Pathology of the large bowel Flashcards
What causes variation in the pathology of the large bowel
Age
Culture
Diseases
Name the 5 most common diseases of the large bowel
Diverticular Disease Ischaemia Antibiotic induced colitis Microscopic colitis Radiation colitis
Describe the appearance of an endoscopic image of the large bowe in diverticular disease
Lots of little holes and outpouches
Why might outpouches appear blue?
They may be filled with blood
Why are the holes often arranged in rows?
Due to the muscle layers - there are points of weakness in between the straps of the longitudinal muscle
What is the most cause of a benign tumour
Diverticular disease
Describe the pathology of diverticular disease
Reduced lumen
Thick muscle band
further small lumina
High presence of inflammatory cells in diverticulitis
Describe diverticular disease
Very common
often assymptomiatic
related to low fibre in the diet
increased intralumenal pressure
List 5 complications of diverticular disease
Inflammation Rupture Abscess Fistula Massive bleeding
How does the inflammation occur
Outpouches contain static faecal material - microorganisms develop a niche with them and expand in number
What could happen if the inflammation goes unchecked
Body forms an abscess - surgical emergency
What happens if the abscess goes unchecked
It can rupture, cause sepsis, shock and death
How can a patient experience a massive haemorrhage
If the abscess lies next to a blood vessel, the vessel can rupture through perforation
Who is most likely to present with ischaemia of the large bowel
Elderly
What side is affected in ischemia
Left side - at the splenic flexture and the sigmoid colon
What is the most common cause of ischaemia of the large bowel
Atherosclerosis of the abdominal aorta and the mesenteric vessles
Describe the histology of Ischaemia of the large bowel
Withering and damage of the crypts and pink smudging of the lamina propria
Fewer chronic inflammatory cells
What are the 3 main complications of ischaemic colitis
Massive bleeding
Rupture
Stricture
What do small white dots significant of in an endoscopy
pseudomembranes
Describe the histology of pseudomembranes
Explosive fibrinopurulent exudate on the surface of the epithelium
Describe the stool from a patient with pseudomembranes
Blood filled and loose
What causes pseudomembranes
Patients who are on a broad spectrum of Antibiotics - especially in the elderly
How do we treat pseudomembranes
Flagyl and Vancomycin
What patient would usually present with watery diarrhoea
A female in their 50s or 60s
Is there usually rectal bleeding in collagenous colitis
No
What category does collagenous colitis fit into
Microscopic colitis
How do we treat collagenous colitis
Immunosuppresion
What are the histological findings of collagenous colitis
Increase in the thickness of subepithelial collagen
Thickened basement membrane
Disease is patchy
Describe the findings in an endoscopy of a patient with microscopic colitis
Nothing - appears normal
What is a key question to ask when investigating the possibility of
Radiation in the past
e.g. Radiotherapy for a pelvic tumours
Describe the appearance of the crypts in radiation collitis
No irregularity
What is the commonest cause of colitis
Radiational collitis
After a patient is discharged, what happens
They need to be followed up cloesly
What are 3 other causes of abnormal pathology in the large bowel
mycophenylate
Graft versus host disease
CMV
