Chapter 35 - Small Bowel Flashcards Preview

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

What is absorbed in the small intestine?

A

nutrients and water

2
Q

What is absorbed in the large intestine?

A

Water

3
Q

In what portion of the duodenum are most ulcers?

A

bulb- 90%

4
Q

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

A

ampulla of vater and duct of santorini

5
Q

What portions of the duodenum are retroperitoneal?

A

descending (2nd) and transverse (3rd)

6
Q

vascular supply of duodenum superiorly? inferiorly?

A

GDA superiorly, Inferior pancreaticoduodenal

7
Q

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

A

100cm, long vasa recta

8
Q

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

A

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

9
Q

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

A

95%; 90%

10
Q

What is the vascular supply of jejunum?

A

SMA

11
Q

Hos long is the ileum?

A

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

12
Q

What is absorbed at the intestinal brush border?

A

maltase, sucrase, limit dextrinase, lactase

13
Q

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

A

3 6 9cm.

14
Q

What is the terminal branch of the SMA?

A

Ileocolic

15
Q

What do goblet cells do?

A

mucin secretion

16
Q

What do paneth cells do?

A

secretory granules, enzymes

17
Q

What do enterochromaffin cells do?

A

APUD, 5-Hydroxytryptamine release, carcinoid precursor

18
Q

What do brunner’s glands produce?

A

alkaline solution

19
Q

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

A

lymphoid tissue; increased in the ileum

20
Q

What are M-cells?

A

antigen presenting cells in intestinal wall

21
Q

What are the phases of gut motility?

A

I - Rest

II - acceleration and gallbladder contraction

III - peristalsis

IV - deceleration

Motilin is most important hormone in migrating motor complex

22
Q

What is fat and cholesterol broken down by?

A

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

23
Q

What are chylomicrons made up of?

A

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

24
Q

What percentage of bile salts are reabsorbed?

A

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

25
Q

What is bile acid conjugated to?

A

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

26
Q

What are the primary bile acids?

A

cholic and chenodeoxycholic

27
Q

What are the secondary bile acids?

A

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

28
Q

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

A

develop stones secondary to inability to reabsorb bile salts

29
Q

How is short gut syndrome diagnosed?

A

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

30
Q

What is a sudan red test?

A

checks for fecal fat

31
Q

What is a schilling test?

A

checks for B12 absorption -radiolabeled B12 in urine

32
Q

how much bowel do you need to survive with TPN?

A

75cm, 50cm with a competent ileocecal valve

33
Q

What are the causes of steatorrhea?

A

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
Q

Causes of Non-healing fistula?

A

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

35
Q

High output fistulas normally occur where?

A

proximal bowel and are less likely to close with conservative management

36
Q

What are most fistulas caused by?

A

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

37
Q

Obstruction without previous surgery usually caused by what?

A

small bowel- hernia large bowel- cancer

38
Q

Obstruction with previous surgery usually caused by what?

A

small bowel- adhesions large bowel- cancer

39
Q

symptoms of bowel obstruction?

A

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

40
Q

What is the air with bowel obstruction from?

A

swallowed nitrogen

41
Q

Conservative treatment for SBO?

A

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

42
Q

What are the surgical indications for bowel obstruction?

A

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

43
Q

What is gallstone ileus?

A

-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
Q

What is meckel’s diverticulum?

A

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

45
Q

What is meckel’s diverticulum caused by?

A

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

46
Q

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

A

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

47
Q

What is the most common presentation of meckels in adults?

A

obstruction

48
Q

How do you localize a meckels?

A

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

49
Q

What do you do with duodenal diverticula?

A

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

50
Q

What are the first signs of Crohn’s disease?

A

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

51
Q

What are the extraintestinal manifestations of crohn’s?

A

arthritis, arthralgias, pyoderma gangrenosum, erythema nodosum, ocular diseases, stunted growth, B12/Folate deficiency

52
Q

What is most comon first involved bowel portion in Crohn’s?

A

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

53
Q

What is the pathology of chrons?

A

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

54
Q

What is medical tx of chrons?

A

5-ASA sulfasalazine steroids azathioprine methotrexate remicade Loperamide

55
Q

What are the surgical indications?

A

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

56
Q

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

A

take appendix if cecum not involved

57
Q

When is stricturoplasty indicated in patients with Chron’s?

A

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

58
Q

What are the complications from removal of terminal ileum?

A

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

59
Q

What are kulchitsky cells?

A

produce serotonin (enterochromoffin cell or argentaffin cells)

60
Q

what is the breakdown product of serotonin?

A

5-HIAA can be found in urine

61
Q

serotonin is part of what GI system?

A

amine precursor uptake decarboxylase system - APUD

62
Q

what is the precursor to serotonin?

A

tryptophan

63
Q

what can increased levels of tryptophan lead to?

A

niacin deficiency and pellagra

64
Q

other than serotonin, what do carcinoid tumors also secrete?

A

bradykinin

65
Q

When do you get carcinoid syndrome?

A

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

66
Q

how do you treat carcinoid syndrome?

A

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

67
Q

What are the GI sx in carcinoid caused by?

A

vasoconstriction and fibrotic desmoplastic rxn

68
Q

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

A

octreotide scan

69
Q

where is the most common site for carcinoid?

A

appendix

70
Q

small bowel carcinoid is at increased risk for what?

A

multiple primaries and second unrelated malignancies

71
Q

what do you do with carcinoid in appendix?

A

2 cm or involving base - right hemi

72
Q

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

A

treat like ca- segmental resection w lymphadenectomy

73
Q

What is chemo for carcinoid?

A

streptozocin and 5FU

74
Q

what is a palliative tx for carcinoid?

A

octreotide

75
Q

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

A

Aprotinin

alpha blockers

fruits

pentagastrin

76
Q

What causes intussusception in adults?

A

small bowel or cecal tumors presents with bleeding or obstruction resection

77
Q

what is most common small bowel tumor?

A

leiomyoma- usually extraluminal

78
Q

where are most adenomas of small bowel found?

A

ileum

79
Q

what inheritence is peutz-jehgers? What are sx?

A

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

80
Q

what is most common small bowel malignancy?

A

adenocarcinoma most in duodenum may need whipple

81
Q

what are risks for duodenal ca?

A

FAP gardners polyps adenomas von recklinghausens

82
Q

where are leiomyosarcomas of small bowel usually found?

A

jejunum and ileum most extraluminal hard to differenciate from leiomyoma

83
Q

where are small bowel lymphomas usually found?

A

ileum mediterranean variant occurs in young males- they get clubbing

84
Q

what is obstruction rate with loop ileostomies?

A

1-2%

85
Q

what types of ostomies have increased risk of parastomal hernia?

A

loop colostomies

86
Q

what is most common stomal infection?

A

candida

87
Q

when do you get diversion colitis and from what?

A

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

88
Q

what is most common cause of stenosis of stoma?

A

ischemia tx with dilation

89
Q

what are abscesses under stoma site caused by?

A

irrigation device

90
Q

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

A

ileostomy

91
Q

sx of appendicitis?

A

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

92
Q

most common age for appendicitis?

A

20-35

93
Q

what does appendicitis look like on CT?

A

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

94
Q

What part of appendix is most likely to perf?

A

midpoint of antimesenteric border

95
Q

What is most common cause of appendicitis in children?

A

hyperplasia- can follow viral illness

96
Q

most common cause of appendicitis in kids?

A

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

97
Q

when is appendicitis non-operative?

A

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

98
Q

why are children and elderly more likely to perf?

A

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

99
Q

what do you do abt appendicitis in pregos?

A

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
Q

what is fetal mortality with perf’d appendix?

A

35%

101
Q

what is a mucocele?

A

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

102
Q

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

A

10%

103
Q

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

A

do appy anyway

104
Q

most common cause of ileus?

A

surgery trauma hypokalemia ischemia drugs dilatation is uniform

105
Q

What do you get with typhoid enteritis?

A

bleeding/perforation fever headaches maculopapular rash leukopenia tx with bactrim