What anatomical feature distinguishes between upper and lower GI?
Ligament of Trietz; at the duodenojejunal junction.
Presentation of Upper GI bleeding
- hematemesis (bright red blood)
- blood or coffee grounds detected during nasogastric lavage
- melena (black/sticky feces); may be as little as 50-100mL
- BUN to serum creatinine ratio greater than 30
Lower GI bleeding presentation
- blood clots in stool
- red blood that is mixed with solid brown stool
- dripping of blood into toilet after a BM
- hematochezia: red or maroon colored stool
When might you see hematochezia? What color is it?
generally from lower GI source but can occur with a loss of more than 1000mL of blood in the upper GI tract.
Red/maroon colored stool
What causes coffee-ground emesis?
blood sitting in the stomach acid causes the iron to oxidize resulting in the appearance of coffee ground-like flakes.
Describe the features of Upper and Lower GI bleeding:
- severity
- site
- presentation
- nasogastric lavage
- bowel sounds
- BUN/Creat Ratie
Upper GI (2/3 of casses): -severity: more likely to have significant bleeding
- site: above the ligament of trietz
- presentation: hematemesis, melena, heamtochezia with massive UGI of greater than 1000mL
- nasogastric lavage: blood
- bowel sounds: hyperactive
- BUN/Creat: greater than 30:1
Lower GI Bleed:
-severity: likely to present with shock or require transfusion
- Site: below the ligament of trietz
- presentation: hematochezia (red/maroon)
- nasogastric lavage: clear fluid
- Bowel sounds: normal
BUN/Creat: normal
Where does BUN come from?
when protein is used for energy the carbon is cleaved from the amino acid and leaves behind a nitrogen. The N takes up 3H+ creating ammonia.
Ammonia processed through the liver to become urea, once it enters the blood stream it is called BUN.
Top 3 etiologies of Upper GI bleeds
- peptic ulcer dz (NSAIDS, PUD)
- portal HTN (cirrhosis, varices)
- Mallory-Weiss Tears (retching, ETOH)
Upper GI bleed Causes:
- vascular anomalies; what are these?
- what are some other causes that are cause less significant bleeding?
Vascular anomalies: angiodysplasia & telangectasias (associated with CT dz like CREST and HTT)
HTT = hereditary hemorrhagic telangectasia; these bleed all the time.
Other causes:
- gastric neoplasm
- erosive gastritis
- erosive esophagitis
- aortoenteric fistula
- hepatic tumor
- angioma
- penetrating trauma
- pancreatic malignancy
Etiology of Lower GI bleeding:
- less than 50YO
- greater than 50 YO
Less than 50:
- infectious colitis
- anorectal dz (hemorrhoids, fissures; bright red blood noted on toilet paper, blood streaked stool)
- inflammatory bowel Dz (primarily ulcerative colitis)
Greater than 50:
- diverticulosis
- angioectasia
- malignancy
- ischemia (may also be seen in younger patients post long distance running)
What causes 50% of Lower GI bleeds?
Etiology of acute, painless, large volume of maroon or bright red hematochezia?
Diverticulosis causes 50% of lower GI bleeds.
Diverticulitis
Initial Management of GI Bleeding
Stabilization:
Blood Replacement:
GI consult for upper or lower endoscopy
Labs: CBC, PT/INR, CMP, Blood Types and screening
Assessing the degree of bleeding:
- what SBP and HR is noted with
- -severe bleeding
- -moderate bleeding
- -minor bleeding
Severe: SBP less than 100mmHg & HR greater than 100BPM
Moderate: SBP greater than 100mmHg & HR greater than 100BPM
Minor: normal BP and HR
WHat do you do to stabilize a patient with GI bleeding??
- 2 large bore IVs
- NS or lactated ringer solution
- NG tube +/- (can lavage with saline and aspirate contents looking for blood to confirm upper souce)
- IV PPI for UGI
- IV octreotide or somatostatin to reduce splanchnic blood flow and portal pressures if d/t varices from portal HTN.
blood replacement in GI bleeding:
- what is target hgb?
- how many units RBC raises hgb 1g/dL?
- what is the RBC/FFP ratio?
- when do you transfuse platelets?
- at what INR level do you need to give FFP?
- uremic pts may benefit from what medications?
- target is to maintain Hgb of 7-10g/dL
- hgb should increase 1g/dL for each unit transfused
- give one unit of FFP for each 5 units of packed RBC
- transfuse platelets if less than 50K and actively bleeding
- FFP if INR greater than 1.8
- uremic pts may benefit from DDAVP (activates VW factor)
Endoscopy with GI bleeding
unless very unstable usually prefer to do a bowel prep if colonoscopy is needed.
upper endoscopy can enhance stomach emptying by the administration of IV erythromycin
Endoscopy can be dx as well as therapeutic:
- sclerosis or banding of varices
- cautery of bleeding vessels
Tx of GI bleeding?
Depending upon the underlying cause of GI bleeding:
- may require surgical repair
- intra-arterial embolization
- decompression of portal vein with a shunt placement if varices are not manageable.
if abd pain and peritoneal signs consider what as a dx?
How long might it take for HCT to reflect the current state of blood volume?
consider bowel or esophageal perforation.
May take HCT 24hrs or more to reflect the current state of blood volume, so act clinically.
If blood loss is acute RBCs should be? If chronic?
If acute RBCs should be normocytic, all indicies are normal they are just low.
Chronic: microcytic and hypochromic.
