AGA Technical Review on the Evaluation and management of Occult and Obscure Gastrointestinal Bleeding

Gastroenterology 2000;118:201-221

Reporter :Intern 陳美舒2002/10/28

Bleeding Definitions ( )Ⅰ

Overt or visible bleeding: GI bleeding manifest as visible bright red or altered blood in emesis or feces

Occult bleeding: initial present of IDA and/or positive FOBT; no visible blood in feces

Obscure bleeding: Recurrent or persistent IDA, positive FOBT ,or visible bleeding with no bleeding source found at original endoscopy

Bleeding Definitions ( )Ⅱ

Obscure-occult bleeding: subcategory of obscure characterized by recurrent or persistent IDA and/or positive FOBT with no source found at original endoscopy; no visible blood in feces

Obscure-overt bleeding: subcategory of obscure characterized by recurrent or persistent overt/visible bleeding with no source found at original endoscopy; bleeding manifest as visible blood in emesis or feces

Bedside Examination

History: especially drug history( NSAID, Aspirin, KCl, anticoagulation) and family history.

Physical Examination: cutaneous manifestations VS. GI bleeding

It has been proposed that information on either upper or lower intestinal symptoms can direct the initial endoscopic approach to patients with occult bleeding.

Evaluation of Occult Bleeding( )Ⅰ

Study design factors: The method of stool collection ( digital collection or spontaneously passed stool); dietary modification; Guaiac-based tests or immunochemical test for hemoglobin

Evaluation of Occult Bleeding( )Ⅱ

Endoscopic evaluation: colonoscopy and upper endoscopy remain the cornerstones for investigation of occult blood loss.

Colon cancer screening trial: 78%-86% FOBT (+) p’ts performed colonoscopy:

2.2%-17% colon cancer; 16.7%-40% adenomatous polyps annual FOBT reduced mortality from colorectal cancer

Evaluation of Occult Bleeding( )Ⅲ

Bidirectional Endoscopy

-IDA and positive FOBT results are unaccounted for in up to 52% of cases

-a lesion identified as responsible for occult blood loss was located in the upper GI tract (29%-56%) more than in the lower GI tract(20%-30%)

Evaluation of Occult Bleeding( )Ⅳ

Radiographic Evaluation - Single-column barium enemas: discontinued, 20% miss rate

of colon cancer - double-contrast enemas have been used primarily when

results of colonoscopy are suboptimal -air-contrast barium enemas preferably with flexible

sigmoidoscopy: sensitivity of 98% for carcinoma and 99% for adenoma VS. ACBE alone missed 25% cancer and polyps in the rectosigmoid region

Evaluation of Obscure Bleeding( )Ⅰ

Small bowel Repeat upper endoscopy and colonoscopy : 35% bleeding source identified (29% upper, 6%

colonoscopy) Upper GI tract: erosion of hiatal hernias, peptic ulcer,

vascular ectasia Colon: angiodysplasia and neoplasia Enteroscopy in place of repeat upper endoscopy

Evaluation of Obscure Bleeding( )Ⅱ

Small bowel biopsy: celiac sprue

Peroral and transnasal enteroscopy:

-push enteroscopy: standard approach to exam the proximal small bowel

-Sonde enteroscopy : potential for direct exam of the entire small bowel mucosa,but less popular.

Evaluation of Obscure Bleeding( )Ⅲ

Retrograde enteroscopy: examination of the distal ileum at colonoscopy

-low diagnostic rate (2.7%) and should be reserved for instances in which other evidence indicates a potential source of blood loss in the terminal ileum

Intraoperative enteroscopy (IOE): apply in cases of transfusion dependent bleeding that is not localized in spite of extensive diagnostic evaluation.

Evaluation of Obscure Bleeding( )Ⅳ

-IOE: the ability to identify potential bleeding lesions ranging from 70%-93%

-Laparotomy has been coupled with the passage of an endoscope orally, per rectum, transnasally, or through enterotomy

-IOE through an enterotomy: decreased intestinal dead space and decreased trauma to the bowel.

Evaluation of Obscure Bleeding( )Ⅴ

Small bowel x-ray series and enteroclysis

-enteroclysis: higher radiation exposure and discomfort; higher diagnostic yield, sensitivity, shorter procedure time.

-enteroclysis: the radiological study of choice for the investigation of suspected gross disorder of the small bowel. (diagnostic rate of neoplasia of 95%)

Evaluation of Obscure Bleeding( )Ⅵ

Nuclear scans: technetium 99m-labeled red blood cell (TRBC)scan

-long half-life , bleeding rate:0.1-0.4 mL/min

-significant false localization and miss rate →alternate test: angiography or endoscopy before an invasive therapeutic procedure

Evaluation of Obscure Bleeding( )Ⅶ

Angiography

-active bleeding rate >=0.5 mL/min → extravasation of contrast may be found

- diagnostic rate:27%-77% in acute lower intestine bleeding

-repeat angiography: increased diagnostic rate from 43% to 54% in patient with no initial diagnosis.

Exploratory laparotomy

Etiology( )Ⅰ

Etiology ( )Ⅱ

Management

Endoscopic therapy Angiographic therapy Pharmacotherapy Surgery Nonspecific therapy

Endoscopic Therapy

Thermal contact probes, injection sclerotherapy, argon plasma coagulation,Nd:YAG laser

decrease the requirement for blood transfusion requirement

slightly higher rebleeding rates( up to 34%) have been reported with the use of thermal contact devices

Angiotherapy

The number of patients successfully treated with vasopressin infusion or embolization for obscure-overt small bowel bleeding is limited.

Vessopressin- cardiovascular complications rate up to 9%-21%

embolization-complication rate: 17% Embolozation may have utility in patients with coronary

disease or other disorders wherein vasopressin infusion is relatively contraindicated or as an alternative to surgery.

Pharmacotherapy

Reserved for diffuse disease, lesion in area inaccessible endoscopic therapy, rebleeding with unknown source

estrogen-progesteron combination therapy octreotide danazol and desmopressin

Surgery

Bleeding tumor, bleeding with high transfusion requirement,

angiographic localization of the bleeding source assisted resection: the lowest rebleeding rates after bowel resection for bleeding angiodysplasia

Nonspecific Measures

Iron supplymentation: IDA with unknown bleeding source--anemia resolved in 83% with no recurrence over a mean F/U period of 20 months

obs. and intermittent transfusion :54%had no rebleeding episodes during a 3-year follow-up period

elderly patient, slowly blood loss rate,risk for further diagnostic evaluation

Outcomes

The overall prognosis in occult bleeding is generally good , with no early mortality noted in prospective studies.

There appears to be no single efficient diagnostic approach or therapeutic panacea in the management of obscure bleeding.