Surgery - Colorectal Flashcards
What are the peaks of incidence of IBD
2 peaks
10-40yrs
50-70yrs
Crohn’s more common than UC
What effect does smoking have in IBD?
Smoking ?helps UC
What is the pathophysiology of IBD
autoimmune, inappropriate response to gut flora in genetically susceptible individuals
- immunological
- environmental
- genetics
- diet
- psychosocial
- genetics
At the level of the colon describe the differences between UC and CD
UC:
- colon and rectum only
- continuous
- mucosa only
- reduced goblet cells
- polyps and crypt abscesses
CD:
- anywhere mouth to anus (commonly TI)
- skip lesions
- transmural
- normal goblet cells
- granulomas and fistulas
Fistulas = entero-enteric, colovesicle, colovaginal, enterocutaneous
What are the GI and extra-GI features of IBD?
GI: abdo pain, weight loss, tenesmus (UC), blood in stool, anal strictures, finger clubbing
Extra-GI: erythema nodosum, pyoderma gangrenosum, oral ulcers, finger clubbing, enteropathic arthritis
What is Truelove and Witts score?
Used to assess the severity of a UC flare
- no. bloody stools, HR, temp, Hb, ESR/CRP
What investigations are carried out for IBD/and IBD flare?
Bloods: FBC, ESR/CRP, U&E, LFT, INR, ferritin, TIBC, B12, folate Blood cultures Stool microbiology (exclude infection) Stool cultures (?C.Diff) Faecal calprotectin (will always be raised acutely) Colonoscopy and biopsy Capsule endoscopy CTMRI
What are the treatments for CD?
Acutely: fluids, nutrition, prophylactic heparin, smoking cessation
Medical =
- steroids
- biologics
- thiopurines (steroid sparing anti-inflammatories e.g. mercaptopurine/azathioprine)
- 5-ASA (steroid sparing anti-inflammatory chemically related to aspirin)
- METHOTREXATE
Surgery = resection, stricturoplasty, perianal drainage
What are the treatments for UC?
Acutely: fluids, nutrition, prophylactic heparin, smoking cessation
Medical =
- steroids
- biologics
- thiopurines (steroid sparing anti-inflammatories e.g. mercaptopurine/azathioprine)
- 5-ASA (steroid sparing anti-inflammatory chemically related to aspirin)
Surgery = resection, stricturoplasty, perianal drainage
What are complications of IBD?
- NSAIDs can exacerbate disease
- bowel obstruction
- toxic dilatation
- fistulae
- cancer
- malnutrition
What are the causes of bowel obstruction?
Mechanical = structural pathology blocks intestinal contents passing Functional = no mechanical blockage, due to -> inflammation, electrolyte imbalances, recent surgery (ileus)
Name causes of SB obstruction
adhesions from previous surgery (75%)
hernias
cancers/growth
Name causes of LB obstruction
cancers
diverticular strictures
rare (hernias/volvulus)
Why does third-spacing occur in bowel obstruction
Occluded bowel segment -> proximal dilatation -> increased peristalsis, increased hydrostatic pressure and large fluid movements into the bowel
What is volvulus and how is it managed?
Twisting of bowel on its mesentery common areas: - sigmoid (coffee bean sign) - caecum Increased risk of ischaemia and perforation - Treat by deflating through anal canal
What are the S/Sx of bowel obstruction?
Abdominal pain (crampy)
Vomiting (gastric contents -> bilious -> faecal)
Abdo distension
Complete constipation
O/Ex: scars from previous surgery, absence of bowel sounds
How is potential bowel obstruction investigated?
Bloods: FBC, U&E, CRP, LFT, G&S/CM
Venous blood gas: ?high lactate, assess degree of metabolic derangement (e.g. dehydration and vomiting)
Imaging: AXR, CT (erect CXR ?perforation)
What are features of SB obstruction on AXR?
- dilatation >3cm
- central swelling
- valvulae conniventes/plicae circularis (completely across diameter)
What are features of LB obstruction on AXR?
- dilatation >7cm (>9 in caecum)
- peripheral location
- haustral lines visible (half way)
How is bowel obstruction managed?
- urgent A-E and fluid resuscitation
- conservative: drip and suck (NG tube and IV fluids), catheter, analgesia, anti-emetics
- surgery (usually laparoscopic) if = ischaemia, closed loop obstruction, strangulation, pt has a virgin abdomen
What are complications of bowel obstruction?
Bowel ischaemia
Perforation and faecal peritonitis
Dehydration and AKI
Name three inherited bowel genetic conditions and describe them
1) FAP (familial adenomatous polyposis)
- APC mutations, many polpys develop and 100% pts have CRC by 40yrs, get prophylactic colectomy
2) HNPCC (hereditary non-polyposis colorectal cancer)/Lynch syndrome
- MMR mutation, quick progression of adenoma -> carcinoma sequence, Lynch 2 associated with endometrial/gastric/breast cancer
3) Peutz-Jeghers syndrome
- SKT11 mutation, mucosal hyperpigmentation, polyps, intusseption and haemorrhage
What are symptoms of a R sided CRC?
anaemia
weight loss
abdominal pain
What are symptoms of a L sided CRC?
tenesmus
altered bowel habit
blood/mucous PR
PR mass
Describe the staging methods of CRC
TNM
Duke's: A) confined to the bowel wall B) through the bowel wall C) through the bowel wall + LN involvement D) distant metastases
How is suspected CRC investigated?
1) Examination (abdo + PR)
2) Bloods - FBC, LFT, haematinics, tumour markers (CEA, AFP)
3) Imaging - CXR (mets), liver USS (mets), CT/MRI (staging), barium enema (apple core)
4) Endoscopy - flexible sigmoidoscopy/colonoscopy
What are the treatment options for CRC
Surgery +/- neoadjuvant chemo
Palliative bypass, stenting also options
Describe a right hemicolectomy
removal of caecum and ascending colon
Describe a left hemicolectomy
removal of splenic flexure and descending colon
Usually an anastomosis and no stoma needed
Describe an anterior resection
For rectal/sigmoid disease
Removal of sigmoid colon and rectum
May anastomose end of descending colon to anal stump but put on a stoma at first to allow anastomosis to heal, then later reverse the stoma in a few months
Describe an AP (abdominal perineal) resection
Removal of sigmoid colon, rectum and anus
Formation of an end colostomy
Describe a Hartmann’s procedure
Usually performed for an obstructing cancer/diverticular disease
Resection of sigmoid colon +/- rectum (with rectum it is called a procto-sigmoidoscopy)
Can be temporary or permanent
Distal anal end can be stitched closed if permanent, or can be brought to the surface creating a mucous fistula
Describe the screening process for CRC
1) FOB testing: 50-74yr olds (2 yrly)
- ~70-80% sensitivity
3) new Q-FIT (quantitative faecal IHC testing)
- will have ~90% sensitivity
What are the 4 layers of the colon?
Mucosa
Submucosa
Muscularis propria/externa
Serosa/adventitia
Describe diverticular disease and its causes
the clinical state relating to symptoms caused by colonic diverticulae
Diverticular disease = altered bowel habit, L colic (relieved by defectation), nausea, flatulence
Diverticulitis = impacted faeces causes infection, LIF tenderness, pyrexia and localised peritonitis
Can be congenital or acquired
Rare <60yrs
Due to genetics + low fibre diet and environmental factors (NSAID use, collagen structure)
How is diverticular disease investigated?
Colonoscopy (gold standard for diagnosis, but NOT used in acute setting)
Bloods - FBC, CRP, ESR, amylase (raised), G&S, CM
Imaging - CT abdo, erect CXR (perf?), AXR (obstruction?)
What staging system is used for Diverticular disease and describe it
Hinchey classification - looks at the degree of infective complications with diverticular disease and the need for surgery
1A - phlegmon
1B - pericolic abscess
2 - pelvic abscess
(surgery rarely needed and CT-guided percutaneous drainage sufficient)
3 - generalised purulent peritonitis
4 - generalised faecal peritonitis
(need surgery)
How is diverticular disease managed?
High fibre diet
Hospital admission if uncontrolled pain and fluids not tolerated
Medical: NMB, IV fluids, analgesia, laxatives, antibiotics
Surgery: if perforation/strictures/obstruction/haemorrhage -> usually Hartmann’s procedure to resect the diseased bowel
What is ano-rectal sepsis
due to a perianal abscess
What is fistula-in-ano
Formation of an anal fistula between the bowel & skin in the perineal/perianal area
Name the 6 types of anal fistula
Named based on the tissues through which they track
- submucosal
- inter-sphincteric
- transphincteric (high or low)
- supratransphincteric
- extratransphincteric
How is ano-rectal sepsis managed?
Antibiotics (manage symptoms but will not cure underlying disease)
Surgical
- Drainage
- Lateral internal sphincterotomy (to reduce internal pressure and allow fissure to heal)
- Fissurectomy (removal of tract)
- Anal advancement flap (avoids need to cut sphincter muscles and less risk of incontinence)
Describe the types of colonic polyps
Pedunculated (on a stalk)
Sessile (flat)
Or can be a combination of both
How do colonic polyps present?
Normally asymptomatic and found on imaging/scopes Can present with: - bleeding - mucous discharge - prolapse (if low in the rectum)
How are colonic polyps investigated:
Colonoscopy Genetic mutation testing: APC gene = FAP MMR gene = HNPCC STK11 gene = Peutz-Jeghers syndrome
Describe haemorrhoids and risk factors for developing them:
XS amounts of the normal endovascular cushions consisting of:
- anorectal mucosa
- submucosal tissue
- mucosal blood vessels (small arterioles and veins)
Common in young adults and RFx include:
- constipation
- pregnancy
- chronic straining
- irregular bowel habits
- obesity
- genetics (absence of valves in haemorrhoid veins)
How are haemorrhoids described
Classified by dentate line as internal/external
(dentate line divides lower 1/3rd anal canal from upper 2/3rds)
- typically occur in the same location as the main anal blood vessel pedicles:
11 o’clock
3 o’clock
7 o’clock
How might haemorrhoids present?
Internal = painless bleeding and itch External = bleeding, swelling, mucous, painful!
How can haemorrhoids be managed?
Medical (diet, high fibre, creams)
Surgical (banding, HALO = haemorrhoid artery ligation operation, stapled anopexy, haemorrhoidectomy)
Describe causes of rectal bleeding
Anorectal = bright red blood on paper/in stool
- haemorrhoids
- fissures
- proctatisis (rectal inflammation)
- rectal prolapse
Rectosigmoid = darker blood with clots
- rectal tumour
- proctocolitis
- diverticular disease
What is a pilonidal sinus and how it is caused?
A sinus existing in the midline of the buttock clefts
Usually contains - hair, secretions, debris
Lateral tracts may run into neighbouring buttock tissue
Commonest in men/hirsute people
Often precipitated by long periods of sitting:
- lorry drivers
- computer operators
