Q3 Least sensitive in detecting a source of obscure Gi Bleed from small bowel
a) Barium Meal Follow through
b) Enteroclysis
c) Technitium Labelled Nuclear scan
d) Angiography
Q4. What is not true about Technetium labelled nuclear scans ?
a) They are helpful only during active bleeding
b) There are two types of scans done commonly Sulphur colloid and RBC scan
c) Diagnostic yield of these scans has a wide variation from 15-70%
d) They can identify the etiology correctly if they are positive
Q5. What is not true about the role of Angiography in Obscure GI Bleed
a) It is a useful diagnostic and therapeutic tool in patients who are actively bleeding
b) The Sensitivity of angiography is less than nuclear medicine scans
c) Diagnostic yield is about 40%
d) It can identify smaller arterial lesions such as vascular ectasia and even venous bleeding
Answers
1. c
Obscure GI bleed is a one in which no source could be found despite endoscopy and colonscopy. These can be obscure occult or obscure overt.
Approximately 10% to 20% of these patients,do not have an identifiable bleeding source. A small proportion (approximately 5% overall) of these patients have recurrent bleeding of unclear etiology leading to extensive and repetitive testing
The source of bleeding is generally not found because of the
a. Slow and intermittent nature of bleeding
b. Anemia and volume contraction has caused it to stop at that time
c. Lesions in small bowel are difficult to detect
2) b
Although all of these are important and should be asked, jaundice is last on the list. People with hemobilia will give history of jaundice.
Age is important beacuse in older people malignany and in younger Meckel's Diverticulum is common
In patients with haematemesis generally the lesion in proximal to the ligament of treitz.he appearance of the stool, which is largely dependent on blood transit time, may also be suggestive of location of the bleeding. Blood that has been in the GI tract for less than 5 hours is usually red, whereas blood present for more than 20 hours is usually melenic.
patients with slow oozing from the distal small bowel or cecum may have melena and occasional patients with aggressive bleeding from an upper GI source may present with hematochezia.
Recent surgery might be an indicator of anastomotic site bleeding or Aorto Enteric fistula
3. a
Small Bowel Follow through (BMFT) can pick up Diverticulosis, Malignant lesion or Crohn's disease. The mere presence of diverticuli does not mean they are bleeding. The sensitivity of BMFT is very low
Diagnostic yield of Enteroclysis can be 12-30%. Mostly they can detect small bowel tumors. Crohn's disease
With the advent of capsule endoscopy, however, the use of SBFT or enteroclysis for obscure GI bleeding has declined substantially.
4. d
Because of their mode of action, bleeding scans are only useful in the setting of active GI bleeding. Two types of nuclear scans are used technetium 99m-labeled red blood cell scan and the technetium 99m-labeled sulfur colloid scan
It can reportedly detect active bleeding at a rate of 0.10 mL/min.
In patients with obscure GI bleeding, there are several drawbacks to nuclear scanning. First, nuclear scanning localizes active bleeding to a region of the abdomen, not a specific site; even a positive scan cannot provide an etiology for the bleeding..
Scanning is not therapeutic, a follow-up study, such as arteriogram or endoscopic examination, must be subsequently performed
5. d
Angiography does not pick up venous bleeding
The rate of bleeding should be 0.5 ml/min - 1 ml/min to be detected on angiography
Angiography has a high incidence of complications such as contrast induced and mechanical complications
