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MBBS IV - Junior Clerkship WCS > JC61 (Surgery) - Lower GI bleed > Flashcards

JC61 (Surgery) - Lower GI bleed Flashcards

1
Q

Lower GIB

Anatomical definition
Possible sections of GIT involved

A

Definition: bleeding from gut distal to ligament of Treitz

Small bowel, colon, rectum and anus

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2
Q

Causes of massive UGIB and Small bowel bleed that lead to LGIB

A

Massive Upper GIB: Peptic ulcer, variceal bleed

Small bowels (~5%)
Diverticulum: Meckel’s*, jejunoileal diverticula
Vascular lesions: angiodysplasia, haemangioma
Small bowel tumours
Small bowel ulcers: NSAID-induced
Enteritis: Crohn’s disease, TB
Aortoenteric fistula

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2
Q

Causes of anorectal bleed

A

Anorectal (~10%):

  1. Haemorrhoids
  2. Fissure-in-ano
  3. Anal or rectal ulcers
  4. Rectal varices
  5. Proctocolitis: IBD, radiation, infection
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3
Q

Causes of large bowel bleed

A

Diverticular disease* (17-40%)
Angiodysplasia* (2-30%)
Colitis (9-11%):

  • Infective: C. dificile, CMV, amoebic, TB
  • Inflammatory: ulcerative colitis, Crohn’s disease
  • Ischaemic colitis
  • Radiation

Neoplasm (7-33%): carcinoma, large polyps, post-polypectomy

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4
Q

Features of LGIB that suggests outlet bleeding

A
  • Fresh blood
  • Separated from stool
  • Variable, usu. small amount
  • Anorectal symptoms
  • No haemodynamic disturbance
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5
Q

Diverticular bleeding

  • Prevalence
  • Cause
  • GIT site
  • S/S
  • Dx
  • Mx
A
  • Prevalence = Most common
  • Cause = Outpouching of intestinal wall through blood vessel penetration defects >> Rupture of Vasa recta into diverticulum
  • GIT site = more commonly on the right
  • S/S = self-limiting, painless hematochezia, but recur frequently
  • Dx = endoscopy, angiography
  • Mx = resuscitation, endoscopic therapy, semi-elective resection after 2nd bleeding episode
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6
Q

List 3 vascular causes of LGIB

A

Angiodysplasia

Hemorrhoids

Rectal varices

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7
Q

GIT angiodysplasia

  • Definition
  • Cause
  • Demographic
  • Site in GIT
  • Associated diseases
A
  • Definition = dilated, tortuous submucosal vessels
  • Cause = usually degenerative condition
  • Demographic = occur in elderly (2/3 at >70y) but is uncommon
  • Site in GIT = commonly on Rt colon/caecum
  • Associated vascular diseases = Osler-Weber-Rendu disease, aortic stenosis (Heyde syndrome)
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8
Q

GIT angiodysplasia

S/S

Dx

Mx

A

S/S:

  • INTERMITTENT BLEED
  • painless haematochezia of variable severity, mostly self-limiting (85-90%)
  • can be overt (tends to bleed less than diverticular disease as it is venous bleeding)
  • rebleed in 25-85%

Dx: endoscopy, (angiography)

Mx: endoscopic therapy, (angiography)

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9
Q

Hemorrhoids

Definition

Risk factors

S/S

Dx

Mx

A

Due to dilated vascular cushions of anal canal (haemorrhoidal plexus)
Very common! – 4.4% in general population
RFs: chronic straining, obesity/prolonged sitting

S/S:

  • typically painless haematochezia that is related to defecation (typically coats stool or stains tissue paper),
  • may be a/w anorectal S/S, eg. mucus discharge, sense of prolapse, anal itchiness, pain

Dx: proctoscopy
Mx: banding, haemorrhoidectomy

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10
Q

Rectal varices

Cause

S/S

Mx

A

Due to portal hypertension (portosystemic shunt between superior and inferior rectal vv.)

S/S: often presents with severe bleeding
Mx: injection sclerotherapy (local), TIPS/ Shunting (if uncontrolled bleeding)

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11
Q

Radiation proctocolitis

Cause

Pathogenesis

Time to onset of S/S

S/S

A

Cause: RT for pelvic malignancies

Pathogenesis:

  • epithelial atrophy and fibrosis associated with obliterative endarteritis >> chronic mucosal ischaemia
  • Formation of vascular telengiectasia

Timing: can be acute (<6w) or delayed (>9mo but can be >10y)

S/S: diarrhoea, rectal uregency/tenesmus, bleeding

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12
Q

Radiation proctocolitis

Dx

Mx

A

Dx: to r/o other causes of proctocolitis + endoscopy with Bx

Mx:

  • *- Topical: sucralfate or glucocorticoid enema**
  • *- Endoscopic: argon plasma, Infra-red coagulation, laser, 4% formalin injection**

Surgery: unstoppable bleeding

-Diversion or Proctectomy (deadly, not done)

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13
Q

IBD

  • Pathogenesis
  • 2 major clinical entities
  • Different sections of bowel involved
A

Pathogenesis: Defects in epithelial cell junctions > bacterial components infiltrate gut mucosa > Chronic inflammatory disorder of small and/or large intestine, hyperactive mucosal immune response

Crohn’s disease and Ulcerative colitis

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14
Q

Colorectal cancer LGIB

Cause

S/S

Mx

A

result of overlying erosion or ulceration

S/S:

  • low-grade, intermittent bleeding (may presents with iron-deficiency anaemia or FOBT+),
  • may be a/w changes in bowel habit (alternating diarrhoea and constipation, penciling of stool, tenesmus)

Mx: endoscopic Tx has limited role

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15
Q

Outline 11 key questions in history taking for LGIB

A

Bleeding history:

  • Presentation: acute or chronic, occult or overt?
  • How was blood found? Mixed with stools, on stool, on toilet paper, after defecation, overt?
  • Severity of bleeding: mild or heavy?
  • Color of blood?
  • Previous history of bleeding episodes?

GI symptoms:

  • Bowel output? – frequency, consistency, colour, anorectal symptoms
  • UGIB signs? Pain?

Malignancy screening: risk factors, bowel habits, constitutional symptoms, metastatic symptoms?

Complications?

  • Shock: extreme thirst, confusion, pallor, oliguria
  • Symptomatic anaemia: SOB on exertion, postural dizziness, syncope, chest pain, palpitation, lethargy or fatigue

PMH?

  • Previous bleeding +/- Investigations, significant co-morbid conditions?

Drugs?

→ NSAIDs: can give rise to small bowel ulcers
→ Antiplatelets, anticoagulants

16
Q

Differentiate likely GIT location of LGIB based on following presentations

→ Blood mixed with faeces
→ Blood on surface of stool
→ Blood on toilet paper
→ Blood after defecation
→ Blood by itself: torrential bleeding

A

→ Blood mixed with faeces: from above sigmoid
→ Blood on surface of stools: from anus/rectum
→ Blood on toilet paper: usually mild bleeding from sources close to anal margin
→ Blood after defecation: from anus, eg. haemorrhoids
→ Blood by itself: torrential bleeding, eg. diverticular disease, angiodysplasia

17
Q

List common causes of mild LGIB mixed with stools

List common causes of heavy LGIB (overt)

A

mild LGIB: anorectal pathologies, carcinoma, colitis

Heavy, overt LGIB : diverticular disease, angiodysplasia, Meckel’s diverticulum, ischaemic colitis, rectal varices

18
Q

Red flag S/S of LGIB suggestive of malignancy

A

□ Risk factors: >50y, male, smoker, FHx, Hx of IBD, polyps and colorectal CA

□ Bowel habits: alternating constipation and diarrhoea, pencil thin stools, tenesmus

□ Constitutional symptoms: loss of appetite, loss of weight, malaise

□ S/S of spread: intractable pain (sacral n. invasion), irritative urinary symptoms (bladder), ascites (peritoneal), jaundice/RUQ discomfort (liver), bone pain (bone), SOB (lungs)

19
Q

First-line management/ resuscitation of LGIB

A

Resuscitation and stabilization of haemodynamics

ABC:
□ A: intubate if decompensated (confused) or massive haematemesis
□ B: O2 cannula
□ C: large bore IV cannula with crystalloid infusion ± blood transfusion

Monitor haemodynamic status by:
□ Shock chart hourly
□ Vitals: BP/P, RR, body temp
□ Foley’s catheter: urine output ≥0.5mL/kg/h
□ Cardiac monitor, pulse oximetry
□ ± CVP line for PAWP

First-line blood:
□ CBC: Hb, haematocrit
□ RFT: hydration status, pre-renal failure, electrolyte imbalance
□ LFT, clotting profile: coagulopathy
□ T/S for transfusion

20
Q

Indications for blood transfusion for LGIB

A

Transfuse if
□ Profuse bleeding
□ Persistent haemodynamic instability despite crystalloid resuscitation
□ Symptomatic anaemia
□ Acute MI/unstable angina with low Hb

21
Q

Modalities to localize LGIB (6 + additional subtypes)

(except small bowel bleeds)

A
  1. Proctoscopy, sigmoidoscopy (exclude anorectal bleed)
  2. NG tube: bile-stained aspiration excludes UGIB
  3. Endoscopy: OGD first-line**

→ Colonoscopy for lower GI bleeding
→ Enteroscopy for small bowel bleeding
→ Upper endoscopy to exclude upper GI bleeding
→ Intraoperative endoscopy during laparotomy to assess both intra- and extraluminal pathologies

  1. CT Angiography
  2. Radionuclude scans: RBC scan, sulphur colloid scan
  3. Other imaging: CT scan, small bowel enteroscopy
22
Q

Why should OGD be performed before colonoscopy for LGIB

A

(1) PUD management is easier than LGIB
(2) ‘E’ colonoscopy without bowel prep is not ideal
(3) If the source is from upper GI, then ‘E’ colonoscopy cannot see anything because it will be full of blood

23
Q

Colonoscopy for LGIB

  • Function
  • Bowel preparation required or not?
  • Advantages
  • Therapeutic modalities
A

Function:

  • localize bleeding, performed early to obtain a diagnosis before bleeding stops
  • intubate the ileocaecal valve to exclude distal SB bleeding

Bowel preparation: preferred if possible

  • Increase diagnostic yield without increase morbidity
  • NOT feasible in unstable patients

Advantages:

  • Low complication rate
  • Shorter hospital stay
  • Diagnostic yield 75-90%

Therapeutic modalities:

  • Sclerosant/vasoconstrictor injections, heat probe, electrocoagulation, laser, haemoclips, argon beam coagulation
24
Q

Modalities to localize occult LGIB

A

Repeat upper endoscopy or colonoscopy

Look for small bowel bleed:
→ Enteroscopy/ video capsule enteroscopy
→ Angiography
→ RBC scan: non-specific
→ Contrast CT scan
→ Small bowel enema

25
Q

Indications for surgery for LGIB

A

Indications:
→ Haemodynamic instability despite adequate resuscitation
→ Massive blood transfusion (>6 units)
→ Frequent re-bleeding
→ On anticoagulant or antiplatelets

26
Q

Surgical treatment options for LGIB

Rebleeding rate for each option

A

With localization: segment resection

Without localization

  • Subtotal/total colectomy if bleeding from colon
  • Intraoperative colonoscopy or enteroscopy for localization

Segmental resection with localization = 0=15%

Blind segmental resection = 75%

Subtotal colectomy = 0-40%

27
Q

Outline P/E for LGIB

A

General examination:
□ Anaemia: pallor, tachycardia
□ Dehydration: capillary refill time, dry tongue
□ Any extra-abd manifestation of IBD

Abdominal examination: usually normal
□ Mass
□ Tenderness

Digital rectal examination + proctoscopy:
□ Confirm haematochezia
□ Look for any anorectal pathologies, eg. haemorrhoids,
fissure-in-ano, masses

28
Q

Therapeutic colonoscopy is effective in management of which LGIB

A

Angiodysplasia

Diverticular disease

Post-polypectomy bleeding/ post-polypectomy coagulation syndrome*

(* development of abdominal pain, fever, leukocytosis, and peritoneal inflammation in the absence of bowel perforation after polypectomy with electrocoagulation)

29
Q

CT angiography for LGIB

  • Advantages
  • Indication
  • Function
A
  • Advantages: Fast, Non-invasive, higher precision, higher diagnostic yield than colonoscopy
  • Indication: Hemodynamically unstable, shock index >1, active bleeding
  • Function: Localize site of bleeding loss before planning endoscopic or radiological therapy
30
Q

Angiography for LGIB

  • Procedure
  • Detection sensitivity
  • Diagnostic yield
  • Complications
  • Therapeutic techniques? recommended?
A

Procedure:

  • Selective catherization of SMA, IMA and Celiac artery by Seldinger technique
  • Observe extravasation of contrast

Detection: 1-1.5mL/min bleed

Diagnostic yield: Poorer than CT angiography and Ccolonscopy (27-67%)

Complications: Contrast allergy, renal failure, bleeding from puncture site

Therapeutic angiography: for embolization to stop bleeding, or injection of vasopressin

Not recommended, risk of bowel ischemia and infarction, vasopressin with cardiac S/E

31
Q

Radionucleotide scan for LGIB

  • Types
  • Advantages
  • Disadvantages
A

Tc-99 labeled sulphur colloid, tag RBC

Labeled RBC not cleared rapidly and not taken up by liver and spleen

Advantages: High sensitivity (0.1mL/min)

Disadvantages: No therapeutic value, Less specific/ cannot localize precisely

32
Q

IBD

Compare 2 major type morphology/ histology

A
33
Q

Compare clinical features between Crohn’s and UC

A

Crohn’s

  • Abdominal pain
  • Diarrhea
  • Weight loss
  • Malaise, anorexia, fever
  • Extra-intestinal manifestations: Uveitis, arthritis, ankylosing spondylitis, sclerosing cholangitis…etc

UC:

  • BLOODY diarrhea with MUCUS
  • Lower abdominal pain
  • Milder malaise, anorexia
  • Extra-intestinal manifestations: similar to Crohn’s
34
Q

Compare complications between Crohn’s and UC

A

Crohn’s

  • Strictures - IO
  • Fissures - perforation
  • Fistula with nearby structures: urinary bladder, vagina, anal…etc
  • Colorectal cancer

UC

  • Toxic megacolon and rupture
  • Colorectal cancer
35
Q

Modalities to localize small bowel bleed presenting as LGIB

Specify extent of examined GIT in each modality

A

Enteroscopy modalities

  • Push enteroscopy: beyond DJ flexure
  • Single/ Double balloon enteroscopy: entire small bowel
  • Intra-operative enteroscopy: entire small bowel
  • Capsule video capture: entire GIT
36
Q

Intraoperative endoscopy for LGIB

  • Indication
  • Procedure
  • Routes of insertion
A
  • Indication: prior localizations not made/ emergency
  • Procedure: Foley catheter inserted through appendicostomy or enterotomy, bowel preparation by on-table antegrade irrigation, effluent from anus
  • Routes of insertion: Transanal, Peroral, Through enterotomy, Laparoscopic assisted

MBBS IV - Junior Clerkship WCS (131 decks)

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