Gastroenteritis Flashcards
What is gastrotenteritis?
- Inflammation of GI tract
- Considered infective in origin usually (but can be non-infective)
- Usually transient and associated with diarrhoea, vomitting and abdominal pain
Most common cause of gastroenteritis
Viral
Length of time between ingestion of food and development of symptoms - organism cause?
- Hours = bacterial toxins
- Days = viruses
- Weeks = bacteria
- Months = parasites
Define diarrhoea
3 or more loose stools or stools with increased liquid per day
Acute vs chronic diarrhoea
Chronic lasts more than 14 days
What is dysentery?
- Gastroenteritis characterised by loose stools with blood and mucus
What is travellers diarrhoea?
- More than 3 loose stools commencing within 24hrs of foreign travel
- With or without cramps, nausea, fever or vomiting
RF for gastroenteritis
- Poor food preparation - esp in handling and cooking
- Immmunocompromised
- Poor personal hygiene
Symptoms of gastroenteritis
- Cramp like abdominal pain
- Diarrhoea +/- mucus or blood
- Vomitting
- Night sweats
- Weight loss
Examination of patient with gastroenteritis
Dehydrated and pyrexial
Features from history to ask about re infective gastroenteritis
- Bowel movements - blood? watery?
- Affected family or friends?
- Recent travel abroad
- Recent use of abx within last 4 weeks - c.diff?
Complications that can present from gastroenteritis
- Guillain Barre syndrome
- Reactive arthiritis
- Haemolytic ureamic syndrome
Investigations for gastroenteritis presentation
- None usually needed as self limiting
- Stool culture if blood/mucus, immunocompromised or if severe/persistent
Management - general gastroenteritis
- Rehydrate - encourage oral fluid intake, if severe and cannot tolerate oral fluids - admit for IV maybe
- Education to prevent further episodes
- Exclusion from work - 48hrs from last episode of vomitting or diarrhoea
Notifiable disease - when?
- Food poisoning
- Infectious bloody diarrhoea
Diagnosing doctor has DUTY to inform
- Campylobacter and Salmonella also are but the lab inform public health about this
Viral causes of gastroenteritis
- Norovirus
- Rotavirus
- Adenovirus
Noravirus presentation
- Most common in adults - single stranded RNA virus
- Abdominal cramps, watery diarrhoea, vomitting
- Lasting 1-3 days
Rotavirus - presentation
- Double stranded RNA virus
- Severe diarrhoea in infants and young children
- Generally self resolves in less than 1 week
Adenovirus presentation
- Double stranded DNA virus
- Common cause of diarrhoea in children
Bacterial causes of gastroenteritis
- Campylobacter
- E-coli
- Salmonella
- Shigella
Campylobacter presentation
- Most common cause food poisoning - typically chicken, eggs or milk (gram -ve bacilli)
- Prodrome of fatigue, fever or myalgia, then nausea abdominal cramps and diarrhoea
What complications can Campylobacter cause?
- Guillan Barre syndrome
- HUS
- Thrombotic thrombocytopaenic purpura
E-coli presentation
- Transmitted through contaminated food usually (but can be from animals to human and person to person)
- Several forms exist - enterotoxigenic e-coli is most common cause travellers diarrhoea
Which form of e-coli can cause HUS?
- Serotype 0157:H7
Salmonella presentation
- Undercooked poultry or raw eggs
- Fever, vomitting abdominal cramps and bloody diarrhoea
Shigella presentation
- Contaminated dairy products and water
- Fever, abdominal pain, bloody diarrhoea
Bacterial toxin causes of gastroenteritis
- Staphylococcus aureus - meat and dairy exotoxin not destroyed by heat
- Bacillus cereus - reheated rice
- Clostridium perfringens - reheating meat
- Vibrio cholera - contaminated water, oral vaccine available
Parasite causes of gastroenteritis
- Cryptosporidium
- Entamoeba histolytica
- Giardia intestinalis
- Schistosoma
Cryptosporidium presentation
- Self limiting watery diarrhoea and abdominal cramps
- Diagnosis made by stool culture for ova, cysts and parasites
Entamoeba histolytica
- Ingestion of food/water contaminated with faeces
- Bloody diarrhoea, abdominal pain and fever
- Can also cause lliver absces
- Stool culture for ova, cysts and parasites needed for diagnosis - treat with Metronidazole
Giardia intestinalis
- Direct contact or faeco-oral route
- Acute disease - diarrhoea, fever, fatigue, nausea and bloating OR
- Chronic disease - steatorrhoea, malabsorption, weight loss
- Stool culture for ova, cysts and parasites for diagnosis - Metronidazole treats
Schistosoma presentation
- Contaminated water
- Acute develops a month after initial infection = fever, malaise, abdominal pain, bloody diarrhoea
- Severe causes –> chronic liver disease
- Eosinophilia on FBC sometimes
- Stool culture for ova, cysts and parasites needed - treat with Praziquantel
Hospital acquied gastroenteritis - main pathogens
- C.diff - then produces large amounts of exotoxins A&B
- Gram +ve organism
- Develops post use of broad spec abx distrupting normal microbiota of bowel
What do the c.diff exotoxins do to the bowel?
- Trigger large immune response
- = inflammatory exudate on colonic mucosa
- This presents clinically with severe bloody diarrhoea and has potential to develop into toxic megacolon - bowel becomes severely dilated and high risk of perf if untreated
Investigations for ?c.diff
- Stool culture
- C.difficile toxin testing (CDT)
Non-infective causes of gastroenteritis
- Radiation colitits
- Inflammatory bowel disease
- Microscopic colitis - macroscopically normal on endoscopy but biopsy shows increase in inflammatory cells
- Chronic ischaemic colitis - usually splenic flexure watershed area, endoscopy may show blue swollen mucosa
