Gastroenteritis Flashcards
What is gastroenteritis?
Inflammation of the GI tract usually considered infective in origin.
What is important to consider in gastroenteritis?
The subtle differences in the length of time between ingestion of food and development of symptoms.
How long does it take for the following to present:
Bacterial toxin
Viruses
Bacteria
Parasites
Bacterial toxins = hours
Viruses = days
Bacteria = weeks
Parasites = months
Definition of diarrhoea
3 or more loose stools or stools with increased liquid per day
Definition of…
Acute diarrhoea
Chronic diarrhoea
Dysentery
Traveller’s diarrhoea
Acute diarrhoea = Lasting < 14 days
Chronic diarrhoea = > 14 days
Dysentery = Loose stools with blood and mucus.
Travellers’ diarrhoea = More than 3 loose stool commencing within 24 hours of foreign travel, with or without cramps, nausea, fever or vomiting.
Risk factors
Poor food prep
Immunocompromised
Poor personal hygiene
Clinical features
Cramp-like abdo pain and diarrhoea +/- blood or mucus.
Can have vomiting, night sweats and weight loss.
Dehydration and potential pyrexia.
What are important questions to ask about features of history?
Bowel movements (blood-stained, mucus or profusely watery)
Affected family or friends
Recent travel abroad
Recent use of abx (can be C. diff)
What specific complications may patients present with?
Guillain Barre syndrome
RA
HUS
Investigations
Usually not necessary as most infections are self-limiting
Stool culture is often warranted especially with blood or mucus in the stool, if the patient is immunocompromised or if severe/persistent.
General management
Rehydration to encourage oral fluid intake where possible.
If there is severe dehydration or can’t tolerate oral fluid they might need admission for IV fluids.
Education on future episodes
Exclusion from work
In UK both food and infectious bloody diarrhoea are notifiable diseases and it is the duty of the diagnosing doctor to notify the appropriate body.
What certain organisms are also notifiable on their own?
Campylobacter
Salmonella
This is the duty of laboratory identifying organism to notify Public health body
Viruses that can cause it
Norovirus
Rotavirus
Adenovirus
Features of Norovirus
ssRNA that is the most common viral gastroenteritis in adults
Abdo cramps
Watery diarrhoea + vomiting
Usually lasts 1-3 days
Features of Rotavirus
dsRNA
Causes severe diarrhoea among infants and young children
Generally self-resolves in less than a week
Features of adenovirus
dsDNA that is a common cause of diarrhoea in children
Bacteria that can cause gastroenteritis
Campylobacter
E. coli
Salmonella
Shigella
Features of campylobacter
Most common cause of food poisoning from chicken, eggs or milk.
Prodrome of fatigue, fever or myalgia
Followed by nausea, abdo cramps and diarrhoea.
Complications of campylobacter
RA
Guillain Barre syndrome
HUS
TTP
Features of E. coli
G- bacillus that is typically transmitted through contaminated food.
It can also spread from animals to human or from person to person.
ETEC is the most common cause of Travellers’ diarrhoea
What is E. coli 0157:H7 associated with?
HUS
Do not give abx.
Features of salmonella
G- flagellated bacillus with two common serotypes - S. typhimurium and S. enteritidis.
Transmitted through undercooked poultry or raw eggs
Results in fever, vomiting, abdo cramps and bloody diarrhoea
Features of shigella
G- bacillus
Commonly acquired from contaminated dairy products and water
Presents with fever, abdo pain or bloody diarrhoea.
Toxins from bacteria often cause an acute onset and vomiting.
Symptoms tend to last less than 24h.
Give examples of bacterial toxins
S. aureus toxin
Bacillus cereus
Clostridium perfringes
Vibrio cholera
Features of S. aureus toxin
Typically found in meat or dairy products
Even re-heating of the cooked food does not destroy the exotoxin even if the bacteria are destroyed.
Features of bacillus cereus
Found in reheated rice and can cause rapid-onset vomiting and abdominal cramps
Features of clostridium perfringes
Acquired from re-heating meat dishes.
Causes diarrhoea yet vomiting is less common.
Features of vibrio cholera.
Acquired most commonly from contaminated water supplies
Causes profound watery painless diarrhoea.
There is an oral vaccina available for this.
In any patient with Travellers’ diarrhoea, parasites are more likely to be the causative organism.
Give examples of parasites that can cause gastroenteritis.
Cryptosporidium
Entamoeba histolytica
Giardia intestinalis
Schistosoma
Features of cryptosporidium
Protozoan that causes a self-limiting watery diarrhoea and abdo cramps
The diagnosis is made with stool cutlure for ova, cysts and parasites.
This can be life-threatening in immunocompromised patients.
Features of entamoeba histolytica
Anaerobic amoebozoan that becomes acquired from the ingestion of food or water contaminated with faeces.
Presents with bloody diarrhoea, abdo pain and fever
Stool culture for ova, cystss and parasites will confirm diagnosis.
Treatment with metronidazole or tinidazole.
Features of giardia intestinalis.
Parasite transmitted through direct contact or faeco-oral route
Can cause acute disease with diarrhoea, fever, fatigue, nausea and bloating
Can also cause chronic disease with steatorrhoea, malabsorption and weight loss.
Stool culture for ova, cysts and parasites will confirm diagnosis.
Metronidazole or tinidazole is the treatment
Features of schistosoma
Fluke
Acquired throught contaminated water.
Acute schistosomiasis develops about a month after initial infection and presents with fever, malaise, abdo pain and blood diarrhoea.
Severe cases can cause chronic liver disease
Eosinophilia can be seen on FBC. Stool culture for ova, cysts and parasites will confirm diagnosis.
Treatment is praziquantel
What is the main pathogen of hospital acquired gastroenteritis?
C. diff
Features of C. diff
G+ that can develop following the use of broad spectrum abx due to the disruption of the normal microbiota.
This leads to overgrowth of C. diff and production of exotoxins A & B.
Explain the consequence of exotoxin A&B
Produce a sizeable immune response from bowel.
This leas to inflammatory exudate on the colonic mucosa.
This leads to severe bloody diarrhoea and a risk of developing toxic megacolon.
Ix of C. diff
Stool culture and C. diff toxin testing (CDT)
Treatment of C. diff
IV fluid rehydration
Oral metronidazole or potentially vancomycin if severe disease or no improvement within 72h.
Non-infective causes of gastroenteritis.
Radiation colitis
IBD
Microscopic colitis
Chronic ischaemic colitis
What is microscopic colitis
Colon is macroscopically normal but on biopsy there is an increased number of inflammatory cells present.
Explain chronic ischaemic colotis
Due to compromised blood supply to colon.
Most commonly affect the watershed area around the splenic flexure.
Diagnosis is confirmed on endoscopy with a blue swollen mucosa
Important causes of dysentery
Campylobacter
Shigella
Salmonella
Norovirus
What should be considered if the patient has travelled abroad?
Parasites
ETEC
