Colorectal Flashcards
Complications of stomas
Early: necrosis, obstruction from edema, high stoma output, enterocutaneous dehiscence, leakage -peristomal excoriations
Intermediate: prolapse, retraction, infection, bleeding
Late: stenosis, parastoma fistula, skin excoriation, parastomal hernia, psychological
High output stoma definition
output > 1000ml/day (significant when >2000)
Causes of high output stoma
physiological output (diagnosis of exclusion)
sx with <200cm residual small bowel and no colon
intra-abdominal sepsis
enteritis (c difficile)
disease relapse in remaining bowel (UC)
Medication (withdrawal of steroids, pro-kinetics - metoclopramide)
bowel obstruction
Cx of high output stoma
Dehydration
Renal impair - low urine o/p
Electrolytes: HypoNa, HypoMg, HypoK (sec hyperald)
Undernutrition
Frequent stoma empty prob - leakage/ excoriation++
Mgx of high output stoma
rule out intra ab sepsis and IO. check med lists. check for enteritis.
Rehydration IV 0.9 NS. Restrict PO fluids to 500ml daily. Restrict hypotonic soln correct elec, strict fluid balance, daily weights, serum biochem - inc mg lvls Anti diarrhoea - loperamide Omeprazole to reduce gastric secretions
refer to dietician if suspect undernutrition
Aim of stoma
Decompress, Defunction, Drain
rest an inflammed distal portion
What is
- rigler sign/ double wall sign
- thumbprinting
- lead pipe
- pneumatosis intestinalis
- claw sign
- falciform ligament sign
- pneumoperitoneum
- bowel edema/ inflammation
- loss of haustra, long standing ulcerative colitis
- ischemic bowel w necrosis (gas gangrene)
- intussusception
- pneumoperitoneum
Hinchey classification and mgx
Classification of colonic perforation due to divertiticulosis
I: paracolonic abscess: IV fluid, abx, nbm KIV IR
II: pelvic abscess: IR, KIV sx for 1stage segmental colectomy with Pri anastomosis
III: purulent peritonitis
IV: feculent peritonitis
both - Hartman + sec re-anas 3 months later
Blood supply of rectum
upper 1/3: superior rectal artery (IMA)
mid and lower 1/3: int iliac artery
Dentate line - what is it and significance
aka pectinate line
separates upper 2/3 and lower 1/3 of anal canal (4cm)
distal margin of tumour must be 1-2cm above dentate line (7cm above anal verge) for sphincter conserving surgery of rectal CA
Cx of Rectal Sx
Immediate: damage to surrounding structures (ureter)
Early: stoma complications, anastomotic leak (free/ contained), bleed, infection
Late: stoma complications, tumour recurrence, anastomotic stricture, anterior resection syndrome (urinary and stool urgency, fecal incontinence), impotence
What is TME
Trans mesorectal excision
indicated for low anterior resection
reduces local recurrence rates
RF for CRC
Modifiable: smoking, alcohol, obesity, processed/ red meat
Non modifiable: age >50, male, Chinese, family history (age at diagnosis), CRC syndromes, HNPCC, previous polyps, colitis (UC, Crohns)
ask for scopes, scans, screenings
protective: fruits, veg, high fibre, vit supplements, exercise, HRT, aspirin, NSAIDs
HNPCC diagnosis
Amsterdam II Criteria
3 - 3 relatives with histo confirmed CRC or HNPCC related CAs (1 must be first deg relative with another)
2 - 2 consecutive generations
1 - 1 whose diagnosis <50yo
FAP excluded
Management of internal hemorrhoids
based on Banov staging
I: does not prolapse - lifestyle, daflon
II: prolapse, spontaneously reduce - lifestyle, daflon, elastic ligation
III: manual reduction of prolapse - above + hemorrhoidectomy (staple/ open)
IV: unable to reduce - same
Difference between internal and external haemorrhoids
Internal
- above dentate line (endoderm)
- porto venous system
- prolapse, ulceration
External
- below dentate line (ectoderm)
- superficial venous system
- thrombosis, mucus, pruritus, bleeding
- causes more symptoms
Causes of haemorrhoids
- impaired venous return (e.g. high intra-abdominal pressure), low fibre diet, straining
- portal hypertension
- increased rectal vein pressure: prolonged sitting, obesity
Most common location of hemorrhoids
3, 7, 11 o’clock position
Acutely thombosed haemorrhoids mgx
<24h: surgical excision of thrombosis, wound left open
>48h: symptomatic support
How to acutely reduce prolapsed hemorrhoid
gauze with lignocaine + cold water + dextrose soln (hyperosmolar solution)
Complications of hemorrhoidectomy
ARU, UTI, sphincter damage, bleeding, infection, anal stenosis
stoma siting principles
- over rectus sheath (reduce prolapse
- away from sx incision (reduce infx)
- away from skin creases, bony prominences (red skin gaps > excoriation)
- away from old sx scar (incisional hernia)
- sited for easy accessibility (pt can care/reach)
- low tension area during op (vascularity to prevent necrosis)
Advice for anal fissures
increased fibre lactulose sitz baths topical nifedipine ointment GTN paste botulinum toxoid injections
What is the Goodsall rule for anal fistulas
For fistula within 3cm of the anal verge and posterior to line drawn through ischial spines if
o Anterior to transverse anal line: straight radially directed tract into anal canal
o Posterior to transverse anal line: curve tract open into anal canal midline posteriorly (at
level of dentate line) 6OC
mgx of anal fistulas
based on Garg classification
I/II will benefit from fistulotomy
III-V will not
low fistula: fistulotomy and lay open/ fistulectomy
high fistula: seton
Classification of bowel prep
Boston classification
Cx of colectomy
immediate:
- damage to surrounding organs
Early:
- anas leak (D4-7)
- wound infx
- bleeding
- early stoma cx
Late: impotence, adhesions, anas strictures, diarrhoea, late stoma cx, anterior resection syndrome (urgency, fecal incontinence, frequency), tumour recurrence
diff between high, low and ultraslow AR
- High: anas above peritoneal reflection
- Low: colon anastomosed to small anal rectal remains (below)
- Ultra low: anas within 2cm of dendate line
Margins for rectal ca sphincter sparing sx
proximal 5cm distal - 2cm if above distal mesolectal margin - 1cm if at or below margin radial: 1mm
Cx of sphincter conserving sx and mgx
LARS syndrome
Fecal urgency, frequency, clustering, incontinence, emptying difficulties, increased intestinal gas (25-80%)
Mgx
- kegel exercise
- stoma enema & irrigation
- tx as per LARS score
Types of anal fistula
Park classification
- intersphincteric
- transphincteric
- suprasphincteric
- extraesphincteric
Radiological signs of pneumoperitoneum
- Rigler sign (adjacent side must not be bowel)
- Falciform ligament sign
- Football sign
- Continuous diaphragm sign
Ix of LGBIT
colonoscopy (rates doesn't matter) radionuclide imaging 0.1-0.5ml/min - tagged RBC - technetium sulphur colloid CT angiography (0.3-0.5ml/min) Mesenteric angiography (0.5-1ml/min)
last resort: laparotomy with saline lavage (on table angiogram)
- oversew of bleeding vessel
- colectomy
CEA normal levels
- other causes of raised CEA?
n: 0-2.5
smokers: 0-5
what causes raised CEA: smoking, adjuvant therapy with 5FU, inflammatory states (pancreatitis, diverticulitis, cholecystitis) and cancers (stomach, lung, breast, pancreas, cervix, bladder, kidney)
Bowel prep for colonoscopy
MEDS:
- stop Fe tablet 5 day
- stop anticoag
- adjust insulin/ metformin
- NSAIDs, aspirin can continue
DIET
- low residue > clear feed 1 day prior > NBM for 6-8h
PREP
- evening 4L PEG OR
- split dose (2L evening, 2L AM)
ADJUNCT: metoclopramide
resection margins required for CRC
5cm proximally and distally
Reconstruction options after colectomy for colon cancer
straight colonial anastomosis is a/w poor function - reservoir function
- colonic J pouch (ileal pouch anal anastomosis)
- coloplasty
Extracolonic manifestations of FAP
Benign: ABCDE (adrenal glands, bony osteoma (of skull/ mandible), congenital hypertrophy of retinal pigment epithelium, desmoid tumors, epidermoid tumors)
Malignant: hepatoblastoma, thyroid Ca (follicular, papillary), brain tumour (medulloblastoma - CP angle turcot syndrome), pancreatic/ duodenal cancers
Screening for colon cancer
- normal risk
- HNPCC
- FAP
- UC/ Crohns
-
Cancers a/w HNPCC
colorectal, small bowel, gastric
endometrial, ovarian
hepatobiliary
urinary: renal pelvis, ureter cancers
Indications for urostomy
bladder Ca, neuropathic bladder, resistant urinary incontinence
RF for diverticulosis
i. Non modifiable: ADPKD pt on dialysis
ii. Modifiable
Red meat, low dietary fiber, high fat
lack of exercise, high BMI, smoking
Meckel’s diverticulum features
Rule of 2s
- 2 inches in length, 2cm wide
- 2 feet from iliocecal valve
- 2% of population
- 2:1 male to female
- 2-4% symptomatic
- 2 types of ectopic tissue: gastric, pancreatic
Cx of Meckel’s divert
hematochezia IO: intussusception, volvulus, little hernia, diverticulitis Diverticulitis Chronic peptic ulceration perforation tumour umbilical fistula
IX and Mgx of meckel
Ix: Meckel scan (find gastric mucosa), barium study, CT angio
Mgx:
- asymptomatic: resect if seen during sx for young pts or adults <50 (with >2cm, large base >2cm, palpable)
- do not resect in pt >50yo
- symptomatic: sx
> broad base: wedge ileal resection with anastomosis
> narrow: resection of diverticulum
main arterial supply of the colon
SMA (ileocecal, right colic, middle colic, appendiceal branches)
IMA (left colic, sigmoid and superior rectal branches)
how do you assess bowel viability intra-operatively
give 100% O2 and warm packs to reverse any low flow rates
2 main techniques:
Visible light spectrophotometry (VLS)
Laser Doppler flowmetry (LDF)
