small and large BO, anal and rectal dz Flashcards
vascular supply to the small intestine is primarily from
superior mesenteric artery
List the extraluminal causes of small bowel obstruction
- Post-op surgical Adhesions (60%)
- Neoplasms (20%)
- Hernias (10%)
- malrotation
- intraabdominal abscess
What are the some intraluminal causes of small bowel obstruction
- intussception
- neoplasm
- crohn’s
In a patient who presents with abd pain, why is it important to ask for a h/o abd surgery
- adhesions are present in 2/3 of patients after abd surgery
- post op surgical adhesions account for 60% of small bowel obstructions
small bowel obstruction leads to what volume status
- hypotension
- intravascular fluid depletion -> edematous wall leads to fluid sequestration in lumen
Obstipation
- inability to pass either gas or stool
clinical presentation
- abd pain, intermittent -> steady
- abd distension
- N/V
- constipation
- obstipation
- high pitched or absent bowel sounds
- typmany on percussion
obstruction
What films would you order to assess for small bowel obstruction?
- plain films: supine and upright
- CT scan
- plain films are negative but high clinical suspicion
List the red flags when assessing for SBO -> surgery consult
- pneumoperitoneum
- retroperitoneal air
- peritoneal signs
- shock
List signs on xray/CT that are consistent with obstruction
- dilated proximal bowel
- distal collapsed loops
- air fluid levels
- bowel wall thickening > 3 mm
- sub-mucosal edema
- ascites
management of small bowel obstruction
- volume resuscitation, NPO, decompression with NG tube, abx
- consult surgeon
- only 1/4 of patients with SBO require surgery
What percentage of partial small bowel obstructions resolve spontaneously
80%
Name two ways to differentiate between complete and partial small bowel obstruction
- cessation of passage of stool or gas > 12-24 hrs supports complete SBO
- absence of air or fluid in distal small bowel or colon supports complete SBO
List causes of complicated bowel obstruction
- complete obstruction
- close loop obstruction
- incarcerated hernia: causes highest complication rate
- bowel ischemia, necrosis, or perforation
List three causes of intestinal strangulation
- strangulated hernia
- volvulus
- intussusception
clinical presentation
- rebound tenderness
- tenderness to percussion
- pain with light palpation/bumps
- diminished bowel sounds
peritonitis
currant jelly stools is characteristic for
intussusception
clinical presentation following abdominal surgery
- obstipation
- intolerance of oral intake
- absent or hypoactive bowel sounds
paralytic ileus
- certain degree is normal following surgery
- due to anesthetics, narcotics, and manipulation
- more likely with larger incisions
How can you determine (using symptoms) if an ileus is physiologic or pathologic post operatively
- no return of bowel function in 4-6 days post-op
- absence of flatus or stool 6 days post-op
- N/V requiring cessation of PO intake
- requirement for NGT after day 5 post-op
how is paralytic ileus diagnosed
- plain films
- KUB shows dilated loops and air in small bowel AND colon
management of paralytic ileus
- fluids
- pain managment (not narcotics)
- NGT in some
- PPN, TPN
- ambulate
blood supply to large bowel
- SMA and IMA
percentage of bowel obstructions in small and large bowel
- small bowel 80%
- large bowel 20%
List the causes of large bowel obstruction
- adenocarcinoma (65%)
- stricture due to diverticulitis/ichemia
- volvulus
- IBD, foreign body, fecal impaction
what films would you order when assessing for large bowel obstruction
- plain films: supine and upright
- CXR: look for free air under diaphragm
- Gastrograffin enema
- if xrays are unclear
- localization for surgery
- CT scan if diagnosis still in question
managment of large bowel obstruction
- IV fluids, NPO
- abx
- decompression if vomiting
- can start bowel cleanse to prep for surgery
what is a volvulus
- abnormal twisting of a portion of the GI tract, usually intestine, which can impair blood flow
List the two most common types of volvulus
- sigmoid volvulus
- cecal volvulus
which type of volvulus is the most common? Mean age of patients who get it?
- sigmoid volvulus
- 70 yo
imaging is suggestive of
- KUB/upright: U shaped “bent inner tube” sign
- CT scan: whirl pattern and birds beak
sigmoid volvulus
tx of sigmoid volvulus
-
reduction
- flexible sig to decompress and de-rotate
- interval surgery to resect redundant sigmoid and fix colon so it can not rotate again
cecal volvulus commonly affects what age group
mean age 33-53 yo
imaging suggestive of
- KUB/upright: comma or coffee bean sign with air fluid levels
cecal volvulus
tx of cecal volvulus
- right colectomy
- cecopexy with cecostomy tube: if pt unstable
- cecostomy tube alone in debilitated pt
What line seperates innervation of anus? Where is somatic innervation?
- pectinate or dentate line
- somatic innervation is below line: pt feels pain here
causes of hemorrhoids
- prlonged sitting, straining, pregnancy, advanced age
why do hemorrhoids itch
- swelling in the tissue allows fecal mattter to infiltrate and cause localized dermatitis
clinical presentation
- bright red blood per rectum - on toilet paper or stool (not mixed in)
- pruritus
hemorrhoids
what is the most common cause of rectal bleeding
- internal hemorrhoids
differentiate between internal and external hemorrhoids
- internal: above dentate line
- not painful
- may bleed and prolapse
- external: below dentate line
- do not bleed
- May thrombose
- pain, itching
diagnostic evaluation of hemorrhoids
- rectal exam
- CBC
- anoscope
- if in doubt, flexible sigmoidoscopy vs colonoscopy
differentiate between the 4 classes of internal hemorrhoids
- 1st degree: bulge in anal canal
- 2nd degree: protrude with defecation, spontaneous reduction
- 3rd degree: require manual reduction
- 4th degree: permanently protruded
list the two options for hemorrhoid treatment
- non-operative symptomatic relief
-
rubber band ligation of grade II and II internal hemorrhoids
- will cause necrosis
-
rubber band ligation of grade II and II internal hemorrhoids
- surgical hemorrhoidectomy
- internal or external hemorrhoids with extensive thrombosis, pain, and persistent bleeding
List the 4 types of anorectal abscesses due to obstruction of perianal crypt glands
- perianal (60%)
- ischiorectal
- intersphincteric
- supralevator
causative organisms of anorectal abscess
- e-coli
- proteus
- strep bacteriodes
tx of anorectal abscess
- surgical drainage: all require I&D
- possible broad spectrum abx
- wound care
untreated perianal infections can lead to
Fournier’s gangrene
what is a anal fistula
- abnormal connection between anal canal (internal opening) and the perianal skin (external opening)
- 50% chance after abscess
List the causes of fistula
- opened or ruptured abscess
- crohns disease
- diverticulitis
- fistula in ano
managment of fistula
- fistulotomy: unroofing the fistula tract to allow healing
tx for fistula in ano
- delineation of fistula tract
- drainage and curettage of fistula tract
- placement of seton
what are anal fissues
- linear tears in the lining of the anal canal below the level of the dentate line
causes of anal fissues
- foreign body
- very hard bowel movement
anal fissues are most common where
- posterior wall
- lowest blood supply
clinical presentation
- severe rectal pain with BM
- afraid to have a BM
- rectal bleeding
anal fissues
how is anal fissues diagnosed
- felt on DRE
- if unsure, get flex sig or colonoscopy
tx of anal fissues
- aim for soft, formed BM
- nitroglycerin ointment
- reduced spasm and increases blood flow
- if not healed in 3-4 weeks, needs surgery
