Large bowel disease Flashcards
What are the main differences between Crohn’s and ulcerative colitis?
Crohn’s vs UC:
- Patchy and segmental vs continuous and diffuse
- Anywhere in tract vs only in colon and rectum
- Skip lesions common vs not
- Thickened bowel and stricture vs mucosal ulceration and thin wall
- Transmural inflammation vs superficial
- Granulomas vs none
- Fistulae are common vs not
- Cancer risk moderate vs very high
- Extra GI manifestations are rare vs common
What are the similarities between Crohn’s and ulcerative colitis?
both chronic, unknown aetiology, ulceration, inflammation, relapsing course, bloody diarrhoea and both increase the risk of cancer
What is Crohn’s disease?
Crohn’s disease is a chronic inflammatory disease that can occur anywhere from mouth to anus
It most commonly occurs in the terminal ileum and colon
Who does Crohn’s affect?
- Young patients so late adolescence and early adulthood
- Common in males
What is the pathology of Crohn’s disease?
- patchy and segmental disease
- chronic active colitis with granuloma formation
- increased chronic inflammatory cells will be seen in the lamina propria
- crypt branching with non-caseating granuloma
- skip lesions
- cobblestoning with thickened wall and fissures
What are the causes of Crohn’s?
- smoking
- sterile environment
- genetic defects (common gene identified is NOD2)
What is the clinical presentation of Crohn’s?
abdominal pain small bowel obstruction diarrhoea bleeding PR anaemia weight loss - symptoms depend on what part of the tract is affected
What are the test for Crohn’s?
Bloods: raised CRP, ESR, white cell and platelet
Stool tests
Imaging and colonoscopy (to determine large bowel involvement)
MRI or white cell scan to see small bowel involvement
Staging of the disease
What is the treatment for Crohn’s?
- steroids
- immunosuppressants
- anti-TNF therapy
What are the complication for Crohn’s?
- Malabsorption as iron, vitamins won’t be -Gallstones
- Fistulas between many different organs
- Anal disease
- Intractable disease
- Bowel obstruction-Perforation
- Malignancy etc
- Stricture or abscess caused by flares
What is ulcerative colitis?
- Ulcerative colitis is a chronic inflammatory disorder that is only in the colon and rectum
- It comprises of mucosal and submucosal inflammation
Who gets ulcerative colitis?
Young patients
More common in males
What is the pathology of UC?
- inflammation is confined to the mucosa and submucosa
- no granulomas in this disease
- many inflammatory cells
- irregular branching crypts
- cryptitis
- crypt abscesses
- ulceration with fibrinopurulent exudate
- always starts in rectum
What are the causes of UC?
Unknown
Possible environmental factors such as smoking, drugs, stress, hygiene and diet
What is the presentation of UC?
- diarrhoea
- mucus and blood PR
- non-GI manifestations such as uveitis, arthritis, erythema nodosum etc
- need to defecate in night and increased urgency
What are the investigations for UC?
blood tests, stool tests, imaging (extent, transition, zone, loss of vessel pattern, granular mucosa or contact bleeding), endoscopy and histology, look for polyps
What are the treatments for UC?
- 5ASA
- steroids
- immunosuppressants
- anti-TNF therapy
What are the complications of UC?
- Intractable disease
- Toxic megacolon (massively swollen colon that will rupture)
- Colorectal carcinoma
- Blood loss etc
- primary sclerosing cholangitis
What is a polyp?
a protrusion above the normal epithelial surface
What can a polyp be and what is it most likely to be?
- can be an adenoma, a serrated polyp, a polypoid carcinoma or other
- most common are neoplastic adenomas and metaplastic polyps
What are the different types of polyps classified by shape?
pedunculated, sessile or flat
What do polyps look like?
have a stalk of normal mucosa but will have an irregular surface
What are adenomas?
- benign epithelial tumour which forms from the glands
- not invasive and don’t metastasise
What are the types of adenomas?
tubular, villous or tubulovillous
What type of tissue makes up an adenomas?
dysplastic
Why are adenomas always removed?
can commonly develop into adenocarcinomas so must all be removed as they are premalignant
What are adenocarcinomas?
malignant epithelial tumours which forms from glands
What is the primary treatment for adenocarcinomas?
surgical and the colon is then sent to pathology for staging
What are the features of an adenocarcinoma?
tumour will be an ulcerating and stricturing tumour mass and can burst through the bowel wall
What are the histological features of and adenocarcinoma?
moderate differentiation and a dirty necrosis pattern
What staging is used for adenocarcinomas?
Dukes staging is used to see how far the cancer has gone and prognosis varies with this staging
- A is confined to muscularis propria
- B is through the muscularis propria
- C is metastasis to the lymph nodes
What are the possible gross appearances for adenocarcinomas?
sigmoid tumour, transverse tumour, caecal mass or nodal mets
What are the two types of inherited cancer syndromes for colorectal cancer?
hereditary non polyposis coli or familial adenomatous polyposis
What are the features of hereditary non polyposis coli?
HNPCC: late onset, autosomal dominant, right sided tumour and inflammatory response
What are the features of familial adenomatous polyposis?
FAP: early onset, autosomal dominant, defect in tumour suppressor, tumours throughout colon with no inflammatory response
What are diverticula?
pouches protruding from the intestinal wall when the mucosa and submucosa herniate through the muscle layer
Where are most diverticula found?
in the sigmoid colon and are found by accident
How is diverticular disease diagnosed?
- endoscopy
- Ba enema (white outpourings seen)
- raised inflammatory markers in diverticulitis
What are the clinical features of diverticulitis?
LIF pain or tenderness
sepsis
altered bowel habits
What are the complications of diverticulitis?
pericolic abscess perforation haemorrhage fistula stricture
How does a fistula between bladder and bowel present?
frequent UTIs
pneumaturia (air in the bladder)
How are uncomplicated diverticular disease patients treated?
oral antibiotics
no treatment
high fibre diet recommended
How is complex diverticulitis treated?
Hartmann’s procedure
primary resection or anastomosis
What is colitis?
inflammation of the colon
What are the causes of colitis?
infective
ulcerative
Crohn’s
ischaemic
How does acute colitis present?
bloody diarrhoea
abdominal cramps
dehydration
sepsis
What are some other common features of chronic colitis?
weight loss
anaemia
How is colitis diagnosed?
XR
sigmoidoscopy for biopsy
stool culture
What is the treatment for colitis?
IV fluids
IV steroids
resting of GI tract
surgery if the colitis doesn’t settle
What is ischaemic colitis?
- occurs in the elderly
- can be an acute or chronic occlusion of the IMA
What is colonic angiodysplasia?
a vascular abnormality that causes GI bleeding in the right side of the colon
How is angiodysplasia treated and diagnosed?
- difficult to diagnose
- treated with embolisation, endoscopic ablation and surgical resection
What is large bowel obstruction caused by and how is it treated?
- caused by colorectal cancer, benign stricture or volvulus
- treatment is surgical
What is a sigmoid volvulus?
a twist of the bowel on the mesentery which can become gangrenous
How is sigmoid volvulus diagnosed?
XR abdomen
rectal constrast
What is the treatment for sigmoid volvulus?
endoscopic decompression or surgical resection
What is a pseudo-obstruction?
presentation of an obstruction but there is no real blockage which is usually die to a biochemical problem that can’t be fixed by surgery
What is a false diverticula?
lacks a muscularis propria
When does diverticulitis present?
when it becomes complicated eg when it is inflamed
What does ischaemia look like histologically?
- withering crypts
- pink smudging of lamina propria
- fewer chronic inflammatory cells
What are the features of ischaemia in the colon?
- seen in the elderly
- left sided disease
What is ischaemia caused by?
CVS atherosclerosis of mesenteric vessels AF shock embolus
What are the complications of ischaemia in the colon?
massive bleeding
rupture
stricture
What is seen in antibiotic induced colitis?
- patchy yellow exudates on colonic mucosal surface
- fibrinopurulent exudate on surface of cells
- explosive lesions on mucosa
- whole colon
What causes pseudomembranous colitis?
C. diff
broad-spectrum antibiotics
What are the features of pseudomembranous colitis?
massive diarrhoea and bleeding
What is pseudomembranous colitis treated with?
Flagyl/Vancomycin and may need a colectomy or else is fatal
What are the two types of microscopic colitis?
lymphocytic and collagenous
What does microscopic colitis present with?
watery diarrhoea and a microscopically normal mucosa
What is seen microscopically with collagenous colitis?
- membrane under the epithelial cells that has a large increase in collagen
- thickened basement membrane will be seen and patchy disease with intraepithelial inflammatory cells
What is different about lymphocytic colitis?
- too many intraepithelial lymphocytes in the large bowel
- no thickening of the basement membrane
What is radiation colitis?
normal on endoscopy but not on histology
What is seen under the microscope in radiation colitis?
- dilated capillary blood vessels are seen with scarring fibrosis
- telangiectasia
- bizarre stromal cells and vessels
What is the presentation and causes of radiation colitis?
rectal bleeding and is caused by radiotherapy of previous tumours
What is seen microscopically in acute or infective colitis?
- busy epithelium
- cryptitis but otherwise the mucosa will be normal
- acute inflammation but no chronic injury
What is infective or acute colitis caused by?
an infection or rarely drugs
What are the most common presentations of IBD?
altered bowel habits and rectal bleeding
What is the overlap between UC and Crohn’s called?
indeterminate colitis
What is the typical presentation of Crohn’s vs UC?
- Crohn’s is abdominal pain and peri-anal disease
- UC is diarrhoea and bleeding
What is the pathogenesis of IBD?
- genetic predisposition
- environmental triggers
- mucosal immune system
What is the most important gene in IBD?
- NOD2 is an important factor
- coding of a protein that is involved in bacterial recognition on the gut mucosa
- increases likelihood of getting the disease, especially in homozygotes
What are the aggravators or delivers of Crohn’s and UC?
- smoking aggravates C but protects UC
- NSAIDS aggregate both
What is severe UC determined by?
- fever
- tachycardia
- anaemia
- CRP
- albumin
What do the complications of UC depend on?
- severity of inflammation
- duration of disease
- extent of disease
What can both IBD diseases have an effete on outside extra-gastrointestinally?
skin, joints, eyes, deranged LFTs or oxalate renal stones
What is perianal disease characterised by?
recurrence of abscesses which can result in fistulas and affect sphincters
What are the special history questions for UC?
travel antibiotics NSAIDs family history smoking and skin eyes joints
What are the aims of IBD therapy?
- heal mucosa
- control inflammation
- restore normal bowel habit
- improve QoL
- avoid complications
What are the lifestyle recommendations for IBD?
- stop smoking esp for Crohn’s
- diet makes symptoms better so modules or gut rest
How do 5ASAs work?
- Aminosalicylates
- topical effect
- anti-inflammatory and reduce risk of colon cancer
eg Mesalazine
What are the types of 5ASAs?
- oral (prodrugs, pH dependent release or delayed release)
- topical for left-sided disease (suppositories or enema)
What are the side-effects of 5ASAs?
diarrhoea or nephritis
How do corticosteroids work?
- systemic anti-inflammatory agents
- induce remission
- short-course as too many side-effects if long term use
eg prednisolone or budesonide
What are the side effects of corticosteroids?
- MSK (avascular necrosis or osteoporosis)
- cutaneous (acne)
- metabolic (weight gain, diabetes and hypertension)
- gastrointestinal
- neuropsychiatric
How do immunosuppression drugs work?
- used in UC for steroid-sparing
- used in CD for maintenance therapy
- when more potent suppression of inflammation is required
- eg thiopurines or methotrexate
What are thiopurines for?
when patients need steroids or if they still have active colitis despite 5ASAs
What is ciclosporin for?
severe UC that isn’t helped by steroids
What are the side-effects of immunosuppression and how is this checked for?
marrow suppression leucopenia hepatitis pancreatitis - do regular FBC and liver tests
What is anti-TNF therapy?
- promotes apoptosis of T cells
- rapid onset
- antibodies for TNFa which is proinflammatory
eg chimeric or humanised
When are anti-TNF used?
long-term with immune suppression
with surgery
supportive
eg infliximab
What is a complex fistula?
involves the sphincter itself
What are the surgeries for Crohn’s?
resection stricture removal fistulas anal disease gastrojejunostomy ileocolic disease surgery
What are the surgeries for UC?
- proctocolectomy with end ileostomy, ileorectal anastomosis or pouch
- emergency is colectomy or subtotal colectomy
What is an ileostomy?
stands up out of abdomen and is from the terminal ileum
acidic fluid comes out
What is a colostomy?
wider and is from anywhere out of the colon
faeces comes out of this
What are indications for elective surgery?
unresponsive disease
malignancy
failure of growth in children
What is the criteria to assess UC emergency severity?
Truelove and Witt
What is Rigler’s sign?
air in the abdomen so seeing outside of bowel wall on AXR meaning there is a perforation
What are the indications for surgery in CD?
?stenosis with obstruction fistula abscess bleeding free perforation
How do you manage fistula?
SNAP Sepsis Nutrition Anatomy Plan or Prolonged hospital stay
What is UC treated with when there is acute flare, toxic megacolon, chronic disease or dysplasia?
- Subtotal colectomy and end-ileostomy
- Ileoanal pouch
- Panproctocolectomy and end-ileostomy
What is failure of medical therapy in CD treated with?
limited intestinal resection and ileorectal anastomosis
What is complications in CD treated with?
limited intestinal resection and strictureplasty
What is perianal sepsis in CD treated with?
- examination under anaesthesia
- drainage of sepsis
- seton if a fistula has formed
What does colorectal cancer develop from?
- left side usually
- benign polyps
What is the epidemiology of colorectal cancer?
- very common
- more in men
- peaks at 60-80 years old
What is the change that occurs in the colon for a cancer to develop?
- polyp eg adenoma or a serrated polyp
- becomes an adenocarcinoma
What are the characteristics that would make a polyp more malignant?
- subtype (villous are highest risk and tubular are lowest risk)
- grade
- size
- number of polyps
What are the risk factors for colorectal cancer?
- old
- low fibre
- obesity
- smoking
- lack of exercise
- mutations in APC or p53
- long-standing IBD esp UC
What is the bowel screening test used in tayside?
FIT test for 50-72 year old and if this is positive then a colonoscopy is done
What is the presentation of right-sided cancers of the colon?
Iron deficiency anaemia Persistent tiredness Bowel habit changes Weight loss Abdominal colicky pain Lump in the abdomen
What is the presentation of left-sided cancers in the colon?
Rectal bleeding
Incomplete emptying
Worsening constipation
What is seen on examination of colorectal cancer?
- normal
- maybe iron deficiency anaemia so koilonychia or pale conjunctiva
- occasional palpable mass
What are the main steps in diagnosing a colorectal cancer?
- Bloods: iron deficiency anaemia, markers cause by mets to bone and liver
- Sigmoidoscopy: for fresh blood, only sigmoid seen
- Colonoscopy: entire colon
- CT colonography: requires bowel prep
- CT of abdominal, pelvis and thorax to look for mets
What are the hardest polyps to remove?
- sessile are flat and harder to remove
- pedunculated are mushroom shaped and easier remove
What is the key preventative treatment of colorectal cancer?
removing benign polyps before they become malignant by endoscopic resection
What is used to treat bowel obstruction secondary to a colorectal cancer?
metal stent
What is the main treatment of colorectal cancer?
surgery
the type of surgery depends on the location of the tumour but it will be either open or laparoscopic
When is radio or chemotherapy used in colorectal cancer?
- radio is only used in the rectum
- chemo is used for advanced colonic cancer
What are the possible palliative treatments for colorectal cancer?
- stenting
- palliative radio or chemo
- defunctioning
- bypass
