GI: Colorectal Disease Flashcards
What is the role of the colon?
Absorption of water and electrolytes
Propulsion of the contents of the caecum into the anorectal region
What is constipation?
Consistent difficulty defecating resulting in straining and passage of hard stools
What can cause constipation?
Inadequate fibre intake Diabetes Hypothyroidism IBS Calcium channel blockers + Antidepressants Intestinal obstruction
What is faecal incontinence?
Recurrent uncontrolled passage of flatus and/or stool
What are diverticula?
Pouches of mucosa which extend through weakened areas of the colonic muscular wall
What is diverticulitis?
Inflammation of diverticula
How does acute diverticulitis present?
Colicky left iliac fossa pain
Bloody diarrhoea
Fever
Raised CRP and white cells
How is acute diverticulitis diagnosed?
CT scan
How is acute diverticulitis treated?
Cephalosporin and metronidazole
Which part of the colon is most susceptible to diverticular disease?
Sigmoid colon
Which vessels supply blood to the colon?
Superior and inferior mesenteric arteries
What is the main cause of ischaemic colitis?
An occlusion in the mesenteric arteries
Who is at risk of ishaemic colitis?
The elderly
Women on the oral contraceptive pill
Patients with thrombophilia
How does ischaemic colitis commonly present?
Abdominal pain and rectal bleeding
What investigation is done for ischaemic colitis?
Sigmoidoscopy (as sigmoid colon is most commonly affected)
Which organism causes antibiotic induced colitis? How does it do this?
C.Diff. Produces toxins A and B which attack epithelium
Which organisms commonly cause infective colitis?
C.diff
Campylobacter
E.Coli
What are the symptoms of infective colitis?
Diarrhoea (±blood)
Cramping pain
dehydration
weight loss
What investigations would be done in a patient suspected of having infective colitis?
Stool culture
AXR
Sigmoidoscopy
What is a polyp?
A protrusion of an epithelial surface
What are the three types of polyp?
Pedunculated (stalks)
Serrated (from villous)
Flat
What is an adenomatous polyp?
A benign epithelial tumour that produces glands
What is familial adenomatous polyposis (FAP)?
A type of colorectal cancer caused by mutations in APC gene (tumour suppressor gene)
What is hereditary non-polyposis colorectal cancer (HNPCC)?
Accelerated progression from adenoma to cancer due to mutations in DNA mismatch repair genes
