Pathology of the large bowel

Question 1

What causes variation in the pathology of the large bowel

Answer 1

Age
Culture
Diseases

Question 2

Name the 5 most common diseases of the large bowel

Answer 2

Diverticular Disease 
Ischaemia 
Antibiotic induced colitis
Microscopic colitis 
Radiation colitis

Question 3

Describe the appearance of an endoscopic image of the large bowe in diverticular disease

Answer 3

Lots of little holes and outpouches

Question 4

Why might outpouches appear blue?

Answer 4

They may be filled with blood

Question 5

Why are the holes often arranged in rows?

Answer 5

Due to the muscle layers - there are points of weakness in between the straps of the longitudinal muscle

Question 6

What is the most cause of a benign tumour

Answer 6

Diverticular disease

Question 7

Describe the pathology of diverticular disease

Answer 7

Reduced lumen
Thick muscle band
further small lumina
High presence of inflammatory cells in diverticulitis

Question 8

Describe diverticular disease

Answer 8

Very common
often assymptomiatic
related to low fibre in the diet
increased intralumenal pressure

Question 9

List 5 complications of diverticular disease

Answer 9

Inflammation
Rupture 
Abscess 
Fistula 
Massive bleeding

Question 10

How does the inflammation occur

Answer 10

Outpouches contain static faecal material - microorganisms develop a niche with them and expand in number

Question 11

What could happen if the inflammation goes unchecked

Answer 11

Body forms an abscess - surgical emergency

Question 12

What happens if the abscess goes unchecked

Answer 12

It can rupture, cause sepsis, shock and death

Question 13

How can a patient experience a massive haemorrhage

Answer 13

If the abscess lies next to a blood vessel, the vessel can rupture through perforation

Question 14

Who is most likely to present with ischaemia of the large bowel

Answer 14

Elderly

Question 15

What side is affected in ischemia

Answer 15

Left side - at the splenic flexture and the sigmoid colon

Question 16

What is the most common cause of ischaemia of the large bowel

Answer 16

Atherosclerosis of the abdominal aorta and the mesenteric vessles

Question 17

Describe the histology of Ischaemia of the large bowel

Answer 17

Withering and damage of the crypts and pink smudging of the lamina propria
Fewer chronic inflammatory cells

Question 18

What are the 3 main complications of ischaemic colitis

Answer 18

Massive bleeding
Rupture
Stricture

Question 19

What do small white dots significant of in an endoscopy

Answer 19

pseudomembranes

Question 20

Describe the histology of pseudomembranes

Answer 20

Explosive fibrinopurulent exudate on the surface of the epithelium

Question 21

Describe the stool from a patient with pseudomembranes

Answer 21

Blood filled and loose

Question 22

What causes pseudomembranes

Answer 22

Patients who are on a broad spectrum of Antibiotics - especially in the elderly

Question 23

How do we treat pseudomembranes

Answer 23

Flagyl and Vancomycin

Question 24

What patient would usually present with watery diarrhoea

Answer 24

A female in their 50s or 60s

Question 25

Is there usually rectal bleeding in collagenous colitis

Answer 25

No

Question 26

What category does collagenous colitis fit into

Answer 26

Microscopic colitis

Question 27

How do we treat collagenous colitis

Answer 27

Immunosuppresion

Question 28

What are the histological findings of collagenous colitis

Answer 28

Increase in the thickness of subepithelial collagen
Thickened basement membrane
Disease is patchy

Question 29

Describe the findings in an endoscopy of a patient with microscopic colitis

Answer 29

Nothing - appears normal

Question 30

What is a key question to ask when investigating the possibility of

Answer 30

Radiation in the past

e.g. Radiotherapy for a pelvic tumours

Question 31

Describe the appearance of the crypts in radiation collitis

Answer 31

No irregularity

Question 32

What is the commonest cause of colitis

Answer 32

Radiational collitis

Question 33

After a patient is discharged, what happens

Answer 33

They need to be followed up cloesly

Question 34

What are 3 other causes of abnormal pathology in the large bowel

Answer 34

mycophenylate
Graft versus host disease
CMV