Pathology of the large intestine Flashcards
What is the longiduinal stripe on the large bowel?
Tenaie coli
What causes diverticular disease?
Low fibre diet and increased intralumenal pressure
Stool is solid so peristalsis has to work harder increasing intraluminal presure so that the mucosa of the colon herniates through the bowel wall
What are the 2 types of diverticular disease?
True (penetrates all of the walls of bowel such as meckel’s diverticulum)
False
What are the common complications of diverticular disease?
Inflammation Rupture Abscess Fistula Massive bleeding
Who is likely to be affected by ischeamia of the large bowel?
Elderly Left dises CVS disease Atherosclerosis of mesenteric vessels Shock A. Fib Embolus Vasculutis
What are the microscopic changes of ischaemia of the large bowel?
Withering of crypts and smudging of lamina propria
Eosinophilic change within the lamina propria
What are common complications of ischaemic colitis?
Massive bleeding
Rupture
Stricture
What causes pseudomembranous colitis?
Patients on broad spectrum antibiotics, C. diff selected out
Toxin A and B attack endothelium and epithelium
What are the symptoms of pseudomembranous colitis?
Massive diarrhoea
Bleeding
How is psedommebranous colitis treated?
Flagyl/vancomycin
Many need colectomy
What 4 antibiotics are known to cause C.diff?
Cephalosporins
Co-amoxiclav
Ciprofloxacin
Clindamycin
What are the different types of diarrhoea?
Blood
Mucus
Simply more watery version of normal stools
What is the histological finnsings of collagenous colitis?
Thick band of collagen in subepithelium due to an autoimmune reaction
Thickened basement membrane
Acssociated with intraepithelial inflammatory cells
No chronic architecular changes
What are the common signs of collagenous colitis?
Water diarrhoea Normal endoscopy Drug history (lansoprazole and NSAIDs have been associated with collaegnous colitis)
What are the histological changes in lymphocytic colitis?
No chronic architectural changes in cryps
Intraepithelial lymphocytes are raised
No thickening of BM
What should be looked for in the history when susepecting lymphocytic colitis?
Normal endoscopy
Raise possibility of coeliac disease
What is the histological appearance of radiation colitis?
Disturbed colonic architecture, branches crypts, random distribution, not much inflammation, spaces in lamina propria
What causes acute infective colitis?
Infection, rarely drugs, ischaemia, endoscopy prep
What sort of bacteria can cause acute colitis?
Salmonella Shigella Campylobacter E. coli Cholera
What does acute colitis look like?
Acute inflammation in the bowel wall without any chronci structural changes int the mucosa
What is diverticular disease?
Mucosal herniation through muslce coat
How is diverticulosis diagnosed?
Clinical
Barium enema
Sigmoidoscopy
What are the clinical features of diverticulitis?
LIF pain/tenderness
Septic - high fever, tachycardia, tachypnoeic, hypotension
Altered bowel habit
How is uncomplicated diverticulitis treated?
IV antibiotics - usually self-limiting
How is complex diverticulitis treated?
Hartmann’s procedure
Primary resection / anastomosis
Percutaneous drainage
Laprascopic lavage and drainage
What can cause acute and chronic colitis?
Infective colitis
Ulcerative colitis
Crohn’s colitis
Ischaemic colitis
What are symptoms of colitis?
Diarrhoea +/- blood Abdominal cramps Dehydration Sepsis Weight loss Anaemic
How is colitis diagnosed?
Plain x-ray
Sigmoidoscpy and biopsy
Stool cultures
Barium enema
How is UC/Crohn’s colitis treated?
IV fluids IV steroids GI rest Rescue medical therapy Surgery
What is colonic angiodysplasia?
Submucosal lakes of blood
Obscure cause of rectal bleeding
Usually right side of colon
How is colonic angiodysplasia diagnosed?
Angiography
Colonoscopy
How is colonic angiodysplasia treated?
Embolisation
Endoscopic ablation
Surgical resection
What can cause large bowel obstruction?
Colorectal cancer
Benign stricture
Volvulus (common in sigmoid, transverse and caecum)
How is large bowel obstruction treated?
Resuscitate
Operate
Stenting
What can cause a sigmoid volvulus?
Bowel twists on mesentery
May become gangrenous
How is sigmoid volvulus diagnosed?
Plain AXR
Rectal contrast
What are examples of functional bowel disorders?
Chronic constipation
Faecal impaction
