Infections and Infestations of the GI tract Flashcards
What is diarrhoea?
Defined as 3 or more loose stools in a day
What are some conditions that cause diarrhoea?
- Gastroenteritis
- Diverticulitis
- Irritable bowel syndrome
- Inflammatory Bowel Disease
- Colorectal cancer
- Coeliac disease
What are some non-infectious causes of diarrhoea?
=> Drugs
- Laxatives
- Magnesium
- Antacids
=> Endocrine
- Thyrotoxicosis
- Appendicitis
- Diabetes
- Zollinger-Ellison syndrome
=> Pancreatic
- Chronic pancreatitis
What is Gastroenteritis?
Inflammation of the GI tract
Can occur whilst at home or abroad (travellers diarrhoea)
What is the most common cause of Gastroenteritis?
E.Coli
What are the other infectious causes of gastroenteritis?
=> E. Coli:
- Most common
- Watery stools
- Abdominal cramps and nausea
=> Giardiasis:
- Prolonged non bloody diarrhoea
=> Cholera:
- Profuse watery diarrhoea
- Severe dehydration and weight loss
=> Shigella:
- Bloody diarrhoea
- Vomiting
- Abdominal pain
=> Staph Aureus:
- Severe vomiting
- Short incubation period
=> Campylobacter:
- Flu like prodome
- Diarrhoea which may be bloody
- Abdominal pain and fever
=> Bacillus cereus:
- Either vomiting within 6 hours usually due to reheating rice
- Or diarrhoea after 6 hours
- Type A = reheating rice
- Type B = meat/dried beans
=> Amoebiasis:
- Gradual onset
- Bloody diarrhoea
- Abdominal pain and tenderness
How can you determine the infectious cause of gastroenteritis cased on the incubation period?
1-6 hours - Staphlococcus Aureus, Bacillus cereus
12-48 hours - Salmonella, E. Coli
48-72 hours - Shigella, Campylobacter
> 7 days - Giardiasis, Amoebiasis
What is the pathophysiology of Gastroenteritis?
=> Several different mechanisms though which the pathogen can cause infection:
- bacteria can adhere to and efface mucosa, causing watery stools
- bacteria can invade and destroy mucosa, causing bloody diarrhoea
- bacteria release endotoxins that increase fluid secretion from enterocytes, causing secretory diarrhoea
What are the investigations in suspected cases of infectious bacteria?
=> Upper GI endoscopy
=> Stool microscopy and culture
Stool C&S
Stool for toxin identification
Stool O&P
=> Seradiagnosis
=> Abdominal imaging
To exclude bowel perforation
What is the management of diarrhoea?
- Oral rehydration therapy
- Anti-motility agents - Laperamide
- Anti-emetic agents - Metaclopramide
=> Antibiotics are only given in cases of severe diarrhoea. Avoid in cases of E.Coli due to HUS
