35 Small Bowel Flashcards
Most common causes of small bowel obstruction?
Adhesion (requires previous surgery)
Hernia
Cancer
Most common causes of large bowel obstruction?
Cancer
Signs and symptoms of proximal small bowel obstruction?
Intermittent pain (intense, colicky, relieved with vomiting)
Large volume vomiting (bilious)
Epigastric or periumbilical tenderness (mild)
No distention
+/- obstipation
Signs and symptoms of distal small bowel obstruction?
Intermittent/constant pain Low volume vomiting (progressively feculent) Diffuse and progressive tenderness Moderate to marked distention Obstipation
Signs and symptoms of closed loop small bowel obstruction?
Progressive, intermittent, constant pain; rapidly worsening May have prominent vomiting (reflex) Diffuse and progressive tenderness Absent distention \+/- Obstipation
Signs and symptoms of colon and rectum obstruction?
Continuous pain Intermittent vomiting (feculent) Diffuse tenderness Marked distention Obstipation
Symptoms of bowel obstruction?
Nausea and vomiting
Crampy abdominal pain
Failure to pass gas or stool
AXR findings in obstruction?
Air-fluid level
Distended loops of small bowel
Distal decompression
Absence of air in the colon or rectum
Why do you need aggressive fluid resuscitation in obstruction?
3rd spacing of fluid into the bowel lumen occurs
Why do you get air with a bowel obstruction?
Swallowed nitrogen (O2 can be absorbed)
Treatment of small bowel obstruction?
Bowel rest
NG tube
IV fluids
(Response - 80% of partial SBO, 40% of complete SBO)
Indication for surgical intervention in SBO?
Progessing pain
Peritoneal signs, Fever, Increasing WBCs (suggestive of strangulation/perforation)
Failure to resolve
anatomy and physiology: fund of small and large intestines
small = nutrient and water absorption … large = water absorption
anatomy and physiology: duodenum - parts
bulb = first portion, 90% of ulcers here …. descending = 2nd portion = contains ampulla of vater (duct of Wirsung, panc and CBD ducts meet) and duct of Santorini (accessory duct) … transverse = 3rd … ascending = 4th
anatomy and physiology: duodenum - retroperitoneal parts
descending (2nd portion with ducts entering) and transverse (3rd)
anatomy and physiology: duodenum - unique characteristic of 3rd and 4th portions
transition point at the acute angle between the aorta (posterior) and SMA (anterior)
anatomy and physiology: duodenum - vascular supply
superior (off GDA) and inferior (off SMA) pancreaticoduodenal arteries … both have anterior and posterior branches …. many communications between these arteries
anatomy and physiology: jejunum - describe
100cm long, long vasa recta, circular muscle folds
anatomy and physiology: jejunum - function
site of max absorption of everything except B12 (t ileum), bile acids (non conjugated at ileum, conjugated at terminal ileum), iron (duod), folate (t ileum) …. 95% of NaCl and 90% of water absorbed in jejunum
anatomy and physiology: jejunum - vasular supply
SMA
anatomy and physiology: ileum - describe, absorption, vascular supply
150cm long, short vasa recta, flat …. absorb non conj bile acids (ileum), conj bile acids, folate, B12 (t ileum)
anatomy and physiology: describe jejunum vs ileum
jej = 100cm, long vasa recta, circular muscle folds …. ileum = 150cm, short vasa recta, flat
anatomy and physiology: absorption throughout small bowel
jejunum = max site of all absorption, except …. ileum = non-conj bile acids … t ileum = con bile acids, b12, folate
anatomy and physiology: vascular supply throughout small bowel
duo = superior (off GDA which is off celiac then common hepatic) and inferior (off SMA) pancreaticoduodenal arteries (both with anterior and posterior branches) … jej = SMA, long vasa recta …. ileum = SMA, short vasa recta
anatomy and physiology: enzymes in intestinal brush border
maltase, sucrase, limit dextrinase, lactase
anatomy and physiology: normal sizes of small bowel, t colon, cecum
3, 6, 9cm
anatomy and physiology: branches of SMA
inferior pancreaticoduodenal artery … jejunal and ileal branches … ileocolic artery, appendicular artery, accessory appendicular artery … right colic artery … middle colic artery
anatomy and physiology: cell types
absorptive cells …. goblet cells (mucin secretion) … paneth cells (secretory granules, enzymes) … enterochromaffin cells (APUD, 5-hydroxytryptinase release, carcinoid precursor) … Brunner’s glands (alkaline solution) … Peyer’s patches (lymphoid tissue, increased in ileum) … M cells (APCs in intestinal wall)
anatomy and physiology: IgA
released into gut, also in mom’s milk
anatomy and physiology: Fe
small bowel has both heme and Fe transporters
anatomy and physiology: gut motility
migrating motor complex … phase 1 = rest …. phase 2 = acceleration and GB contraction … phase 3 = peristalsis, motilin is most important hormone and acts here …. phase 4 = deceleration
anatomy and physiology: bile salts/acids absorption
95% of bile salts are reabsorbed … 50% passive (non conj), 45% t ileum, 5% colon … 50% active (conj), only in t ileum (Na/K ATPase) - get gallstones after t ileum resection 2/2 malabsorption of bile acids
short gut syndrome: sx
diarrhea, steattorhea, weight loss, nutritional deficiency (lose fat, b12, electrolytes, water)
short gut syndrome: dx
based on sx, not length of bowel …. sudan red stain checks for fecal fat … schilling test = checks for b12 absorption (radiolabeled b12 in urine)
short gut syndrome: amnt of bowel needed
about 75cm to survival off TPN, 50cm with competent ileocecal valve
short gut syndrome: tx
restrict fat, PPI to reduce acid, lomotil (diphenoxylate and atropine)
steatorrhea: causes
(1) gastric hypersecretion of acid —> dec pH —> inc intestinal motility —> interferes with fat absorption ….. (2) interruption of bile salt resorption (i.e. terminal ileum resection) interferes with micelle formation and fat absorption)
steatorrhea: tx
control diarrhea (lomotil), dec oral intake esp of fats, pancrease, PPI
nonhealing fistula: causes
FRIENDS = Foreign body, Radiation, IBD, Epithelialization, Neoplasm, Distal obstruction, Sepsis/infection
nonhealing fistula: high output fistulas
more common with proximal bowel (duo or prox jejunum) and are less likely to close with conservative mgmt
nonhealing fistula: colonic fistulas
more likely to close than small bowel fistulas
nonhealing fistula: workup of pts w persistent fever
check for abscess (fisulogram, abd CT, upper GI with SBFT)
nonhealing fistula: MC causes and mgmt of fistulas
most fistulas are iatrogenic and treated conservatively (NPO, TPN, skin protection / stoma appliance, ocreotide), most close without surgery
nonhealing fistula: surgical options
(most heal with conservative mgmt) - resect bowel segment containing fistula and perform primary anastomosis
obstruction: MC causes
without previous surgery - small bowel 2/2 hernia, large bowel 2/2 cancer …. with previous surgery - small bowel 2/2 adhesions, large bowel 2/2 cancer
obstruction: sx
n/v, crampy abd pain, failure to pass gas or stool
obstruction: abd xray
air-fluid level, distended loops of small bowel, distal decompression
obstruction: fluid issues
3rd spacing of fluid into bowel lumen, need aggressive fluid resuscitation
obstruction: air with bowel obstruction
from swallowed nitrogen
obstruction: tx
bowel rest, NGT, IVF … cure 80% of partial SBO and 40% of complete SBO
obstruction: surgical indications
80% partial and 40% complete SBOs can be managed conservatively …. progressing pain, peritoneal signs, fever, increasing WBCs (all signs of strangulation or perforation), or failure to thrive
signs and sx of bowel obstruction: pain, vom, tenderness, distenion, obstipation - proximal small bowel, open loop
pain is intermittent, intense, colicky, often relieved with emesis …. vom is large V, bilious, frequent … tenderness is epigastric or periumbilical, mild unless strangulated bowel … distention absent …. +/- obstipation
signs and sx of bowel obstruction: pain, vom, tenderness, distenion, obstipation - distal small bowel, open loop
pain is intermittent to constant … vom is low V and frequency, progressively feculent with time … TTP is diffuse and progressive … distention is moderate to marked … +obstipation
signs and sx of bowel obstruction: pain, vom, tenderness, distenion, obstipation - small bowel, closed loop
pain is progressive, intermittent, constant, rapidly worsens … vom may be prominent (reflex) … TTP is diffuse, progressive … distention often absent … +/- obstipation
signs and sx of bowel obstruction: pain, vom, tenderness, distenion, obstipation - colon and rectum
pain is continuous …. vom is intermittent, not prominent, feculent when present … TTP is diffuse … distention is marked … obstipation is present
signs and sx of bowel obstruction: open loop prox small bowel, open loop distal small bowel, closed loop small bowel, colon and rectum - pain
intermittent, intense, colicky, often relieved w emesis …. intermittent to constant … progressive, intermittent, constant, rapidly worsens … continuous
signs and sx of bowel obstruction: open loop prox small bowel, open loop distal small bowel, closed loop small bowel, colon and rectum - emesis
large V, bilious, frequent … low V, low freq, progressively feculent … may be prominent (reflex) … intermittent, not prominent, feculent if present
signs and sx of bowel obstruction: open loop prox small bowel, open loop distal small bowel, closed loop small bowel, colon and rectum - TTP
epigastric or peiumbilical, mild unless strangulated bowel …. diffuse and progressive … diffuse, progressive, diffuse
signs and sx of bowel obstruction: open loop prox small bowel, open loop distal small bowel, closed loop small bowel, colon and rectum - distention
absent …. moderate to marked …. often absent … marked
signs and sx of bowel obstruction: open loop prox small bowel, open loop distal small bowel, closed loop small bowel, colon and rectum - obstipation
+/- …. present … +/- …. present
gallstone ileus: describe
SBO 2/2 gallstone, usually in t ileum
gallstone ileus: imaging findings
classically air in biliary tree in a pt w SBO