Small Bowel 2 Flashcards
1
Q
What is the most common malignant neoplasm of small bowel?
A
CARCINOID
2
Q
What are the top 4 malignant neoplasms of small bowel?
A
- CARCINOId
- Adenocarcinoma
- Lymphoma
- GISTs
3
Q
Most common symptoms of malignant small bowel neoplasms?
A
pain + weight loss
4
Q
These small bowel neoplasms arise from the enterochromaffin cells (Kulchitsky cells) in the crypts of Lieberkuhn;
A
carcinoids
5
Q
Carcinoid of small bowel arise form what cells?
A
enterochromaffin cells (Kulchitsky cells) in the crypts of Lieberkuhn
6
Q
The GI tract is the most common site for carcinoid tumors, the small intestine is the 2nd most common site, what’s first?
A
APPY
7
Q
In the small intestine, carcinoids almost always occur where?
A
within last 2 feet of ileum
8
Q
What do carcinoids secrete?
A
serotonin + substance P
9
Q
What symptoms characterize carcinoid syndrome?
A
cutaneous flushing
bronchospasm
diarrhea
vasomotor collapse
10
Q
What are the top 3 locations we see carcinoids in the GI tract?
A
appendix–> 45% (only 3% will mets)
ileum–> 28% (35% will metastasize)
rectum –> 16%
11
Q
Small bowel carcinoids tend be multi-centric, in what % of pts?
A
20-30%
12
Q
What % of pts with carcinoids develop carcinoid syndrome?
A
10%
13
Q
What do we need to develop carcinoid syndrome?
A
you need hepatic mets or extra-abdominal disease due to first pass metabolism of vasoactive peptides
14
Q
Common signs and symptoms of carcinoid syndrome?
A
flushing diarrhea hepatomegaly cardiac lesions (right heart valve dx) asthma
15
Q
What causes diarrhea in carcinoid syndrome?
A
increased serotonin levels circulating
16
Q
How do we diagnose carcinoid syndrome??
A
carcinoids make serotonin–> metabolized by liver/lung into 5-HIAA
- measure urine levels of 5-HIAA over 24 hrs
- *measure plasma levels of chromogranin A (seen in 80% of pts with carcinoid tumors)
17
Q
Surgical management of carcinoids of small bowel?
A
tumors < 1 cm, without LN involvement–> segmental intestinal resection
tumors > 1 cm, LN involved, multiple tumors–> wide excision of bowel + mesentery
lesion of terminal ileum–> R-Hemi
small duodenal tumors–> local excision
more extensive duodenal tumors–> pancreaticoduodenectomy
18
Q
Connection between carcinoid tumors and anesthesia?
A
anesthesia can precipitate a carcinoid crisis;
hypotension, bronchospasm, flushing
19
Q
How do we treat carcinoid crisis precipitated by anesthesia?
A
IV bolus of 50-100 micro-grams of octreotide
20
Q
What is the role of surgery in pts with carcinoid tumors an widespread metastatic disease?
A
surgical debulking still done to provide relief of sxs
21
Q
Medication used to tx symptoms of carcinoid syndrome?
A
somatostatin analogues like ocreotide
22
Q
Why is there limited success with chemotherapy for carcinoids?
A
they’re slow growing
23
Q
Role of chemo for carcinoids?
A
limited to pts non-responsive to anything else
pts who have a high proliferation rate
24
Q
5 yr survival rates in pts with carcinoids?
A
resection of carcinoid tumor localized to primary site–> 100%
pts with regional disease–> 65%
pts with distant mets–> 25-35%
25
Peak incidence of adenocarcinoma of small bowel?
7th decade
26
Where do we find most adenocarcinomas?
duodenum + prox. jejunum
27
Treatment for duodenal adenocarcinoma?
pancreaticoduodenectomy unless found in 3rd or 4th part of duodenum
jejunal + ileal adeno--> segmental resection + mesentery
28
Where do we find small bowel lymphomas?
ileum--> greatest concentration of gut-associated lymphoid tissue
29
What is neoadjuvant therapy for malignant GIST?
imatinib
30
What is imatinib?
tyrosine kinase inhibitor that blocks c-kot in malignant GISTs, inhibits BCR-ABL
31
What is the most common acquired diverticulum of small bowel and what is the most common congenital diverticulum of small bowel?
acquired--> duodenal diverticulum
congenital--> Meckel's
32
These represents 2nd most common cause of diverticula after colon:
duodenal diverticula
| commonly seen peri-ampullary around D2
33
Tx for duodenal diverticula?
most are asymptomatic, when found should be left alone
symptomatic diverticula--> diverticulectomy with Kocher maneuver
34
Most commonly encountered congenital anomaly of the small intestine occurring in 2% of the population:
Meckel's diverticulum
35
Is Meckel's diverticulum a true diverticulum?
YES
36
What is a Meckel's diverticulum?
failure or incomplete closure of the omphalomesenteric/vitelline duct
37
Where do we commonly see a Meckel's diverticulum?
2ft proximal to ileocecal valve
38
Why is not uncommon to find different tissues within a Meckel's?
the cells of the vitelline duct are pluripotent
can see gastric mucosa (50% of time)
can see pancreatic mucosa (5% of time)
39
Do we see Meckel's in the mesenteric or anti-mesenteric border of the bowel?
ANTI-mesenteric border
40
Most common clinical presentation of a Meckel's?
bleeding (seen in 25-50% of pts)
41
What causes the bleeding encountered in Meckels?
chronic acid producing gastric mucosa adjacent to ileum
42
Are Meckel's malignant vs benign?
majority benign
43
How does a Meckel's cause SB obstruction?
SB volvulizes around the fibrotic Meckel's band attached to abdominal wall
44
What is a Littre's hernia?
inguinal hernia containing Meckel's diverticulum
45
How does a Meckel's cause intussussception?
the diverticulum, if broad, can invaginate into the SB lumen and be carried forward by peristalsis
46
How do we try and treat intussussception caused by a Meckel's?
usually barium enema
will ultimately need diverticular resection to prevent recurrence
47
This should be on the differential alongside appendicitis in someone with RLQ:
Meckel's diverticulitis
if operating for suspected appendicitis and the appendix is normal, check the distal ileum for an inflamed Meckel's
48
Best test for Meckel's?
Pertechnetate scan --> which is taken up preferentially by gastric mucosa cells and ectopic gastric tissue in the diverticulum
49
What do you do for asymptomatic Meckel's diverticula found in child vs adults?
children--> remove
adults--> controversial
50
What is pneumatosis intestinalis?
multiple gas-filled cysts found in the GI tract
cysts seen in subserosa, submucosa, rarely muscle
most common in jejunum
spontaneous rupture of cysts give rise to pneumoperitoneum
51
WHat causes pneumoperitoneum in pneumatosis intestinalis?
rupture of thin walled gas-filled cysts found in subserosa, submucosa of intestinal wall
peritonitis is unusual
** pneumatosis intestinalis represents one of few cases of sterile pneumoperitoneum
52
In pts with free abdominal air but no signs of peritonitis, we can consider this on differential;
pneumatosis intestinalsis
53
Most cases of pneumatosis intestinalis assc with what?
COPD
| immunocompromised states
54
Pneumatosis intestinalis in neonates usually assc with what?
necrotizing enterocolitis
55
What is the tx for pneumatosis intestinalis?
no tx unless rare complications occur;
volvulus
tension pneumo
rectal bleeding
56
What is vascular compession of the duodenum called by the SMA?
SMA syndrome, AKA Wilkie's syndrome
57
What is Wilkie's syndrome?
compression of duodenum by SMA
58
What portion of duodenum compressed by SMA resulting in Wilkie's syndrome?
D3
59
This medication has been shown to significantly decrease severity of nausea/vomiting in pts with malignant bowel obstruction?
ocreotide
60
The two most common types of ectopic tissue seen in a Meckel's are?
gastric
| pancreatic
61
Nodal and distant mets are common with carcinoids 1-2 cm in size, with nodal spread seen in what % and liver spread in what %?
nodal spread in 60-80%
liver mets 20%
62
Carcinoid syndrome results from what ?
circulating vasoactive products; serotonin, histamine, kallikrein, bradykinin, prostaglandins
normally these products deactivated by monoamine oxidase in liver
for carcinoid syndrome to occur these products must be released in the systemic circulation through primary bronchial carcinoid, retroperitoneal mets or another source that does not drain thru portal circulation or have haptic mets that overwhelm liver's MAO
63
How do we treat liver mets in carcinoid syndrome?
usually removed, helps provide symptomatic relief in pts who don't respond to the somatostatin analogues
64
SB adenocarcinoma is relatively rare, found mostly where?
duodenum + jejunum -->80%
***+ surgical margin assc. with poor prognosis
65
In pts with Peutz-Jeghers syndrome, 90% of pts have what small bowel lesions?
hamartomatous polyps, mostly in jejunum
66
69% of pts with Peutz-Jeghers syndrome, that have hamartomatous polyps in the small bowel, develop what?
intussussception
67
Complication rates of stricturoplasties vs segmental resections for strictures in Crohn's?
stricturoplasties have higher complications rates; post-op bleeding from suture line
thus stricturoplasties for Crohn's are used to preserved substantial bowel length, they're not used to small strictures that can be segmentally resected due to higher risk of complications
68
Gold standard to diagnose intussussception, showing characteristic 'bull's eye sign";
CT with IV/PO contrast
69
In adults that present with intussussception, the lead point is ususally?
a small bowel tumor 80% of the time
thus a segmental resection of affected area, don't reduce the intussussception, lymphadenectomy, anastomosis
70
Why don't we reduce intussussception in adults?
tumor cells can be shed or tumor can be disrupted given inflamed nature of the bowel
71
Most common xray findings in intussussception and most pathognomonic xray finding in intussussception:
most common--> non-specific air fluid levels, no gas in colon
pathognomonic--> sausage shaped soft tissue density, outlined by two strips of air
72
Best test to diagnose Crohn's?
c-scope with bx
73
What are the two forms of pneumatosis intestinalis?
cystic---> seen in submucosa as cysts
linear--> seen in subserosa, muscualris as a thin linear gas pattern
74
Mortality rate from enterocutaneous fistulas?
15-20%
75
Majority of enterocutaneous fistulas are caused by?
iatrogenic 85%
predisposing conditions; Crohn's diverticulitis, malignancy, trauma (20%)
anastomotic leaks, bowel injury, erosion by suction catheters, lacs to bowel by mesh or retention sutures
76
Differences in proximal vs distal fistulas?
proximal fistulas--> higher output, more fluid & electrolyte loss
distal fistulas--> lower output, tend to close spontaneously
77
What is a high output fistula?
>500 cc/day
78
What are some factors that prevent spontaneous fistula closure?
```
high output
radiation enteritis
cancer
active IBD
distal obstruction
undrained abscess
foreign body in fistula tract
epithelialization of fistula tract
fistula tract < 2.5 cm long
```
79
MC cause of death in pts with fistulas?
historically was malnutrition and dehydration
now it's sepsis
80
How do we manage fistulas surgically?
source control, nutritional optimization
conservative course for 4-6 weeks, if it hasn't closed, then surgery should be considered
ideally you want to wait 3-6 months
81
Role of ocretide in fistula management?
shown to reduce fistula outputs
not provided an improvement in fistula closure rates
82
Preferred operation for fistulas?
fistula tract excision
segmental resection of the involved segment of intestine
reanastomose
83
This is a rare condition manifested by diarrhea, stetatorrhea, megaloblastic anemia, weight loss, abd pain and malabsorption of fat soluble vitamins (ADEK):
blind loop syndrome
84
What causes blind loop syndrome?
bacterial overgrowth in a stagnant area of small bowel
usually due to stricture, stenosis, fistula, diverticula
85
What causes megaloblastic anemia in blind loop syndrome?
bacterial overgrowth due to stagnant area of bowel
these bacteria compete for B12
86
How do we treat megaloblastic anemia caused by bacterial overgrowth in blind loop syndrome?
course of broad spectrum abx, adding IF does not help
87
How can we confirm blind loop syndrome?
can get cultures from an intestinal tube
C-xylose breath test
Schilling test--> C-labeled Vit B12 is absorbed, and excretion in urine is noted (usually 0-6% in blind loop syndrome, normal is 7-25%)
88
Tx for blind loop syndrome?
IV B12
| broad spectrum abx--> augmentin, kefflex + flagyl
89
For radiation enteritis, what's the dose that can cause damage to the intestine?
dosages > 5000 cGy
90
Various drugs have been used to help with radiation enteritis, what's the most promising?
amifostine
sulhydryl compound that is converted intra-cellularly to an active metabolite --> binds to free radicals and prevents cell damage
91
What is short bowel syndrome?
total SB length that is inadequate to support nutrition
92
Of cases of short bowel syndrome, 75% are due to massive intestinal resections from what?
mesenteric occlusion
volvulus
trauma to superior mesenteric vessels
93
MC cause of short bowel syndrome in neonates is?
necrotizing enterocolitis
94
Clinical hallmarks of short bowel syndrome?
diarrhea, malnutrition, fluid + electrolyte deficiency
95
Why do we see an increase in gallstones and kidney stones with short bowel syndrome?
decrease in enterohepatic circulation
hyperoxaluria causes kidney stones
96
What are some common causes of Wilkie's syndrome?
vascular compression of duodenum usually due to weight loss, supine immobilization, scoliosis, body cast
97
Operative treatment for duodenal vascular compression by SMA?
duodeno-jejunostomy
98
Characterize fistulas and their outputs:
low output--> less than 200 cc/day
moderate--> 200-500
high output --> greater than 500 cc/day
99
IF a fistula remains open after 6-8 weeks, spontaneous closure is?
unlikely
100
In pts with carcinoid syndrome, they can become hypotensive unresponsive to fluids and pressors, what do we give?
ocreotide (somatostatin analogue)
101
Strongest risk factor for developing sxs with a Meckel's?
ectopic gastric tissue
102
What are some risk factors assc with developing sxs due to a Meckels?
male sex
age less than 50
diverticulum > 2 cm
ectopic tissue
103
For a pt with an acute flare up for Crohn's dx, initial management includes?
oral steroids--> then taper
infliximab usually reserved for pts who have not responded to other therapies
104
This is a potent vasodilator that does not increase intestinal O2 uptake:
papaverine
105
What is MALT?
mucosal associated lymphoid tissue--> seen in stomach, asscs with h.pylori --> once h pylori treated, MATL regresses
when found in small bowel and isolated, resection takes care of it, nothing else to do
106
ALmost 80% of these small bowel tumors arise in duodenum and proximal jejunum and may assc. ulcers;
adenocarcinomas
frequently cause obstruction
107
Most appropriate antibiotics for small bowel intestinal overgrowth?
rifaximin (inhibits DNA dependent RNA polymerase)
usually for 14 days
108
Why do we need screening in pts with FAP if they've had a total procto-colectomy with ileo-anal anastomosis?
polyps typically seen throughout colon and rectum
but also seen in stomach, duodenum thus screening w/anoscopy and EGD recommended post-op regularly
109
Fistulization between gallbladder and duodenum?
produces gallstone ileus
110
What's Bouveret's syndrome?
GOO caused by gallstone in duodenum
111
Extrinsic compression of CBD by gallstone?
Mirizzi syndrome
112
Treatment for high risk GISTs?
prolonged adjuvant therapy usually with imatinib if ckit positive for 3 yrs or more
113
In pts with blind loop syndrome this test can aid in the diagnosis;
d-xylose test (carb breath test)
bacteria in blind loop break down carbs to hydrogen and methane which is detected in the breath
114
Bile salts and vit B12 are absorbed where?
terminal ileum
if terminal ileum resected, bile salts are not re-absorbed, introduced to colon, interfere with colonic absorption of fluids and electrolytes
pts experience diarrhea
Tx--> oral cholestyramine
115
What medications are known to be protective against radiation enteritis?
ACEi
| statins
116
This syndrome characterized by severe post-prandial epigastric abdominal pain and nonbilious emesis, usually in pts w/gastric bypass surgery;
afferent loop syndrome
117
This medication indicated in pts with short bowel syndrome who can't be weaned off TPN;
teduglutide
glucagon-like-peptide 2 analog
(ocreotide usually used short-term in pts with short gut syndrome)
118
Blind loop syndrome is most commonly associated with what procedure?
antecolic biliroth II with a long >30 cm afferent limb
(retrocolic loop gastroenterostomy is preferred)
Tx--> convert to a biliroth I or a Roux-en-Y
119
The vitelline duct connects the yolk sac to the midgut of the embryo, and self-involutes during 9th week of development, failure to involute leads to a?
Meckel's
120
Crohn's disease can have a 10-12 fold increased risk of what small bowel cancer?
adenocarcinoma
usually in the terminal ileum
121
Duodenal Crohn's dx is unusual, tx of choice for Crohn's involving the 1st and 2nd portions of the duodenum include?
gastrojejujonostomy and vagotomy (vagotomy done to prevent marginal ulcers)
duodenojejunostomy indicated for refractory strictures of 3rd/4th part of duodenum
***pancreaticoduodenectomy is not performed for duodenal Crohn's
122
Most common complication following reversal of a loop ileostomy?
SBO - 7%
followed by SSI
123
Lymphomas of small bowel tend to be found where?
ileum
tend to be large when found
perforation occurs in 25% of pts
124
Different types of small bowel stricturoplasties:
single short segment 5-7 stricture; H-Mickulicz
medium segment 10-15 cm; Finney
>15 cm segment; Michelassi
large bowel does not respond well to stricturoplasties,
in large bowel strictures need resection, 7% chance of having cancer
125
Small bowel lymphomas are more commonly of B cell or T cell origin?
B cell
126
What part of small bowel do most small bowel lymphomas originate?
ileum---> has Peyer's patches
127
Pts with a hx of this disease are more likely to develop T-cell lymphoma of small bowel;
celiac dx
128
Who is at higher risk of developing T cell lymphoma of small bowel?
pts w/celiac dx
| immunocompromised pts
129
Most common small bowel location for lymphoma?
ileum
130
In what part of small intestine is most protein absorption taking place?
jejunum
131
How is protein digested?
begins in stomach, gastric acid denatures protein
small intestine, protein comes in contact with pancreatic proteases
trypsinogen gets activated by brush border enterokinase in duodenum
activated trypsin activates other enzymes
132
Approx. 80-90% of protein digestion and absorption occurs in the?
jejunum
133
A Heineke-Mickulicz stricturoplasty is indicated for strictures what size?
5-7 cm long
134
How to perform a Heineke-Mickulicz stricturoplasty?
make a longitudinal incision across the stricture
place two stay sutures on either end
close in a tranverse fashion with simple interrupted silk sutures
135
FInney stricturoplasties are best suited for what length strictures?
10-15 cm long
