Lower gastrointestinal bleeding can have various causes like diverticulosis, angiodysplasia, inflammation, and cancers. A thorough history, physical exam, and initial tests like colonoscopy are important to determine the source and severity of bleeding. Colonoscopy allows for both diagnosis and potential treatment but often requires bowel prep, while angiography and CT angiography can localize active bleeding but lack therapeutic options. Together, these diagnostic tests aim to safely identify the cause and guide appropriate clinical management of lower GI bleeding.

1. INVESTIGATIONS IN LOWER
GASTROINTESTINAL BLEEDING
By
Dr E Aravind
UnderGuidance of
Dr DSVL Narasimham MS
Dr R Hemanthi MS
Dr P S Sitaram MS

2.  Lower
gastrointestinal
bleeding is defined
as abnormal
hemorrhage into
the lumen of the
bowel from a source
distal to the
ligament ofTreitz

3. Epidemiology
 Overall mortality <5%. [Frequency and
severity of UGIB > LGIB]
 LGIB is more common in women > men.
 Incidence and prevalence related to specific
etiologies.

4. Categorization based on
intensity
 Massive
 Moderate
 Mild

6. Risk factors
 Low fiber diet
 Obesity, Physical Inactivity
 Radiation
 NSAID or Aspirin usage
 Advancing age
 Co morbidities

7. Causes in adults
 Diverticulosis (30 - 50%)
 Angiodysplasia (20 - 30%) (or AVM, orVascular Ectasias)
 Neoplastic (10- 15%)
o Polyps
o Cancer
 Inflammatory (15 - 20%)
o Radiation - Intestinal damage due to fibrosis and ischemia.
o IBD
- Ulcerative colitis
- Crohn’s Disease
o Infectious (E. Coli 0157:H7, C. Difficile,C. Jejuni …)
o Ischemic (Hypoperfusion andVasoconstriction)
- Hypotension, Heart Failure, Arrhythmia
oVasculitis

8.  Others (5 – 10%)
o Post-polypectomy bleeding
o Aortoenteric fistula
o Coagulation deficiency
 Hemorrhoids (< 50 y.o. most common) (5 – 10%)
 Unknown (10 – 15%)

9. Causes in children
 Anal Fissure
 Infectious Colitis
 IBD
o Crohn’s Disease
o Ulcerative Colitis
 Polyps
 Intussusception
 Meckel’s Diverticulum (embryonic diverticulum)
 Pseudomembransous Colitis

11. History
 We should assess the chronicity of bleeding and
medication use .
• anti coagulants such as warfarin.
• low molecular weight heparin.
• inhibitors of platelet aggregation such as NSAID
• clopidrogel this can associated with mesentric
ischemia
• Use of digitalis should be documented because this
can associated with mesenteric ischemia
 Comorbid medical conditions like cardiac conditions.
 Family history of colorectal cancer
 Coagulopathy

12. Signs and Symptoms
 Hematochezia (most often painless)
 Anemia
 Occult blood in stool
 Rarely melena (UGIB most common)
 Normal Bowel Sounds, Normal Renal
Function (BUN/Cr)
 Nasogastric aspirate usually clear

13.  some patients with massive upper
gastrointestinal bleed can present with
hematochezia.
 An NG aspirate that contains bile and no
blood effectively rules out upper tract
bleeding in most patients.

14.  Majority of cases bleeding regresses
spontaneosly
 Outcome depends on risk stratification
 Predictors of poor outcome in lower GI bleed
• Hemodynamic instability
• Ongoing hematochezia
• Presence of comorbid illness

15. Manangement
 Includes
• Identification of site of bleeding
• Stopping the bleeding and treating the cause
 Digital rectal examination should be done to
exclude anorectal pathology as well as
confirm the patient’s description of stool
color.

16. Investigations
 CBC - Anemia, Infection,Thrombocytopenia,
Protein Levels, Iron, Crossmatch
 Coagulation
 Hemoccult and Stool cultures
 ECG

17. Endoscopic investigations
 Proctoscopy
 Sigmoidoscopy
 Colonoscopy
 Video Capsule Endoscopy
 Double balloon endoscopy
 Intraoperative Endoscopy

18. Radiological investigations
 Abdominal X rays
 Angiography
 Radionuclide scintigraphy
• Technetium Sulfur Colloid
• 99mTc pertechnate-labeled RBC
 Multidetector row CT (MDCT)
 Barium studies have no role in lower GI
bleeding

20. Colonoscopy
 Usually done after stabilizing the patient
 Provide both diagnosis and hemostasis
 Better than Sigmoidoscopy
 The diagnostic yield of urgent colonoscopy in
acute lower GI bleed has been reported to be
between 75-97% depending on the definition
of the bleeding source, patient selection
criteria, and timing of colonoscopy

21.  Bowel preparation
 Recent studies have suggested that
performing colonoscopy shortly after
presentation is advantageous

22. Criteria have been suggested for identifying
site of bleeding on colonoscopy
 Active colonic bleeding
 Non bleeding visible vessel
 Adherent clot
 Fresh blood localized to a colonic segment
 Ulceration of diverticulum with fresh blood in
adjoining area
 Absence of fresh bleed in terminal ileum with
fresh blood in the colon

24. Video Capsule Endoscopy
 Capsule endoscopy uses a small capsule
with a video camera that is swallowed and
acquires video images as it passes through
the GI tract.
 This modality permits visualization of the
entire GI tract, but offers no interventional
capability.
 It is also very time consuming

26. Double balloon endoscopy
 Visualizes entire
gastrointestinal tract in
real time
 The two balloons
inflate and deflate
intermittently creating
a peristaltic movement
so that the scope can
move forward

27. Intraoperative Endoscopy
 Intraoperative enteroscopy is reserved for
patients who have transfusion-dependent
obscure-overt bleeding in whom an
exhaustive search has failed to identify a
bleeding source.
 This typically uses a pediatric colonoscope
introduced through an enterotomy in the
small bowel made by the surgeon.

28. Abdominal X rays
 Perforation
 Obstruction
 “Thumb-printing” = Ischemic/Infectious
Colitis
 Megacolon

29. Angiography
 Both diagnostic and
therapeutic
 Requires a bleeding
rate of at least 0.5 to
1.0 ml/min
 Done in
hemodynamically
unstable patients
 Reserved for massive
bleeding

30.  Vasopressin was the first therapeutic modality
 Major complications occurred in 10% to 20% of
patients and included arrhythmias, pulmonary
edema, hypertension and ischemia
 Re bleeding occurred in up to 50% of patients
 Earlier embolization was associated with
infraction
 Technologic advances in coaxial microcatheters
and embolic materials have enabled the
embolization of specific distal arterial branches
with increased success and fewer complications

31. Radionuclide scintigraphy
 Non-invasive
 Done as screening before angiography
 More sensitive
 Detects bleeding as low as 0.1 ml/min
 Major disadvantage false localisation
 Two methods are used
• Technetium Sulfur Colloid
• 99mTc pertechnate-labeled RBC

32.  Tc-99m Red Blood Cells
• Tc-99m RBCs remain in the vascular
compartment
• In vitro or modified in vivo labeling of RBC is
done
• Allows continuous monitoring of the whole
gastrointestinal tract for a long period
• False-positive readings due to
misinterpretation of intravascular activity and
the possibility of free pertechnetate
accumulation
 sensitivity and specificity of this method are
very high

33.  Tc-99m sulfur colloid
 Rapid blood clearance of this tracer from
circulation allows for increased detection at
very low bleeding rates (0.05 to 0.1 ml/min)
 Detects bleeding only up to 15 minutes after
intravenous injection

35. Multidetector row CT (MDCT)
 Show contrast
extravasation into any
portion of the
gastrointestinal tract
 Detects bleeding rates as
low as 0.3 to 0.5 cc per
minute
 The average yield of MDCT
for lower GI bleed Is 60%,
with yields ranging from
25% to 95%.
 Lack of therapeutic
capability is a major
limitation
 Useful in guiding further
angioembolisation

37. Advantages and disadvantages of common diagnostic procedures used in the evaluation of lower
gastrointestinal bleeding
Procedure Advantages Disadvantages
Colonoscopy • Therapeutic possibilities • Bowel preparation required
• Diagnostic for all sources of
bleeding
• Can be difficult to orchestrate without on -
call endoscopy facilities or staff
• Needed to confirm diagnosis in
most patients regardless of initial
testing
• Invasive
• Efficient/cost -effective
Angiography • No bowel preparation needed • Requires active bleeding at the time of the
exam
• Therapeutic possibilities • Less sensitive to venous bleeding
• May be superior for patients with
severe bleeding
• Diagnosis must be confirmed with
endoscopy/surgery
• Serious complications are possible
Radionuclide
scintigraphy
• Noninvasive • Variable accuracy (false positives)
• Sensitive to low rates of bleeding • Not therapeutic
• No bowel preparation • May delay therapeutic intervention
• Easily repeated if bleeding recurs • Diagnosis must be confirmed with
endoscopy/surgery
Flexible
sigmoidoscopy
• Diagnostic and therapeutic • Visualizes only the left colon
• Minimal bowel preparation • Colonoscopy or other test usually
necessary to rule out right -sided lesions
• Easy to perform