small intestine and appendix Flashcards
the duodenum
- extends from pylorus to ligament of treitz
- retroperitoneal
- 4 segments: duodenal bulb and descending duodenum which house major/minor duodenal papillae
minor and major papilla
minor- drainage of dorsal pancreatic duct (accessory duct of Santorini)
major- drains common bile duct and main pancreatic duct (duct of wirsung)
jejunum
more prominent plica circualres and longer vasa recta than ileum
blood supply of small intestine
primarily the superior mesenteric artery (SMA)
duodenum also supplied by gastroduodenal artery, originating from celiac axis via common hepatic artery
venous drainage of small intestine
superior mesenteric vein (SMV) which is joined by splenic and inferior mesenteric veins to constitute the portal vein
lymphatic drainage of small intestine
lacteals and lymphatic channels paralleling the venous drainage, joining at the cisterna chyli in upper abd below the aortic hiatus of the diaphragm
lymphatic tissue of terminal ileum
known as Peyer’s patches and terminates at ileocecal valve
nerve supply of small intestine and appendix
autonomic nervous system
parasympathetic fibers from vagus nerve and traverse to gut via celiac plexus
sympathetic fibers travel via splanchnic nerves from ganglion cells in superior mesenteric plexus
intestinal distention- sympathetic visceral afferent fibers
appendix
arises from the cecum at the confluence of the taenia coli and accompanied by an adjacent mesentery (mesoappendix) which courses the appendiceal artery as a terminal branch of ileocolic artery
how is the primary function of digestion and absorption of the small intestine accomplished
intestinal motility, activity of digestive enzymes, secretion of digestive juices, and absorptive processes predicted on both simple diffusion and active transport
autonomic and endocrine regulation
4 phases of migrating motor complex (MMC)
- quiescent w no spikes or contractions
- accelerating and intermittent spike and contractile activity
- sequence of high amplitude spiking activity and corresponding strong, rhythmic gut contractions
- brief migrate down the small intestine
total duration of cycle is 90-120m
where is vit b12, a, d,e,k and bile salts, calcium and iron absorbed
b12,a,d,e,k,bile salts- terminal ileum
ca/fe- duodenum and proximal small bowel
what does IgA for the gut immune system
suppress bacterial growth and adherence to epithelial cells
neutralizes bacterial toxins and viruses
what happens with SBO
lumen of the small intestine is blocked causing small bowel effluent to back up resulting in abd distension, n, v
mesentery can be compromised causing strangulation of the intestine w resulting ischemia and potentially bowel necrosis
closed loop bowel obstruction
complete obstruction where a portion of small intestine is obstructed both proximally and distally
high risk for strangulation and requires immediate surgery
intraluminal causes of SBO
foreign bodies, barium inspissation (colon), bezoar, inspissated feces, gallstone, meconium (cystic fibrosis), parasites, intussusception, polypoid
intramural causes of SBO
congenital (atresia, stricture, stenosis, web, meckels diverticulum)
inflammatory process (crohns, diverticulitis, ischemia, radiation enteritis, medication induced)
neoplasms (primary bowel, seconday)
trauma
extrinsic causes of SBO
adhesions, congenital (ladd/meckels bands, postop, postinflammatory)
hernias (ext/int)
volvulus
external mass effect (abscess*, annular pancreas, carcinomatosis, endometriosis, pregnancy, pancreatic pseudocyst)
MC SBO cause in industrialized and nonindustrialized
indust- postsurgical adhesions or scar tissue
nonind- inguinal or umbilical hernia
SBO due to internal hernias after laparoscopic gastric bypass
small mesenteric defects can be created through which small bowel can herniate and cause obstruction and potentially strangulation
metastatic peritoneal cancer as cause of extrinsic SBO
metastatic peritoneal implants, commonly from ovarian or colon cancer, may compress the small bowel lumen causing an intestinal obstruction
how do instrinsic causes affect the small bowel
causes thickening of the bowel wall and causes lumen to compromise forming a stricture within the small intestine not allowing solids to pass through the narrow lumen causing abdominal crampy pain
MC cause for benign stricture
Crohn’s disease
less common- radiation enteritis, ulcers from nsaids, previous small bowel resection
is strangulation assoc w bowel obstructions caused by strictures
not likely since mesentery is not compromised
how a foreign body (intraluminal cause) causes SBO
in some the ileocecal valve produces a slight narrowing that may form a barrier for some larger foreign bodies so they become impacted at the valve and an obstruction develops
what is the most serious complication of SBO
strangulation of the involved intestine because the bowel becomes ischemic and eventually infarcts as edema and kinking of the mesentery impact mesenteric vascular patency
indicators of a higher risk of strangulation
fever
tachycardia
leukocytosis
localized abd tenderness
pt w intermittent, intense, colicky pain relieved by vomiting of the epigastric region
proximal sbo (open loop)
pt with intermittent to constant pain that is diffuse and progressive, moderate abd distention, obstipation, and mild vomiting
distal sbo (open loop)
pt with progressive diffuse pain that was intermittent but rapidly worsened and is now constant, no abd distention
sbo closed loop
pt w continuous diffuse pain, w intermittent vomiting, marked abd distention and obstipation
colon and rectum obstruction
what should you be concerned about if pain and tenderness begin to localize in a more somatic pattern
bowel ischemia and peritonitis w attendant parietal peritoneal irritation
in an obese pt what may be the only clue to bowel incarceration within an otherwise occult hernia
areas of focal contour change, erythema or tenderness near a surgical scar
when will diffuse mild tenderness improve usually w sbo
after acute decompression via a nasogastric tube
initial imaging studies for sbo
abd series- supine and upright abd films
upright chest radiograph
imaging findings for sbo
bowel distention proximal to point of obstruction and collapse of bowel distal to same point
what do air fluid levels on an upright film indicate
lack of normal propulsive activity in affected loops of intestine
what represents closed loop obstruction on abd series
focal loops of intestine that are persistently abnormal
if the bowel is massively distended with air and it is difficult to distinguish the small and large bowel what should be done
water soluble contrast enema to exclude the possibility of a large bowel obstruction mechanism
when are contrast studies of the small intestine useful
pt w persistent partial obstructive symptoms or when it is difficult to distinguish paralytic ileus from mechanical obstruction
lab tests for sbo
helpful in excluding other causes
leukocytosis- if persists despite ng decompression and fluid resuscitation can mean progression toward ischemia
electrolytes closely monitored
hypokalemic- contraction of alkalosis w adv dehydration
hyperamylasemia- sbo but w marked degree heighten suspicion for acute pancreatitis
UA- excluding evidence for infection or stone
lactic acidosis- bowel ischemia
what is the most frequent ddx considered in setting of possible sbo
paralytic ileus
process of paralytic ileus
bowel motility is suppressed as a consequence of systemic or inflammatory illness and bowel may become distended and pt obstipated ; no mechanical obstruction
pt with minimal abd pain, n/v, obstipation, cant pass gas, abd distention, dec/absent bowel sounds, gas in small intestine and colon on xray
paralytic ileus
pt with crampy abd pain, n/v, obstipation, abd distention, norm/inc bowel sounds, gas in small intestine on xray
sbo
cause of POI
stress of surgery, fluid and electrolyte imbalances, pain management with narcotics
fast tract protocol
used to try and minimize POI by avoiding ng tubes, early ambulation, avoidance of fluid overload and early intro of diet
medication approved to dec length of POI
alvimopan- opioid antagonist that specifically targets the mu receptor responsible for the gi side effects of opioids
doesnt cross bbb so selectively blocks the peripheral receptors contributing to POI wout sig altering central analgesic effects of opioids
what does tx for sbo begin with
resuscitation, correction of fluid and electrolyte deficits
what is the best tool for assessing adequacy of volume replacement
foley catheter to assess urine output
at least 0.5mL/kg
what does an ng tube placement do
control emesis, relieve intestinal distention proximal to obstruction, lower risk of aspiration, allow monitoring of ongoing fluid and electrolyte losses
reduction en mass
hernia sac is reduced w the contents as a unit and therefore the contents may remain compromised despite being internalized
if there is question in regard to bowel viability what is an intraoperative assessment that is done
intraop assessment w fluorescein dye or doppler us to asses perfusion along with clinical evaluations of bowel viability such as color, bleeding, and peristalsis
what should be done if intussusception if found in adults
resection because of high likelihood of a lead point lesion
what are some complications that may complicate operative intervention for sbo
wound infection, anastomotic leak, abscess, peritonitis, and fistula formation
features of crohns ds
involves segments of GI tract other than the colon
sparing or skip lesions between affected areas
transmural involvement and assoc tendency to dev fistulas
noncaseating granulomata on histology
gradual onset with progression of abd pain, diarrhea, and weight loss
crohns
as progresses have malaise, fatigue, fever, weight loss, anorexia, n/v
dx crohns
colonoscopy w visualization of terminal ileum or barium enema w inspection of terminal ileum and small bowel contrast studies
biologies for crohns
infliximab
adalimumab
certolizumab
indications for surgery w crohns disease
perforation
fibrotic stricture- acute complete or chronic partial BO
fistula
what if a pt w a fistula fails to respond to medical management
resection of the communicating bowel and simple debridement or limited excision of the communicating cutaneous or nonenteric visceral tract
how long does the small intestine have to be maintained in order for them to sustain oral intake
100cm
complications of crohns
malnutrition, obstruction, fistulous ds, electrolyte distrubances
medication se
progression of ds resistant to medical therapy
wound infx, short bowel syndrome, wound healing problems, fistulae
anal incontinence
4 major etiologies for acute mesenteric ischemia (AMI)
sma embolism
sma thrombosis
mv thrombosis
nonocclusive mesenteric ischemia
SMA embolism
- originate from heart and assoc w afib
- thrombus forms win the heart and becomes dislodged, the clot passes downt he sma and lodges as the vessel narrows just distal to the take off of the middle colic artery completely occluding downstream flow
sma thrombosis
- freq assoc w vascular ds like CAD,PVD, chronic renal insuff
- chronic stenosis of the sma and if the vessel forms an acute thrombosis, ami may occur
- usually begins at origin of SMA and more likely to lead to complete SB infarction
smv thrombosis
- result of hypercoag state
- clot forms in smv obstructing venous outflow which results in venous htn, inc bowel wall edema and dec arterial flow
nonocclusive mesenteric ischemia (NOMI)
- usually dx in ICu setting in critically ill pts
- hx of toehr sig atherosclerotic ds
- in severe shock, blood shunted away from GI tract and if process cont there can be sig vasospasm of the splanchnic circulation, resulting in ischemia of sm/lg intestine
pt presents w severe rapid onset of pain, abd exam unimpressive
AMI
pain out of proportion to PE
presentation of SMV thrombosis and NOMI
smv- insidious onset, pain for several days or weeks, diffuse and nonspecific
nomi- min abd pain that is overshadowed,**hemodynamic instability (primary cause)
dx mesenteric ischemia
direct visualization of vascular tree via mesenteric arteriogram
delayed films to obtain a venous phase to determine if smv is thrombosed
CT is replacing
initial tx for mesenteric ischemia
rapid resuscitation and correction of any metabolic abnorm
abx
rapidly restore blood flow to gut, resect necrotic bowel and min reperfusion injury
tx for pt w sma embolism
immediate embolectomy via laparotomy
sma isolated and arteriotomy is performed
catheter placed directly into artery above clot and balloon inflated and catheter removed along with clot
tx for sma thrombosis
revasc required since sma chronically narrowed by severe atherosclerotic ds
sma bypass procedure or sma endovasc stent
tx for smv thrombosis
supportive and prompt anticoag w iv heparin
tx nomi
underlying pathology and aggressive resucitation efforts
avoid alpha adrenergic vasopressors and digoxin since the induce spasm and vasospasm is major part of nomi
mc benign lesion of small intestine
leiomyomas, which occur mc in jejunum but can occur anywhere in digestive tract are on the benign spectrum of mesenchymal tumors of the GI tract and now referred to as GI stromal tumors (GISTs)
where do leiomyomas or GISTs arise from
interstitial cells of cajal
other nonepithelial benign small bowel lesions
hemangiomas important potential cause of occult bleeding Osler Weber Rendu syndrome
hamartomas- peutz jeghers syndrome
lymphangiomas
neurogenic tumors (schwannomas, neurofibromas)
epithelial benign lesions of small intestine
tubular adenomas
villous adenomas- more likely malignant so need to be excised
brunner’s gland adenomas- duodenum, asymp
mc malignancy affecting individuals w familial polyposis after proctocolectomy
duodenal carcinoma of periampullary region
adenocarcinomas of small intestine
mc in duodenum w dec incidence as move distally
obstruction assoc w wl mc presentation
occult bleeding and anemia
endoscopic screening of periampullary region
carcinoid tumors of small intestine
- arise from kulchitsky cells in crypts of lieberkuhn part of APUD
- mc in ileum
- obstruction is mc finding due to intense desmoplastic reaction that occurs in adjacent bowel mesentery, others inlcude anorexia, fatigue and wl
- dx made laparotomy
- tx wide excision of bowel and adjacent mesentery
carcinoid syndrome
- episodic cutaneous flushing, bronchospasm, intestinal cramping/diarrhea, vasomotor instability, pellagre like skin lesions and right sided valvular heart ds
- dx urinary measurement of 5-hiaa, serum measurement of serotonin or chromogranin a
- tx resection
lymphoma (small intestine mc site of extranodal lymphoma)
- ileum mce to peyers patches
- nonspecific symp: vague abd pain, wl, fatigue, malaise
- nodularity and thickening of wall on contrast studies or ct
- surgical resection w subsequent chemo or radiation
what is the mc congenital anomaly of small intestine
meckel’s diverticulum- represents a remnant of the embryonic vitelline or omphalomesenteric duct
rule of twos for meckels diverticulum
2% of population
2:1 male to female
2 types mucosae
located within 2 ft of ileocecal valve
anatomy of meckels diverticula, where does the diverticulum arise from, and blood supply
- evolve when there is incomplete obliteration of the viteline duct which arises from the midgut and typically closes between 8th and 10th week of gestation
- arises from antimesenteric border of ileum usually within 60cm (2ft) of ileocecal valve
- blood supply from vitelline vessels, arising from ileal blood supply
what is the most common type of heterotopic mucosa found within the diverticulum
gastric-may cause ulceration of adjacent small intestinal mucosa and hemorrhage because of its capacity to produce acid in direct proximity to small bowel mucosa
less freq is pancreatic and colonic
what happens if there is a complete persistence of vitelline duct
sinus from the umbilicus to ileum may result presenting as an enteric fistula at the umbilicus itself
what happens if the vitelline duct obliterates but leaves a fibrous cord remnant
remnant may act as a point of fixation of the small intestine to the abd wall and facilitate bowel obstruction
clinical presentations in meckels diverticula
hemorrhage-bright red/maroon per rectum, painless, infants under 2
ileus
intussusception
diverticulitis
perforation
misc.- obstruction, inflammation, umbilical fistula
how i hemorrhage related to meckels dx
radionuclide scanning using technetium-99m pertechnetate which is taken up by ectopic gastric mucosa
enhanced by cimetidine or pentagastrin
how does an intestinal obstruction occur in meckels
because of volvulus of the small bowel around the diverticulum or constrictive effect of a mesodiverticular band
tx of meckels
resection of the diverticulum
if outside of pediatric age- narrow base, when a mesodiverticular band is present, or when heterotopic tissue is evident
base of diverticulum is closed transversely to minimize luminal narrowing
intestinal malrotation
- 4th-10th weeks of gestation
- 270deg rotation of proximal midgut places duodenum in retroperitoneum behind superior mesenteric vessels
- 270deg rotation of distal midgut places cecum in rlq and transverse colon draped anterior to superior mesenteric vessels
- if both turns are incomplete or not made at all abnorm exist
what is the mc manifestation of malrotation
midgut volvulus in an infant w an incomplete rotation
- the proximal midgut fails to rotate beyond the midline remaining to the right of sup mes vessels w the duodenum covered ant by Ladd’s bands
- distal midgut only rotates 90-180 and cecum becomes fixed to abd wall in ruq near duodenum
- twisting becomes small bowel volvulus leading to ischemia and necrosis
signs, dx and tx of midgut volvulus
- bilious emesis w progression to distention, tenderness/shock late findings
- radiographic upper GI series
- emergent laparotomy w detorsion of the bowel, division of Ladd’s bands, broadening of the mesentery and placement of the small intestine on the right and colon on the left side of abdomen
- also do appendectomy
what is short bowel syndrome (short gut)
vermiform appendix anatomy
- located in rlq at confluence of taenia coli on cecal apex
- appendiceal artery travels in mesoappendix and originates from ileocolic artery
- lined by columnar epithelium and rich in lymphatic follicles
location determines the location of tenderness as ds progresses
what causes acute appendicitis
- consequence of obstruction of appendiceal lumen
- mc is lymphoid hyperplasia causing luminal obstruction
- also accumulation of fecal material or fecalith
what happens as the appendiceal lumen becomes compromised
-mucus secretion by the epithelium leads to distention of the appendix distal to the narrowed lumen w eventual compromise of venous outflow as the organ becomes increasingly turgid and ischemic
what can progression of swelling, infection and ischemia assoc w acute appendicitis lead to
gangrene and perforation
the resulting peritonitis may be walled off by omentum or other adjacent visceral structures
if ifx not controlled, spread of infx into portal system via venous effluent (pylephlebitis)may result giving rise to air in portal system or liver abscesses
mcburneys point
located 1/3 of distance from anterior superior iliac spine to the umbilicus (appendicitis)
tx for appendicitis
- preop IV fluid resucitation coverage suitable for colonic flora
- 2nd gen ceph, broad spectrum penicillin or fluroquinolone and anaerobic coverage w metronidazole (no perf=24hr, perf=afebrile,norm wbc, gi function)
- surgery
open appendectomy
open: muscle splitting incision centered on McBurneys pt, appendix mobilized into wound and mesoappendix taken down allowing isolation of base of appendix where it joins the cecum; appendix removed after ligature control of its base
lap appy
less postop pain and lower wound infection rates allows inspection of peritoneal cavity before committing to given operative exposure
complications of appy
wound infx, pelvic abscess, fecal fistula, appendiceal remnants
appendiceal tumors
- carcinoid, carcinoma, mucocele
- 2cm in diameter, a right hemicolectomy to allow removal of lymphatic drainage pathway
43yo w 3d hx abd distention, n, v, dec urine outpt. hx of total abd hysterectomy 5yrs ago for benign ds. no meds. pulse is 110beats/min. abd distended and mild diffuse tenderness. bowel sounds hyperactive. serum electrolytes are sodium 140, chloride 90, bicarb 32, potassium 4.0. most appropriate initial iv fluid to administer
normal saline
K not added until volume restoration is achieved, lactated ringers may worsen metabolic alkalosis because lactate converted to bicarb in the liver, and colloidal solutions do not correct the hypochloremia and electrolyte imbalances and are not called for in resuscitating hypovolemic dehydrated pt
what 3 segments is the small intestine composed of
duodenum- pylorus to ligament of treitz
jejunum-first 40% of small bowel distal to duodenum
ileum- remaining 60%
A 38-year-old man has undergone four operations for Crohn’s disease in the last 10 years and recently underwent the last of these for treatment of recurrent disease proximal to a prior ileocolic anastomosis. Which of the following agents Is most useful for managing acute exacerbations rather than helping to maintain him in remission from active disease?
prednisone
A 65-year-old woman comes to clinic with a vague history of diffuse abdominal discomfort over the past 3 weeks. She denies any history of trauma or prior abdominal surgery and has no known stigmata of peripheral vascular disease. She takes vitamin D and calcium supplements. On exam, she has diffuse mild to moderate subjective tenderness without guarding or peritoneal signs. She is In sinus rhythm on EKG. Which of the following is the most likely diagnosis?
mesenteric venous thrombosis
A 63-year-old woman comes to clinic with symptoms of nonspecific abdominal pain. Her past medical history is unremarkable. She takes vitamins and calcium supplements. A recent CT scan shows a small bowel mass lesion. Laboratory evaluations show an elevated serum level of c-kit protein, with normal chromogranin A. Which of the following intestinal tumors is this consistent with?
gastrointestinal stromal tumor
The elevated c-kit level is specific to gastrointestinal stromal tumor (GIST) tumors and Is the key information leading to this answer. The other small bowel lesions mentioned could present with similar vague symptoms but are not associated with the c-kit proto-oncogene mutation and associated serum protein marker. Carcinoid tumors may be associated with elevated levels of 5-HIAA (5-hydroxyindole acetic acid) on 24 urine testing. Osler-Weber-Rendu lesions are telangiectasias and may be associated with bleeding and characteristic visible telangiectasias in other mucosal areas including the oral cavity and skin. Hamartomas may be associated with Peutz-Jeghers syndrome. Brunner’s gland adenomas are seen In the proximal duodenum, where these glands are part of the mucus and alkaline mucosal protection mechanism of the proximal small Intestine.
A 24-year-old female graduate student comes to the emergency department because of abdominal pain for the past 12 hours. Initially she had vague mid-abdominal pain that has localized to the RLQ about 3 hours ago. She is otherwise healthy and takes no medications. Her temperature is 37°C. There Is guarding and rebound tenderness in the right lower quadrant and a positive Rovsing’s sign. A CT scan shows fat stranding around a dilated appendix. At surgery, there is a 2.5-cm firm, smooth yellowish mass at the base of an inflamed appendix. There Is no evidence of perforation and no other abnormalities are found. Frozen section biopsy is consistent with a neuroendocrine tumor. Which of the following is the most appropriate management at this time?
right hemicolectomy
This patient has a carcinoid tumor. A right hemicolectomy Is needed because of the heightened risk of lymph node metastases. A simple appendectomy would not be appropriate for a carcinoid at the base of the appendix but would be appropriate for a carcinoid tumor
A 38-year-old man has undergone four operations for Crohn’s disease in the last 10 years and recently underwent the last of these for treatment of recurrent disease proximal to a prior ileocolic anastomosis. Which of the following agents Is most useful for managing acute exacerbations rather than helping to maintain him in remission from active disease?
prednisone
A 65-year-old woman comes to clinic with a vague history of diffuse abdominal discomfort over the past 3 weeks. She denies any history of trauma or prior abdominal surgery and has no known stigmata of peripheral vascular disease. She takes vitamin D and calcium supplements. On exam, she has diffuse mild to moderate subjective tenderness without guarding or peritoneal signs. She is In sinus rhythm on EKG. Which of the following is the most likely diagnosis?
mesenteric venous thrombosis
A 63-year-old woman comes to clinic with symptoms of nonspecific abdominal pain. Her past medical history is unremarkable. She takes vitamins and calcium supplements. A recent CT scan shows a small bowel mass lesion. Laboratory evaluations show an elevated serum level of c-kit protein, with normal chromogranin A. Which of the following intestinal tumors is this consistent with?
gastrointestinal stromal tumor
The elevated c-kit level is specific to gastrointestinal stromal tumor (GIST) tumors and Is the key information leading to this answer. The other small bowel lesions mentioned could present with similar vague symptoms but are not associated with the c-kit proto-oncogene mutation and associated serum protein marker. Carcinoid tumors may be associated with elevated levels of 5-HIAA (5-hydroxyindole acetic acid) on 24 urine testing. Osler-Weber-Rendu lesions are telangiectasias and may be associated with bleeding and characteristic visible telangiectasias in other mucosal areas including the oral cavity and skin. Hamartomas may be associated with Peutz-Jeghers syndrome. Brunner’s gland adenomas are seen In the proximal duodenum, where these glands are part of the mucus and alkaline mucosal protection mechanism of the proximal small Intestine.
A 24-year-old female graduate student comes to the emergency department because of abdominal pain for the past 12 hours. Initially she had vague mid-abdominal pain that has localized to the RLQ about 3 hours ago. She is otherwise healthy and takes no medications. Her temperature is 37°C. There Is guarding and rebound tenderness in the right lower quadrant and a positive Rovsing’s sign. A CT scan shows fat stranding around a dilated appendix. At surgery, there is a 2.5-cm firm, smooth yellowish mass at the base of an inflamed appendix. There Is no evidence of perforation and no other abnormalities are found. Frozen section biopsy is consistent with a neuroendocrine tumor. Which of the following is the most appropriate management at this time?
right hemicolectomy
This patient has a carcinoid tumor. A right hemicolectomy Is needed because of the heightened risk of lymph node metastases. A simple appendectomy would not be appropriate for a carcinoid at the base of the appendix but would be appropriate for a carcinoid tumor
what marks the end of the duodenum and start of the jejunum
ligament of treitz
what provides blood supply to small bowel
branches of superior mesenteric artery
what does the terminal ileum absorb
b12, fatty acids, bile salts
pt w abd discomfort, cramping, n, abd distention, emesis, high pitched bowel sounds
sbo
what labs are performed w sbo
electrolytes, cbc, type/screen, ua
what are electrolyte/acid base findings w proximal obstruction
hypovolemic hypochloremic, hypokalemia, alkalosis
what must be ruled out on pe in pts with sbo
incarcerated hernia
what major axe findings are assoc w sbo
distended loops of small bowel air fluid levels on upright film
what is the danger of complete sbo
close loop strangulation of the bowel leading to bowel necrosis
initial manage of all pts w sbo
npo, ngt, ivf, foley
abc’s of sbo
adhesions
bulge (hernia)
cancer/tumors
besides abc’s what are other causes of sbo
gallstone ileus intussusception volvulus external compression sma syndrome
bezoars, bowel wall hematoma
abscesses
diverticulitis
crohns radiation enteritis annular pancreas meckels diverticulum peritoneal adhesions stricture
what is sma syndrome
seen w wl, sma compresses duodenum causing obstruction
tx for complete sbo
lap and lysis of adhesions (LOA)
tx for incomplete sbo
conservative tx w close observation plus ngt decompression
intraop how can level of obstruction be determined in pts w sbo
transition from dilated bowel proximal to decompressed bowel distal to obstruction
mc cause abd surgery w crohns
sbo due to strictures
after sb resection why should mesenteric defect always be closed
prevent internal hernia
what may cause sob if pt is on coumadin
bowel wall hematoma
what are the signs of strangulated bowel w sbo
fever, shock, peritoneal signs, acidosis
severe/cont pain, hematemesis, gas in bowel wall or portal veing, abd free air
absolute indication for operation w partial sbo
peritoneal signs, free air on axr
what tumor classically causes sob due to mesenteric fibrosis
carcinoid tumor
s/sx of sb tumor
abd pain, wl, obstruction, perforation
mc benign sb tumor
leiomyoma
mc malignant sb tumor
adenocarcinoma
workup of small bowel tumor
ugi w small bowel follow through, enteroclysis, ct scan, enteroscopy
tx for malignant sb tumor
resection and removal of mesenteric draining lymph nodes
what malignancy is classically assoc w metastasis to small bowel
melanoma
usual location of meckels diverticulum
within 2ft of ileocecal valve on anti mesenteric border of bowel
major ddx assoc w meckels
appendicitis
complications of meckels
intestinal hemorrhage, intestinal obstruction, inflammation
s/sx meckels
lower gi bleed, abd pain, sbo
meckels scan
scan for ectopic gastric mucosa in meckels diver; uses technetium pertechnetate iv which is taken up by gastric mucosa
hernia assoc w incarcerated meckels diver
Littre’s hernia
mc cause small bowel bleeding
small bowel angiodysplasia
what vessel provides blood supply to appendix
appendiceal artery- branch of ileocolic artery
mesentery of appendix
mesoappendix
how to locate appendix once find cecum
follow taenia coli down
what is appendicitis
inflammation of appendix causes by obstruction of appendices lumen, producing closed loop w resultant inflammation that can lead to necrosis and perforation
causes of appendicitis
lymphoid hyperplasia, fecalith
s/sx appendidicitis
periumbilical pain
n/v
anorexia
pain migrates to rlq
valentines sign w append
rlq pain/peritonitis from succus drainage down to rlq from perforated gastric or duodenal ulcer
labs for append
cbc- inc wbc w left shift
ua- look for pyelo or stones (can have hematuria/pyuria w append)
in acute append what comes first pain or vomiting
pain
radiographic signs of append on axr
fecalith, sentinel loops, scoliosis away from right because of pain, abscess, loss of psoas shadow, loss of pre peritoneal fat stripe, free air
ct findings of append
periappendiceal fat stranding, appendiceal diameter >6mm, periappendiceal fluid, fecalith
preop meds/prep
rehydration w iv fluids (LR)
abx
tx for nonperf acute append
prompt appy, 24hrs of abx, discharge home POD 1
tx for perf acute append
iv fluid resuscitation and prompt appy
all pus is drained w postop abx cont for 3-7d
wound left open in most cases of perf after closing fascia
tx appendiceal abscess that is dx preop
percutaneous drainage of abscess
abx
elective appy 6 wks later
duration abx for nonruptured append and what abx
24hrs
cefoxitin, cefotetan, unasyn, cipro, flagyl
abx for perf appy
broad spectrum abx- amp/cipro/clinda or penicillin like zosyn
until normal abc, afebrile, ambulating, eating reg diet
complications of append
pelvic abscess, liver abscess, free perf, portal pylethrombophlebitis
what bacteria assoc w mesenteric adenines closely mimic acute append
yersinia enterolytica
complications of appy
sbo, enterocutaneous fistula, wound infx, infertility w perf, inc incidence of right inguinal hernia, stump abscess
mc postop complication of appy
wound infx
difference between mcburneys incision and rocky davis incision
mcburnerys is angled down (follows ext oblique fibers)
rocky straight across (transverse)
layers of abd wall during mcburney incision
skin subq fat scarpai fascia ext oblique int oblique transversus muscle trasversali fascia pre peritoneal fat peritoneum
steps in lap appy
- id append
- staple mesoappendix
- staple and transect appendix at base
- remove append from abdomen
- irrigate and aspirate until clear
which way should finger sweep trying to find appendix
lateral to medial along lateral peritoneum so don’t tear mesoappendix
how to get to retrocecal and retroperitoneal appendix
divide lateral peritoneal attachments of cecum
why use electrocautery on exposed mucosa on appendices stump
kill mucosal cells so don’t form mucocele
if find crowns in terminal ileum, will you remove appendix
yes if cecal/appendiceal base is not involved
mc appendiceal tumore
carcinoid tumor
tx of appendices carcinoid
appy
tx of appendices carcinoid >1.5cm
right hemicolectomy
what type of appendices tumor can cause pseudomyxoma peritonea if appendix ruptures
malignant mucoid adenocarcinoma
appendicitis definition
inflammation of the appendix caused by obstruction of the appendiceal lumen, producing a closed loop w resultant inflammation that can lead to necrosis and perforation
