INVESTIGATIONS IN LOWER GASTROINTESTINAL BLEEDING
ByDr E Aravind
UnderGuidance of Dr DSVL Narasimham MSDr R Hemanthi MSDr P S Sitaram MS
Lower gastrointestinal bleeding is defined as abnormal hemorrhage into the lumen of the bowel from a source distal to the ligament of Treitz
Epidemiology
Overall mortality <5%. [Frequency and severity of UGIB > LGIB]
LGIB is more common in women > men.
Incidence and prevalence related to specific etiologies.
Categorization based on intensity
Massive
Moderate
Mild
Risk factors
Low fiber diet
Obesity, Physical Inactivity
Radiation
NSAID or Aspirin usage
Advancing age
Co morbidities
Causes in adults Diverticulosis (30 - 50%)
Angiodysplasia (20 - 30%) (or AVM, or Vascular 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 and Vasoconstriction)
- Hypotension, Heart Failure, Arrhythmia
o Vasculitis
Others (5 – 10%)
o Post-polypectomy bleeding
o Aortoenteric fistula
o Coagulation deficiency
Hemorrhoids (< 50 y.o. most common) (5 – 10%)
Unknown (10 – 15%)
Causes in children
Anal Fissure
Infectious Colitis
IBD
o Crohn’s Disease
o Ulcerative Colitis
Polyps
Intussusception
Meckel’s Diverticulum (embryonic diverticulum)
Pseudomembransous Colitis
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
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
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.
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
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.
Investigations
CBC - Anemia, Infection, Thrombocytopenia, Protein Levels, Iron, Crossmatch
Coagulation
Hemoccult and Stool cultures
ECG
Endoscopic investigations
Proctoscopy
Sigmoidoscopy
Colonoscopy
Video Capsule Endoscopy
Double balloon endoscopy
Intraoperative Endoscopy
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
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
Bowel preparation
Recent studies have suggested that performing colonoscopy shortly after presentation is advantageous
Criteria have been suggested for identifyingsite 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
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
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
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 colonoscopeintroduced through an enterotomy in the small bowel made by the surgeon.
Abdominal X rays
Perforation
Obstruction
“Thumb-printing” = Ischemic/Infectious Colitis
Megacolon
Angiography
Both diagnostic and therapeutic
Requires a bleeding rate of at least 0.5 to 1.0 ml/min
Done in hemodynamicallyunstable patients
Reserved for massive bleeding
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 microcathetersand embolic materials have enabled the embolization of specific distal arterial branches with increased success and fewer complications
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
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 pertechnetateaccumulation
sensitivity and specificity of this method are very high
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
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
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
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