Occult GI Bleed July 2015
Occult GI Bleed Occult vs Obscure Occult positive FOB and/or IDA, but no evidence of visible blood loss to pt or physician Obscure GI bleed that persist/ recurs without obvious aetiology after endoscopy and radiologic evaluation of small bowel Obscure occult (no evidence of visible blood loss) Obscure overt (bleeding visible to pt or clinician e.g. melaena)
Testing FOB Guaiac based FOB Identifies Hb by the presence of peroxidase reaction that turns guaiac-impregnated paper blue (from Guaiacum tree) Different reagents diff sensitivity and specificity More GI blood loss more likely to be positive (e.g. 10ml of GI loss needed for Hemoccult II test to be positive 50%) Restrictive diet not needed (false + with red meat, dietary peroxidases) High rate of false positive PPV 0.9 to 18.7% Immunochemical test Immunologic test that react only to human Hb (do not detect upper GI bleed since Hb is ingested in small bowel) More specific and equal or more sensitive than Guaiac (may detect as little as 0.3mg Hb per gram of stool)
Diagnostic tests Upper endoscopy Note: even though pt doesn t have iron def anemia or sx referable to upper GI, prevalence of lesions in the upper GI tract is greater than or equal to that of colonic lesion (36-56% for + FOB and IDA, 29% for +FOB without IDA) Colonoscopy Most pt should undergo colonoscopy due to high prevalence of colorectal cancer and polyps CT colonography (unable to biopsy or do polypectomy)
Diagnostic tests Small bowel evaluation Traditional small bowel follow through ingesting dilute liquid barium and use X-ray to follow the passage of barium through the stomach and small bowel evaluate the small intestine in terms of diameter, peristalsis, abnormal filling defect within the bowel, abnormal holdup to the flow of barium Enteroclysis infusion of 500 to 1000 ml of thin barium sulfate into the intestine through a duodenal tube and viewed using fluoroscopy or radiography taken at intervals may take 6 hours or longer and quite uncomfortable CT or MR enterography (use contrast to distend small bowel)
Diagnostic tests Small bowel evaluation Wireless capsule endoscopy 26 x 11 mm Non invasive, examination of the entire length of small bowel 50,000 60,000 images per 8hrs Doesn t permit tissue sampling or therapeutic intervention, not all small bowel mucosa is visualised CI: small bowel obstruction, pregnancy, unable to swallow capsule and?ppm and ICD In pt with overt bleeding, perform as soon as possible to the bleeding episode May need a repeat study if no lesions found / suboptimal (due to debris) Risk is retention which may require endoscopic retrieval or surgical Small bowel enterosocpy Laparosocpy/ laparotomy with intraoperative enteroscopy
Diagnostic tests Small bowel evaluation Small bowel enteroscopy Push, deep small bowel enteroscopy Push evaluate proximal small bowel, 25-80cm of jejunum can be evaluated Dedicated enteroscope or paediatric colonoscopy Instrument 2-2.5m, depth of insertion is limited by pt s discomfort Able to sample tissue and therapeutic procedures as compared to capsule Potential complication : bleeding, perforation
Diagnostic tests Small bowel evaluation Small bowel enteroscopy Push, deep small bowel enteroscopy Deep small bowel enteroscopy Single, double balloon enteroscopy and spiral enteroscopy Initial double balloon enteroscopy is cost-effective compared to capsule-directed double balloon, but associated with more complications Treatment of bleeding lesions, dilation of strictures, removal of polyps or masses, biopsy of abnormal tissue, and removal of foreign objects risks similar to those for colonoscopy or upper endoscopy (rare instances of mild pancreatitis or ileus (less than one percent) have been reported) double balloon enteroscopy spiral enteroscopy
Diagnostic tests Small bowel evaluation Laparosocpy/ laparotomy with intraoperative enteroscopy Intraoperative Insertion of endoscope through an enterotomy site or per orally or per rectally Possible complications: serosal tears, avulsion of mesenteric vein, ileus Radionuclide scanning Detect bleeding (minimum 0.1 to 0.5 ml/min) Involve labelled autologous RBC Angiography Use for pt with severe bleeding who requires transfusion (minimum 0.5 ml / minute) Can be used for embolisation
References Uptodate Aafp.org Asge.org youtube
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