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A1-G Surg Note Small Bowel > Sabiston Small Bowel > Flashcards

Sabiston Small Bowel Flashcards

1
Q

Anatomy , Lengths

A

duodenal length 20 cm
jejunal length at 100 to 110 cm
ileal length at 150 to 160 cm.

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2
Q

Anatomy , Jejunum Vs Ileum

A

jejunum :
larger circumference, thicker
can be identified during surgery by examining mesenteric vessels, only one or two arcades send out long, straight vasa recta to the mesenteric border

Ileum : blood supply to the ileum may have four or five separate arcades with shorter vasa recta

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3
Q

Mucosa of Small bowel

A

characterized by transverse folds (plicae circulares), which are prominent in the distal duodenum and jejunum

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4
Q

Blood Supply to Duodenum

A

Superior mesenteric artery > distal duodenum.
The celiac artery > proximal duodenum

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5
Q

Blood Supply to Small Bowel

A

-superior mesenteric artery (except for the proximal duodenum )

-SMA > courses anterior to the uncinate process of the pancreas and the third portion of the duodenum, it divides to supply the pancreas, distal duodenum, entire small intestine, and ascending and transverse colons.

-abundant collateral blood supply provided by vascular arcades coursing in the mesentery

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6
Q

Innervation

A

parasympathetic and sympathetic divisions of the autonomic nervous system

The parasympathetic fibers > the vagus nerve, traverse the celiac ganglion and influence secretion, motility, and probably all phases of bowel activity.

The sympathetic fibers > splanchnic nerves > located in a plexus around the base of the superior mesenteric artery

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7
Q

Location of myenteric (Auerbach) plexus and (Meissner plexus)

A

myenteric (Auerbach) plexus > muscularis propria (between the muscles)

(Meissner plexus) > networks of lymphatics, arterioles, and venules > in Submucosa

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8
Q

lamina propria Location and Role

A

between the epithelial cells and muscularis mucosae

Contains > plasma cells, lymphocytes, mast cells, eosinophils, macrophages, fibroblasts, smooth muscle cells, and noncellular connective tissue

protective role > rich supply of immune cells

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9
Q

Main functions of the crypt epithelium and Villous Epithelium

A

crypt epithelium > cell renewal, exocrine, endocrine, water, and ion secretion

villous epithelium > digestion and absorption.

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10
Q

What are the Four main cell types are contained in the mucosal layer

A

(i) absorptive enterocytes
(ii) goblet cells, which secrete mucus
(iii) Paneth cells, which secrete lysozyme, (TNF), and cryptdins, which are homologues of leukocyte defensin peptides related to the host mucosal defense system
(iv) enteroendocrine cells,produce the gastrointestinal hormone

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11
Q

What is the Main Cell in the Mucosa

A

Absorptive enterocytes

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12
Q

Function of The brush border of the small intestine

A

contains the enzymes
lactase, maltase, sucrase-isomaltase, and trehalase

split the disaccharides into their monosaccharides

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13
Q

Transport of the released hexoses (glucose, galactose, and fructose) is by

A

active transport.

The major routes:
sodium-glucose transporter 1 (SGLT-1), glucose transporter 5 (GLUT-5), and glucose transporter 2 (GLUT-2).

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14
Q

Protein Digestion

A

Pancreatic trypsinogen is secreted in the intestine by the pancreas in an inactive form > activated by the enzyme enterokinase, a brush border enzyme in the duodenum to an activated form of trypsin.

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15
Q

Bile Acid

A

-unconjugated bile acids absorbed into the jejunum by passive diffusion

-conjugated bile acids that form micelles are absorbed in the ileum by active transport

-then reabsorbed from the distal ileum and pass through the portal venous system to the liver for secretion as bile.

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16
Q

Vitamins Absorbtion

A

Calcium > duodenum and jejunum by active transport
facilitated by an acid environment and is enhanced by vitamin D and parathyroid hormone

Iron > as a heme or nonheme component > duodenum by an active process.
total absorption of iron is dependent on body stores of iron and the rate of erythropoiesis

Potassium, magnesium, phosphate, and other ions actively absorbed throughout the mucosa

Vitamin B1 > jejunum by an active process similar to the sodium-coupled transport system for vitamin C.

Vitamin B2 > the upper intestine by facilitated transport.

vitamin B12 > terminal ileum.
derived from cobalamin, freed in the duodenum by pancreatic proteases, binds to intrinsic factor

Vitamin B6 > simple diffusion into the proximal intestine

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17
Q

Motility

A

Sympathetic activity inhibits motor function

parasympathetic activity stimulates it.

motilin, its peak plasma level during phase III (intense bursts of myoelectrical activities resulting in regular, high-amplitude contractions) of migrating myoelectric complexes

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18
Q

The gut-associated lymphoid tissue is localized in four areas

A

-Peyer patches > activate and prime B and T cells
-lamina propria lymphoid cells
-Paneth cells
-intraepithelial lymphocytes > unique subtype of T cells.

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19
Q

major protective immune mechanisms for the intestinal tract is

A

the synthesis and secretion of IgA.

produced by plasma cells in the lamina propria

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20
Q

Which Primary colonic cancers Present Like SBO

A

Tumors arising from the cecum and ascending colon

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21
Q

MC Cause of SBO

A

Adhesions 60%
Malignant 20%
Hernia 10%
Crohns 5%

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22
Q

Early in the course of an obstruction

A

intestinal motility and contractile activity increase > diarrhea

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23
Q

Later in the course of obstruction

A

intestine becomes fatigued and dilates > water and electrolytes accumulate intraluminally and in the bowel wall itself > massive third-space fluid loss > dehydration and hypovolemia

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24
Q

proximal obstruction vs Distal obstruction

A

Proximal > dehydration, hypochloremia, hypokalemia, and metabolic alkalosis

Distal > large quantities of intestinal fluid into the bowel; however, abnormalities in serum electrolyte levels are usually less dramatic.

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25
Q

Sepsis in SBO

A

-the jejunum and proximal ileum Normally have only 103 to 105 (CFU/mL) of bacteria.

-With obstruction (most commonly Escherichia coli, Streptococcus faecalis, and Klebsiella spp.) > reaching concentrations of 109 to 1010 CFU/mL.

increase in the number of indigenous bacteria translocating to mesenteric lymph nodes and even systemic organs

> amplifies the local inflammatory response leading to intestinal leakage and subsequent increase in systemic inflammation.

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26
Q

higher obstruction vs Distal

A

Higher > Nausea and vomiting , hyperactive bowel sounds

distally > less emesis;
initial and most prominent symptom is cramping abdominal pain, minimal or no bowel sounds are noted

As the obstruction becomes more complete with bacterial overgrowth, the vomitus becomes more feculent, indicating a late and established intestinal obstruction.

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27
Q

Plain abdominal film signs of SBO

A

Supine :
-Dilated gas or fluid filled small bowel >3 cm
-Dilated stomach
-Small bowel dilated out of proportion to colon
-Stretch sign
-Absence of rectal gas
-Gasless abdomen
-Pseudotumor sign

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28
Q

Plain abdominal film signs of SBO

A

Upright or Left Lateral Decubitus :
-Multiple air fluid levels
-Air fluid levels longer than 2.5 cm
-Air fluid levels in same loop of small bowel of unequal lengths
-String of beads sign

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29
Q

why put NGT in SBO

A

-empties the stomach
-reducing the hazard of pulmonary aspiration of vomitus
-minimizing further intestinal distention from swallowed air

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30
Q

Radiation enteropathy causing SBO Tx

A

can be treated nonoperatively with tube decompression and the potential addition of corticosteroids, particularly during the acute setting.

In the chronic setting, laparotomy will be required with possible resection of the irradiated bowel or bypass of the affected area.

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31
Q

If intestinal viability is questionable

A

the bowel segment should be completely released and placed in a warm, saline-moistened sponge for 15 to 20 minutes and then reexamined.

If normal color has returned and peristalsis is evident, it is safe to retain the bowel

Another options : Doppler probe, administration of fluorescein and Intraoperative near-infrared angiography or second-look laparotomy 18 to 24 hours after the initial procedure.

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32
Q

consideration of laparoscopic management in SBO

A

-mild abdominal distention
-proximal or partial obstruction;
-anticipated single-band obstruction
-and those with low risk of strangulation or perforation

laparoscopic found to be of greatest benefit in
-patients with fewer than three previous operations
-were seen early after the onset of symptoms
-and were thought to have adhesive bands as the cause.

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33
Q

the most effective means of limiting the number of adhesions

A

is a good surgical technique :
-gentle handling of the bowel to reduce serosal trauma
-avoidance of unnecessary dissection
-exclusion of foreign material from the peritoneal cavity
-the use of absorbable suture material when possible,
-avoidance of excessive gauze sponge use,
-the removal of starch from gloves
-adequate irrigation and removal of infectious and ischemic debris
-preservation and use of the omentum around the site of surgery or in the denuded pelvis

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34
Q

Causes of ileus.

A
  • After laparotomy
  • Metabolic and electrolyte derangements (e.g., hypokalemia, hyponatremia, hypomagnesemia, uremia, diabetic coma)
  • Drugs (e.g., opiates, psychotropic agents, anticholinergic agents)
  • Intraabdominal inflammation
  • Retroperitoneal hemorrhage or inflammation
  • Intestinal ischemia
  • Systemic sepsis
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35
Q

Ileus vs SBO

A

-Plain abdominal radiographs may reveal distended small bowel as well as large bowel loops.

-In cases that are difficult to differentiate from obstruction, barium studies may be beneficial

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36
Q

Etiology of Crohns

A

-infectious : Mycobacterium paratuberculosis and enteroadherent E. coli.

-immunologic : Humoral and cell-mediated immune reactions , cytokines, such as interleukin (IL)-1, IL-2, IL-8, and TNF-α

genetic : NOD2, MHC, and MST1 3p21

Environmental factors : smoking

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37
Q

the single strongest risk factor for development of Crohns disease

A

-is having a first-degree relative with Crohn disease

-The most important gene in Crohn disease development is NOD2

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38
Q

The NOD2 gene is associated with a decreased expression of

A

antimicrobial peptides by Paneth cells.

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39
Q

Which Gene is a predictor of ileal disease, ileal stenosis, fistula, and Crohn-related surgery.

A

NOD2

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40
Q

Which gene can distinguish Crohn disease from ulcerative colitis

A

CARD15 > strongly associated with Crohn disease

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41
Q

CARD15, leads to impaired activation of

A

the transcription factor nuclear factor kappa B (NF-κB)

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42
Q

tumor suppressor gene play a role in the pathogenesis of Crohn disease and development of Crohn disease–related cancers

A

The FHIT gene located on 3p14.2

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43
Q

Environmental factors that increase the risk of Crohn disease

A

medications (oral contraceptives, aspirin, [NSAIDs]), decreased dietary fiber, and increase fat intake.

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44
Q

dysbiosis in which organisms increase the risk

A

decrease in intraluminal Bacteroides and Firmicutes

increase in Gammaproteobacteria and Actinobacteria

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45
Q

Ileal involvement has been shown with mutations of

A

IL10, CRP, NOD2, ZNF365, and STAT3

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46
Q

ileocolonic involvement has been shown with mutations

A

ATG16L1, TCF4, and TCF7L2

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47
Q

colonic involvement has been associated with mutations

A

HLA, TLR4, TLR1, TLR2, and TLR6.

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48
Q

What characteristic can distinguish it from ulcerative colitis

A

rectal sparing

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49
Q

Gross pathologic features at exploration

A

1- thickened gray-pink or dull purple-red loops of bowel
2- areas of thick gray-white exudate or fibrosis of the serosa.
3- skip areas
4- extensive fat wrapping caused by the circumferential growth of the mesenteric fat around the bowel wall, (creeping fat)
5- bowel wall thickened, firm, rubbery, and almost incompressible
6- uninvolved proximal bowel may be dilated secondary to obstruction
7- Involved segments adherent to adjacent intestinal loops or other viscera, with internal fistulas
8- The mesentery of the involved segment is thickened, with enlarged lymph nodes
9- On opening of the bowel, the earliest gross pathologic lesion is a superficial aphthous ulcer noted in the mucosa.

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50
Q

on opening the bowel, the earliest gross pathologic lesion is

A

superficial aphthous ulcer noted in the mucosa.

With disease progression, the ulceration becomes results in transmural inflammation

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51
Q

characteristics of The ulcers

A

linear
may join to produce transverse sinuses with islands of normal mucosa in between

thus giving the characteristic ‘‘cobblestone appearance’’

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52
Q

Characteristic histologic lesions of Crohn disease are

A

noncaseating granulomas with Langerhans giant cells.

Granulomas appear later in the course and are found in the wall of the bowel or in regional lymph nodes

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53
Q

massive gastrointestinal bleeding in CD can occasionally occur, particularly in

A

duodenal Crohn disease > chronic ulcer formation

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54
Q

long-standing Crohn disease can develop

A

Dysplasia
Adenocarcinoma

MC in the Ileum

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55
Q

Extraintestinal cancer with CD

A

squamous cell carcinoma of the vulva and anal canal
Hodgkin and non-Hodgkin lymphomas

especially those treated with immunomodulators

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56
Q

Serologic markers useful in the diagnosis of Crohn disease.

A

-Perinuclear antineutrophil cytoplasmic antibody
(target proteins bactericidal/permeability increasing protein [BPI], lactoferrin, cathepsin G and elastase)

-Anti–Saccharomyces cerevisiae antibody (ASCA)
useful in differentiating Crohn disease from ulcerative colitis

-outer membrane porin of flagellin (anti-CBir1),

-outer membrane porin of E. coli (OmpC-IgG)
> predict development of IBD even in Low risk patients

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57
Q

inflammatory markers specific to the intestine

A
  • Stool lactoferrin, an iron-binding protein in the secretory granules of neutrophils
  • fecal calprotectin, a protein with antimicrobial properties released by squamous cells in response to inflammation,
  • both calprotectin and lactoferrin levels correlate with CT enterography (CTE)
    -Helpful screening tools for detecting early small bowel Crohn disease
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58
Q

Montreal classification of Crohn disease

A

see

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59
Q

MRE may be superior to CTE in detecting

A

intestinal strictures and ileal wall enhancement

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60
Q

the gold standard for the diagnosis of Crohn disease.

A

Ileocolonoscopy with biopsies of the terminal ileum

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61
Q

Endoscopic advances that allow better evaluation of the small intestine include

A

-single-balloon enteroscopy
-double-balloon enteroscopy
-spiral enteroscopy

the most well-established technique is double-balloon enteroscopy, which allows increased enteral intubation (240–360 cm)
push enteroscopy (90–150 cm)
ileocolonoscopy (50–80 cm)

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62
Q

Best Modality for identification of intestinal ulceration.

A

capsule endoscopy has been found to be superior to any other modality in the identification of intestinal ulceration.

criterion for an abnormal finding is the presence of three or more ulcers in the absence of NSAID use.

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63
Q

Aminosalicylates

A

-Sulfasalazine (azulfidine) is an aminosalicylate with 5-aminosalicylic acid
-use in maintenance therapy has fallen out of favor

-Mesalamine, a slow release of 5-aminosalicylic acid
-If remission is achieved with induction,continued for maintenance
-SE: interstitial nephritis (1%)

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64
Q

Corticosteroids

A

-Budesonide, high first-pass hepatic metabolism, allows targeted delivery to the intestine mitigating the systemic effects of steroid therapy.
-The preferred primary treatment for patients with mild to moderately active Crohn disease with localized ileal disease
-9 mg/day

-prednisone, in moderate to severe CD.
-not ideal for maintenance therapy (50% become “steroid dependent,”)
-Parenteral corticosteroids indicated for severe disease once the presence of an abscess has been excluded
-40–60 mg daily

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65
Q

How to taper Steroids ?

A

tapered by 5 to 10 mg/ week until 20 mg
and then by 2.5 to 5 mg weekly until cessation

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66
Q

What Should you do when starting steroids ?

A

-Dual-energy x-ray absorptiometry scan
-calcium and vitamin D supplementation
-consideration of bisphosphonate therapy

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67
Q

Antibiotics

A

-metronidazole
-ciprofloxacin
-rifaximin
-clofazimine
-ethambutol
-isoniazid,
-rifabutin

-used in septic complications and beneficial in perianal disease.

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68
Q

Immunosuppressive agents

A

-AZT and 6-MP are effective for maintaining steroid-induced remission

-weekly IV MTX is effective for both induction and maintenance therapy.

SE: pancreatitis, hepatitis, fever, and rash.
chronic liver disease, bone marrow suppression, and the potential for malignant transformation.

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69
Q

What regulates Immunosupressive Therapy ?

A

thiopurine methyltransferase (TPMT), which is the primary enzyme that metabolizes AZT and 6-MP

decreased TPMT activity > increased risk of fatal bone marrow suppression

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70
Q

Any test can be done before starting immunosupressive therapy ?

A

TPMT genotype testing > determine genetic predisposition to adverse outcomes

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71
Q

MTX side effects

A

hepatotoxicity
myelosuppression
not used in pregnant women.

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72
Q

Other agents help in fistula?

A

FK-506 inhibits the production of IL-2 by helper T cells

effective for fistula improvement, but not fistula remission

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73
Q

patients with severe disease who do not respond to IV steroids, what to give ?

A

cyclosporine and FK-506.

74
Q

Anti-TNF therapy

A

-Infliximab for moderate to severe Crohn disease
-For induction and maintenance agent
-can results in perineal fistula closure

75
Q

Which agent is ideal in pregnant and nursing women

A

certolizumab (humanized antibody fragment)

does not cross the placenta and is not excreted in breast milk

76
Q

Anti TNF Concern

A

-increased risk for TB reactivation
-invasive fungal and opportunistic infections,
-demyelinating CNS lesions
-activation of latent multiple sclerosis
-exacerbation of congestive heart failure
-concerns for increased risk of melanoma

77
Q

Patients who develop a flare while on anti-TNF agents

A

measurement of serum drug concentrations and antidrug antibodies

increase dosage (if low drug concentration and low antibodies)

switch to another anti-TNF agent (high antidrug antibodies)

switch to another drug class (normal drug concentration).

78
Q

Novel therapies

A

-used if the patient has failed or is unable to tolerate anti-TNF therapy

-Natalizumab
-vedolizumab
-Ustekinumab

79
Q

What extraintestinal complications of Crohn disease Does not Subside after resection

A

ankylosing spondylitis and hepatic complications.

80
Q

Do Fistulizing disease requires operative intervention

A

rarely requires operative intervention unless the fistula involves the bladder, vagina or skin

81
Q

New Technique minimize anastomotic restenosis in Crohn disease

A

antimesenteric functional end-to-end hand-sewn anastomosis (known as Kono-S anastomosis)

82
Q

Why anastomotic recurrence happens in CD

A

fecal stasis and subsequent bacterial overgrowth

83
Q

At exploration, the appendix is found to be normal, but the terminal ileum is edematous and beefy red with a thickened mesentery and enlarged lymph nodes

A

this patient has acute ileitis, Due to early CD or Bacteriologic > Campylobacter and Yersinia

Intestinal resection should not be performed

In the absence of acute inflammatory involvement of the appendix or the cecum, appendectomy should be performed.

84
Q

In patients for whom it is difficult to determine whether the site of obstruction is caused by an acute exacerbation or a chronically strictured segment

A

stool lactoferrin and calprotectin levels may help identify acute inflammation

85
Q

There are two types of bypass operations: exclusion bypass and simple (continuity) bypass

A

-proximal transected end of the ileum is anastomosed to the transverse colon in an end-to-side fashion with or without construction of a mucous fistula using the distal transected end of the ileum (exclusion bypass)

-or an ileotransverse colonic anastomosis is made in a side-to-side fashion (continuity bypass).

86
Q

Indications for Bypass

A

-severe gastroduodenal CD not amenable to strictureplasty
-older poor-risk patients
-patients who have had several prior resections and cannot afford to lose any more bowel
-those in whom resection would necessitate entering an abscess or endangering a normal structure.

87
Q

Sx for Fistula

A

-fistula between two or more adjacent loops of diseased bowel > segments should be excised

-fistula involves an adjacent normal organ (bladder or colon) > only the segment of the diseased small bowel and fistulous tract should be resected, and the defect in the normal organ should simply be closed

-ileosigmoid fistulas do not necessarily require resection of the sigmoid because the disease is usually confined to the small bowel.

-However, if the segment of sigmoid is also found to have Crohn disease, it should be resected along with the segment of diseased small bowel.

88
Q

Abscess Tx

A

abscess < 3 cm and have not been on biologics or have an associated fistula can be treated with antibiotics alone.

Abscesses that do not meet these criteria should undergo percutaneous drainage

89
Q

Patient with generalized peritonitis

A

safer option > create an ostomy until the intraabdominal sepsis is controlled Then return for restoration of intestinal continuity after a period of 4 to 6 weeks

90
Q

The most common urologic complication in CD

A

-ureteral obstruction, secondary to ileocolic disease with retroperitoneal inflammatory compression

91
Q

after abdominoperineal resection in patients with Crohn disease

A

Wound filled with well-vascularized pedicles of muscle (e.g., gracilis, semimembranosus, rectus abdominis) or omentum or by using an inferior gluteal myocutaneous graft.

92
Q

Tx for perianal

A

-nonoperative unless an abscess or complex fistula develops

-Nonsuppurative, chronic fistulization or perianal fissuring treated with antibiotics, immunosuppressive agents (e.g., AZT or 6-MP), and infliximab

Several uncontrolled studies have shown some benefit with cyclosporine or FK-506 treatment.

93
Q

Fistula Tx

A

fistulotomy > superficial, low trans-sphincteric, and low intersphincteric fistulas

High transsphincteric, supra-sphincteric, and extrasphincteric fistulas > noncutting seton

94
Q

Fissure Tx in CD

A

usually lateral, relatively painless, large, and indolent and often respond to conservative management

95
Q

Duodenal disease in CD

A

Gastrojejunostomy to bypass the disease rather than duodenal resection is the procedure of choice

96
Q

the leading cause of disease-related deaths in patients with Crohn disease

A

Gastrointestinal cancer

97
Q

Typhoid Enteritis

A

-contaminated water supplies and inadequate waste disposal.
-primarily by Salmonella typhi
-penetrate the small bowel mucosa, > lymphatics
-Hyperplasia of the reticuloendothelial system, including lymph nodes, liver, and spleen
-Peyer patches > hyperplastic > ulcerate > hemorrhage or perforation.
-Diagnosis > organism from blood, bone marrow, and stool cultures
-Tx fluoroquinolones and third-generation cephalosporins.
-single perforation in the terminal ileum > simple closure
-Multiple perforations > resection with primary anastomosis

98
Q

Protozoa Enteritis in AIDS

A

-Cryptosporidium, Isospora, and Microsporidium
-most frequent class of pathogens causing diarrhea in patients with AIDS
-Diagnosis > acid-fast staining of the stool or duodenal secretions
-Immunochromatography Stool
-Tx > prophylactic cotrimoxazole and a highly active antiretroviral therapy

99
Q

Bacteria Enteritis in AIDS

A
  • Salmonella, Shigella, and Campylobacter
    -diagnosis of Shigella or Salmonella > stool cultures.
    -Campylobacter > PCR techniques evaluating stool and serum
    -Bacteremia and serious infections > IV imipenem or ciprofloxacin if the organisms are multiply resistant

the pregnant patient may be safely treated with erythromycin

100
Q

Mycobacteria in Immunocopromised

A

-Mycobacterium tuberculosis or Mycobacterium avium complex (MAC)
-most frequent site of intestinal involvement of M. tuberculosis is the distal ileum and cecum
-bowel wall appears thickened, and an inflammatory mass often surrounds the ileocecal region
-Stricture and Fistula can Form
-caseating granulomas found most commonly in the lymph nodes
-Radiographic > thickened mucosa with distorted mucosal folds and ulcerations
-CT > thickening of the ileocecal valve and cecum.
-Tx for MAC > amikacin, ciprofloxacin, cycloserine, and ethionamide, Clarithromycin

101
Q

Viruses

A

-CMV is the most common viral cause of diarrhea in immunocompromised
-Enteric CMV > mucosal ischemic ulcerations
-Diagnosis > viral inclusion > intranuclear inclusion > owl’s eye appearance
-Tx > ganciclovir

102
Q

MC Locations for Small Bowel Tumors

A

-Adenocarcinoma is the most common malignant neoplasm (30% to 50%)
-Neuroendocrine tumors (NETs) (25% to 30%)

-Adenocarcinomas are more prevalent in the proximal small bowel
-Other malignant lesions are more common in the distal small bowel

103
Q

MC benign Tumor, and MC one to produce Symptoms

A

-Adenomas are the most common benign tumors

-stromal tumors are the most common benign small bowel lesions that produce symptoms.

104
Q

when a benign tumor is identified at operation, What would You Do ?

A

-resection is indicated because symptoms are likely to develop over time.

-At operation, a thorough search of the remainder of the small bowel is warranted because multiple tumors are not uncommon

105
Q

Patients with GIST, nearly 20% of patients are found to have

A

metastatic disease, most commonly in the liver

106
Q

How to Confirm Diagnosis of GIST

A

biopsy with immunohistochemical staining for
-KIT (95%)
-anoctamin-1 (98%)

stromal tumors express
-CD117
-the KIT proto-oncogene protein that is a transmembrane receptor for the stem cell growth factor
-and 70% to 90% express CD34, the human progenitor cell antigen.

-These tumors infrequently stain positive for
actin (20%–30%), S100 (2%–4%), and desmin (2%–4%)

107
Q

How to measure or predict Mets or Recurrence

A

-Tumors larger than 5 cm, regardless of mitotic index, have higher rates of metastasis and recurrence

-those with a high mitotic index have a higher risk of metastasis and recurrence regardless of size.

108
Q

Adenomas MC found in which part

A

20% duodenum
30% jejunum
50% ileum.

109
Q

Which type of Adenoma is considered Premalignant

A

Both true and villous adenomas are thought to proceed along a similar adenoma-carcinoma sequence as colorectal adenomas

110
Q

in FAP , you perform Screening , when to take Bx

A

biopsy of all suspicious, villous, or large (>3 cm) adenomas in addition to random duodenal biopsy specimens

111
Q

When to Perform pancreaticoduodenectomy or pancreas-preserving duodenectomy in Fap adenomas

A

high-grade dysplasia
carcinoma in situ
or a Spigelman stage IV

112
Q

Spigelman

A

see

113
Q

Recommended surveillance in relation to the Spigelman classification.

A

see

114
Q

Hamartomas in PJS MC location

A

are most commonly found in the jejunum and ileum

115
Q

Patients with Small Bowel Hamartomas may also have ?

A

50% of patients may also have rectal and colonic lesions, and 25% of patients have gastric lesions

116
Q

How To treat Surgically

A

-Resection > limited to the segment of bowel that is producing complications.

Because of the widespread nature of intestinal involvement, cure is not possible; therefore, extensive resection is not indicated.

117
Q

MC Symptom in PJS is Abd pain Why ?

A

recurrent colicky abdominal pain, usually the result of intermittent intussusception

118
Q

PJS Extracolonic cancers where ?

A

occurring in 50% to 90% of patients (small intestine, stomach, pancreas, ovary, lung, uterus, and breast).

119
Q

Hemangiomas of Small Bowel

A

-submucosal proliferation of blood vessels.
-jejunum MC location
-can be part of Osler-Weber-Rendu disease.
-Turner syndrome > cavernous hemangiomas of the intestine.
-MC Symp intestinal bleeding.
-Angiography and Tc-99m RBC scanning > diagnostic studies.

-If a hemangioma is localized preoperatively, resection of the involved intestinal segment is warranted.
-Intraoperative transillumination and palpation may help to identify a nonlocalized hemangioma.

120
Q

In contrast to benign lesions, malignant neoplasms almost always

A

-produce symptoms
the most common > pain and weight loss.

-Obstruction usually the result of tumor infiltration and adhesions.

121
Q

NENs Divided into Groups , Mention them

A

-divided > NETs and neuroendocrine carcinomas

-NETs > benign or malignant type

-subdivided : (grade 1, G1)
(grade 2, G2) and (grade 3, G3) tumors

based on > appearance, mitotic rates, behavior (invasion of other organs, angioinvasion), and Ki-67 proliferative index.

On the other hand, neuroendocrine carcinomas are all G3, poorly differentiated malignant tumors

122
Q

NETs are also categorized based on the embryologic site of origin and secretory product

A

-foregut (respiratory tract, thymus)
>produce low levels of serotonin (5-hydroxytryptamine) but may secrete 5-hydroxytryptophan or adrenocorticotropic hormone

-midgut (jejunum, ileum and right colon, stomach, proximal duodenum)
>high serotonin production

-hindgut (distal colon, rectum)
> rarely produce serotonin but may produce other hormones, such as somatostatin and peptide YY.

123
Q

In the small intestine, NETs almost always occur within

A

the last 2 feet of the ileum

124
Q

the most prominent secreted humoral agents by Nets

A

serotonin and substance P

125
Q

carcinoid syndrome, secondary to serotonin or tachykinin production, is characterized by

A

episodic attacks of cutaneous flushing
bronchospasm
diarrhea, and vasomotor collapse

is present mostly in those patients with hepatic metastases

126
Q

Primary tumors that secrete directly into the venous system, bypassing the portal system

A

(e.g., ovary, lung), give rise to carcinoid syndrome without metastasis.

127
Q

MC Location for NETs in GIT ?

A

small intestine (38%)
rectum (34%)
Colon (16%)
stomach (11%)

in Korea, the most common site for NETs is the rectum

128
Q

The malignant potential for NETs (ability to metastasize) is related to

A

location, size, depth of invasion, and growth pattern

smaller than 1 cm> 2% associated with Mets
1 to 2 cm > 50%
larger than 2 cm > 80% to 90%

129
Q

gross appearance of NETs

A

-Small, firm, submucosal nodules , yellow on the cut surface.
-subtle as a small whitish plaque seen on the antimesenteric border of the small intestine.

-associated with a larger mesenteric mass caused by nodal disease and desmoplastic invasion of the mesentery.

-tend to grow very slowly, but after invasion of the serosa, the intense desmoplastic reaction produces mesenteric fibrosis, intestinal kinking, and intermittent obstruction.

130
Q

unusual observation in NETs

A

-coexistence of a second primary malignant neoplasm of a different histologic type.

-synchronous adenocarcinoma (most commonly in the large intestine) > occur in 10% to 20% of patients with NETs.

-Multiple endocrine neoplasia type 1 is associated with NETs in approximately 10% of cases

131
Q

Secretory products of neuroendocrine tumors

A

see

132
Q

Malignant carcinoid syndrome

A

vasomotor, cardiac, and gastrointestinal manifestations

cutaneous flushing (80%)
diarrhea (76%)
hepatomegaly (71%)
cardiac lesions, most commonly right-sided heart valvular disease (41%–70%)
and asthma (25%)

133
Q

Cutaneous flushing in the carcinoid syndrome may be of four varieties:

A
  1. diffuse erythematous, > short-lived > face, neck, and upper chest;
  2. violaceous, > attacks may be longer > develop a permanent cyanotic flush, with watery eyes and injected conjunctivae
  3. prolonged flushes > up to 2 or 3 days > entire body and > profuse lacrimation, hypotension, and facial edema
  4. bright-red patchy flushing > gastric NETs.
134
Q

The three most common cardiac lesions are

A

pulmonary stenosis (90%)
tricuspid insufficiency (47%)
tricuspid stenosis (42%)

135
Q

Malabsorption and pellagra ?

A

> Niacin deficiency VitB3 (dementia, dermatitis, and diarrhea) are occasionally present and are thought to be caused by excessive diversion of dietary tryptophan.

136
Q

Diagnose Carcinoid

A

A combination of serum CgA measurement with 24-hour urine 5-HIAA is an acceptable diagnostic combination with increased sensitivity.

137
Q

CT Diagnose Carcinoid

A

CT> solid mass with spiculated borders and radiating surrounding strands that is associated with linear strands within the mesenteric fat and kinking of the bowel, a diagnosis of gastrointestinal NET can be made

138
Q

Diagnosis for Carcinoid

A

-CT Scan
-MRI Liver ( For Mets )
-18F-fluorodeoxyglucose PET Scan
18FDG is taken up only in high-grade NETs (e.g., high Ki-67 expression) > most NETs have low Ki-67 expression
-18F-L-dihydroxyphenylalanine (18F-DOPA)
> improved the sensitivity of PET
-Scintigraphic localization
> Octreotide is a synthetic analogue of somatostatin, and indium (111In)-labeled pentetreotide specifically binds to somatostatin receptor subtypes 2 and 5.
-Somatostatin receptor imaging with gadolinium 68Ga–DOTATATE PET/CT

139
Q

68Ga-DOTATATE PET/CT is a clinically useful imaging technique to

A

-localize primary tumors in patients with neuroendocrine metastases of unknown origin
-to define the existence and extent of metastatic disease.

140
Q

The benefits of 64Cu-DOTATATE imaging

A

-better true positive lesion detection
-longer shelf life and scanning window when compared with 68Ga-DOTATATE, making it an ideal diagnostic too

141
Q

Tx of NETs

A

-tumors < 1 cm without regional LN Mets
> segmental resection

  • > 1 cm, with multiple tumors, or with regional LN Mets, regardless of the size of the primary tumor, wide excision of bowel and mesentery is required.

-Lesions of the terminal ileum > right hemicolectomy.

-Small duodenal tumors > excised locally
-more extensive lesions may require pancreaticoduodenectomy

142
Q

anesthesia may precipitate a carcinoid crisis , how to Tx

A

characterized by hypotension, bronchospasm, flushing, and tachyarrhythmias.

treated with IV octreotide bolus of 50 to 100 μg
> may be continued as an infusion at 50 μg/hr.

143
Q

Mets to liver Tx

A

-Even with liver metastasectomy > high recurrence rate of 75%.

-In these cases, transarterial chemoembolization or radioembolization has been shown to provide liver-directed control of disease.

-resection of the primary tumor, with or without mesenteric resection, > improve survival and to slow progression of hepatic metastases in patients with unresectable disease

144
Q

Medical therapy

A

-Somatostatin analogs (SSAs) are the standard of care
-octreotide (Sandostatin) and lanreotide
-relieve symptoms and delay cancer progression (antiproliferative effect)
-Octreotide LAR is recommended for Grade 1 and 2 NETs and not recommended in grade 3

145
Q

For patients who have disease progression on SSA therapy

A

-Everolimus, a mammalian target of rapamycin (mTOR) inhibitor, initially developed as immunosuppressant therapy, is approved for the treatment of nonfunctional gastrointestinal NETs with unresectable, locally advanced or metastatic disease

146
Q

somatostatin refractory diarrhea in the setting of carcinoid syndrome

A

the serotonin synthesis inhibitor, telotristat etiprate

147
Q

Currently, the role of chemotherapy ?

A

streptozotocin, 5-fluorouracil (5-FU), and cyclophosphamide.

-to patients with G2 metastatic disease who are symptomatic, are unresponsive to other therapies, or have high tumor proliferation rates.

148
Q

Resectable adenocarcinomas in the second portion of the duodenum are treated with

A

pancreaticoduodenectomy
regional lymphadenectomy of the periduodenal, peripancreatic, and hepatic lymph nodes as well as involved vascular structures is necessary.

149
Q

For Adenocarcinoma patients with metastatic disease

A

FOLFOX
(oxaliplatin, 5-FU, and leucovorin)

FOLFIRI
(irinotecan, 5-FU, and leucovorin)

as first-line therapy significantly improves the performance status and progression-free survival

150
Q

the main prognostic factor for adenocarcinoma

A

LN invasion

moreover, the number of lymph nodes assessed and the number of positive lymph nodes are of prognostic value

(Required > 10 LN)

151
Q

Lymphoma

A

-in children younger than 10 years, they are the most common intestinal neoplasm.
-most commonly found in the ileum
-RF > celiac disease and immunodeficient states e.g AIDS
-Asymptomatic small bowel lymphomas > chemoresponsive and do not require surgery.
-B-cell lymphomas > chemosensitive than T-cell lymphomas and have high remission rates

-T-cell lymphomas > more resistant to therapy > progress to symptoms of obstruction or perforation if not resected.

-Regardless of cell type, resection is indicated at any onset of symptoms because progression to life-threatening hemorrhage or perforation portends a dismal prognosis

152
Q

GISTs MC Found in ?

A

more common in the jejunum and ileum

153
Q

GISTs mostly arise from

A

the muscularis propria

154
Q

The most useful indicators of survival and the risk for metastasis include

A

the size of the tumor at presentation
mitotic index
evidence of tumor invasion into the lamina propria.

155
Q

GIST Tx capsule rupture occurs, What to Do

A

-receive adjuvant therapy regardless of the extent of the tumor before surgery.

-It is advisable to perform an en bloc resection, to include adjacent organs, for prevention of tumor capsule rupture.

-A laparoscopic approach in patients with large tumors is strongly discouraged.

156
Q

Radiologic criteria for unresectability for GISTS

A

-infiltration of the celiac trunk, superior mesenteric artery, or portal vein.

157
Q

Small GISTs (<2 cm) found incidentally in surgical specimens, What to Do

A

do not require further treatment.

158
Q

Algorithm for GIST Tx

A

see

159
Q

effective treatment for advanced GISTs after failure of either imatinib or sunitinib

A

Regorafenib > second-generation tyrosine kinase inhibitor that targets c-kit, RET, BRAF, VEGFR, PDGFR, and fibroblast growth factor receptor.

-Sorafenib > VEGF, c-kit, PDGFR, and BRAF inhibitor and has been effective in imatinib- and sunitinib-resistant tumors

160
Q

All intraluminal duodenal diverticula require treatment

A

True, because recurrence of symptoms is certain.

161
Q

For Duodenum diverticula embedded deep within the head of the pancreas

A

duodenotomy is performed,
with invagination of the diverticulum into the lumen, which is then excised, and the wall is closed

Alternative methods for duodenal diverticula associated with the ampulla of Vater include an extended sphincteroplasty through the common wall of the ampulla in the diverticulum

162
Q

perforated diverticulum

A

excised and the duodenum closed with a serosal patch from a jejunal loop.

If the surrounding inflammation is severe, > divert the enteric flow> gastrojejunostomy or duodenojejunostomy.

Interruption of duodenal continuity proximal to the perforated diverticulum > pyloric closure with suture or a row of staples.

163
Q

f the diverticulum is posterior and perforates into the substance of the pancreas,

A

operative repair may be difficult and dangerous.

Wide drainage with duodenal diversion may be all that is feasible

Surgical jejunostomy should also be considered for all patients with acute perforation to ensure nutrition

164
Q

Jejunal and Ileal Diverticula causing malabsorption

A

secondary to the blind loop syndrome and bacterial overgrowth in the diverticulum can usually be given antibiotics.

165
Q

Obstruction may be caused by enteroliths that form in a jejunal diverticulum , Tx ?

A

subsequently dislodged and obstruct the distal intestine.

treated by enterotomy and removal of the enterolith, or sometimes the enterolith can be milked distally into the cecum.

When the enterolith causes obstruction at the level of the diverticulum, bowel resection is necessary.

166
Q

Why there is heterotopic tissues in meckels ?

A

Cells lining the vitelline duct are pluripotent;

167
Q

incarceration of the diverticulum in an inguinal hernia

A

(Littre hernia)

168
Q

When the appendix is found to be normal during exploration for suspected appendicitis

A

the distal ileum should be inspected for the presence of an inflamed Meckel diverticulum.

169
Q

Neoplasms can also occur in a Meckel diverticulum

A

NET as the most common malignant neoplasm (77%).

Other histologic types include adenocarcinoma (11%), which generally originates from the gastric mucosa, GIST (10%), and lymphoma

170
Q

how to increase the sensitivity of 99mTc-pertechnetate scan for Meckels

A

Cimetidine may be used to increase the sensitivity of scintigraphy by decreasing the peptic secretion, while not affecting radionuclide uptake

171
Q

Incidental Meckels , What to do ?

A

It is generally recommended that asymptomatic diverticula found in children during laparotomy should be resected.

The treatment of Meckel diverticula encountered in the adult patient, however, remains controversial.

Meckel diverticulum becoming symptomatic in the adult > 2% or less

172
Q

The factors associated with a higher risk of complications, and warranting consideration of resection

A

age younger than 50 years
male sex
diverticulum length >2 cm
ectopic tissue or palpable abnormalities.

173
Q

Small Bowel Ulceration

A

-more commonly in the ileum, with single or multiple ulcerations noted

-Complications necessitating operative intervention include bleeding, perforation, and obstruction.

-NSAIDs are known to induce an enteropathy characterized by increased intestinal permeability leading to protein loss and hypoalbuminemia, malabsorption, and anemia.

-Treatment of complications from small bowel ulcerations is segmental resection and intestinal reanastomosis

174
Q

Multiple factors prevent the spontaneous closure of fistulas

A

retained foreign body
radiation enteritis
inflammatory bowel disease or infection
epithelialization of the fistula tract
neoplasm
distal obstruction.

175
Q

Factors predictive of nonoperative fistula closure

A

see

176
Q

Blind loop syndrome in small bowel

A

> diarrhea, steatorrhea, megaloblastic anemia, weight loss, abdominal pain, and deficiencies of the fat-soluble vitamins as well as neurologic disorders.

> bacterial overgrowth in stagnant areas of the small bowel produced by stricture, stenosis, fistulas, or diverticula (e.g., jejunoileal or Meckel diverticulum)

177
Q

Blind Loop

A

> vitamin B12 Deficiency > megaloblastic anemia.

confirmed by > cultures obtained through an intestinal tube or > 14C-xylose or 14C-cholylglycine breath tests.

> the Schilling test (57Co-labeled vitamin B12 absorption) > pattern of urinary excretion of vitamin B12 resembling that of pernicious anemia (a urinary loss of 0% to 6% of vitamin B12 compared with the normal of 7%–25%).

Tx > course of a broad-spectrum antibiotic (e.g., tetracycline) should return vitamin B12 absorption to normal.

178
Q

Radiation Enteritis

A

morbidity risk increases with dosages exceeding 5000 cGy.

179
Q

pharmacologic interventions to reduce the side effects of radiation enteritis

A

1- Angiotensin-converting enzyme inhibitors
2- statins
reduce acute gastrointestinal symptoms during radical pelvic radiotherapy.

3- Sucralfate, > stimulate epithelial healing and form a protective barrier , help in bleeding from radiation proctitis

4- Superoxide dismutase, a free radical scavenger,

5- glutathione, antioxidants (e.g., vitamin A, vitamin E, beta-carotene), histamine antagonists, and the combination of pentoxifylline and tocopherols

6- probiotics as having a radioprotective effect in the gut;

7- The most effective radioprotectant agent appears to be amifostine

180
Q

Which part of Small bowel can increase absorptive capacity more efficiently

A

Proximal bowel resection is tolerated better than distal resection because the ileum can adapt more than the jejunum.

181
Q

Pharmacological tx for Short Bowel

A

-teduglutide, a GLP-2 analogue > restoration of intestinal functional and structural integrity through significant intestinotrophic and proabsorptive effects.

-Somatropin, a recombinant human growth hormone that elicits anabolic and anticatabolic influence
direct effect or indirectly through IGF-I

182
Q

superior mesenteric artery syndrome or Wilkie syndrome,

A

RF > supine immobilization, scoliosis, and placement of a body cast > cast syndrome.
after proctocolectomy and J-pouch anal anastomosis

Dx : barium upper gastrointestinal series or hypotonic duodenography

Tx : conservative, duodenojejunostomy, gastrojejunostomy to bypass the obstructing segment, or duodenal derotation (Strong procedure)

A1-G Surg Note Small Bowel (10 decks)

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