Chapter 35 - Small Bowel Flashcards
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, lipas, 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
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
```
