Colorectal Flashcards
Differentiate between an ileostomy and colostomy
Ileostomy V Colostomy
Location : Right iliac fossa V More likely on the left
Appearance: Spouted (to keep irritant contents away from skin) V Flushed
Output: Liquid V Solid
What is a gastrostomy used for? Where is it found?
Use:
Gastric decompression or fixation
Feeding
Site:
Epigastrium
What is a loop jejunostomy used for? Where is it found?
Use:
Seldom used as very high output
May be used following emergency laparotomy with planned early closure
Site: wherever needed
What is a Percutaneous jejunostomy used for? Where is it found?
Use:
Feeding
Site:
LUQ (proximal bowel)
What is a Loop ileostomy used for? Where is it found?
Use:
Defunctioning of colon e.g. following rectal cancer surgery
Does not decompress colon (if ileocaecal valve competent)
Site:
RIF
What is an End ileostomy used for? Where is it found?
Use:
Usually following complete excision of colon or where ileocolic anastomosis is not planned
May be used to defunction colon, but reversal is more difficult
Site:
RIF
What is an End colostomy used for? Where is it found?
Use:
Where a colon is diverted or resected and anastomosis is not primarily achievable or desirable
Site:
Either left or right iliac fossa
What is a loop colostomy used for? Where is it found?
Use:
To defunction a distal segment of colon
Since both lumens are present the distal lumen acts as a vent
Site:
May be located in any region of the abdomen, depending upon colonic segment used
Key features of anal fissures?
Typically presents with painful rectal bleeding
Intense pain post defecation
Location: midline 6 & 12 o’clock position. Distal to the dentate line
Chronic fissure > 6 weeks: triad: Ulcer, sentinel pile, enlarged anal papillae
3 major causes of proctitis?
Crohn’s, ulcerative colitis, Clostridioides difficile
Causes of ano-rectal abscess?
Position?
E.coli, staph aureus
Positions: Perianal, Ischiorectal, Pelvirectal, Intersphincteric
Cause of anal fistula? Location?
Usually due to previous ano-rectal abscess
Intersphincteric, transsphincteric, suprasphincteric, and extrasphincteric. Goodsalls rule determines location
Associations of rectal prolapse?
childbirth and rectal intussceception
Cause of pruritus ani?
Extremely common
In children is often related to worms, in adults may be idiopathic or related to other causes such as haemorrhoids.
Most common anal neoplasm?
Squamous cell carcinoma
Associations of rectal ulcer?
Signs on histology?
Associated with chronic straining and constipation.
Histology shows mucosal thickening, lamina propria replaced with collagen and smooth muscle (fibromuscular obliteration)
Define haematochezia
passage of fresh blood per rectum
generally caused by bleeding from the lower GI tract
Common causes of acute lower GI bleeding?
diverticular disease
ischaemic / infective colitis
haemorrhoids
malignancy
angiodysplasia
Crohn’s disease / UC
radiation proctitis
What is the most common cause of lower GI bleeding?
Diverticulosis
Diverticula are outpouchings of the bowel wall that are composed only of mucosa, most commonly in the descending and sigmoid colon
What are haemorrhoids?
pathologically engorged vascular cushions in the anal canal that can present as a mass, with pruritus, or fresh red rectal bleeding
Key questions to ask in a hx for a PR bleed?
Nature of bleeding – duration, frequency, and colour, and whether related to stool and defecation
Associated symptoms – including pain (especially association with defaecation), any haematemesis or melena, any PR mucus, previous episodes, or weight loss
Family history – bowel cancer or inflammatory bowel disease
What score can be used to help stratify patients presenting with a lower GI bleed to determine if outpatient management is feasible?
The Oakland Score
Factors used:
Age, Sex, Previous Admissions for Lower GI bleeding, PR findings, Heart Rate, Systolic BP, and Hb Concentration.
Investigations for rectal bleeding?
If unstable?
FBC, U&Es, LFT, clotting profile
Group and Save
Stool cultures to exclude infective causes
Further investigations:
colonoscopy to exclude left-colonic pathology (especially malignancy)
if no abnormality on colonoscopy = OGD
If haemodynamically unstable:
resuscitate using blood products and correct any coagulopathy
urgent CT angiogram (before any endoscopic therapy)
Key risk factors for adverse outcomes from any acute rectal bleeding?
haemodynamic instability
ongoing haematochezia
age >60yrs
serum creatinine >150µmol/L
significant co-morbidities
Management of rectal bleeding?
95% settle spontaneously
unstable rectal bleeding = urgent resuscitation
- wide bore IV access and blood products and urgent reversal of any anticoagulation
any patient with a Hb <70g/L (or <80g/L in those with CVD) requires transfusion
Further management:
Endoscopic haemostasis methods: injection (diluted adrenaline), contact and non-contact thermal devices, and mechanical therapies (endoscopic clips and band ligation)
Arterial embolisation- patients with an identified bleeding point (“blush”) of sufficient size on angiogram
What is the aetiology of colorectal cancer?
most commonly adenocarcinoma
“adenoma-carcinoma sequence”:
progression of normal mucosa > colonic adenoma (polyps) > invasive adenocarcinoma
What genetic mutations predispose to colorectal cancer?
Adenomatous polyposis coli (APC)
Mutation of the APC gene (tumour suppressor) = growth of adenomatous tissue, such as Familial Adenomatous Polyposis (FAP)
Hereditary nonpolyposis colorectal cancer (HNPCC)
Mutation to HNPCC (DNA mismatch repair gene) = defects in DNA repair, such as Lynch syndrome
Risk factors for colorectal cancer?
75% are sporadic
older male
fam hx (present in 10–20% of all patients)
inflammatory bowel disease
low fibre diet and high processed meat intake
smoking and alcohol
Clinical features of bowel cancer?
Common : change in bowel habit, rectal bleeding, WL, abdo pain, and symptoms of iron-deficiency anaemia
Right-sided colon cancers – abdo pain, iron-deficiency anaemia, palpable mass in RIF, often present late
Left-sided colon cancers – rectal bleeding, change in bowel habit, tenesmus, palpable mass in left iliac fossa or on PR exam
Which patients should be referred for urgent investigations for bowel cancer?
≥40yrs with unexplained weight loss and abdominal pain
≥50yrs with unexplained rectal bleeding
≥60yrs with iron‑deficiency anaemia or change in bowel habit
Positive occult blood screening test
Major differentials for colorectal cancer?
Inflammatory bowel disease – The average age of onset is younger (20-40yrs) than with colorectal cancer and typically presents with diarrhoea containing blood and mucus
Haemorrhoids – Bright red rectal bleeding on the pan or surface of the stool but rarely presents with abdo pain, altered bowel habits, or weight loss
What colorectal cancer screening is offered in the UK?
FIT tests every 2 years for people aged 60-75
Investigations for colorectal cancer?
FBC (anaemia) LFTs and clotting
CEA should NOT be used as a diagnostic test (poor sensitivity and specificity) but can be used to monitor disease progression
(elevated baseline CEA = worse prognosis)
gold standard for diagnosis of colorectal cancer is via colonoscopy with biopsy
Once diagnosis made:
CT CAP: distant mets and local invasion
MRI rectum: (for rectal cancers) to assess depth of invasion and need for pre-op chemo
Endo-anal USS : (for early rectal cancers, T1 or T2 only) to assess suitability for trans-anal resection
When would you use a Right Hemicolectomy or Extended Right Hemicolectomy?
caecal tumours or ascending colon tumours
extended option for any transverse colon tumours
During the procedure the branches of the SMA (ileocolic, right colic, and right branch of the middle colic) are divided and removed with their mesenteries
When would you use a Left Hemicolectomy?
descending colon tumours
the left branch of the middle colic vessels (branch of SMA/SMV), the inferior mesenteric vein, and the left colic vessels (branches of the IMA/IMV) are divided and removed with their mesenteries
When would you use a Sigmoidcolectomy?
sigmoid tumour
IMA is fully dissected out with the tumour in order to ensure adequate margins are obtained
When would you use an anterior resection?
high rectal tumours, typically if >5cm from the anus
favoured as leaves the rectal sphincter intact if an anastomosis is performed (unlike AP resections)
Often a defunctioning loop ileostomy is performed to protect the anastomosis and reduce complications in the event of an anastomotic leak, which can then be reversed electively four to six months later
General management of colorectal cancer?
Surgery is the mainstay of curative management
regional colectomy - removal of the primary tumour with adequate margins and lymphatic drainage, followed by primary anastomosis or formation of a stoma
When would you use an Abdominoperineal (AP) Resection?
low rectal tumours typically <5cm from the anus
excision of the distal colon, rectum and anal sphincters, resulting in a permanent colostomy
What is a Hartmann’s procedure?
complete resection of the recto-sigmoid colon with the formation of an end colostomy and the closure of the rectal stump
used in emergency bowel surgery e.g. obstruction or perforation
What is the Duke’s staging system?
Used for staging of colorectal cancer
A - Confined beneath the muscularis propria - 90% survival
B - Extension through the muscularis propria - 65% survival
C - Involvement of regional lymph nodes - 30% survival
D - Distant metastasis - <10% survival
What is the FOLFOX regime for patients with metastatic colorectal cancer?
FOLinic acid, Fluorouracil (5-FU), and OXaliplatin
Which colorectal cancer can radiotherapy be used for?
Rectal
Rarely used in colon cancer due to risk of damage to small bowel
What is a diverticulum?
an outpouching of the bowel wall
most commonly found in the sigmoid colon
Pathophysiology: in an aging bowel that has become weaker over time, movement of stool and increased luminal pressure can cause outpouchings at weaker parts of the wall (e.g. at junctions of muscular sheets)
What are the 4 different manifestations of diverticular disease?
Diverticulosis – the presence of diverticula (asymptomatic, incidental on imaging)
Diverticular disease – symptoms arising from the diverticula
Diverticulitis – inflammation of the diverticula
Diverticular bleed – where the diverticulum erodes into a vessel and causes a large volume painless bleed
How is diverticulitis classified?
Simple or complicated
Complicated diverticulitis = abscess presence or free perforation
Risk factors for diverticula?
age
low dietary fibre intake
obesity
smoking
NSAID use
family history
How might diverticular disease present?
Diverticulosis often asymptomatic and picked up incidentally
Diverticular disease:
intermittent colicky lower abdo pain, may be relieved by defecation
altered bowel habit, associated nausea, and flatulence
Acute diverticulitis:
sharp abdo pain usually localised to LIF, worsened by movement
localised tenderness
decreased appetite, pyrexia, nausea
Perforated diverticulum:
peritonitis, often v unwell
How can diverticular (pericolic) abscesses be managed?
<5cm = managed with conservatively with intravenous antibiotics
larger = radiological drainage
complicated multi-loculated abscesses (or patients who clinically deteriorate) = surgical intervention
- laparoscopic washout or a Hartmann’s procedure
Investigations for suspected diverticular disease?
FBC, CRP, and U&Es
consider urine dip to rule out other pathology
If suspected diverticulitis:
- group and save and VBG
- CT abdo-pelvis
if suspected uncomplicated diverticular disease:
- flexible sigmoidoscopy to identify any obvious rectosigmoidal lesion
- CT colonography if not suitable for endoscopy
CT findings suggestive of diverticulitis?
thickening of the colonic wall, pericolonic fat stranding, abscesses, localised air bubbles, or free air
How can acute diverticulitis be staged?
Hinchey classification
How can uncomplicated diverticular disease be managed? When might someone be admitted?
can often be managed as an outpatient with simple analgesia and encouraging oral fluid intake
outpatient colonoscopy required to rule out masked malignancy
Reasons for admission:
uncontrolled pain, concerns of dehydration, significant co-morbidities or immunocompromise, significant PR bleeding, or symptoms persisting for longer than 48 hours despite conservative management
How should diverticular bleeds be managed?
most cases self limiting
if significant bleeding: blood products and stabilisation
may need embolisation or surgical resection
Management of acute diverticulitis?
Usually abx , intravenous fluids, and analgesia
- symptoms tend to improve after 2-3 days, if clinical deterioration then rescan
Surgical intervention is required in those with perforation with faecal peritonitis or overwhelming sepsis - Hartmann’s procedure
Recurrence of diverticulitis after first episode is around 10-35%. What complications can occur in severe, recurrent or persistent cases?
Diverticular stricture:
- due to scarring and fibrosis
- can cause LBO and sigmoid colectomy may be required
Fistula formation:
Colovesical fistula form between the bowel and the bladder
- recurrent UTIs, pneumoturia (gas bubbles in the urine), or passing faecal matter in the urine
Colovaginal fistula form between the bowel and the vagina
- copious vaginal discharge or recurrent vaginal infections
How can disease severity be classified in Crohn’s?
The Montreal Score can be used to classify disease severity of Crohn’s disease
Age at diagnosis
A1 = below 16yrs; A2 = between 17yrs and 40yrs; A3 = above 40yrs
Location
L1 = ileal; L2 = colonic; L3 = ileocolonic; L4 = isolated upper disease
Behaviour
B1 = non‐stricturing & non‐penetrating; B2 = stricturing; B3 = penetrating
Add a “p” if concurrent perianal disease is present
What imaging can be used in Crohn’s disease?
colonscopy gold standard investigation
CT abdo-pelvis in severe disease - can demonstrate bowel obstruction (from stricturing), bowel perforation, or intra-abdominal collections
MRI imaging to assess disease severity
- small bowel involvement and presence of any enteric fistulae (MRI small bowel) and for peri-anal disease (MRI pelvis)
Examination Under Anaesthesia (EUA) with proctosigmoidoscopy - examine and treat any perianal fistulae
What drugs should be avoided in acute attacks of Crohn’s disease?
Anti-motility drugs, such as loperamide - can precipitate toxic megacolon
Surgical intervention is indicated in Crohn’s in those with failed medical management or severe complications (such as strictures or perforation). Bowel-sparing methods should be used to prevent short-gut syndrome.
What options are available?
Ileocaecal resection (removal of terminal ileum and caecum with primary anastomosis)
Small bowel resection or large bowel resection
Surgery for peri-anal disease (e.g. abscess drainage, seton insertion, or laying open of fistulae)
Stricturoplasty (division of a stricture that is causing bowel obstruction)
Complications of Crohn’s disease?
Gastrointestinal:
Fistulae- interovesical, enterocutaneous, or rectovaginal fistula
Recurrent perianal fistulae – common and often difficult to treat
Strictures
GI malignancy – small bowel cancer is about 30x more common in those with Crohn’s disease
Extraintestinal:
Malabsorption, including growth delay in children
Osteoporosis, secondary to malabsorption or long-term steroid use
Increased risk of gallstones, due to reduced reabsorption of bile salts at the terminal ileum
Increased risk of renal stones – malabsoprtion means calcium remains in the lumen and oxalate is then absorbed freely - hyperoxaluria and formation of oxalate stones in the renal tract
What is the most common manifestation of ulcerative colitis?
proctitis (inflammation is confined to the rectum)
PR bleeding and mucus discharge, increased frequency and urgency of defecation, and tenesmus
The severity of a UC exacerbation can be graded using the Truelove and Witt criteria.
How does this use number of bowel movements each day to stratify severity?
Mild < 4
Moderate 4-6
Severe >6
AXR features of acute ulcerative colitis flares?
mural thickening and thumbprinting - severe inflammatory process in the bowel wall
lead-pipe colon is often described (best seen on barium studies)
Acute severe UC flare will need what investigation?
urgent flexible sigmoidoscopy for biopsy - to exclude other causes of colitis, including CMV colitis
Indications for acute surgical treatment of UC? What surgery will be used?
disease refractory to medical management, toxic megacolon, or bowel perforation
segmental bowel resection (usually subtotal colectomy) and defunctioning stoma, as primary anastomosis during acute IBD flare is not advised
for elective cases, total proctocolectomy is curative
Complications of UC?
Toxic megacolon
- severe abdominal pain, abdominal distension, pyrexia, and systemic toxicity
- decompression of the bowel is required as soon as possible
Colorectal carcinoma
Osteoporosis
Pouchitis - inflammation of an ileal pouch in those who have undergone an IPAA, with typical symptoms of abdominal pain and bloody diarrhoea; this can be treated with metronidazole and ciprofloxacin
What is a volvulus?
twisting of a loop of intestine around its mesenteric attachment - closed loop bowel obstruction
can lead to ischaemia, bowel necrosis and perforation
Why do most volvuli occur at the sigmoid colon?
long mesentery of the sigmoid colon (which increases with age) means that this segment bowel is more prone to twisting on its mesenteric base
Risk factors for volvulus?
Male gender
Increasing age
Neuropsychiatric disorders
Resident in a nursing home
Chronic constipation or laxative use
Previous abdominal operations
How do patients with sigmoid volvulus present?
How can it be differentiated from other causes of obstruction?
Clinical features of bowel obstruction
colicky pain, abdominal distension, and absolute constipation occur earlier on
vomiting is usually a late sign
OE: abdomen tympanic to percussion
compared to other causes of bowel obstruction has a rapid onset (few hours) and causes significant distension
Differentials for sigmoid volvulus?
alternative causes for bowel obstruction
severe constipation
pseudo-obstruction
severe sigmoid diverticular disease
Investigations for sigmoid volvulus?
Routine bloods - electrolytes, Ca2+, and TFTs to exclude any potential pseudo-obstruction
CT abdomen-pelvis with contrast - classic ‘whirl’ sign
AXR - coffee bean sign arising from LIF
Management of sigmoid volvulus?
most pts treated conservatively - decompression by sigmoidoscope and insertion of a flatus tube
- flatus tube is often left in situ for up to 24 hours after initial decompression to allow continued passage of contents
if unsuccessful formal decompression with flexible sigmoidoscope is required
What are the indications for surgery (which is usually a laparotomy for a Hartmann’s procedure) in sigmoid volvulus?
Colonic ischaemia or perforation
Repeated failed attempts at decompression
Necrotic bowel noted at endoscopy
Patients with recurrent volvulus who are otherwise healthy may choose to have an elective procedure ( usually sigmoidectomy with primary anastomosis) to prevent recurrence
Complications of sigmoid volvulus?
bowel ischaemia and perforation
longer term complications are mainly risk of recurrence (up to 90% of patients) and complications from a stoma if placed
Where is the second most common site for a volvulus?
What is it associated with?
the caecum
younger group - intestinal malformation or excessive exercise
older patients - chronic constipation, distal obstruction, or dementia
Thrombosed haemorrhoids are characterised by anorectal pain and a tender lump on the anal margin. How should they be managed?
Present within 72 hours = excision
> 72-hour history = stool softeners, ice packs and analgesia
What is the most commonly performed operation for rectal tumours?
Anterior resection (mid-high rectal tumours)
abdominoperineal excision of rectum is for low rectal or anal tumours
Emergency presentations of poorly controlled UC that fails to respond to medical therapy should usually be managed with what procedure?
sub total colectomy is safest
end ileostomy is usually created and the rectum either stapled off and left in situ
Severe rectal Crohns that has developed complications such as haemorrhage and multiple fistulae is usually best managed with what procedure?
proctectomy
What elective procedure is available for surgical management of UC when the patient wants to avoid a permanent stoma?
Panproctocolectomy and ileoanal pouch
As well as being used for screening, the FIT test is also recommended for patients with new symptoms who do not meet the 2-week criteria, for example:
patients >= 50 years with unexplained abdominal pain OR weight loss
patients < 60 years with changes in their bowel habit OR iron deficiency anaemia
patients >= 60 years who have anaemia even in the absence of iron deficiency
What is used to defunction and decompress the distal colon in obstructing cancers?
Loop colostomy
Management of anal fissures?
acute anal fissure (< 1 week):
soften stool
high-fibre diet with high fluid intake
bulk-forming laxatives are first-line
chronic anal fissure
topical GTN is first-line
if topical GTN is not effective after 8 weeks then referral should be considered for sphincterotomy or botox
A 24-year-old woman presents with a long history of obstructed defecation and chronic constipation. She often strains to open her bowels for long periods and occasionally notices that she has passed a small amount of blood. On examination she has an indurated area located anteriorly approximately 3cm proximal to the anal verge.
Diagnosis?
Solitary rectal ulcer syndrome
biopsy to exclude malignancy
triad of vomiting, pain and failed attempts to pass an NG tube =
gastric volvulus!!!
Main benefit of epidural anaesthesia used for abdo surgery?
Faster return of normal bowel function
Patients with diverticulitis flares can be managed with oral antibiotics at home. If they do not improve within 72 hours, what is indicated?
admission to hospital for IV ceftriaxone + metronidazole
strongest risk factor for anal cancer?
HPV infection
Management of fistula in ano?
Lay open if low, no sphincter involvement or IBD
If complex, high or IBD insert seton and consider other options
Management of peri-anal abscess?
Incision and drainage, leave the cavity open to heal by secondary intention
