bloody diarrhoea
abdominal pain - A stool sample or rectal swab for culture is taken from these patients
- Patients are given ciprofloxacin 500mg BD for 3-5 days and their progress is reviewed
What kind of bacterium is C difficile?
Anaerobic gram positive spore forming bacillus
What are risk factors for C diff infection?
Antibiotics:
All, but greatest risk with broad spectrum e.g. fluoroquinolones, cephalosporins, clindamycins, broad spectrum penicillins
Medications:
PPI
H2RA
Advanced age - at least 65 years old
Chemotherapy, chronic renal disease, underlying IBD
What drugs should be avoided in pseudomembrinous colitis?
Antibiotics which may be precipitating it
opiates
Anti-peristaltic drugs
PPIs
What is the treatment for pseudomembranous colitis?
Oral therapy more reliable than parenteral therapy
Non-severe: metronidazole
Severe/failure of metronidazole: vancomycin
Do not use IV vancomycin
What is the treatment for the 1st presentation of uncomplicated CDI?
Oral metronidazole for 14 days Stop other antibiotics Review PPIs Dont use anti-motility agents No re testing unless symptomatic Should improve within 3-5 days
What is the treatment for CDI if it responds poorly to oral metronidazole, if the disease is severe, or if there is more than one severity marker?
Get help
Start oral vancomycin 125mg qds 10-14 days
Vancomycin isn’t absorbed so stays in the bowel to kill bacteria
Why can C diff infection relapse?
Because although the bacteria are killed, they can leave behind spores
What should be considered in persistent diarrhoea that lasts for more than a week?
Parasites
Screen for IBD
Should antibiotics be used to treat Ecoli 0157?
No
Which pathogens cause travel-related diarrhoea?
Amoebiasis
Giardiasis
Cryptosporadiasis
What is the average duration of untreated traveller’s diarrhoea?
4 days
How long can traveller’s diarrhoea persist for?
Up to 2 months, but this is only in 1-2% of people
What is amoebiasis?
How is it spread?
How is it diagnosed?
A protozoal infection
It is spread by faeco-oral route or by an ill or asymptomatic carrier
Diagnosed by examination of hot stool for ova and cyts.
Serology may be of use, especially in extra-intestinal disease
What can amoebiasis cause?
Acute bloody diarrhoea
Extra-intestinal spread to produce an abscess can occur
What is giardiasis?
Protozoon Giardia lambia trophozoites colonizes the small bowel mucosa to produce diarrhoea and malabsorption; often explosive, protracted and foul smelling
How is giardiasis spread?
Infection spread by cysts found in normal drinking water
How is Giardiasis diagnosed?
Diagnosis is examination of stools for ova and cysts but more accurately by duodenal aspiration
What is an important cause of traveller’s diarrhoea?
enterotoxigenic E coli
What is Cryptosporidiosis?
A parasitic disease cryptosporidium, which is a protozoan parasite.
How is Cryptosporidiosis transmitted?
Water, food, contact with animals. It is highly infectious and resilient.
Does Cryptosporidiosis require treatment?
It is self limiting.
It is severe in immunosuppressed patients
How is Cryptosporidiosis diagnosed?
Duodenal aspirate/stool
What is the treatment for Cryptosporidiosis?
Supportive
