Pathology of the Gastrointestinal Tract - Stomach, SI and LI

Question 1

what is peptic ulcer disease (PUD)?

Answer 1

a number of diseases that involve ulceration of the gastric mucosa caused by the affects of gastric acid, the lining of the stomach becomes ulcerated causing damage to the rugae

Question 2

why is PUD comparatively rare in western countries?

Answer 2

because helicobacter pylori was identified as a common causative agent and the so powerful anti-acid meds were developed

Question 3

what are the most common manifestation of PUD?

Answer 3

Duodenal ulcers - virtually always benign, 95% occur in the duodenal bulb

Question 4

which are less common manifestations of PUD?

Answer 4

gastric ulcers but up to 5% are malignant

Question 5

how can PUD also be caused/worsened ?

Answer 5

drugs such as aspirin or NSAIDs (e.g. Ibuprofen), corticosteroids, severe physiological stress/illness

Question 6

what is the appearance of an ulcer?

Answer 6

classic erosive concave crater located in the stomach

Question 7

where are convex polyp-type appearances found?

what do they resemble?

Answer 7

pylorus/duodenum
a tumour - abnormal growths of the gastric tissue and don’t have the breakdown of the mucosa so exhibit less symptoms but can become pathogenic growths

Question 8

what is the main investigation for suspected peptic ulceration?
in an acute setting?

Answer 8

barium studies were but endoscopy has replaced the barium meal
CT for assessing patients with acute abdominal pain

Question 9

where are ulcers 4x more likely to appear

Answer 9

duodenum

Question 10

what are ulcers usually due to?

Answer 10

the breakdown of the mucosa due to the caustic effects of the acidic environment caused by action of pepsin

Question 11

what is gastric adenocarcinoma? - 3 points

Answer 11

the most common gastric malignancy
over 95% of tumours in the stomach
tend to be found in the pyloric area, the lesser curvature and the cardia of the stomach

Question 12

what are the symptoms of gastric adenocarcinoma? - 6 points

Answer 12

often no specific symptoms but up to 50% of patients do experience non-specific gastro-intestinal complaints such as dyspepsia (indigestion)
may also present with weight loss, abdominal pain (can be vague in nature), nausea, vomiting

Question 13

which is the most sensitive and diagnostic method for investigating gastric adenocarcinoma and why

Answer 13

endoscopy because it allows direct visualisation of the tumour location, extent of mucosal involvement and biopsy can be undertaken

Question 14

what other 2 examinations can be used to investigate gastric adenocarcinoma and why

Answer 14

fluoroscopic guided barium meal to detect irregular filling defects and large craters in the stomach wall
CT to assess local spread and detect nodal involvement and distant metastases

Question 15

what is Intussusception

Answer 15

the most common cause of bowel obstruction in children aged 3 months - 6 years
the inversion of one portion of the intestine within another

Question 16

what is Crohn’s disease

Answer 16

an idiopathic inflammatory bowel disease (IBD) which has widespread GIT involvement but often occurs in the terminal ileum, diagnosed typically between 15-25 years old

Question 17

how do patients present with crohn’s disease

Answer 17

chronic diarrhoea and recurrent abdominal pain

can be other extra-intestinal manifestations as well

Question 18

how does crohn’s disease progress?

Answer 18

initially the disease is limited to the mucosa but as it progresses the entire bowel wall is involved with ulcerations extending deep into the bowel wall itself , predisposing it to fistulae (abnormal tube between organ and body surface)
inflammation also extends into the mesentery (fold of peritoneum that attaches organs to posterior wall of abdomen) and can lead to chronic fibrotic changes and strictures

Question 19

what is affected by crohn’s disease

Answer 19

small bowel - 70-80%
small and large bowel can both be involved - 50%
large bowel - 15-20%

Question 20

what exams are used to investigate ?crohn’s disease and why

Answer 20

small bowel follow through exam can identify mucosal ulcers - if severe = ‘cobblestone’ appearance and may lead to fistulae, the bowel loops can appear widely separated (due to fatty proliferation) and have thickened folds due to oedema = ‘string sign’
CT using both IV and intraluminal contrast (+ve and -ve) and is able to give valuable information on extra-intestinal findings

Question 21

what is the treatment for crohn’s disease

Answer 21

wherever possible with medication, surgery is only performed if complications require it

Question 22

what is Meckel diverticulum?

Answer 22

congenital diverticulum that occurs at the terminal ileum, tends to be the most common structural congenital anomaly of the GIT, it is a remnant of the connection from the yolk-sac to the SI present during embryonic development

Question 23

why is Meckel’s diverticulum a true diverticulum?

Answer 23

as it has all layers of the GIT present in its wall

Question 24

what are the symptoms for Meckel’s diverticulum?

Answer 24

pain, malaena (result of internal bleeding), SBO, volvulus (obstruction due to twisting of stomach), perforation

a meckel’s diverticulum can become inflamed, ulcerate, bleed, perforate or cause obstruction of the small bowel - if inflamed or perforated = surgery

Question 25

how are meckel's diverticulum usually found?

Answer 25

incidentally via imaging or identified if there is a complication

Question 26

how is diverticular disease caused?

Answer 26

by a weakness in the colonic musculature which allows areas of the mucosa to herniate through the wall of the bowel

Question 27

where does diverticular disease most commonly occur? - 2 points what size are the diverticula?

Answer 27

more frequently over the age of 50 in the sigmoid colon but can present throughout the bowel can range from a few mm to a few cm

Question 28

what exam is used for diverticular disease and how would it appear

Answer 28

double contrast barium enema round or oval outpouchings of barium projecting beyond the confines of the lumen, tend to be multiple and occur in clusters although a solitary diverticulum is occasionally found

Question 29

what occurs when a divertiulum is 'en face'

Answer 29

appears similar to a polyp but can be distinguished by the presence of pooling of contrast within the diverticulum

Question 30

what other modality can be used to investigate diverticular disease and how do they appear

Answer 30

CT | diverticulum - outlined with gas, the colon may be thickened and on CTVC demonstrated as complete delineating rings

Question 31

what is diverticulitis - 2 points

Answer 31

a complication of diverticular disease leading to the development of a peridiverticular abscess retained faecal matter trapped in a diverticulum causing inflammation of the mucosal lining leading to perforation

Question 32

what is a common complication of diverticulitis

Answer 32

the development of fistulas to adjacent organs (bladder, vagina, ureter, small bowel)

Question 33

what are the symptoms and treatment of diverticular disease what is the treatment for diverticulitis

Answer 33

asymptomatic and usually no treatment needed non-invasive treatment, using dietary modifications and exercise = first choice Antibiotics surgery usually only if perforation - requiring surgical repair

Question 34

what is ulcerative colitis how is it characterised who is most commonly affected? what is variable?

Answer 34

inflammatory disease affected predominately the colon by ulceration of the lining of the bowel young adults severity, clinical course, prognosis

Question 35

what is the cause of ulcerative colitis and what is can aggravate it

Answer 35

unknown but autoimmune has been suggested stress

Question 36

what are the main symptoms for ulcerative colitis - 5 points what is a characteristic feature?

Answer 36

``` chronic diarrhoea (usually bloody) tenesmus (need to pass but no/little passing) abdominal pain fever weight loss ``` alternating periods of remission and relapse

Question 37

what does ulcerative colitis usually involve? what do plain x-ray images demonstrate?

Answer 37

only the mucosal layer of the colon evidence of toxic megacolon (extreme dilatation of a segment of colon with systemic toxicity) - ominous complication that can lead to spontaneous perforation of the colon

Question 38

what other exam can be performed and what would be seen - 3 points how is it contraindicated

Answer 38

double contrast barium enema detail of the colonic mucosa to be visualised, mucosal inflammation gives a granular appearance to the surface of the bowel and as inflammation increases the bowel wall and haustra thicken during a recognised attack of toxic megacolon due to the risk of perforation

Question 39

what occurs in chronic cases of ulcerative colitis

Answer 39

the bowel becomes featureless with loss of normal haustral markings, luminal narrowing, bowel shortening - 'lead or stove pipe' sign

Question 40

what is a polyp where can they develop

Answer 40

an abnormal growth of tissue projecting from a mucous membrane benign growth of the lining of the colon can grow in the stomach and nose but often found in the bowel growing in the lumen

Question 41

how may patients present with a polyp - 5 points what usually happens to polyps what is the likelihood of cancer with polyps

Answer 41

severe stomach pain, watery diarrhoea, rectal bleeding, pain, constipation - often no symptoms and an incidental finding usually removed as specific times may be pre-cancerous less than 1cm are not usually malignant, multiple polyps are thought to increase the likelihood of malignancy

Question 42

what are the size of polyps? what is the type of cell involved with polyps?

Answer 42

2mm up to 5cm or more in diameter the type of cell varies and is important for determining whether it will turn into cancer

Question 43

describe malignant polyps

Answer 43

tend to be sessile lesions (without stalks) unlike benign polyps which are usually smooth with a stalk (penduculated)

Question 44

what is the examination of choice for polyp and why

Answer 44

colonoscopy is first diagnostic tool with CT colonography as alternative imaging for diagnosis of bowel cancer

Question 45

what is colorectal carcinoma who does it affect most? what are the predisposing factors? - 4 points

Answer 45

most common cancer of the GIT and 2nd most frequently diagnosed malignancy in adults (98% = adenocarcinomas) between 60-80 yrs (slightly younger for rectal carcinoma) low fibre & high fat diet obesity IBD (ulcerative colitis/crohn's) family history

Question 46

what is the prognosis for CRC and what can affect the prognosis? where is there evidence that many carcinomas arise from?

Answer 46

curable if discovered early and therefore if there is a delay in diagnosis then this is a significant factor of a poor prognosis pre-existing polyps

Question 47

what are common clinical indications for CRC? where can these carcinomas usually be found?

Answer 47

``` altered bowel habit iron deficiency anaemia (from chronic occult blood loss) bowel obstruction heavy bleeding metastatic disease ``` anyway from caecum to rectum (recto-sigmoid = most common - 55%

Question 48

what is the imaging method of choice for CRC?

Answer 48

was double contrast barium enema but now it is CT colonography because less false negatives

Question 49

why was DCBE used for CRC?

Answer 49

filling defects were demonstrated which typically appear as sessile masses or may be annular carcinoma ('apple core' deformity)

Question 50

why is CT used for CRC?

Answer 50

used to stage the process of the disease and assess recurrence

Question 51

why are PET scans used for CRC?

Answer 51

usng 18-fluoro-deoxyglucose (FDG) there is a high accuracy for detecting distant nodular metastases and recurrence

Question 52

what is the treatment for CRC?

Answer 52

resection in almost all cases with post-op chemotherapy or radiotherapy