Colorectal Flashcards
Altered bowel habit means?
Changes in
- Frequency
- Consistency
How to estimate roughly how much blood is in stool?
How many times do they go toilet to pass out blood in a day
Criteria for urgent referral colonoscopy within 2 weeks
> Unexplained rectal bleed with >= 1 of following:
- fresh blood
- blood mixed with stool
- altered bowel habit
- significant LOW
AND/OR
> Unexplained IDA
AND/ OR
> Palpable abdominal or rectal mass
Symptoms of right CCA vs left CCA vs rectal ca
> Right
- IDA
- Abdominal mass (cauliflower type)
> Left
- Intestinal obstruction (annular ring tumour, lumen smaller)
> Rectal
- Tenesmus
- Mucoid stool
- Pencil-thin stool
Investigation for colon Ca
> Diagnosis
- Colonoscopy (direct visualization, biopsy, detection of synchronous lesion)
> Staging
- CT TAP for CCA
- MRI rectum for rectal Ca
- EUS: depth of invasion
- PET and Bone scan
> Assess complicaiton
- FBC: IDA
- RP: increase Cr at risk of contrast nephropathy
- LFT: albumin for nutrition status, ALP for liver mets
- Erect and supine AXR: intestinal obstruction
- Erect CXR: air under diaphragm for perforated tumour
Management of rectal Ca
> From anal verge
- 17-10cm: HAR
- 10-5cm: LAR
- 5-0cm: ULAR
- Sphincter involved: APR
> Total mesorectal excision
- as part of LAR for middle and lower rectum Ca
> According to staging
- T1: local excision
- T2: local excision + adjuvant chemo/ RT OR radical resection
- T3/4: Neoadjuvant CCRT before radical resection
Follow up for colorectal Ca
- History, physical examination and CEA levels every 3-6 months for 5 years
- Surveillance colonoscopy at year 1 and every 3-5 years thereafter
- CT TAP performed annually for 3 years
Bowel prep for colonoscopy
- Stop Fe tablet >5 days prior +- stop anticoagulant
- Low residual diet 2-5 days prior
- Clear liquid 1 day prior
- NBM 6-8 hours prior
- FLEET osmotic agent 2-3 packs (4pm, 8pm)
TNM staging for colorectal Ca
> Primary tumor
- T1: invade submucosa
- T2: invade muscularis propria
- T3: invade through the muscularis propria into pericolorectal tissues
- T4a: penetrate to the surface of visceral peritoneum
- T4b: invades or adherent to other organs or structures
> Regional LN
- N1: 1-3
- N2: 4 or more
> Distance metastasis
- M0: No
- M1: Distance metastasis
Consent for a colon operation
> Explain about the surgery
Risk and complication
- injury to BV which may cause bleeding
- bleeding which may require a blood transfusion
- risk of transfusion: transfusion reaction, cross-infection (eg: HIV, Hep B/C)
- risk of injury to surrounding organs (eg: small bowel, bladder, liver)
- post-operative - wound infection/ breakdown
- general anesthesia risk and complication
Difference between ileostomy and colostomy
> Ileostomy
- RIF
- 3cm “spout” to prevent ileal content (corrosive) to contact the skin
- watery greenish output
> Colostomy
- LIF
- flushed to the skin
- firm brown fecal output
Complication of stoma
> Early
- Infection
- Necrosis
- Obstruction (fecal impaction/ adhesion)
- Leakage
- Stoma diarrhea
> Intermediate
- Prolapse of bowel
- Retraction
> Late
- Parastomal hernia
- Stenosis
- Skin excoriation
- Fistulae
Cause of increased output in stoma patient (>1000ml/day)
- Primary: loss of normal daily secretion (1.5L saliva, 2-3 gastric juice, 1.5L pancreatico-biliary)
- Other: intra-abdominal sepsis, infective enteritis, intermittent bowel obstruction
What is rule of 2?
> For Merkel's diverticulum ○ 2 inches in length, 2cm wide ○ 2 feet (60cm) from ileocecal valve ○ 2% of the population ○ 2:1 ratio (M:F) ○ 2-4% symptomatic
Investigation for Merkel’s diverticulum
○ Blood
§ Same as IO/ LGIB
○ Imaging
§ Meckel's scan
□ Technetium-99m pertechnetate scan
□ Detect gastric mucosa
§ Barium studies
□ Small bowel enterocolitisDefinitive management of Merkel’s diverticulum
§ Broad base - wedge ileal resection with anastomosis
§ Narrow base - resection of the diverticulum
What is pectate line
- Irregular circle form by anal valve
- Divide anal canal into endodermal and ectodermal origin
What is McBurney point
- Point that lies 1/3 of the distance laterally on a line drawn from the umbilicus to the right ASIS
3 cardinal features of appendicitis
- Low grade pyrexia
- Localized abdominal tenderness
- Muscle guarding and rebound tenderness
Rovsing sign
RIF pain with deep palpation of the LIF
Psoas sign
RIF pain with right hip flexed (as inflamed appendix lying on psoas muscles)
Obturator sign
RIF pain with internal rotation of a flexed right hip (for pelvic appendix)
Component of Alvarado score
> MANTRELS
- Migratory RIF pain
- Anorexia
- Nausea/ Vomiting
- Tenderness at RIF (2 points)
- Rebound tenderness
- Elevated temperature (>37.3’C)
- Leukocytosis (2 points)
- Shift of neutrophils to left
Management of appendicitis
> Supportive
- NBM, IV drip, IV antibiotics
- Antiemetics and analgesia
> Definitive
- Appendectomy (open/ laparoscopic)
- Peritoneal toilet
Hinchey classification
> Staging for diverticulitis
- Stage 1 Pericolonic/ Mesenteric abscess
- Antibiotics, NBM, IV fluids
- KIV percutaneous drainage of acute pericolonic abscess
- Stage 2 Pelvic/ retroperitoneal abscess
- Percutaneous drainage under radiological guidance
- KIV elective 1 stage surgery - resection of segmental colectomy with primary anastomosis
- Stage 3 Purulent peritonitis * Debate whether same as stage 2 or 4
- Stage 4 Fecal peritonitis - 2 stage operation - Hartmann’s procedure + secondary re-anastomosis 3 months later
Investigation for acute diverticulitis
- FBC: leukocytosis, ESR
- Erect CXR: r/o perforation
- AXR: ileus, air fluid level
- Contrast CT: diverticular elsewhere, confirm colitis
- Laparoscopic: if diagnosis doubt
- AVOID barium enema, colonoscopy
Management of acute diverticulitis
> Uncomplicated - CONSERVATIVE
- NBM
- Analgesia
- IV Abx (10-14 days)
- Colonoscopy 4-6 weeks later (confirm diagnosis + exclude colon Ca)
> Complicated - SURGICAL
Complication of acute diverticulitis
- LGIT hemorrhage
- Fistula formation
- Perforation (phlegmon -> diverticular abscess -> peritonitis)
- Bowel obstruction
Small vs Large bowel obstruction
> Small bowel
- More acute
- Central and colicky pain
- Early, profuse, biliary vomiting
- Radiological: central, 30mm diameter, valvular conniventes
> Large bowel
- More gradual onset
- Localized tenderness
- Vomiting: late, feculent, may be absent
- Radiological: peripheral, 60mm, haustra might present
Diagnostic investigation for intestinal obstruction
Erect AXR
- Air fluid level ≥5
Supine AXR
- Jejunum (>3cm), Colon (>6cm), Cecum (>9cm)
- Valvular conniventes/ Haustration might present
CT abdomen
- Perform if not complete obstructed
- Determine site/ cause of obstruction (transition point hard to see in X-ray)
Barium enema/ Gastrografin
- Rarely needed due to availability/ accuracy of CT
Hartmann’s procedure describe
- Involves resecting the diseased colonic segment
- Creating an end colostomy and a rectal stump
- Reversing the colostomy in the future (50% did not perform due to technically difficult with high morbidity and mortality rate)
Risk factor colon Ca
> Modifiable
- Diet: red meat
- Lifestyle: smoking, alcohol
> Non-modifiable
- Age >40 years old
- Chinese
- Family history
- FAP/ HPNCC
HPNCC (Lynch syndrome) vs FAP
> HPNCC
- 1-3% of all CRC
- Autosomal dominant
- Age: >40 (15% cancer by 40)
- Fewer polyps
- Right-sided Ca
> FAP
- 1% of all CRC
- Autosomal dominant
- Age: 20 (90% cancer by 45)
- Usually >100 polyps
- Left-sided Ca (80%)
Surgery for sigmoid cancer + describe
- Sigmoid colectomy
- Removes the sigmoid colon, including the associated mesentery, with the inferior mesenteric vessels ligated close to their origin to optimally resect lymphovascular tissue
Complication for hemicolectomy
> Immediate
- Damage to ureter
> Early
- Anastomosis leakage
- Wound infection
- Bleeding
> Late
- Impotence
- Adhesion
- Tumor recurrence
Lanz vs Gridiron incision
Lanz incision
- Transverse
- More aesthetically pleasing
- Reduce scarring
Gridiron incision
- Oblique
Etiology of acute appendicitis
- Fecaliths
- Lymphoid hyperplasia
- Less common cause: Parasites, TB, Tumor, FB
Non-operative management of acute appendicitis
- Only when appendicular mass present
- Ochsner-Sherren regimen (hospitalization + IV fluid + antibiotics + analgesics + strict vital sign monitoring)
- 80-90% mass resolve without complication
- Debate continues as immediate surgery may reduce hospital stays and obviate need for second admission
Cause of umbilical pain in acute appendicitis
- Stimulation of visceral afferent nerve that arise from T10 (innervate umbilicus also)
- Well-localized pain later when involve adjacent peritoneum
Complication of appendicectomy
- Stump
- Hemorrhage
- Infection
- Paralytic ileus
How to classify intestinal obstruciton
- Pathological: mechanical vs functional
- Anatomical: small vs large
- Clinical: acute vs chronic
- Pathological changes: simple vs strangulated
- Severity: partial vs complete
Causes of intestinal obstruction
> More common
- Intraperitoneal adhesion
- Tumors
- Complicated hernia
> Others
- Volvulus
- Gallstones
- Intussusception
Definition keyword of surgical site infection
- 30 days following surgery
- 90 days if implant involved
Type of SSI
- Superficial incisional SSI
- Deep incisional SSI
- Organ or space SSI
Imaging for acute appendicitis
> Abdominal ultrasound
- Diameter >6mm
- Peri-appendicular fluid collection
> CECT abdomen
- Enlarge diameter
- Thicken wall
- Fat stranding
- Appendicolith
> Erect CXR
- R/o perforation, lobar pneumonia
Investigation for PUD
> OGDS
- Confirmation + location
- Biopsy TRO malignancy, H. pylori
- Therapeutic
> FBC
- IDA if bleeding
- Leukocytosis if perforated
> Urea breath test
- H. pylori infection
Indication for biopsy PUD
- Malignant looking (irregular, thickened margin)
- Benign looking but in area with high incidence
Management of peptic ulcer disease
> Medical and lifestyle
- PPI
- Smoking and alcohol cessation
- NSAID discontinue
- H. pylori eradication
> Endoscopic therapy
- Injection therapy
- Thermal coagulation
- Hemoclip
> Surgery
- Duodenal ulcer: Truncal vagotomy with pyloroplasty
- Gastric ulcer: Wedge resection/ Antrectomy/ Total gastrectomy
Describe H. pylori eradication therapy
> First line:
- Omeprazole 20mg BD for 6 weeks
- Amoxicillin 1g BD, Clarithromycin 500mg BD for 10-14 days
> If failed -> quadruple therapy
- Colloidal bismuth sub-citrate 120mg QDS, Tetracycline 500mg QDS, Metronidazole 400mg BD, Omeprazole 20mg BD for 7-14 days
How and where injection adrenaline peptic ulcer
- 30ml diluted adrenaline (1:10000)
- 4 quadrant around the ulcer
Describe CLO test
- Urease convert urea into ammonia that raise pH of medium, detect by phenol red and color changed from yellow (negative) to red (positive)
Risk factor for SSI
> Non-modifiable
- Older age
> Modifiable
- Cigarette smoking
- Vascular disease
- Obesity
- Malnutrition
- Diabetes
- Immunosuppressive disease
How TB infection cause intestinal obstruction
- Through progressive stricture and adhesion
Cause of persistent high CEA after colon ca resection
- Overlooked metastases
- Inadequate surgery
- Smoking habit
- Renal insufficiency
- Chronic liver disease
What is CEA
- Protein normally found in embryonic or fetal tissue
- Serum level disappear almost completely after birth, but small amount may be present in colon
- Elevated in malignancy that produce the protein (eg: GIT, ovary)
Ulcerative colitis vs Crohn’s disease
> Ulcerative colitis
- Affects only large intestine
- Continuous inflammation
- Mucosal and submucosal affected
> Crohn’s disease
- May affect any part of the GIT
- Discontinuous patchy inflammation
- Transmural (affects the full thickness of the bowel wall)
Why Crohn’s disease cause fistula
- Due to the transmural inflammatory nature of Crohn’s disease that lead to formation of sinus tracts or fistula
- Eg: enterovesical, enterocutaneous, enteroenteric, enterovaginal
When do we do reversal of Hartmann
- At least after 6-9 months (No consensus yet)
- Allow the adhesion to soften, reducing operative difficulty
- Longer time may have inferior outcome -> due to shrinkage of rectal stump?
Complication of reversal of Hartmann
- Anastomotic leakage
- Wound infection
- Incisional hernia
- Ileus
- Complication rate high, reason why many patient never reverse
Principle of colon Ca surgery
- En-bloc resection of tumor: 5cm proximally and distally
- Resect adjacent draining LN
- Reconstruct the bowel, if possible
Chemotherapy regime for colon Ca
- Initiate within 6-8 weeks of surgery
- 6 months course of oxaliplatin based regimen
(FOLFOX: oxaliplatin + leucovorin and short term infusion 5-FU) - Each cycle last 2 weeks (2 days infusion, 12 days rest), might up to 12 cycles
How to follow up after colon Ca
- 3 monthly for the first 2 years, then 6 monthly for the next 3 years, and subsequent yearly
- History, PE, and CEA every 3-6 months for 5 years
- Surveillance colonoscopy at year 1 and every 3-5 years thereafter
- CT TAP performed annually for 3 years
Complication of colonoscopy
- Complication related to sedation (eg: cardiopulmonary)
- Complication related to preparation (eg: fluid and electrolyte imbalance, abdominal bloating)
- Perforation (from mechanical trauma, barotrauma, or electrocautery injury during polypectomy)
- Infection (rare, due to improper endoscope reprocessing)
Management of perforation during colonoscopy
- Immediate erect CXR - air under diaphragm
- NBM, IV fluid, IV Abx
- Surgical consultation immediately
Dukes’ classification
- A: confined to mucosa
- B1: growth into muscularis propria
- B2: growth through muscularis propria and serosa
- C1: spread to 1-4 regional LN
- C2: spread to >4 LN
- D: distance metastasis
TMN vs Duke’s classification
- TMN is preferred over traditional Duke classification
- Duke primarily to determine prognosis
- TMN can aid determination of optimal therapy and assessment of response to therapy
Clinical sign of anastomotic leak
- Pain
- Fever
- Peritonitis
- Feculent drainage
- Purulent drainage
Management of anastomotic leak
- IV fluid resuscitation and broad spectrum Abx
- Bowel rest, percutaneous drainage
- Colonic stenting
- Surgery: resection of the anastomosis with end stoma/ resection of the anastomosis with re-anastomosis and proximal diversion
Open vs Laparoscopic appendectomy for perforated appendicitis
> Open
- Lower intra-op complication
- Lower hospital cost
> Laparoscopic
- Shorter hospital stay
- Lower risk of SSI
- Feasible for experience surgeon
Therapeutic function of colonoscopy
- Polypectomy
- Endoscopic hemostasis
- Dilation of colonic or anastomotic strictures
- Stent placement for malignant disease
- Endoscopic mucosal resection/ submucosal dissection of GIT tumor
- Foreign body removal
Screening for colorectal ca
> Average risk
- No family hx, age >50
- Yearly iFOBT, stop at 75
> Moderate risk
- > 1FDR; 1FDR and >1 SDR; >3 and one must be FDR
- Diagnosed <60 y/o: colonoscopy @ age 40/ 10 year younger than affected FDR; repeat 3-5 years
- Diagnosed >60 y/o: colonoscopy @ age 40; repeat 10 years
- Stop at 75
> High risk
- CRC <50, FAP, HPNCC
- Colonoscopy @ age 40/ 10 year younger than affected FDR; repeat 3-5 years
When can patient return to activity after appendicectomy
- Jogging: 1 week
- Weight lifting: 3 months
If do open surgery and found appendix not inflamed
- Still remove the appendix to avoid future confusion due to the scar
Cause of terminal ileitis
- Crohn’s disease
- NSAID use
- Tuberculosis
- Radiation
- Autoimmune disorder
What are Batson plexus
- Network of paravertebral veins with no valve drain the bladder, prostate, and rectum to the internal vertebral venous plexus
- Provide route for cancer metastases or infection to the spine
Define synchronous tumor
- Second primary cancer is diagnosed within 6 months of the primary cancer; (metachronous = more than 6 months)
Signs of bowel viability
- Color of serosa surface
- Presence of bowel peristalsis
- Pulsation and bleeding from the marginal artery
Investigation for intestinal obstruction
> Diagnosis
- Erect/ Supine AXR
- CT abdomen
- Barium enema
> Complication
- BUSE/ Cr (electrolyte imbalance)
- ABG (alkalosis from vomiting)
Management for intestinal obstruction
> Acute management
- Keep NBM, NG tube suction
- Analgesics
- Urinary catherization to monitor urine output
- Correct electrolyte abnormalities
- Surgical intervention: strangulated/ failed conservative >72 hours
Presentation of gastric outlet obstruction
- Epigastric pain
- Nausea, vomiting
- Early satiety
- Abdominal distension or bloating
- Weight loss
Condition associated with multiple anal fistula
- Crohn disease
- TB
- Actinomycosis
Describe Goodsall’s rules
- Used to predict the trajectory of fistula tract
- All fistula tracks with external opening within 3cm of the anal verge and posterior to a line drawn through the ischial spines travel in a curvilinear fashion to the posterior midline
All tracks with external openings anterior to this line enter the anal canal in a radial fashion - Fistula tracks longer than 3cm from the anal verge do not necessarily follow Goodsall’s rule; they often have an internal opening in the posterior midline
X-ray finding for sigmoid volvolus
- Coffee bean sign
- Distended large bowel proximal to the sigmoid
- Air fluid level in the small bowel
2 causes of sigmoid volvulus
- Anatomic factors: long redundant sigmoid colon with narrow mesenteric attachment
- Colonic dysmotility: prolonged colonic transit through the sigmoid colon and rectum
Management for sigmoid volvulus
- Sign of perforation/ peritonitis -> immediate surgical resection management; generally, should not have their volvulus detorsed to avoid reperfusion injury
- No sign of perforation/ peritonitis -> flexible sigmoidoscopy to detorsed the twisted segment, if successful, surgical resection shortly thereafter
