LOWER GASTROINTESTINAL PATHOLOGY

Question 1

Ulcerative colitis

Answer 1

5-15 cases per 100,000.
UC more common in urban.
Smoking is protective to ulcerative colitis
Presents with bloody diarrhoea
fulminant colitis –> toxic megacolon = surgical emergency.
Begins in rectum and spreads around to colon.
Colorectal cancer can develop but usually only ever after 8/10 years of disease.

Question 2

Crohns disease- TRANSDURAL and ALL gi tract

Answer 2

5-15 cases per 100,000.
Chrons more common in women
Smoking pre disposes you to crohns disease
chronic relapsing disease.
Diarrhoea, palpable abdominal mass (as can feel thickened abdo wall), weight loss, fever, oral ulcers.
Granuloma are specific to this.
Fistulas can occur. increases risk of carcinoma.

Question 3

Ischaemic bowel disease

Answer 3

colonic injury secondary to an acute, intermittent or chronic reduction in blood flow. 80% are transient.
most commonly affects the right colon. Splenic flexure usually affected cos its a blood supply watershed area so poorly supplied.
Acute onset of cramping abdominal pains, urge to defecate, bloody diarrhoea and rectal bleeding.
Majority of symptoms improve within 48 hours.

Question 4

Diverticular disease

Common in developed ( western ) world

Answer 4

Protrusions of mucosa and submucosa through the bowel wall.
Commonly sigmoid colon.
Congenital or Acquired: more common and made of mucosa and sub mucosa that protrude through the bowel wall.
Age related +60. vegetarians have less risk.
Caused by: Increased intra-luminal pressure due to Irregular uncoordinated peristalsis which generates bubbles where the pressure increases.
90% asymptomatic
25% people get acute complication eg haemorrhage.
10% get chronic obstruction/scarring/fistula

Question 5

Colorectal polyps
(Bigger the adenoma, plaque like flat adenomas and severe high grade dysplasia too = more malignant)

Answer 5

mucosal protrusion, solitary or multiple. Small or large, due to mucosal or submucosal pathology / lesion deeper in the bowel wall.
Hyperplastic polyp is common. 1-5 mm in size, often multiple
Juvenile polyp: commonest type pf polyp in children. Often spherical and pedunculated: 10-30mm. Occur in rectum and distal colon. Sporadic have no malignant potential, although genetic Juvenile polyposis is associated with increased risk of colorectal and gastric cancer
Peutz-Jeghers syndrome: autosomal dominant mutation in STK11 gene chromosome 19. Present clinically in teens with abo pain and bleeding. They have multiple gastro-intestinal polyps.

Question 6

Colorectal cancer

2nd commonest type of cancer in women and 3rd in men.

Answer 6

risk factor = diet, obesity, dietary fibre and lynch syndrome, FAP (100% risk), HRT, oral contraceptives.
Staging = DUKES and TNM.