GI disease

Question 1

Describe normal histology of the oesophagus

Answer 1

Squamous epithelium (proximal 2/3) and columnar epithelium (distal 1/3), joined by the squamo-columnar junction/ Z-line

Question 2

Characteristics of reflux oesophagitis

Answer 2

GORD
Commonest cause of oesophagitis
Complications: ulceration, haemorrhage, haematemesis/melaena,
Barrett’s oesophagus, stricture, perforation
Los Angeles Classification
Tx: lifestyle changes (stop smoking, weight loss), PPI/H2 receptor
antagonists

Question 3

Characteristics of Barrett’s oesophagus

Answer 3

Intestinal metaplasia of squamous mucosa to columnar epithelium (have goblet cells) following chronic GORD; upwards migration of the SCJ
Seen in 10% of those with symptomatic GORD
Can lead to adenocarcinoma: metaplasia → dysplasia → Ca

Question 4

Characteristics of oesophageal adenocarcinoma

Answer 4

Associated with Barrett’s oesophagus so usually seen in distal 1/3
Other risk factors incl: smoking, obesity, prior radiation therapy
Most common in Caucasians, M»F

Question 5

Characteristics of Squamous cell

oesophageal carcinoma

Answer 5

Associated with ETOH and smoking
Other risk factors incl: achalasia of cardia, Plummer-Vinson syndrome,
nutritional deficiencies, nitrosamines, HPV (in high prevalence areas)
6x more common in Afro-Carribeans, M>F
Usually found in middle 1/3 (50%). Upper 1/3 – 20%, Lower 1/3 – 30%
Presentation: progressive dysphagia (solids then fluids), odynophagia
(pain), anorexia, severe weight loss
Rapid growth and early spread (to LNs, liver and directly to proximal structures); palliative care

Question 6

Characteristics of varices

Answer 6

Engorged dilated veins, usually due to portal HTN (back pressure)
Pt vomits units of blood
Emergency endoscopy -> sclerotherapy/banding

Question 7

Describe normal histology of the stomach

Answer 7

Lined by gastric mucosa, columnar epithelium (mucin secreting) and glands.

Question 8

Characteristics of gastritis

Answer 8

Acute (neutrophils) insult e.g. aspirin, NSAIDs, corrosives (bleach), acute H. pylori, severe stress (burns)
Chronic (lymphocytes and plasma cells) insult e.g. H-pylori tends to be Antral, AI e.g. pernicious anaemia, ETOH, smoking
Special types – Chemical (foveolar hyperplasia, chronic inflammation), Infection (CMV, HSV, strongyloides), Inflammatory Bowel Disease
Complications: Chronic gastritis may lead to gastric ulcer formation
It may also however result in intestinal metaplasia→ dysplasia →cancer

Question 9

Characteristics of gastric ulcer

Answer 9

Breach through muscularis mucosa into submucosa.
Epigastric pain +/- weight loss
Worse with food (contrast with duodenal ulcer), relieved by antacids
RFs: H. pylori, smoking, NSAIDs, stress, delayed gastric emptying. Occurs mainly in elderly
Ix: Biopsy for H. pylori histology status. Punched out lesion with rolled margins.
Complications: anaemia (IDA) and perforation (erect CXR), malignancy

Question 10

Characteristics of gastric lymphoma

Answer 10

Caused by H-pylori – chronic antigen stimulation

Rx: remove cause (H. pylori using triple therapy – PPI, Clarithromycin + Amox or Metro

Question 11

Characteristics of duodenal ulcer

Answer 11

4 times more common than GU
Epigastric pain, worse at night
Relieved by food and milk
Occurs in younger adults
RFs: H. pylori, drugs, aspirin, NSAIDs, steroids, smoking, ↑ drugs, acid secretion
Complications: anaemia (IDA) and perforation (erect CXR)

Question 12

Characteristics of coeliac disease

Answer 12

T cell mediated autoimmune disease ( DQ2, DQ8 HLA status)
Gluten intolerance results in villous atrophy and malabsorption
Presentation: young children (paeds) and Irish women (EMQs)
Symptoms (of malabsorption): steatorrhoea, abdo pain, bloating, n&v, ↓wt, fatigue, IDA, failure to thrive, rash (dermatitis herpetiformis)
Serological tests: Anti-endomysial ab (best sen and spec) , anti-tissue
transglutaminase (IgA), anti-gliadin (poor marker of disease control)
Gold standard Ix: upper GI endoscopy and duodenal biopsy (villous atrophy, crypt hyperplasia, lymphocyte infiltrate)
Rx: Gluten free diet
Around 10% progress to Duodenal T-cell lymphoma if not treated adequately

Question 13

List some congenital GI diseases

Answer 13

● Atresia
● Stenosis
● Duplication
● Imperforate anus 
● Hirschsprung’s disease – Absence of ganglion cells in myenteric plexus (80% males)

Question 14

Categories of acquired GI disease

Answer 14

Mechanical
Inflammatory
Ischaemic

Question 15

List some mechanical GI diseases

Answer 15

● Obstruction – caused by:
o Constipation!
o Diverticular disease = v. common
o Adhesions
o Herniation
o External mass (e.g. fetus, aneurysm, foreign body)
o Volvulus – complete twisting of bowel loop at mesenteric base around vascular pedicle,
small bowel (infants), sigmoid > caecal (elderly)
o Intussusception

Question 16

List some inflammatory causes of GI disease

Answer 16

● Acute colitis – caused by:
o Infection (bacterial, viral, protozoal etc.) à diarrhoea v. common.
o Drug/toxin (esp. abx)
o Chemo/radiotherapy
● Chronic colitis – caused by:
o IBD: Crohn’s disease and ulcerative colitis
o TB

Question 17

Features of ischaemic GI disease

Answer 17

● Ischaemic colitis – arterial or venous occlusion, small vessel disease, low flow states,
obstruction
● Commonly in ‘Watershed areas’ eg: splenic flexure (SMA transition to IMA), rectosigmoid (IMA
transition to internal iliac).

Question 18

Pathophysiology of Crohn’s

Answer 18

− Affects whole GI tract (mouth to 
anus), most common in terminal 
ileum and caecum.
− Patchy distribution: ‘skip 
lesions’. Areas of healthy mucosa lie above diseased mucosa -> ‘cobblestone 
appearance’
− First lesion =’aphthous ulcer’. 
These are deep ‘rosethorn 
ulcers.’ Can join together to form 
serpentine ulcers.
− Non-caseating granulomas
seen
− Transmural inflammation 
− Fistula/fissure formation common

Question 19

Pathophysiology of Ulcerative colitis

Answer 19

− Extends proximally from 
rectum
− Continuous 
involvement of mucosa
− Small bowel not 
affected unless v. 
severe pancolitis 
causes ‘backwash 
ileitis’
− Extensive superficial broad 
ulcers 
− Inflammation superficial, 
confined to mucosa
− No granulomas/ fissures/ 
fistulae /strictures.
− Islands of regenerating 
mucosa bulge into lumen ->
pseudopolyps (can fuse to 
form mucosal bridges)

Question 20

Extra-GI manifestations of IBD

Answer 20

− Malabsorption & Fe def. Anaemia à stomatitis
− Eyes: uveitis (iris & ciliary body), conjunctivitis
− Skin: erythema nodosum (tender bruise-like swellings on shins),
pyoderma gangrenosum, erythema multiforme, digitial clubbing
− Joints: migratory asymmetrical polyarthropathy of large joints (15%),
sacroiliitis, myositis, ankylosing spondylitis
− Liver: pericholangitis, primary sclerosing cholangitis (UC>CD),
steatosis

Question 21

Complications of Crohn’s

Answer 21

− Strictures (requiring bowel 
resection, often recurrent
− Fistulae
− Abscess formation
− Perforation

Question 22

Complications of UC

Answer 22

− Severe haemorrhage
− Toxic megacolon -> perforation 
(damage to muscularis propria 
w/disruption of neuromuscular 
function à colonic dilatation)
− 30% require colectomy within 
3yrs for uncontrollable 
symptoms
− Adenocarcinoma (20-30x risk)

Question 23

Investigations for Crohn’s vs UC

Answer 23

Crohn’s
Systemic markers of inflammation
e.g. ESR, CRP, Barium contrast,
Endoscopy

UC
Rectal biopsy, flexible
sig/colonoscopy, AXR, stool culture

Question 24

Features of diverticular disease

Answer 24

High incidence in West probably due to low fibre diet. High intraluminal pressure results in
outpouchings at ‘weak points’ in wall of bowel (seen on barium enema CT or endoscopy). 90%
occur in left colon
Often asymptomatic, sometimes PR bleed
Complications: Diverticulitis: fever and peritonism; gross perforation, fistula,
obstruction (due to fibrosis)

Question 25

Features of carcinoid syndrome

Answer 25

• Diverse group of tumours of enterochromaffin cell origin, Produce 5-HT (serotonin) • Commonly found in the bowel (but also lung, ovaries, testes) • Usually slow growing Investigation: 24hr urine 5-HIAA (main metabolite of serotonin) Treatment: Octreotide (somatostatin analogue)

Question 26

Clinical findings of carcinoid syndrome and carcinoid crisis

Answer 26

Syndrome Bronchoconstriction, flushing, diarrhoea Crisis Life threatening vasodilatation, Hypotension, Tachycardia, Bronchoconstriction, Hyperglycaemia

Question 27

Characteristics of colon adenomas

Answer 27

- Benign dysplastic lesions that are the precursor lesion to most adenocarcinomas (although most remain benign) − Found in 50% >50yrs in Western world − Mostly asymptomatic so need regular surveillance if over 3.4cm 45% malignant change . − Classified based on architecture as tubular, tubulovillous or villous. − Villous adenoma (rare) à hypoproteinaemic hypokalaemia because they leak large amounts of protein and K. − Large size is most important risk factor for malignancy, in addition to degree of dysplasia and increased villous component. − Adenoma -> carcinoma progression ‘classical chromosomal instability sequence’ o Normal colon: at risk mucosa after “first hit” mutation in 1st copy of APC gene (those with FAP born with this mutation) o At risk: adenoma after “second hit” mutation to remaining APC gene o Progression to carcinoma follows activation of KRAS, LOF mutations of p53

Question 28

Give examples of non-neoplastic polpys and their characteristics

Answer 28

Hamartomous polyp Found sporadically in some genetic/acquired syndromes Juvenile polyps are focal malformations of mucosa and lamina propria, vast majority in those <5yrs old, mostly in rectum à bleeding. Usually solitary, but up to 100 found in juvenile polyposis (AD) that may require colectomy to stop haemorrhage. Also seen in Peutz-Jeghers syndrome (AD - LKB1) = multiple polyps, mucocutaneous hyperpigmentation, freckles around mouth, palms and soles. Have increased risk of intussusception and of malignancy à regular surveillance of GI tract, pelvis and gonads. Hyperplastic polyp een at 50-60yrs, thought to be caused by shedding of epithelium -> cell buildup Inflammatory Pseudo-polyps e.g. IBD

Question 29

Epidemiology of colorectal cancer

Answer 29

2nd commonest cause of cancer deaths in UK. Age 60-79 yrs If found <50yrs consider familial syndrome. Commoner in western population 98% are adenocarcinoma, 45% in rectum

Question 30

Aetiology, clinical features, investigations for colorectal cancer

Answer 30

Diet (↓fibre, ↑fat), Lack of exercise, Obesity, Familial syndromes, chronic IBD, NSAIDS protective (COX2 over-expressed in 90%) Right sided tumours: Fe def. anaemia, weight loss Left sided tumours: change in bowel habit, crampy LLQ pain Proctoscopy, sigmoidoscopy, colonoscopy, barium enema, bloods e.g. FBC, CT/MRI Carcinoembryonic antigen (CEA) – monitor disease

Question 31

Classification of colorecatal cancer

Answer 31

Duke’s Staging- helps determine Rx: (TNM staging also used) A: confined to mucosa (5yr survival >95%) B1: extending into muscularis propria (5yr survival 67%) B2: transmural invasion, no lymph nodes involved (5yr survival 54%) C1: extending to muscularis propria, with LN metastases (5yr survival 43%) C2: transmural invasion, with lymph node metastases (5yr survival 23%) D: distant metastases (5yr survival <10%)

Question 32

Familial syndromes in colorectal cancer

Answer 32

Familial adenomatous polyposis (FAP) − 70% AD mutation in APC gene (C5q1), 30% AR mutation in DNA mismatch repair genes − Present 10-15yrs - >100 adenomatous polyps required for diagnosis, usually 100-1000s seen. ALL will à adenocarcinoma if left untreated by 30yrs therefore most have prophylactic colectomy. − Increased risk of neoplasia elsewhere, eg: ampulla of Vater and stomach − At birth, hypertrophy of retinal pigment epithelium Gardners – like FAP with extra intestinal features eg: osteoma’s, dental caries Hereditary non-polyposis colorectal cancer/Lynch syndrome (HNPCC) − AD mutations in DNA mismatch repair genes − Carcinomas usually in right colon, few polyps but fast progression to malignancy therefore present usually <50yrs − Associated with endometrial, ovarian, small bowel, transitional cell and stomach carcinoma.