Lower gi bleed

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Investigations in lower gastrointestinal bleedingByDr E Aravind

UnderGuidance of Dr DSVL Narasimham MS Dr R Hemanthi MSDr P S Sitaram MSLower 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 LGIB] LGIB is more common in women > men. Incidence and prevalence related to specific etiologies.

Categorization based on intensityMassiveModerate Mild

Risk factorsLow fiber diet Obesity, Physical Inactivity Radiation NSAID or Aspirin usage Advancing age Co morbidities

Causes in adultsDiverticulosis (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 - Crohns 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 Crohns Disease o Ulcerative Colitis Polyps Intussusception Meckels Diverticulum (embryonic diverticulum) Pseudomembransous Colitis

HistoryWe 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 ischemiaUse of digitalis should be documented because this can associated with mesenteric ischemiaComorbid medical conditions like cardiac conditions. Family history of colorectal cancerCoagulopathySigns 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 spontaneoslyOutcome depends on risk stratificationPredictors of poor outcome in lower GI bleedHemodynamic instability Ongoing hematochezia Presence of comorbid illnessManangementIncludesIdentification of site of bleedingStopping the bleeding and treating the cause

Digital rectal examination should be done to exclude anorectal pathology as well as confirm the patients description of stool color.Investigations CBC - Anemia, Infection, Thrombocytopenia, Protein Levels, Iron, Crossmatch Coagulation Hemoccult and Stool cultures ECG

Endoscopic investigationsProctoscopySigmoidoscopyColonoscopy Video Capsule EndoscopyDouble balloon endoscopyIntraoperative Endoscopy

Radiological investigationsAbdominal X raysAngiographyRadionuclide scintigraphyTechnetium Sulfur Colloid 99mTc pertechnate-labeled RBC Multidetector row CT (MDCT)

Barium studies have no role in lower GI bleeding

ColonoscopyUsually done after stabilizing the patientProvide both diagnosis and hemostasisBetter than SigmoidoscopyThe 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 colonoscopyBowel preparationRecent studies have suggested that performing colonoscopy shortly after presentation is advantageous

Criteria have been suggested for identifyingsite of bleeding on colonoscopyActive colonic bleedingNon bleeding visible vessel Adherent clot Fresh blood localized to a colonic segmentUlceration of diverticulum with fresh blood in adjoining area Absence of fresh bleed in terminal ileum with fresh blood in the colon

Video Capsule EndoscopyCapsule 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 timeThe two balloons inflate and deflate intermittently creating a peristaltic movement so that the scope can move forward

Intraoperative EndoscopyIntraoperative 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.

Abdominal X rays Perforation Obstruction Thumb-printing = Ischemic/Infectious Colitis Megacolon

AngiographyBoth diagnostic and therapeuticRequires a bleeding rate of at least 0.5 to 1.0 ml/minDone in hemodynamically unstable patientsReserved for massive bleeding

Vasopressin was the first therapeutic modalityMajor complications occurred in 10% to 20% of patients and included arrhythmias, pulmonary edema, hypertension and ischemiaRe bleeding occurred in up to 50% of patientsEarlier embolization was associated with infractionTechnologic advances in coaxial microcatheters and embolic materials have enabled the embolization of specific distal arterial branches with increased success and fewer complicationsRadionuclide scintigraphyNon-invasive Done as screening before angiographyMore sensitiveDetects bleeding as low as 0.1 ml/minMajor disadvantage false localisationTwo methods are usedTechnetium Sulfur Colloid 99mTc pertechnate-labeled RBC

Tc-99m Red Blood CellsTc-99m RBCs remain in the vascular compartmentIn vitro or modified in vivo labeling of RBC is doneAllows continuous monitoring of the whole gastrointestinal tract for a long periodFalse-positive readings due to misinterpretation of intravascular activity and the possibility of free pertechnetate accumulationsensitivity and specificity of this method are very highTc-99m sulfur colloidRapid 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 tractDetects bleeding rates as low as 0.3 to 0.5 cc per minuteThe average yield of MDCT for lower GI bleed Is 60%, with yields ranging from 25% to 95%.Lack of therapeutic capability is a major limitationUseful 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 Thank you