Large Bowel

Question 1

pathophysiology of appendicitis

Answer 1

typically caused by luminal obstruction via a faecolith, impacted stool and rarely an appendiceal/caecal tumour

lumen is blocked, commensal bacteria colonise and cause acute inflammation, this results in swelling of the appendix

this swelling interrupts venous and lymph drainage and increases the pressure which eventually can turn into ischaemia

ischaemia can then become necrosis of the appendiceal wall and then finally perforation

Question 2

risk factors for appendicitis

Answer 2

genetic factors - 30% of risk

ethnicity - more common in caucasians

Question 3

describe the pain in appendicitis

Answer 3

pain initially starts peri-umbilical and is dull and poorly localised - this is due to inflammation of the visceral peritoneum

the pain then progresses to become sharp and well localised in the RIF region - this is due to inflammation of the parietal peritoneum

Question 4

clinical features of appendicitis

Answer 4

pain - initially peri-umbilical but then progression to RIF region

nausea and vomiting

rebound tenderness, percussion pain and guarding

+ve Rovsing and Psoas sign

Question 5

what is Rovsing and Psoas sign - and what do they indicate

Answer 5

Rovsing = pain in RIF when palpating the LIF

Psoas sign = pain on extension of the right hip (inflamed appendix abutting the psoas muscle in the retrocaecal position)

indicate appendicitis

Question 6

investigations into suspected acute appendicitis

Answer 6

urinalysis - exclude renal or urological cause

pregnancy test - exclude pregnancy in women of reproductive age

routine bloods - especially CRP and other inflammatory markers

Question 7

imaging into suspected appendicitis

Answer 7

clinical diagnosis mainly but USS and CT can be used

with USS being first line - minimal radiation exposure

Question 8

management of appendicitis

Answer 8

mainstay of treatment is via laparoscopic appendectomy

Question 9

what is the most common type of colorectal cancer

Answer 9

adenocarcinoma

Question 10

risk factors for colorectal cancer

Answer 10

increasing age

family history - strong genetic component especially in the instance of FAP

IBD

low fibre, high fat intake diet

smoking and excess alcohol intake

Question 11

what are the common clinical features of colorectal cancer

Answer 11

change in bowel habit

weight loss

abdominal pain

rectal bleeding

symptoms of iron deficiency anaemia

Question 12

how do the presenting sings change in left colorectal vs right sided colorectal cancer

Answer 12

left sided = present earlier, tenesmus, rectal bleeding, change in bowel habit, palpable mass in the LIF.

right sided = present late, abdo pain, iron deficiency anaemia, palpable mass in RIF (present late as it takes longer for bowel changes to occur - further away from rectum)

Question 13

what tumour marker is linked with colorectal cancer

Answer 13

Carcinoembryonic antigen

Question 14

Lab tests and imaging in suspected colorectal cancer

Answer 14

FBC - routine and check for anaemia

CEA - tumour marker

gold standard imaging = colonoscopy with biopsy

CT + MRI - check invasion and mets

Question 15

what is the gold standard imaging technique for a suspected colorectal cancer

Answer 15

colonoscopy with biopsy

Question 16

management of colorectal cancers

Answer 16

only definitive treatment is via surgery

chemo and radiotherapy are used as adjuvant therapy

Question 17

what types of surgery are there for colorectal cancers

Answer 17

right sided hemicolectomy - caecal or ascending colon tumours

left hemicolectomy - descending colon tumours

sigmoidcolectomy - sigmoid colon tumours

Hartmann’s procedure - complete resection of the recto-sigmoid colon

Question 18

what is a diverticulum and where are they most commonly found

Answer 18

its an outpouching of the bowel wall

most commonly found in the sigmoid colon

Question 19

describe diverticulosis vs diverticular disease vs diverticulitis vs diverticular bleed

Answer 19

diverticulosis = presence of diverticula (asymptomatic)

diverticular disease = symptoms arising from the diverticula

diverticulitis = inflammation of the diverticula

diverticula bleed = where the diverticula erodes into a vessel and causes a large volume painless bleed

Question 20

pathophysiology of diverticulosis

Answer 20

aging bowel is already weakened

movement of stool in the lumen causes in increase in luminal pressure

this results in outpouchings of the mucosa in the weaker areas of the bowel wall

diverticulitis then occurs when bacteria overgrow within the outpouchings resulting in inflammation

Question 21

risk factors for diverticulosis

Answer 21

age

low dietary fibre

obesity

smoking

family history

NSAID use

Question 22

clinical features of acute diverticulitis

Answer 22

acute abdo pain

sharp in nature and localised to the LIF

localised tenderness

decreased appetite, pyrexia and nausea

Question 23

imaging of choice in suspected diverticulitis

Answer 23

CT abdo pelvis

Question 24

why should a colonoscopy never be performed on a patient with suspected acute diverticulitis

Answer 24

increased risk of perforation

Question 25

management of diverticulum and associated conditions

Answer 25

mostly conservative; analgesia, abx, IV fluids, increased fluid intake surgical; only in cases of perforation or sepsis - usually involves a Hartmann's procedure

Question 26

what are some complications of diverticulitis

Answer 26

stricture formation and fistula formation; colovesical fistula - bowel and bladder colovaginal fistula - bowel and vagina

Question 27

what is the microscopic appearance of Crohn's disease

Answer 27

non-caseating granulomatous inflammation

Question 28

what is the difference in inflammation depth between UC and Crohn's

Answer 28

UC = mucosal inflammation only Crohn's = transmural inflammation

Question 29

what is the difference in location between UC and Crohn's

Answer 29

Crohn's = affects anywhere in the GI tract, mouth to anus UC = large bowel only

Question 30

what are the characteristic macroscopic changes seen in Crohn's

Answer 30

fistula formation cobblestone appearance (fissures and deep ulcers) skip lesions

Question 31

what are the characteristic features of UC

Answer 31

continuous inflammation - no skip lesions crypt abscesses

Question 32

clinical features of crohn's

Answer 32

episodic abdo pain - colicky in nature chronic diarrhoea - mucus and blood general malaise oral aphthous ulcers and perianal disease (if entire GI tract is affected)

Question 33

extra-intestinal features of crohn's disease

Answer 33

MSK - arthritis, nail clubbing, bone disease skin - erythema nodosum, pyoderma gangrenosum eyes - iritis, uveitis HPB - gallstones renal - renal stones

Question 34

investigations into suspected Crohn's disease

Answer 34

routine bloods faecal calprotectin stool culture - infective cause gold standard = colonoscopy + biopsy

Question 35

what is the gold standard investigation into supsected Crohn's

Answer 35

colonoscopy + biopsy

Question 36

management of Crohn's

Answer 36

inducing remission = corticosteroid and immunosuppression therapy maintaining remission = azathioprine + smoking cessation surgical = usually some sort of resection

Question 37

what histological changes are seen in ulcerative colitis

Answer 37

non-granulomatous inflammation crypt abscesses reduced goblet cells (goblet cell hypoplasia)

Question 38

clinical features of ulcerative colitis

Answer 38

bloody diarrhoea PR bleeding mucus discharge increased frequency and urgency tenesmus

Question 39

extra-intestinal features of UC

Answer 39

MSK - arthritis and nail clubbing skin - erythema nodosum eyes - iritis, uveitis HPB - primary sclerosing cholangitis

Question 40

investigations into UC

Answer 40

routine bloods - baseline + inflammatory markers faecal calprotectin stool sample - infective cause

Question 41

imaging for UC

Answer 41

colonoscopy + biopsy AXR + CT can be used to check for toxic megacolon

Question 42

what causes toxic megacolon

Answer 42

Toxic megacolon occurs when inflammatory bowel diseases cause the colon to expand, dilate, and distend. When this happens, the colon is unable to remove gas or feces from the body. If gas and feces build up in the colon, your large intestine may eventually rupture.

Question 43

what is a characteristic radiological sign of chronic UC

Answer 43

lead pipe colon

Question 44

what is the main complication to be worried about in UC

Answer 44

toxic megacolon

Question 45

what drugs are used to treat UC

Answer 45

corticosteroid, immunosuppressors, biological agents = induce remission (5-ASAs) mesalazine, sulfasalazine or azathioprine = maintain remission

Question 46

what is rigler's sign and what does it suggest

Answer 46

bowel wall visualised on both sides due to intra and extraluminal air air in the peritoneum characteristic of bowel perforation

Question 47

what radiological sign do you expect to see in bowel perforation

Answer 47

riglers sign

Question 48

what is pseudo-obstruction of the bowel

Answer 48

dilatation of the colon due to an adynamic bowel, in the absence of mechanical obstruction

Question 49

pathophysiology of pseudo-obstruction

Answer 49

interruption of the autonomous nervous supply to the colon resulting in the absence of smooth muscle contraction in the bowel wall

Question 50

causes of pseudo-obstruction

Answer 50

electrolyte imbalance medication; opioids, CCBs, anti-depressants recent surgery, illness, trauma neurological disease; parkinson's, multiple sclerosis

Question 51

clinical features of pseudo-obstruction

Answer 51

``` same as bowel obstruction; abdo pain vomiting constipation abdo distension ```

Question 52

investigations into suspected pseudo-obstruction

Answer 52

blood tests - biochemical causes AXR CT abdo-pelvis with IV contrast

Question 53

management of pseudo obstruction

Answer 53

endoscopic decompression and selective use of neostigmine (acetylcholinesterase inhibitor) or surgical resection - for those failing medical management

Question 54

what drug classes are associated with pseudo-obstruction

Answer 54

anti-depressants CCBs opioids

Question 55

what is a volvulus

Answer 55

twisting loop of intestine around its mesenteric attachment, resulting in a closed loop bowel obstruction

Question 56

where is the most common place a volvulus occurs

Answer 56

sigmoid colon

Question 57

risk factors for volvulus

Answer 57

increasing age chronic constipation or laxative use male gender previous abdo surgeries

Question 58

what are the noteworthy clinical features of a sigmoid volvulus

Answer 58

degree of abdo distension rapidity of onset

Question 59

what are the characteristic radiological signs of sigmoid volvulus

Answer 59

whirl sign on CT coffee bean sign arising from LIF on AXR

Question 60

management of volvulus

Answer 60

decompression by sigmoidoscope via rectum surgery in cases of perforation, failed decompression and necrotic bowel

Question 61

what is the 2nd most common place of volvulus

Answer 61

caecal volvulus

Question 62

how can you tell the difference on AXR between caecal and sigmoid volvulus

Answer 62

sigmoid starts from LIF caecal starts from RIF