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