Lower GI disease

Question 1

What is the function of the lower GI tract?

Answer 1

Comprised of large intestine and rectum - most of the digestion and absorption already done. Daily absorbs water and electrolytes to form solid stools

Question 2

What are the classification of pathologies of the lower GI tract?

Answer 2

Inflammation, cancer and infection

Question 3

What is an acute appendicitis?

Answer 3

Sudden onset inflammation of appendix. Obstruction of appendices lumen by tumour, worms etc. causing increased pressure and bacterial invasion. Pain begins in umbilical region of abdomen, migrates to right lower abdomen. Causes localised peritonitis. Treatment: surgery and/or antibiotics

Question 4

What is visceral pain?

Answer 4

An example of referred pain. The pain is felt in a different location from where the pathology is

Question 5

What is parietal pain?

Answer 5

Pain of the skin, linings of the abdominal or thoracic cavities. More localised than visceral pain

Question 6

What is peritonitis?

Answer 6

Inflammation of the peritoneum (the lining of the abdominal cavity and lining of the organs within this cavity). In appendicitis, the inflamed appendix comes into contact with the abdominal wall, causing localised peritonitis.

Question 7

What is antibiotic-associated colitis/pseudomembranous colitis?

Answer 7

Acute inflammation of the colon, characterised by the formation of inflammatory pseudomembranes over the site of mucosal injury. Fever and lower abdominal tenderness. Classically caused by toxins produced by C.diff after broad-spectrum antibiotics. Treatment: stop current antibiotics, hydration and specific antibacterial therapy.

Question 8

What is inflammatory bowel disease?

Answer 8

Chronic inflammatory conditions of unknown aetiology affecting the GI tract. 2 forms of idiopathic IBD: 1) Crohn’s disease, 2) Ulcerative Colitis

Question 9

What is Crohn’s disease?

Answer 9

Skip (not continuous) lesions can occur from mouth to anus. Particularly in terminal ileum (30%), colon alone (20%) and ileum and colon (50%). Non-caseating epitheloid granulomas, can have fistula formation. Complications: anaemia, malabsorption (fat, vitamins A, D, E and K, bile salts), fistulas, extra-intestinal (skin, eyes, joints), increased risk of bowel carcinoma, bowel obstruction and perforation.

Question 10

What is Ulcerative Colitis?

Answer 10

Starts in rectum, occurs in colon only (may involve appendix), continuous (no skip lesions), mucosal disease. Complications: anaemia (iron deficiency from blood loss), electrolyte loss from diarrhoea, extra-intestinal disease (skin, eyes, joints, bile ducts), increased risk of carcinoma (related to duration and severity of disease), need to survey dysplasia.

Question 11

What diseases can mimic IBD?

Answer 11

Ischaemic colitis, radiation colitis, Behcet’s diseases, Pouchitis, diversion colitis, microscopic colitis, infectious colitis, iatrogenic colitis.

Question 12

What neoplasias can arise in the lower GI tract?

Answer 12

• Benign polyps

- Malignant adenocarcinoma (cancer)

Question 13

What is colorectal carcinoma?

Answer 13

Causes:
-Genetic
-Chronic inflammation (IBD)
-Dietary factors? - low fibre, bile aerobes, red meat, lack of vitamins and antioxidants
Symptoms: depends on site of lesions, altered bowel habits, blood PR, iron deficiency anaemia, weight loss. Can be 1) Ulcerating or 2) Polypoid/fungating