Chapter 35 - Small Bowel Flashcards Preview

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Flashcards in Chapter 35 - Small Bowel Deck (105):
1

What is absorbed in the small intestine?

nutrients and water

2

What is absorbed in the large intestine?

Water

3

In what portion of the duodenum are most ulcers?

bulb- 90%

4

What is contained in the second/descending portion of the duodenum?

ampulla of vater and duct of santorini

5

What portions of the duodenum are retroperitoneal?

descending (2nd) and transverse (3rd)

6

vascular supply of duodenum superiorly? inferiorly?

GDA superiorly, Inferior pancreaticoduodenal

7

How long is the jejunem?, how large are the vasa recta?

100cm, long vasa recta

8

The jejunum is the maximum site of absorption for everything except:

B12 - terminal ileum
Bile acids- ileum/terminal ileum
iron- duodenum
Folate- terminal ileum

9

What percentage of NaCl is absorbed in the jejunem? water?

95%; 90%

10

What is the vascular supply of jejunum?

SMA

11

Hos long is the ileum?

150cm, short vasa recta, flat.
Vascular supply from SMA

12

What is absorbed at the intestinal brush border?

maltase, sucrase, limit dextrinase, lactase

13

What is the normal diameter of small bowel? transverse colon? cecum?

3 6 9cm.

14

What is the terminal branch of the SMA?

Ileocolic

15

What do goblet cells do?

mucin secretion

16

What do paneth cells do?

secretory granules, enzymes

17

What do enterochromaffin cells do?

APUD, 5-Hydroxytryptamine release, carcinoid precursor

18

What do brunner's glands produce?

alkaline solution

19

What are peyer's patches? Where are they increased?

lymphoid tissue; increased in the ileum

20

What are M-cells?

antigen presenting cells in intestinal wall

21

What are the phases of gut motility?

I - Rest
II - acceleration and gallbladder contraction
III - peristalsis
IV - deceleration
Motilin is most important hormone in migrating motor complex

22

What is fat and cholesterol broken down by?

cholesterol esteras, phospholipase A, lipas, colipase in combination with bile salts
-form micelles
-TAG's are reformed in intestinal cells and released as chylomicrons

23

What are chylomicrons made up of?

90%TAG's, 10% phospholipids, cholesterol, protein

24

What percentage of bile salts are reabsorbed?

95%
-50% passive- 45% ileum and 5% colon
-50% active resorption in terminal ileum
-conjugated bile is only absorbed in terminal ileum

25

What is bile conjugated to?

taurine and glycine
can be deconjugated in the colon by bacteria and absorbed there

26

What are the primary bile acids?

cholic and chenodeoxycholic

27

What are the secondary bile acids?

deoxycholic and lithiocholic (from bacterial action on primary bile acids in the gut)

28

What can happen with the gall bladder after a terminal ileum resection?

develop stones secondary to inability to reabsorb bile salts

29

How is short gut syndrome diagnosed?

symptoms, not length of bowel
-diarrhea
-steatorrhea
-weight loss
-nutritional deficiency
-Lose fat, B12, electrolytes, water

30

What is a sudan red test?

checks for fecal fat

31

What is a schilling test?

checks for B12 absorption
-radiolabeled B12 in urine

32

how much bowel do you need to survive with TPN?

75cm, 50cm with a competent ileocecal valve

33

What are the causes of steatorrhea?

gastric hypersecretion of acid- increases motility- interferes with fat absorption
-Interruption of bile salt resorption- interferes with micelle formation
Tx:control diarrhea- lomotil, codeine, decreased oral intake

34

Causes of Non-healing fistula?

FRIENDS
F foreign body
R radiation
I irritable bowel
E epithelialization
N neoplasm
D distal obstruction
S sepsis/infection

35

High output fistulas normally occur where?

proximal bowel and are less likely to close with conservative management

36

What are most fistulas caused by?

iatrogenic
-treat conservatively first
-40% close spontaneously
-can resect bowel secoment and perform primary anastamosis

37

Obstruction without previous surgery usually caused by what?

small bowel- hernia
large bowel- cancer

38

Obstruction with previous surgery usually caused by what?

small bowel- adhesions
large bowel- cancer

39

symptoms of bowel obstruction?

nausea, vomitting, crampy pain, failure to pass gas or stool
-x-ray shows air fluid level, distended loops of small bowel, distal compression

40

What is the air with bowel obstruction from?

swallowed nitrogen

41

Conservative treatment for SBO?

NG
IVF
-cures 80% of partial SBO, 20-40% of complete SBO

42

What are the surgical indications for bowel obstruction?

Progressing pain, peritoneal signs, fever, increasing of WBC's, signs of strangulation or perforation, failure to resolve

43

What is gallstone ileus?

-SBO from gallstone in terminal ileum
-Air in biliary tree with SBO
-caused by fistula bw gall bladder and second portion of duodenum
-tx with stone removal
-if sick leave fistula
-if ok remove gall bladder, fix bowel

44

What is meckel's diverticulum?

-A true diverticulum
-2% of population
-2 feet from ileocecal valve
-fist 2 years of life

45

What is meckel's diverticulum caused by?

failure of closure of omphalomesenteric duct
50% of all painless lower GI bleeds in children under 2

46

What is the most common tissue type found in meckel's diverticulum? most common to cause bleeds?

Pancreas is most common type.
Gastric mucosa most common to bleed

47

What is the most common presentation of meckels in adults?

obstruction

48

How do you localize a meckels?

Meckel's scan (99Tc)- can do diverticulectomy

49

What do you do with duodenal diverticula?

observe unless perfrorated?
need to rule out gall bladder disease as a cause
-duodenal>jejunal>ileal
-segmental resection

50

What are the first signs of Crohn's disease?

Intermittent abdominal pain, diarrhea, weight loss, low grade fever
-usually 15-35 at first presentation
-increased in ashkenazia J's

51

What are the extraintestinal manifestations of crohn's?

arthritis
arthralgias
pyoderma gangrenosum
erythema nodosum
ocular diseases
stunted growth (shut your goddamn mouth)
B12/Folate deficiency

52

What is most comon first involved bowel portion?

terminal ileum (40%)
-10% anal perianal first
-colon only 35%
-small bowel only 20%

53

What is the pathology of chrons?

transmural involvement
segmental- skip lesions
cobblestoning
narrow deep ulcers
creeping fat
fistulas

54

What is medical tx of chrons?

5-ASA
sulfasalazine
steroids
azathioprine
methotrexate
remicade
Loperamide

55

What are the surgical indications?

90% will need surgery?
-obstruction
-abscess
-megacolon
-hemorrhage
-blind loop obstruction
-fissures
-EC fistula
-Perineal fistula
-anorectovaginal fistulas

56

What do u do with incidental finding of IBD with normal appendix in presumed appendicitis?

take appendix if cecum not involved

57

When is stricturoplasty indicated in patients with Chron's?

multiple strictures to save small bowel length
not good for first operation
10% leakage/abscess/fistula rate with stricturoplasty

58

What are the complications from removal of terminal ileum?

decreased B12 uptake
decreased bile salt uptake
decreased oxalate binding secondary to increased intraluminal fat that binds calcium--> ca oxalate kidney stones
gallstones

59

What are kulchitsky cells?

produce serotonin (enterochromoffin cell or argentaffin cells)

60

what is the breakdown product of serotonin?

5-HIAA can be found in urine

61

serotonin is part of what GI system?

amine precursor uptake decarboxylase system - APUD

62

what is the precursor to serotonin?

tryptophan

63

what can increased levels of tryptophan lead to?

niacin deficiency and pellagra

64

other than serotonin, what do carcinoid tumors also secrete?

bradykinin

65

When do you get carcinoid syndrome?

bulky liver mets
flushing and diarrhea
asthma symptoms and right heart valve lesions

66

how do you treat carcinoid syndrome?

all pts get abdominal exploration unless unresectable
if resecting liver mets, also do cholecystecomy

67

What are the GI sx in carcinoid caused by?

vasoconstriction and fibrotic desmoplastic rxn

68

what is a good test for localizing carcinoid when cant find it on CT?

octreotide scan

69

where is the most common site for carcinoid?

appendix

70

small bowel carcenoid is at increased risk for what?

multiple primaries and second unrelated malignancies

71

what do you do with carcinoid in appendix?

2 cm or involving base - right hemi

72

what do you do with carcinoid anywhere else in GI tract?

treat like ca- segmental resection w lymphadenectomy

73

What is chemo for carcinoid?

streptozocin and 5FU

74

what is a palliative tx for carcinoid?

octreotide

75

what do you do for bronchospasm in carcinoid? flushing? false 5-HIAA is from what? what can exacerbate sx?

Aprotinin
alpha blockers
fruits
pentagastrin

76

What causes intussusception in adults?

small bowel or cecal tumors
presents with bleeding or obstruction
resection

77

what is most common small bowel tumor?

leiomyoma- usually extraluminal

78

where are most adenomas of small bowel found?

ileum

79

what inheritence is peutz-jehgers? What are sx?

autosomal dominant
-jejunal and ileal hamartomas
-mucocutaneous melanotic skin pigmentation
-extraintestinal malignancies
-slight increase in colon ca
-lipomas, neurogenic tumors
-hemangiomas

80

what is most common small bowel malignancy?

adenocarcinoma
most in duodenum
may need whipple

81

what are risks for duodenal ca?

FAP
gardners
polyps
adenomas
von recklinghausens

82

where are leiomyosarcomas of small bowel usually found?

jejunum and ileum
most extraluminal
hard to differenciate from leiomyoma

83

where are small bowel lymphomas usually found?

ileum
mediterranean variant occurs in young males- they get clubbing

84

what is obstruction rate with loop ileostomies?

1-2%

85

what types of ostomies have increased risk of parastomal hernia?

loop colostomies

86

what is most common stomal infection?

candida

87

when do you get diversion colitis and from what?

Harmann's pouch
secondary to decreased short chain fatty acids- give short chain FA enemas

88

what is most common cause of stenosis of stoma?

ischemia
tx with dilation

89

what are abscesses under stoma site caused by?

irrigation device

90

what ostomy pts have increased risk of gallstones and uric acid stones?

ileostomy

91

sx of appendicitis?

1 anorexia
2 periumbilical pain
3 vomiting
4 migrates to RLQ
can have Normal WBC

92

most common age for appendicitis?

20-35

93

what does appendicitis look like on CT?

diameter >7mm, wall >2mm, looks like bulls eye, fat stranding, no contrast in lumen

94

What part of appendix is most likely to perf?

midpoint of antimesenteric border

95

What is most common cause of appendicitis in children?

hyperplasia- can follow viral illness

96

most common cause of appendicitis in kids?

fecalith
luminal distention followed by distention of appendix, venous congestion/thrombosis, ischemia, gangrene necrosis, rupture

97

when is appendicitis non-operative?

walled off perforated appendix
perc drainage and interval appendectomy
f/u barium enema or colonoscopy to ro perf'd colon ca

98

why are children and elderly more likely to perf?

delayed dx
kids have higher fever, vomitting, diarrhea
elderly may be asymptomatic
Infants rarely get it

99

what do you do abt appendicitis in pregos?

most common cause of acute abdominal pain in 1st tri
more likely in second tri
more likely to perf in third tri (confused for contractions)
Need to make incision where pain is- displaced superior

100

what is fetal mortality with perf'd appendix?

35%

101

what is a mucocele?

can be benign or malignant mucous papillary adenocarcinoma
-right hemi if malignant
-can get pseudomyxoma peritonei w rupture

102

What percentage of pts with regional ileitis go on to have chron's?

10%

103

what do you do if you have presumed appendicitis but find ruptured ovarian cyst or thrombosed ovarian vein?

do appy anyway

104

most common cause of ileus?

surgery
trauma
hypokalemia
ischemia
drugs
dilatation is uniform

105

What do you get with typhoid enteritis?

bleeding/perforation
fever
headaches
maculopapular rash
leukopenia
tx with bactrim