Gastroenteritis

Question 1

What is gastrotenteritis?

Answer 1

• Inflammation of GI tract
• Considered infective in origin usually (but can be non-infective)
• Usually transient and associated with diarrhoea, vomitting and abdominal pain

Question 2

Most common cause of gastroenteritis

Answer 2

Viral

Question 3

Length of time between ingestion of food and development of symptoms - organism cause?

Answer 3

• Hours = bacterial toxins
• Days = viruses
• Weeks = bacteria
• Months = parasites

Question 4

Define diarrhoea

Answer 4

3 or more loose stools or stools with increased liquid per day

Question 5

Acute vs chronic diarrhoea

Answer 5

Chronic lasts more than 14 days

Question 6

What is dysentery?

Answer 6

• Gastroenteritis characterised by loose stools with blood and mucus

Question 7

What is travellers diarrhoea?

Answer 7

• More than 3 loose stools commencing within 24hrs of foreign travel
• With or without cramps, nausea, fever or vomiting

Question 8

RF for gastroenteritis

Answer 8

• Poor food preparation - esp in handling and cooking
• Immmunocompromised
• Poor personal hygiene

Question 9

Symptoms of gastroenteritis

Answer 9

• Cramp like abdominal pain
• Diarrhoea +/- mucus or blood
• Vomitting
• Night sweats
• Weight loss

Question 10

Examination of patient with gastroenteritis

Answer 10

Dehydrated and pyrexial

Question 11

Features from history to ask about re infective gastroenteritis

Answer 11

• Bowel movements - blood? watery?
• Affected family or friends?
• Recent travel abroad
• Recent use of abx within last 4 weeks - c.diff?

Question 12

Complications that can present from gastroenteritis

Answer 12

• Guillain Barre syndrome
• Reactive arthiritis
• Haemolytic ureamic syndrome

Question 13

Investigations for gastroenteritis presentation

Answer 13

• None usually needed as self limiting
• Stool culture if blood/mucus, immunocompromised or if severe/persistent

Question 14

Management - general gastroenteritis

Answer 14

• 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

Question 15

Notifiable disease - when?

Answer 15

• Food poisoning
• Infectious bloody diarrhoea

Diagnosing doctor has DUTY to inform

• Campylobacter and Salmonella also are but the lab inform public health about this

Question 16

Viral causes of gastroenteritis

Answer 16

• Norovirus
• Rotavirus
• Adenovirus

Question 17

Noravirus presentation

Answer 17

• Most common in adults - single stranded RNA virus
• Abdominal cramps, watery diarrhoea, vomitting
• Lasting 1-3 days

Question 18

Rotavirus - presentation

Answer 18

• Double stranded RNA virus
• Severe diarrhoea in infants and young children
• Generally self resolves in less than 1 week

Question 19

Adenovirus presentation

Answer 19

• Double stranded DNA virus
• Common cause of diarrhoea in children

Question 20

Bacterial causes of gastroenteritis

Answer 20

• Campylobacter
• E-coli
• Salmonella
• Shigella

Question 21

Campylobacter presentation

Answer 21

• 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

Question 22

What complications can Campylobacter cause?

Answer 22

• Guillan Barre syndrome
• HUS
• Thrombotic thrombocytopaenic purpura

Question 23

E-coli presentation

Answer 23

• 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

Question 24

Which form of e-coli can cause HUS?

Answer 24

• Serotype 0157:H7

Question 25

Salmonella presentation

Answer 25

* Undercooked poultry or raw eggs * Fever, vomitting abdominal cramps and **bloody** diarrhoea

Question 26

Shigella presentation

Answer 26

* Contaminated dairy products and water * Fever, abdominal pain, bloody diarrhoea

Question 27

Bacterial toxin causes of gastroenteritis

Answer 27

* 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

Question 28

Parasite causes of gastroenteritis

Answer 28

* Cryptosporidium * Entamoeba histolytica * Giardia intestinalis * Schistosoma

Question 29

Cryptosporidium presentation

Answer 29

* Self limiting watery diarrhoea and abdominal cramps * Diagnosis made by stool culture for ova, cysts and parasites

Question 30

Entamoeba histolytica

Answer 30

* 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

Question 31

Giardia intestinalis

Answer 31

* 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

Question 32

Schistosoma presentation

Answer 32

* 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

Question 33

Hospital acquied gastroenteritis - main pathogens

Answer 33

* 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

Question 34

What do the c.diff exotoxins do to the bowel?

Answer 34

* 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

Question 35

Investigations for ?c.diff

Answer 35

* Stool culture * C.difficile toxin testing (CDT)

Question 36

Non-infective causes of gastroenteritis

Answer 36

* 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