2 LGIB, part 1 Flashcards
LGIB
Bleeding distal to the ligament of Treitz
More common than UGIB
What is the most common source of all causes of blood detected in the lower GI system
UGIB
Most common cause of established lower GI bleeding
Diverticular disease
- Colitis
- Hemorrhoids
- Adenomatous polyps/Malignancies
Characterize Diverticulosis (5)
- Painless
- Erosion into penetrating artery of diverticulum
- May be massive; 90% resolve spontaneously
- MOST on left colon
- RIGHT more prone to bleeding
Increased morbidity and mortality in: those w comorbids, need for transfusion, anticoagulant, NSAIDs
Characterize Vascular estasia (3)
- Arteriovenous malformations, angiodysplasias
- Present in small bowel
- Risk factor: Valvular heart disease
What is the most common cause of intestinal ishcemia?
Ischemic colitis
usually transient
RF: Aneurysmal rupture, vasculitis, hypercoagulable states, prolonged strenuous exercise, cardiovascular insult, IBS
Diagnosis of Ischemic colitis is done by?
Endoscopy
Mesenteric ischemia can lead to bowel necrosis by what mechanisms? (4)
- Thrombosis or embolism of SMA
- Mesenteric venous thrombosis
- Nonocclusive mesenteric ischemia
- Low arterial flow with vasoconstriction
Diagnosis: High index of suspicion, >60yo, Afib, CHF, MI, Post prandial ab pain, weight loss
CT is 92% specific 65% sensitive
Poor prognosis, survival of 50% in 24 hours
Study of choice in mesenteric ischemia
Angiography
Meckel’s diverticulim is most commonly found where?
Terminal ileum
embryonic tissue
Most commonly ectopic gastric tissue which secretes enzymes that erode the mucosal wall
Rare, but important in younger population
Most common source of anorectal bleeding
Hemorrhoids
Bleeding is assocaited with bowel movement
Massive hemorrhage is unusual
Factors associated with high morbidity in LGIB (10)
- Hemodynamic instability
- Repeated hematochezia
- Gross bleeding
- Initial Hct <35%
- Syncope
- Non-tender abdomen (predictive of severe bleeding)
- Hx of diverticulosis or angioectasia
- Elevated Crea
- NSAID or aspirin use
- > 2 comorbids
Bleeding + non-tender abdomen suggests?
Bleeding involving vasculature
Diverticulosis or angiodysplasia
Bleeding + Abdominal Tenderness suggests
Inflammatory bowel disorders
Bleeding source higher in the GI tract may elevate BUN levels by what mechanism?
Digestion and absorption of hemoglobin
BUN:Crea ratio of >30:1
Utility of barium studies in LGIB?
Not helpful and can interfere with subsequent endoscopy or angiography
What are the initial diagnostics indicated in LGIB? (3)
- Angiography
- Scintigraphy
- Endoscopy
choice depends on ability, consultant preference and availability
Diagnosis using Angiography requires a bleeding rate of?
0.5ml/min
Detects site of bleeding and guides surgical management
Allows transcatheter arterial embolization and infusion of vasoconstrictive agents
Serious complications can occur in up to 10% of cases
What can be used in detecting site of bleeding in obscure hemorrhage?
Technetium labelled red cells scans
Scintigraphy can localize the site of bleeding at what rate?
0.1ml/min
What has potential value over Angiography?
Scintigraphy
however, requires a 3ml pool of blood
Remarks for CT scan in LGIB
Useful in unstable cases
Can detect bleeding at a rate of 0.4ml/min
Used prior to angiography
sensitivity 100% specificity 99%
93% accuracy in detecting bleeding site
When do you correct coagulopathy in LGIB?
INR >1.5
PC <50,000
When to initiate blood transfusion in LGIB? (3)
- Continued active bleeding
- No improvement after crystalloids
- Hemoblogin <7g/dl
Transfusion is based more on the clinical picture and estimated blood lo
Remarks on Flexible Sigmoidoscopy (2)
Evaluate distal colonic and rectal sources of bleeding
Cannot identify more proximal structures
Remarks on Colonoscopy
Can diagnose diverticulosis and angiodysplasia
Allows for ablation of bleeding sites
Done in 12 to 24 hours of admission
Ablation: injection sclerotherapy, electrocoagulation, heater probe therapy, banding, clipping
Consider endoscopy if no finding
What is the scoring system used to risk stratify patients with LGIB to determine if they can be discharged?
No relieable scoring system exists to risk stratify which patient with lower GI bleeding may be discharged home safely
