Lower GI Surgery Flashcards
what is Meckel’s Diverticulum formed from?
ileal remnant of vitellointestinal duct
(joins yoke sac to midgut lumen)
features of meckels’ diverticulum?
a true diverticulum
2 inches long
2 ft from ileocaecal valve
2% of population
2% symptomatic
what type of tissue does meckel’s diverticulum contain?
ectopic gastric
or pancreatic tissue
presentation of symptomatic meckels’
rectal bleeding - from gastric mucosa
diverticulitis mimicking appendicitis
intussusception
volvulus
malignant change: adenoca
hernia containing meckel’s diverticulum
called?
Littre’s Hernia
what is the investigation of choice for meckel’s diverticulum?
Tc 99 (Technetium-99m) pertechnetate scan
- detects gastric mucosa
Mx of Meckel’s Diverticulum
Surgical resection if symptomatic
Tc-99 pertechnetate scan -?
Meckel’s Diverticulum
causes of intussusception
idiopathic
hypertrophied peyer’s patch- following bacterial/ viral GI infections
Meckel’s Diverticulum
presentation of intussusception?
episodic inconsolable crying
drawing up legs
-> colicky abdo pain
redcurrant jelly stools
sausage-shaped abdo mass
mx of intussusception
resuscitation, nil by mouth, x-match
Reduction by rectal air insufflation
(perform in theatre)
25% failure - conduct surgery
presentation of mesenteric adenitis
abdo pain
presents similarly to appendicitis
fever
tenderness
- post URTI/ concurrent URTI
differentiating features
mesenteric adenitis vs appendicitis
progressively better rather than worse
post viral infection
headache +
higher temp
Types of malignant small bowel neoplasms?
AdenoCa (40%)
Carcinoid (40%)
Lymphoma (EATL assoc w Coeliac)
GI stromal tumours
presentation of small bowel malignancies
often presents late due to non-specific symptoms
weight loss, abdo pain
N+V, obstruction
bleeding
jaundice from biliary obstruction/ liver mets
Imaging of Small Bowel Cancer
- abdo Xray: SBO
- Barium follow through (Small bowel)
- CT scan
features of duodenal atresia?
polyhydramnios
vomiting - usually bile stained
distended stomach
strongly associated w downs syndrome
diagnosis of duodenal atresia?
abdo x ray : double bubble sign
ie. distension of stomach and proximal duodenum w absence of gas throughout the rest of the bowel
tx of duodenal atresia
duodenojejunostomy
or
gastrojejunostomy
+ rehydration and gastric aspiration
syndrome in which a non-insulin-secreting islet cell tumour of the pancreas produces a potent gastrin-like hormone
zollinger-Ellison syndrome
Zollinger-Ellison syndrome:
what is produced that leads to the ulceration?
multiple ulcers due to potent gastrin-like hormone
why do NSAIDs predispose to peptic ulceration?
NSAIDs inhibit the production of protective prostaglandins in the mucosa
what medications may increase risk of peptic ulceration?
NSAIDs
steroids
what lifestyle factors may lead to increased risk of peptic ulceration?
smoking
stress
peptic ulcer assoc with elevated intracranial pressure?
Cushing’s ulcer
peptic ulcer assoc w severe burns?
Curling’s Ulcer
a complication from severe burns when reduced plasma volume leads to ischemia and cell necrosis (sloughing) of the gastric mucosa.
episodic epigastric pain usually 2 h after meal
pain aggravated by spicy foods and relieved by milk and alkalis
Duodenal ulcer
ix with suspected duodenal ulcer?
endoscopy: to visualize oesophagus, stomach and duodenum and obtain biopsy to differentiate between benign/malignant ulcer
H pylori detection: - endoscopic biopsy (urease test), 13C-labelled urea breath test, seological testing of Hy pylori antibodies
Faecal occult blood often positive.
complications of peptic ulcer
chronicity
- long term symptoms of pain
perforation
stenosis
haemorrhage
gastric ulcers may undergo malignant change
tx of peptic ulcer
1st line
eradication of H pylori.
Omeprazole (PPI for acid reduction)
+ Clarithromycin/ Amoxicillin
+ metronidazole
what to avoid when a peptic ulcer is present?
violent gastric acid stimulants e.g. alcohol
medications e.g. aspirin/ NSAIDs
smoking
stress
How were gastric ulcers surgically treated traditionally?
Billroth I gastrectomy.
what was a traditional surgical procedure for duodenal ulcers?
Simple longitudinal duodenotomy, closed as a pyloroplasty, with under-running of the bleeding vessel performed + acid suppression w PPI
and
Polya gastrectomy with under-running of the vessel
surgical tx of gastric / duodenal ulcers?
gastric ulcers: antrectomy + Roux-en-Y gastroenterostomy
duodenal ulcers: removing the bulk of the acid-secreting area of the stomach (the body and the lesser curve), and re-establishing gastric drainage via a Roux-en-Y gastroenterostomy
causes of constipation?
organic obstruction
- colon carcinoma
- diverticular disease
causes of constipation?
painful anal conditions
anal fissure
prolapsed piles
causes of constipation?
causing an adynamic bowel
Hirschsprung’s
senility
spinal cord injuries and disease
myxoedema
Parkinsons’ disease
causes of constipation?
drugs
aspirin
opiate analgesics (codeine e.g.)
anticholinergics
ganglion blockers
causes of constipation?
habit and diet
dehydration
starvation
dyschezia (suppression of urge to defecate)
lack of bulk in diet
what is a true vs a false diverticulum?
true: an outpouching covered by all the layers of the bowel wall
e. g. Meckel’s diverticulum
false: lacking the normal muscle coat of the bowel
e. g. colonic diverticula
what are the appendices epiploicae?
epiploic appendices are small pouches of the peritoneum filled with fat and situated along the colon, but are absent in the rectum.
gas in the urine called?
pneumaturia
most common cause of colovesical fistula?
diverticulitis
ix of diverticulitis?
CT abdo
Sigmoidoscopy (fibreoptic sigmoidoscopes)/ Colonoscopy
Barium Enema
what can a rigid sigmoidoscope visualize?
rectum only
tx of acute diverticulitis
conservative mx
- fluid diet
- antibiotics (metronidazole w penicillin/ gentamicin)
ix of angiodysplasia?
colonoscopy
- lesions appear as bright red 0.5cm-1cm diameter submucosal lesions w small, dilated vessels
mesenteric angiogram
- contrast medium leaks into the lumen
tx of angiodysplasia
blood transfusion if haemorrhage severe
colonoscopic electrocoagulation or argon plasma coagulation may be curative
resection may be necessary
five main causes of colitis
- UC
- Crohns colitis
- antibiotic-associated colitis
- Infective colitis
- Ischaemic colitis
ulcerative colitis - is smoking protective or not?
yes
ulcerative colitis pathology?
crypt abscesses
oedema and submucosal fibrosis in walls of colon
smooth, atrophic mucosa
bowel wall thinned
local complications of ulcerative colitis
toxic dilatation -> peritonitis
haemorrhage
stricture
malignant change
perianal disease
diarrhoea of ulcerative colitis may be controlled by?
codeine phosphate
loperamide
what medication to induce remission in an acute attack of ulcerative colitis?
corticosteroids
what medications to maintain remission of UC?
salicylates such as mesalazine or sulfasalazine
or
anti-TNF antibodies infliximab or adalimumab
or
azathioprine/ ciclosporin
indications for surgery in UC?
fulminating disease not responding to medical treatment
chronic disease not responding to medical tx
prophylaxis against malignant change w long-standing disease
complications of colitis
*usually total removal of the colon and rectum w either a permament ileostomy or an ileoanal anastomosis
non-invasive screening test for familial adenomatous polyposis?
affected individuals usually have hypertrophy of the retinal pigment layer
symptoms of colon ca?
change in bowel habit
intestinal obstruction
perforation of the tumour
what adjuvant chemotx is used post-operatively w colon cancer?
5-fluorouracil (5-FU)
with folinic acid
what does the superior mesenteric artery supply?
midgut components
e.g. caecum, ascending colon, 2/3 of the transverse colon
what does the inferior mesenteric artery supply?
hindgut components
e.g. distal transverse colon, descending colon, sigmoid and rectum
what is the watershed area of the colon?
the area between the superior and inferior mesenteric artery supply
what surgical mx of a right sided lesion?
right hemicolectomy
w ileocolic anastomosis
what surgical mx of a left sided lesion?
left hemicolectomy
or
sigmoid colectomy
w anastomosis of colon to rectum
What surgical mx of a sigmoid lesion?
sigmoid colectomy
elective
or emergency (Hartmann’s)
indications for colostomy formation
to divert faeces to allow healing of a more distal anastomosis or fistula
to decompress a dilated colon, as a prelude to resection of the obstructing lesion
removal of the distal colon and rectum
what is a loop colostomy?
colon brought to surface and antimesenteric border opened
rod used to stop opened bowel loop from falling back inside
- used to divert faeces and is simple to reverse
- loop ileostomy preferred because of better blood supply to the bowel facilitating subsequent closure
complications of colostomy formation
retraction: colon disappears down the hole
stenosis: opening becomes smaller. may be due to ischaemia or poor apposition of colonic mucosa w skin edge
paracolostomy hernia: peritoneal contents herniate through the abdo wall defect made to accommodate the stoma
prolapse: in which colon intussuscepts out of the stoma
lateral space small bowel obstruction
skin excoriation due to ill-fitting stoma appliances or poorly constructed stomas
why are ileostomies spouted?
ileostomy effluent is very irritant and causes severe skin excoriation
-> ileostomy constructed w a spout to keep the effluent off the skin
what helps stoma patients produce bulky, formed stool?
Fybogel or Celevac
what are the usual positions of haemorrhoids in a patient?
3, 7 and 11 oclock
How to grade haemorrhoids?
Grade I: confined to anal canal
II: prolpase on defecation and reduce spontaneously
III: prolapse on defecation and manually replaced
IV: remain prolpased outside anal margin at all times
predisposing factors to haemorrhoids
may be aggravated by factors that produce congestion of the superior rectal veins
e.g.
pregnant uterus
cardiac failure
pelvic tumour
excessive use of purgatives
chronic constipation
rectal ca
what to do examination/ investigation wise when suspecting haemorrhoids
- examination of abdomen
to exclude palpable lesions of the colon or aggravating factors for haemorrhoids (pelvic mass e.g.)
- Rectal exam
- Proctoscopy
- Sigmoidoscopy to eliminate lesion higher in the rectum
- Colonoscopy or flexi sigmoidoscopy when symptoms point to a more sinister condition than internal haemorrhoids
complications of haemorrhoids
anaemia: following severe/ continued bleeding
thrombosis: prolapsed piles strangulated by anal sphincter -> painful + suppuration/ ulceration may occur
conservative advice for haemorrhoids
pt should avoid straining at stool and aim to pass a firm, soft motion daily.
bulk laxative + adequate fluid intake
mx of haemorrhoids
1st line: band ligation
then sclerotherapy (for first / second degree haemorrhoids)
surgery- haemorrhoidectomy for 3rd/4th degree haemorrhoids
what does banding of haemorrhoids involve?
application of small O-ring rubber band to areas of protruding mucosa
- > strangulation of mucosa
- > falls away after few days
must be placed above the detate line, if not pt would feel the application
mx of thrombosed strangulated piles?
foot of bed elevated
opiate analgesia
local cold compresses
often thrombosed piles fibrose completely w spontaneous cure
or
haemorrhoidectomy at once
complications of haemorrhoidectomy
acute retention of urine due to discomfort post-operatively
stricture - when excessive amounts of skin are excised
post operative haemorrhage
anal fissures- usual position?
posterior in the midline
tx of anal fissures
local anaesthetic ointment
+
lubricant laxative
+ GTN or diltiazem cream to relax the anal sphincter
what is a fistula?
an abnormal communication between two epithelial surfaces
what is a sinus?
a granulating track leading from a source of infection to a surface
tx of superficial and low-level anal fistulae?
laid open and allowed to heal by granulation
mx of high fistulae (suprasphincteric, transsphincteric)
fistula track can be injected w fibrin glue/ bio-prosthetic fistula plug
or
lower part of the track laid open and a seton passed through the upper part of the track and left for 2-3 wks so that the spincter is fixed by scar tissue.
the track is then divided by repeated tightening of the ligature.
Systematic approach of AXR?
- Bowel Gas Pattern
- bowel diameter
- position - extraluminal gas (under diaphragm, riglers sign)
- Soft tissues
- Calcification
- Masses
- Bones
Difference between small and large bowel on AXR?
Small bowel:
more central
normal diameter <3 cm
valvulae conniventes - which go across the whole colon
Large bowel:
more peripheral - can see ascending, transverse and descending colon
haustra (only go part of the way across)
normal diameter of transverse <6 cm
caecam < 8cm
Presence of valvulae conniventes
cluster of dilated small bowel loops in the central abdomen
-> Small bowel obstruction (ileus would usually affect both large and small)
most common cause: adhesions from prev surgeries
dilated large bowel from caecum to mid descending colon
diagnosis: large bowel obstruction
(small bowel not obstructed here bec ileocaecal valve is still competent)
gas on both sides of bowel wall
Rigler’s sign
diagnosis: intestinal perforation w free intraperitoneal gas
gas under diaphragm
-> perforation
Distended loop of colon (see haustra) arising from pelvis
diagnosis: sigmoid volvulus (twisting of segment of bowel around its mesentery)
large calcific opacity overlying right renal outline
upper part is same shape as renal collecting system
diagnosis: right renal staghorn calculus
multiple opacities within the pancreas
-> chronic pancreatitis
Gallstones
e.g. calcium oxalate
Pregnancy
- see fetal spine, skull, legs
in general, women of child bearing age imaging of abdo / pelvis using ionising radiation should be restricted to the 10 days following menstruation
presentation of small bowel neoplasm?
often non specific symptoms so present late
n/v, obstruction
weight loss and abdo pain
bleeding
jaundice from biliary obstruction or liver mets
imaging of small bowel neoplasia?
AXR: SBO
Ba follow through
CT
types of benign small bowel neoplasms?
adenomatous polyps (FAP, Peutz-Jeghers)
Haemangioma
Neurofibroma
Leiomyoma
Lipoma
What gut lymphoma is assoc w coeliac disease?
Enteropathy associated t cell lymphoma (EATL)
carcinoid tumours are?
neuroendocrine tumours of enterochromaffin cell origin capable of producing 5HT
may secrete: 5-HT, VIP, gastrin, glucagon, insulin, ACTH
most commonly in appendix
features of carcinoid syndrome?
flushing: paroxysmal, upper body +/- wheals
intestinal: diarrhoea
valve fibrosis: tricuspid regurg and pulm stenosis
wheeze: bronchoconstriction
tryptophan deficiency -> pellagra (3Ds - dementia, diarrhoea, dermatitis)
ix of carcinoid syndrome?
increased urine 5-hydroxyindoleacetic acid
CT/MRI: find primary
mx of carcinoid syndrome?
symptoms: octreotide or loperamide
curative: resection
what is carcinoid crisis?
massive mediator release
-> vasodilation, hypotension, bronchoconstriction, hyperglycaemia
mx of carcinoid crisis?
high-dose octreotide
definition of appendicitis?
inflammation of the vermiform appendix randing from oedema to ischaemic necrosis and perforation
reason behind pattern of abdo pain in acute appendicitis?
early inflammation -> appendiceal irritation
nociceptive info travels in the sympathetic afferent fibres that supply the viscus
-> pain referred to dermatome corresponding to spinal cord entry level of these sympathetic fibres
appendix = midgut = (T10/11)
Late inflammation -> parietal peritoneum irritation
- pain localised in RIF
signs of Acute appendicitis?
guarding and tenderness @ McBurney’s point (1/3 between asis and umbilicus)
appendix mass may be palpable in RIF
Rovsing’s sign: pressure in LIF -> more pain in RIF
Psoas sign: pain on extending the hip- retrocaecal appendix
Cope sign: flexion + internal rotation of R hip -> pain
- appendix lying close to obturator internus
mx of acute appendicitis?
prep for theatre: NBM, x-match, G+S
fluids
abx: cef n met
analgesia: paracetamol, NSAIDs, codeine
diagnostic lap
uncertain dx -> acute observation
complications of acute appendicitis?
appendix mass
appendix abscess
perforation: deteriorating pt w peritonitis
smoking in crohns vs UC?
smoking protective in UC
but increases risk in Crohns
pathology of UC vs Crohns?
UC:
continuous mucosal inflammation from rectum upwards
shallow, broad ulcers
Crohns:
transmural inflammation from mouth -> anus esp terminal ileum
skip lesions
strictures
cobblestone mucosa
marked fibrosis
granulomas
fistulae
skin findings in IBD?
clubbing
erythema nodosum
pyoderma gangrenosum (esp UC)
eyes symptoms in IBD?
anterior uveitis
conjunctivitis
episcleritis
scleritis
joints in IBD?
(enteropathic) arthritis
sacroilitis
ank spond
hepatobiliary features in IBD?
PSC + cholangiocarcinoma (UC)
gall stones (esp crohns)
fatty liver
extra- abdominal features of IBD?
Crohns:
aphthous ulcers, glossitis
perianal abscesses, fistulae, tags
anal strictures
amyloidosis
oxalate renal stones (esp crohns)
Ix in Ulcerative colitis?
Bloods:
FBC etc
blood cultures
Stool cultures to exclude infectious cause
Imaging:
AXR- megacolon, wall thickening
CXR - perforation
Ba/ gastrograffin enema
ileocolonoscopy + regional biopsy
Barium/ gastrograffin enema findings of Ulcerative colitis?
Lead pipe colon: no haustra
thumbprinting: mucosal thickening
pseudopolyps: regenerating mucosa
In Truelove and Witts Criteria determining severity of UC, what is considered severe?
Motions: >6
PR bleed: large
temp: >37.8
HR: >90
Hb <10.5
ESR > 30
In Truelove and Witts Criteria determining severity of UC, what is considered moderate?
Motions 4-6
PR bleed: moderate
Temp: 37.1-37.8
HR 70-90
Hb 10.5-11
In Truelove and Witts Criteria determining severity of UC, what is considered mild?
Motions: <4
PR bleed: small
Temp: apyrexic
HR <70
Hb >11
ESR <30
Mx of acute severe UC?
resus: admit, IV fluids, NBM
Hydrocotrisone IV 100 mg QDS
Transfuse blood if required
Thromboprophylaxis: LMWH
Monitor bloods (FBC, ESR, CRP, U+E), vitals + stool chart, twice daily examination +/- AXR
acute complications of Severe UC?
perforation
bleeding
toxic megacolon (>6 cm)
VTE
mx of acute severe UC with improvement on IV hydrocortisone?
switch to oral pred + a 5-ASA
taper pred after full remission
mx of acute severe UC w no improvement on IV hydrocortisone?
On day 3: stool freg >8 or CRP >45
- > predicts 85% chance of needing a colectomy during the admission
medical: ciclosporin, infliximab
surgical: subtotal colectomy
1st line therapies in inducing remission in ulcerative colitis?
1st line: 5-ASAs
2nd line: prednisolone
medication for Maintaining remission in UC?
1st line: 5-ASAs PO- sulfasalazine or mesalazine
(topical tx may be used in proctitis)
2nd line: azathioprine or mercaptopurine
3rd line: infliximab/ adalimumab
indications for emergency surgery in UC?
toxic megacolon
perforation
massive haemorrhage
failure to respond to medical tx
AXR findings SBO vs LBO?
diameter: SBO ≥3 cm
LBO ≥ 6cm
(Caecum ≥ 9cm)
Location: SBO- central
LBO- peripheral
SBO: valvulae conniventes
LBO: haustra
SBO: many loops
LBO: few
Mx of Bowel obstruction?
Resus: NBM
IV fluids
NGT: decompress upper GIT, stops vomiting, prevents aspiration
catheterise: monitor UO
analgesia
antibiotics: cef n met if strangulation or perf
gastrograffin study: oral or via NGT
consider need for parenteral nutrition
non operative mx sucessful in 80% of pts w SBO w/o peritonitis
otherwise: surgery
indications for elective surgery of ulcerative colitis?
chronic symptoms despite medical therapy
carcinoma or high grade dysplasia
what surgeries are done electively for UC?
panproctocolectomy w end ileostomy or IPAA (ileal pouch anal anastomosis)
or
total colectomy w Ileal rectal anastomosis
UC surgical complications?
abdo: SBO (adhesions), anastomotic stricture, pelvic abscess
Stoma: retraction, stenosis, prolapse, dermatitis
Pouch: pouchitis, faecal leakage
ix (diagnostic) of Crohns?
ileocolonoscopy + regional biopsy
ix of Crohns duriing a severe attack?
high temp, raised HR, high CRP+ ESR, high WCC, low albumin
what blood results are severity markers of crohns?
FBC: low Hb, high WCC
LFT: low albumin
raised CRP/ESR
mx of Severe attack of Crohns?
resus: admit, NBM, IV fluids
Hydrocortisone IV + PR if rectal disease
ABx: metronidazole PO or IV
thromboprophylaxis: LMWH
Dietician review: elemental diet, consider parenteral nutrition
monitoring: vitals, stool chart, daily exam
following mx if improvement following IV + PR hydrocortisone in severe attack of crohns?
Switch to oral prednisolone (40mg/ day)
following mx if no improvement following IV + PR hydrocortisone in acute severe attack of Crohns?
discussion between pt, physician and surgeon
medical: methotrexate +/- infliximab
surgical
inducing remission in mild / mod Crohns disease?
supportive: high fibre diet, vitamin supplements
Oral:
1st line
- ileocaecal: budesonide
- colitis: sulfsalazine
2nd line: prednisolone (tapering)
3rd: methotrexate
4th: infliximab or adalimumab
maintaining remission in Crohns?
1st line: azathioprine or mercaptopurine
2nd: methotrexate
3rd: infliximab/ adalimumab
indications for surgery in Crohns?
emergency:
failure to respond to medical tx
intestinal obstruciton/ perforation
massive haemorrhage
elective:
abscess or fistula
perianal disease
chronic ill health
carcinoma
what surgical procedures are carried out in Crohns disease?
limited resection e.g. ileocaecal
stricturoplasty (alleviate bowel narrowing due to scar tissue)
defunction distal disease w temporary loop ileostomy
complications of surgery in crohns?
stoma complications
enterocutaneous fistula
anastomotic leak or stricture
features of short gut?
<1 -2m small bowel
steatorrhoea
ADEK and B12 malabsorption
bile acid depletion -> gall stones
hyperoxaluria -> renal stones
definition of diverticulum?
outpouching of tubular structure
true = composed of complete wall e.g. Meckels
false = composed of mucosa only (pharyngeal, colonic)
definition of diverticular disease?
symptomatic diverticulosis
definition of diverticulitis?
inflammation of diverticula
pathophysiology of diverticular disease?
assoc w raised intraluminal pressure
(low fibre diet)
mucosa herniates through muscularis propria at points of weakness where perforating arteries enter
most commonly in sigmoid colon
commoner in obese pts
features of diverticular disease?
altered bowel habit
left sided pain /colic
relieved by defecation
nausea
flatulence
mx of diverticular disease?
high fibre diet, mebeverine (relaxing gut muscles) may help
elective resection for chronic pain
presentation of diverticulitis?
faeces -> obstruction of diverticulum
abdo pain and tenderness
- typically LIF
- localised peritonitis
pyrexia
ix in diverticulitis?
Bloods:
WCC, CRP/ESR, Amylase, G+S/x match
Imaging:
erect cxr- look for perforation
AXR- fluid level/ air in bowel wall
contrast CT
gastrograffin enema
endoscopy: flexi sig, colonoscopy (not in acute attack -> can perf)
Mx of acute diverticulitis?
if mild:
treat at home w bed rest (fluids only) and augmentin +/- metronidazole
admit if unwell, fluids not tolerated, pain uncontrolled
Medical: NBM, IV fluids, analgesia, antibiotics: cef n met
most cases settle
if not, Surgery: Hartmanns to resect diseased bowel
indications for surgery in acute diverticulitis
perforation
large haemorrhage
stricture -> obstruction
Surgical mx of Acute Diverticulitis?
Hartmann’s procedure:
surgical resection of the rectosigmoid colon w closure of the anorectal stump and formation of end colostomy
(in emergency, immediate anatomosis is not possible)
complications of diverticulitis?
perforation: sudden onset pain, generalised peritonitis and shock
haemorrhage: sudden, painless bright red PR bleed
abscess: swinging fever, localising signs
fistulae
strictures
mx of perforation in acute diverticulitis?
hartmanns
mx of haemorrhage in acute diverticulitis?
usually stops spontaneously
may need transfusion
colonoscopy +/- diathermy/ adrenaline
embolisation
resection
mx of abscess in acute diverticulitis?
abx + CT/ US guided drainage
features of colovesicular fistulae?
pneumaturia
intractable UTIs
tx: resection
mx of strictures following acute diverticulitis?
resection
stenting
commonest cause of SBO?
adhesions: 60%
hernias
commonest causes of LBO?
colorectal neoplasia: 60%
diverticular stricture: 20%
volvulus: 5%
types of bowel obstruction?
simple: 1 obstructing point + no vascular compromise
may be partial or complete
closed loop:
bowel obstructed @ 2 points
- volvulus
- competent ileocaecal valve
- > gross distension -> perforation
strangulated: compromised blood supply
localised constant pain + peritonism
fever + raised WCC
paralytic ileus may occur when?
usually small bowel ileus
post op
peritonitis
pancreatitis
poisons/ drugs e.g. TCAs
metabolic: low K, Na, mg, uraemia
mesenteric ischaemia
causes of mechanical bowel obstruction?
intraluminal:
impacted matter: faeces, worms
intussusception
gallstones
intramural:
benign stricture (IBD, surgery, diverticulitis, radiotx)
neoplasia
congenital atresia
extramural:
hernia
adhesions
volvulus
extrinsic compression: tumour, abscess, haematoma, pseudocyst, congenital bands (e.g. Ladd’s)
features of bowel obstruction?
colicky abdo pain
distension: increases w lower obstructions
vomiting: early in high obstruction, late or absent in low obstructions
absolute constipation: no faeces or flatus
examination of bowel obstruction?
fluid status
fever
surgical scars
hernias
mass: neoplastic/ inflammatory
bowel sounds: increased / tinkling in mechanical obstruction
decreased in ileus
imaging in bowel obstruction?
erect CXR: free air
AXR: bowel obstruction
CT: can show transition point
Gastrograffin studies: look for mechanical obstruction
follow through may relieve mild mechanical obstruction: usually adhesional
Bloods in Bowel obstruction?
FBC: raised WCC
U+E; dehydration, electrolyte abnormalities
Amylase: raised if strangulation/ perforation
VBG: raised lactate in strangulation
G+S/ clotting: may need surgery
indications for surgical treatment of bowel obstruction?
closed loop obstruction
obstructing neoplasm
strangulation/ perforation -> sepsis, peritonitis
failure of conservative mx (up to 72h)
surgical procedures for SBO?
adhesiolysis
surgical procedures for LBO?
Hartmann’s
Colectomy + primary anastomosis
Palliative bypass procedure
tranverse loop colostomy or loop ileostomy
caecostomy
Sigmoid volvulus
(80% of volvulus)
- > characteristin inverted U/ Coffee bean sign
- long mesentery w narrow base predisposes to torsion
presentation of sigmoid volvulus?
often elderly, constipated, co morbid pts
assoc w neuropsych conditions e.g. parkinsons, schizophrenia
massive distension w tympanic abdomen
AXR signs of sigmoid volvulus?
coffee bean
/ inverted U sign
Mx of sigmoid volvulus?
often relieved by sigmoidoscopy and flatus tube insertion
-> monitor for signs of bowel ischaemia following decompression
sigmoid colectomy occassionally required
-> when failed endoscopic decompression/ bowel necrosis
often recurs -> elective sigmoidectomy may be needed
Caecal volvulus
kidney bean sign
assoc w adhesions
mx of caecal volvulus
only 10% of pts can be detorsed w colonoscopy -> typically requires surgery
right hemicolectomy w primary ileocolic anastomosis
caecostomy
features of gastric volvulus?
triad of gastro-oesophageal obstruction:
vomitng -> retching w regurgitation of saliva
pain
failed attempts to pass an NG tube
risk factors for gastric volvulus?
congenital:
bands, rolling/ paraoesophageal hernia, pyloric stenosis
acquired:
gastric/ oesophageal surgery
adhesions
Ix of gastric volvulus?
Xray shows gastric dilatation and double fluid level on erect films
Mx of gastric volvulus?
endoscopic manipulation
emergency laparotomy
presentation of paralytic ileus?
adynamic bowel secondary to absence of normal peristalsis
usually SBO
reduced or absent bowel sounds
mild abdo pain: not colicky
prevention of paralytic ileus?
decreased bowel handling
laparoscopic approach
peritoneal lavage after peritonitis
unstarched gloves
mx of paralytic ileus?
conservative drip and suck mx
correct any underlying causes: e.g. drugs, metabolic abnormalities
consider need for parenteral nutrition
exclude mechanical cause if protracted
What is Ogilvie’s syndrome?
Colonic Pseudo obstruction
acute dilation of the colon in the absence of any mechanical obstruction in severely ill patients.
massive dilatation of the cecum (diameter > 10 cm) and right colon on abdominal X-ray.
cause of colonic pseudo-obstruction?
aetiology unknown
assoc w:
elderly
cardioresp disorders
pelvic surgery e.g. hip arthoplasty
trauma
Mx of colonic pseudo-obstruction?
neostigmine: anticholinesterase
colonoscopic decompression: 80% successful
types of colonic adenomas?
colonic adenomas are benign precursors to colorectal cancer
characterised by dysplastic epithelium
tubular: small, pedunculated tubular glands
villous: large, sessile, covered by villi
tubulovillous: mixture
presentation of colonic adenomas?
typically asymptomatic
large polyps can bleed -> IDA
villous adenomas can -> low K+ and hypoproteinaemia
what increases the malignant potential of a colonic adenoma?
large size
large amount of dysplasia
increased villous component
what gene mutation is assoc w colorectal cancer?
APC gene
oncogene
also kras
p53
other risk factors for colorectal cancer?
diet: low fibre, high refined carb
IBD
Familial: FAP, HNPCC, Peutz Jeghers
Smoking
Genetics
NSAIDs/ Aspirin: protective
most common type of colon cancer?
95% adenocarcinoma
most commonly in rectum 35% then sigmoid 25%
You are a new Foundation Year 1 (FY1) doctor working on a colorectal surgery ward and notice many patients are having post-operative analgesia given via an epidural.
What is the main benefit of this form of analgesia compared to alternative forms?
faster return of normal bowel function
presentation of colon cancer?
altered bowel habit
PR bleeding/ mucus
tenesmus
PR mass
obstruction
right sized mass: anaemia, weight loss
examination of colon cancer?
abdo exam: palpable mass/ hepatomegaly/ signs of obstruction
PR exam: mass, perianal fistulae
What tumour marker is most assoc w colorectal ca?
CEA
carcinoembryonic antigen
what imaging is required in pt diagnosed w colorectal ca?
CT chest abdo pelvis for complete staging
Entire colon should be evaluated w colonoscopy or CT colonography
those w tumours pelow the peritoneal reflection should have their mesorectum evaluated w MRI
ix for suspected colorectal ca?
Bloods:
FBC- Hb
LFTs- Liver mets
Tumour marker - CEA
Imaging: CXR, US liver- mets
CT and MRI- staging
Ba/ gastrograffin enema - apple core lesion
endoscopy + biopsy: flexi sig/ colonosocopy
staging of Colon cancer?
Dukes criteria
A: confined to bowel wall
B: through bowel wall but no LNs
C: regional LNs
D: distant mets
TNM staging of colon cancer?
TIS: carcinoma in situ
T1: submucosa
T2: muscularis propria
T3: subserosa
T4: through the serosa to adjacent organs
N1: 1-3 nodes
N2: >4 nodes
Grading: low to high based on cell morphology. dysplasia, mitotic index, hyperchromatism
Mx of colon cancer?
MDT
surgical resection of cancer - tailored to tumour location
-> + resection of supplying lymphatic chains (which follows arterial supply)
or palliation: stents, surgical bypass, diversion stomas
then chemotx
prior to surgery for colon ca- what advice?
preop bowel prep (except R sided lesions)
e. g. Kleen Prep (Macrogol: osmotic laxative) the day before and phosphate enema in the AM
consent: discuss stomas
stoma nurse consult for siting
what is required for anastomosis to heal?
adequate blood supply
mucosal apposition
no tissue tension
surrounding sepsis, unstable pts and inexperienced surgeons may compromise these key principles -> may be safer to construct end stoma rather than attempting an anastomosis
Mx of Rectal Cancer?
MDT
Surgeries: Anterior resection or APR (Abdomino-perineal excision of rectum)
+ total mesorectal excision (meticulous dissection of mesorectal fat and LNs) for tumours of the middle and lower third
Neo-adjuvant radio therapy to decrease local recurrence
w rectal ca, when do you decide to anterior resection vs Abdominoperineal excision of the rectum?
APR:
involvement of the sphincter complex or v low tumours (ie. <4 cm from anal verge)
What type of resection and anastomosis is required for cancer in caecum, ascending or proximal transverse colon?
Right hemicolectomy w ileocolic anastomosis
what type of resection and anastomosis is required for cancer in distal transverse and descending colon?
Left hemicolectomy w colo-colon anastomosis
what type of resection and anastomosis is required if cancer is in the sigmoid colon?
high anterior resection w colo-rectal anastomosis
what type of resection and anastomosis is required in cancer in the upper rectum?
anterior resection with total mesorectal excision
and a colo-rectal anastomosis
what type of resection and anastomosis is required in pt w cancer in low rectum?
anterior resection with low total mesorectal excision
and a colorectal anastomosis +/- defunctioning stoma
what type of resection and anastomosis is recommended for pt w ca in anal verge?
abdominoperineal excision of rectum
no anastomosis
is anastomosis of colon done in the emergency setting?
no
in emergency setting e.g. when bowel has perforated the risk of anastomosis is much greater, particularly when anastomosis is colon-colon
end colostomy safer and can be reversed later
resection of sigmoid colon+ end colostomy = Hartmanns procedure
what screening is available for colorectal cancer?
60-75 yrs
home faecal occult blood testing every 2 yrs (2% false positive)
colonoscopy if FOB +ve
what is familial adenomatous polyposis?
autosomal dominant
APC gene on 5q21
100-1000s of adenomas by 16 yrs
- mainly in large bowel
- also affects stomach and duodenum
100% develop colorectal cancer
what is attenuated FAP?
<100 adenomas
Colorectal ca later in life (>50 yrs)
What is Gardener’s syndrome?
subtype of FAP
will lead to colorectal cancer
also TODE
Thyroid tumours
Osteomas of the mandible, skull and long bones
Dental abnormalities: supernumerary teeth
epidermal cysts
what is Turcot’s syndrome?
assoc w FAP/ HNPCC
characterised by multiple adenomatous colon polyps
+ CNS tumours: medullo and glioblastomas
mx of Familial adenomatous polyposis?
prophylactic colectomy before 20 yrs
total colectomy + ileorectal anastomosis
-> requires life long stump surveillance
proctocolectomy + ileal pouch-anal anastomosis
risk of ca in stomach and duodenum remain -> regular endoscopic screening
What is hereditary non polyposis colorectal cancer?
autosomal dominant
commonest cause of hereditary colorectal cancers
assoc with gastric, endometrial, prostate, breast, ovarian ca
dx of HNPCC?
321 rule
≥3 family members over 2 generations w one < 50 yrs
in patients w fulminant UC, why is the rectum not taken out during emergency surgery?
subtotal colectomy is safest tx option
rectum is left in situ as resection of the rectum in these acutely unwell patients carries an extremely high risk of complications
-> if bowel is v oedematous, may be brought to surface as mucous fistula
mx of severe perianal and or rectal crohns?
proctectomy
- ileoanal pouch reconstruction in crohns carries a high risk of fistula formation and pouch failure and is not recommended
what is Peutz Jeghers syndrome?
autosomal dominant
mucocutaneous hyperpigmentation - on palms, buccal mucosa
multiple GI hamartomatous polyps
-> increased risk of haemorrhage, intussusception
increased ca risk of colorectal ca, pancreas, breast, lung, ovaries, uterus
causes of acute mesenteric ischaemia?
arterial: thrombotic (35%), embolic (35%)
non occlusive: splanchnic vasoconstriction secondary to shock
venous thrombosis
trauma, strangulation, vasculitis
presentation of mesenteric ischaemia?
nearly always small bowel
triad:
- acute severe abdo pain +/- PR bleed
- rapid hypovolaemia -> shock
- no abdo signs
degree of illness >> clinical signs
may be in AF
ix of mesenteric ischaemia?
bloods:
high Hb: plasma loss
high WCC
high amylase
persistent metabolic acidosis: raised lactate
imaging:
AXR- gasless abdo
arteriography/ CT/MRI angio
complications of mesenteric ischaemia?
septic peritonitis
SIRS
mx of mesenteric ischaemia?
fluids
abx: gent + met
LMWH
laparotomy: resect necrotic bowel
ileostomy vs colostomy stoma?
small bowel stomas should be spouted so that their irritant contents are not in contact with the skin
usually more high output than colonic stomas
colonic stomas: flat
cause of chronic small bowel ischaemia?
atheroma + low flow state e.g. LVF
features of chronic small bowel ischaemia?
severe, colicky post prandial abdo pain
‘gut claudication’
PR bleeding
malabsorption
weight loss
what is a mucous fistula?
To decompress a distal segment of bowel following colonic division or resection
Where closure of a distal resection margin is not safe or achievable
mx of chronic small bowel ischaemia?
angioplasty
features of chronic large bowel ischaemia?
lower, left sided abdo pain
bloody diarrhoea
pyrexia
tachycardia
ix of chronic large bowel ischaemia?
raised WCC
barium enema: thumb printing
MR angiography
complications of chronic large bowel ischaemia?
may -> peritonitis and septic shock
strictures in the long term
mx of chronic large bowel ischaemia?
usually conservative: fluids, abx
angioplasty and endovascular stenting
causes of lower GI bleed?
rectal: haemorrhoids, fissure
diverticulitis
neoplasm
inflammation: IBD
infection
polyps
large upper GI bleed
angio: dysplasia, ischaemic colitis, HHT
1st line ix for lower GI bleed?
1st: rigid proctoscopy/ sigmoidoscopy
2nd: OGD
mx of lower GI bleed?
resus
abx: if evidence of sepsis or perf
PPI: if upper GI bleed possible
keep bed bound
stool chart
diet: keep on clear fluids
surgery: only if unremitting, massive bleed
role of CEA in colorectal ca?
used to monitor for recurrence in patients post-operatively or to assess response to treatment in patients with metastatic disease
most common type of anal ca?
80% are SCC
ix of angiodysplasia?
exclude other dx:
PR exam, barium enema, colonoscopy
mesenteric angiography or CT angio
Tc labelled RBC scan: identify active bleeding
mx of angiodysplasia?
embolisation
endoscopic laser electrocoagulation
resection
