Rectal Bleeding Flashcards
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
