GI - Lower GI bleed Flashcards
Lower GIB
Anatomical definition
Possible sections of GIT involved
Definition: bleeding from gut distal to ligament of Treitz
Small bowel, colon, rectum and anus
Causes of anorectal bleed
Anorectal (~10%):
- Haemorrhoids
- Fissure-in-ano
- Anal or rectal ulcers
- Rectal varices
- Proctocolitis: IBD, radiation, infection
Causes of large bowel bleed
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
Features of LGIB that suggests outlet bleeding
- Fresh blood
- Separated from stool
- Variable, usu. small amount
- Anorectal symptoms
- No haemodynamic disturbance
Diverticular bleeding
- Prevalence
- Cause
- GIT site
- S/S
- Dx
- Mx
- 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
List 3 vascular causes of LGIB
Angiodysplasia
Hemorrhoids
Rectal varices
GIT angiodysplasia
- Definition
- Cause
- Demographic
- Site in GIT
- Associated diseases
- 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)
GIT angiodysplasia
S/S
Dx
Mx
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)
Hemorrhoids
Definition
Risk factors
S/S
Dx
Mx
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
Rectal varices
Cause
S/S
Mx
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)
Radiation proctocolitis
Cause
Pathogenesis
Time to onset of S/S
S/S
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
Radiation proctocolitis
Dx
Mx
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)
IBD
- Pathogenesis
- 2 major clinical entities
- Different sections of bowel involved
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
Colorectal cancer LGIB
Cause
S/S
Mx
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
Outline 11 key questions in history taking for LGIB
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
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
→ 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
List common causes of mild LGIB mixed with stools
List common causes of heavy LGIB (overt)
mild LGIB: anorectal pathologies, carcinoma, colitis
Heavy, overt LGIB : diverticular disease, angiodysplasia, Meckel’s diverticulum, ischaemic colitis, rectal varices
Red flag S/S of LGIB suggestive of malignancy
□ 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)
First-line management/ resuscitation of LGIB
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
Indications for blood transfusion for LGIB
Transfuse if
□ Profuse bleeding
□ Persistent haemodynamic instability despite crystalloid resuscitation
□ Symptomatic anaemia
□ Acute MI/unstable angina with low Hb
Modalities to localize LGIB (6 + additional subtypes)
(except small bowel bleeds)
- Proctoscopy, sigmoidoscopy (exclude anorectal bleed)
- NG tube: bile-stained aspiration excludes UGIB
- 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
- CT Angiography
- Radionuclude scans: RBC scan, sulphur colloid scan
- Other imaging: CT scan, small bowel enteroscopy
Why should OGD be performed before colonoscopy for LGIB
(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
Colonoscopy for LGIB
- Function
- Bowel preparation required or not?
- Advantages
- Therapeutic modalities
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
Modalities to localize occult LGIB
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
Indications for surgery for LGIB
Indications:
→ Haemodynamic instability despite adequate resuscitation
→ Massive blood transfusion (>6 units)
→ Frequent re-bleeding
→ On anticoagulant or antiplatelets
Surgical treatment options for LGIB
Rebleeding rate for each option
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%
Outline P/E for LGIB
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
Therapeutic colonoscopy is effective in management of which LGIB
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)
CT angiography for LGIB
- Advantages
- Indication
- Function
- 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
Angiography for LGIB
- Procedure
- Detection sensitivity
- Diagnostic yield
- Complications
- Therapeutic techniques? recommended?
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
Radionucleotide scan for LGIB
- Types
- Advantages
- Disadvantages
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
IBD
Compare 2 major type morphology/ histology
Compare clinical features between Crohn’s and UC
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
Compare complications between Crohn’s and UC
Crohn’s
- Strictures - IO
- Fissures - perforation
- Fistula with nearby structures: urinary bladder, vagina, anal…etc
- Colorectal cancer
UC
- Toxic megacolon and rupture
- Colorectal cancer
Modalities to localize small bowel bleed presenting as LGIB
Specify extent of examined GIT in each modality
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
Intraoperative endoscopy for LGIB
- Indication
- Procedure
- Routes of insertion
- 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
Causes of massive UGIB and Small bowel bleed that lead to LGIB
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
