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Flashcards in Rectal Bleeding Deck (18)
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What is melena? From where is it almost always from?

- melena is a black, tarry, very offensive smelling bowel motion
- it is due to the presence of digested RBCs, and is therefore nearly always from the upper 1/3 of the GIT (includes nose bleeds!)
- requires a slow bleed; rapid bleed will result in hematemesis


What exactly gives melena its color, texture, and smell?

- the oxidation of the RBCs' iron


What else can cause very dark/black stool? How can we differentiate it from melena?

- iron tablets and bismuth chelate
- differentiate from melena because these motions smell normal


What can cause a trivial amount of rectal bleeding (ie, some blood on toilet paper)? What about larger amounts of blood (ie, blood in the toilet bowl)?

- trivial: skin tear, hemorrhoids, anal fissure
- large amount: arterial bleeding, ischemic colitis, diverticular rupture


Bleeding with perianal pain indicates what pathology? What about with severe abdominal pain? Mild abdominal pain?

- perianal pain: rectoanal fissure/ external hemorrhoids
- severe abdominal pain: ischemic colitis
- mild abdominal pain: enteritis


Which type of hemorrhoids are painful? Why?

- external hemorrhoids (below the pectinate line) are painful because they receive somatic innervation
- internal hemorrhoids (above the pectinate line) receive visceral innervation and are therefore not painful


What should be suspected in a patient with rectal bleeding on aspirin and NSAIDs? What about a patient with rectal bleeding and vomiting?

- aspirin and NSAIDs: peptic ulcer with bleeding
- vomiting: infection or Mallory-Weiss tear


What serum tests can we run in order to help rule in/out an upper GI bleed? What other symptoms are associated with an upper GI bleed?

- serum urea levels can be elevated because digested blood is a source of urea
- other symptoms: melena, hematemesis, tachycardia, low BP


Elevated urea levels also indicate an issue with renal clearance - how can we differentiate between an issue with the kidneys and an upper GI bleed?

- in an upper GI bleed, urea will be elevated but creatinine will be normal
- (in renal disease, both will be elevated)


What is the most common upper GI cause of rectal bleeding? Most common cause of lower GI bleeding?

- upper: ulcers
- lower: ruptured diverticulosis


What type of bleeding results from ruptured diverticula?

- massive, usually painless rectal bleeding
- fresh blood as well as clots will be in the toilet bowl
- (can lead to shock!)


What is perianal hematoma? What does it result from?

- a painful lump with a dark blue/black appearance
- results from a burst perianal vein due to a heavy effort


What is a hemorrhoid? What do we use to treat them?

- an enlargement of the vascular cushion (which contains A-V connections) in the proximal anal canal
- treat via sclerosant injection, rubber-band ligation, or hemorrhoidectomy


Four Degrees of a Hemorrhoid

- 1st degree: bleeding w/ defecation, no prolapse
- 2nd degree: bleeding and prolapse w/ defecation; spontaneous reduction afterwards
- 3rd degree: bleeding and prolapse w/ defecation; prolapse must be manually reduced (pain)
- 4th degree: bleeding, permanent irreversible prolapse (very painful)


How will patients with an anal fissure present? How do we treat anal fissures?

- intense and constant pain that worsens with defecation, resulting in an apprehension to go
- treat via botulinum toxin (chemical sphincterotomy) or a surgical sphincterotomy


What is the most common source of lower GI bleeding?

- 95% of cases are due to bleeding in the colon


What are the most common causes of lower GI bleeding in patients under 50? In patients over 50?

- under 50: infectious colitis, anorectal disease, IBD (especially ulcerative colitis)
- over 50: diverticulosis, angiodysplasia, malignancy, ischemic colitis


What is the most common source of bleeding resulting in brown stools mixed with blood or with blood streaks? Resulting in large amounts of bright red blood? Resulting in maroon stools? Resulting in black stools?

- stools mixed with blood or w/ streaks: anorectal
- large bright red blood: colon
- maroon stools: right colon or small intestine
- black stools: upper GI