Common Causes of Lower GI Bleeding Flashcards
3 locations for GI bleeding
UGI: esophagus, stomach, duodenum
Small bowel bleeding
Lower GI: colon or rectum
Hematochezia
Passage of red blood or maroon coloured stools
Left vs right colon bleeding
Left: typically bright red in colour
Right: dark or maroon coloured (mixed with stool). Can also present as melena
Is the colour of the stool diagnostic?
No, since melena can be from right colon or small bowel, and hematochezia from massive UGIB
Causes of LGI bleeding
C-HAND Colitis: infectious, inflammatory, ischemic Hemorrhoids Angiodysplasia Neoplastic Diverticulosis
Dentate line
Separates the rectum from anus
Below you have innervation, above you do not
Pain in hemorrhoids vs fissues
Hemorrhoids: usually painless (unless below dentate line)
Fissures: painful
3 ways to diagnose hemorrhoids
History
DRE
Endoscopy
3 ways to manage hemorrhoids/fissues
Lifestyle: high fiber, lots of fluid, dont strain
Medications: hydrocortisone based ointments/suppositories, fissures can be treated with topical Nitro or Diltiazem ointments (vasodilators of the anal canal)
Surgical: banding, hemorrhoidectomy, botox in sphincter for fissures
Diverticulosis
Sac like protrusions of the colon wall
Common in older age
Associated with Western diet
Most in the sigmoid colon (high pressure)
Clinical presentation: large volume bleeding, painless, most stop spontaneously
Clinical presentation of diverticulitis
Pain
Fevers
High WBC
Not typically bleeding
4 investigations/management of diverticulosis
Resuscitation: ABCs
Colonoscopy: limited utility as its hard to find which one is bleeding
Angiography: start with CT, therapy applied directly
Surgery: segmental resection, only for persistent bleeding and instability despite resuscitation
3 different types of colitis
Inflammatory
Ischemic
Infectious
Ischemic colitis
Reduction of blood flow from the mesenteric vasculature
Colorectal circulation has protective collateral, but limited in areas like the rectosigmoid junction and splenic flexure
Caused by non-occlusive colonic ischemia, embolic occlusion, or mesenteric vein thrombosis
2 main places to get ischemic colitis
Rectosigmoid junction
Splenic flexure
Clinical manifestations of ischemic colitis
Acute abdominal pain followed by diarrhea and mild rectal bleeding
Patients are often elderly with other CV risk factors
If colonic infarction develops, can lead to sepsis, peritonitis, and gangrene
3 ways to diagnose ischemic colitis
Lab: anemia, high serum lactate, high WBC
CT scan
Colonoscopy
Treatment for ischemic colitis
Supportive
Antibiotics in patients with severe ischemia and peritonitis (get general surg involved)
Blood thinners only for mesenteric venous thrombosis
Treat underlying CV factors
Clinical manifestations of infectious colitis
Acute onset diarrhea, nausea, vomiting, fevers
Antibiotic for severe bloody diarrhea (high fever, more than 2 days) from infectious colitis
Ciprofloxacin 500 mg BID for 3-5 days
If EHEC suspected (blood diarrhea, pain, no fever, exposure) then don’t use antibiotics due to risk of HUS
Angiodysplasia
Dilated, tortuous submucosal vessels
Associated with end stage renal disease, aortic stenosis, and age
Most commonly in the cecum and right colon
Typically a slow, occult bleed (Fe deficiency)
Treat with argon plasma
Clinical presentation of colon cancer
Bright red blood from left sided lesions, and maroon stools/melena from right sided
Most commonly will see occult iron deficiency
Often have altered bowel habits
Can cause bowel obstruction and also metastasis
Treatment is really surgery
10 high risk features of a lower GI bleed
Hemodynamic instability Significant comorbid illness Advanced age Bleeding in a hospitalized patient Known diverticulosis Blood thinners Persistent bleeding Elevated urea Profound anemia Altered mental status
Labs to order for GI bleed
CBC Electrolytes Creatinine BUN (Blood urea nitrogen) INR (time it takes to clot) Liver enzymes In a large UGI bleed will have an elevated BUN to creatinine ratio (> 20:1)
CT angiography
Contrast enhanced CT scan
Widely available, fast, non invasive
Highly sensitive
Cons: contrast, radiation, no therapeutic capability
Angiography
Performed by interventional radiology
After CT angiography
Transcatheter embolization can stop bleeding from a distal vessel
No need for bowel prep
What is the Hb count to transfuse blood?
Under 80
