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Surgery > Chapter 11 > Flashcards

Chapter 11 Flashcards

1
Q

How long is the small bowel?

What is its major function?

A

8 m

Absorb nutrients

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2
Q

What are the three sections, and how long is each section?

A

Duodenum- 40 cm
Jejunum- 200 cm
Ileum- 300 cm

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3
Q

How are the jejunum and ileum covered and anchored?

A

Covered by visceral peritoneum and tethered to posterior anterior wall by a mesentery

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4
Q

Duodenal bulb

A

Superior to the pancreatic head and anterior to the gastroduodenal artery and common bile duct

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5
Q

Position and blood supply of the duodenal bulb

A

Intraperitoneal position

Blood supply from the supraduodenal branch of the hepatic artery and the gastroduodenal artery

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6
Q

The duodenal bulb is the site of _____ of duodenal ulceration

A

90%

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7
Q

Position of the second part of the duodenum

A

Borders the head of the pancreas

Retroperitoneal

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8
Q

Position of the third part of the duodenum

A

Retroperitoneal, coursing between the SMA and the aorta

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9
Q

From where do the second and third portions of the duodenum receive their blood supply?

A

From the anteriosuperior and posterosuperior pancreaticoduodenal branches of the gastroduodenal artery and anterioinferior and posteroinferior pancreaticoduodenal branches of the superior mesenteric artery

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10
Q

Where does the fourth portion of the duodenum receive its blood supply?

A

First jejunal branch of the superior mesenteric artery

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11
Q

What is an anatomic landmark for the transition between the duodenum and the jejunum?

A

The ligament of Treitz

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12
Q

How is the small bowel differentiated?

A

By the valvulae conniventes, circular folds of mucosa and submucosa that markedly increase absorptive surface area

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13
Q

What is the difference between the jejunum and ileum?

A

The messenteric vessels of the jejunum form only one or two arterial arcades and send out long vasa recta
The ileum contains multiple arterial arcades that give off short vasa recta

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14
Q

From where do the ileum and jejunum derive their blood supply?

A

From the superior mesenteric artery and venous drainage via the superior mesenteric vein

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15
Q

What are the four layers of the bowel wall from inside to outside?

A

Mucosa
Submucosa
Muscularis
Serosa

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16
Q

How can the mucosa be further divided?

A

Muscularis
Lamina propria
Epithelium

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17
Q

Muscularis

A

A thin layer of the muscle separating the mucosa from the submucosa

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18
Q

Lamina propria

A

A continuous layer of connective tissue between the muscularis and epithelium, serves as a supportive base for the villi and a protective barrier against microorganisms

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19
Q

What is one type of cells residing in the lamina propria?

A

Cells of the immune system, including Peyer’s patches (aggregates of lymphoid tissue containing immune cells)

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20
Q

Epithelium

A

Villi and crypts of Lieberkuln

Functions as digestion, absorption, cell renewal, and secretion of hormones

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21
Q

What is the purpose of the submucosa?

A

Support and strength layer

Contains blood vessels, lymphatics and nerves

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22
Q

What is the muscularis (general layer)?

A

An inner circular and an outer longitudinal layer

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23
Q

What is sandwiched between the muscularis layers?

A

Ganglion cells that constitute the myenteric (Auerbach) plexus

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24
Q

What is the serosa composed of?

A

Flattened mesothelial cells

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25
Q

How is pain mediated?

A

Through visceral afferent fibers of the sympathetic nervous system

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26
Q

Sympathetic innervation

A

3 sympathetic ganglia are located around the base of the superior mesenteric artery and control blood vessel tone and to a lesser extent gut secretory function and motility

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27
Q

Parasympathetic innervation

A

Parasympathetic nerve fibers are derived form the vagus nerve and primarily regulate gut secretory function and motility

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28
Q

What is one of the most common pathologic processes affecting the small bowel?

A

Obstruction

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29
Q

What are the most common causes of obstruction?

A

Adhesion (result of >60%)
Hernias
Tumors

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30
Q

What appear to be associated with a higher incidence of adhesive obstruction?

A

Lower abdominal and pelvic operations (appendectomy and adnexal procedures)

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31
Q

Labs for obstruction

A 
Hypokalemic
Hypochloremic
Metabolic alkalosis
Metabolic acidosis
Hematocrit may be falsely elevated d/t volume depletion and anemia may indicate underlying malignancy
32
Q

External hernias

A

Include those found in the inguinal canal, femoral canal, and in previous incisions

33
Q

Internal hernias

A

Include those related to the inadequate closure of mesenteric defects created by prior operations, congenital mesenteric defects, and obturator foramen hernias

34
Q

Imaging for obstruction

A

Upright chest, supine and upright abdominal X-ray

35
Q

Imaging findings for obstruction

A

Dilated loops of bowel and air fluid levels, often with a step-like appearance

36
Q

What may provide a therapeutic effect in some cases of SBO?

A

Oral contrast
Gastrogradin (diatrizoic acid) is a hyperosmolar gastrointestinal water-soluble agent, which has been shown to speed the resolution of partial SBO and has also been shown to reduce hospital length of stay

37
Q

Strangulation

A

Thickening of the bowel wall, pneumatosis instestinalis, ascites or mesenteric hematoma

38
Q

Tx of SBO

A

Partial SBO- initially nonoperative
-Defined as no or minimal sx in 3-5 days
-Parenteral nutrition should be started
-Pts who initially resolve a partial SBO but then recur need surgical exploration
Pts with a complete SBO are at a high risk of strangulation

39
Q

Surgical tx of SBO

A

Lysis of adhesions, resection of nonviable or diseased bowel with anastamosis or intestinal bypass
One should palpate the root of the small bowel mesentery for a pulse in the SMA to be certain vascular compromise is not d/t occlusion of the SMA

40
Q

How can bowel viability be further confirmed?

A

Fluorescein angiography

Doppler u/s

41
Q

Fluorescein angiography in SBO

A

Hemogenous hyperfluorescence with a fine granular or reticular pattern suggests nl bowel, wheras patchy fluorescence or nonfluorescence suggests nonviable bowel

42
Q

Doppler u/s in SBO

A

If nonviable bowel is identified during abdominal exploration, it should be resected and a “second-look” laparotomy 24-48 hrs after to reassess bowel viability

43
Q

What are intraoperative techniques to decrease the formation of adhessions?

A

Moistening of the mesothelium
Reduction of intra-abdominal foreign materials
Irrigation to remove intra-abdominal blood and clot
Use of sharp scalpel dissection as opposed to cautery
Avoidance of unnecessary bowel manipulation

44
Q

Agents to decrease adhesion rate

A 
Intercede
Gore-Tex
Fibrin sheets
Polyethylene glycol spray
Hyaluronic acid gel
Glucose peritoneal installates
45
Q

Additional causes of SBO

A

Gallstone ileus
Intussusception
Volvulus
Intestinal pseudo-obstruction

46
Q

Gallstone ileus

A

The development of a cholecystoduodenal fistula with distal propagation of a gallstone

47
Q

How common is a gallstone ileus?

A

Uncommon, but associated with considerable morbidity and mortality

48
Q

Who is more likely to get a gallstone ileus?

A

Elderly
In pts with severe concomitant dz
In pt with gallstones 2-5 cm in diameter

49
Q

Sx of gallstone ileus

A

Intestinal obstruction
Pneumobilia
Gallstone
Change of position of a gallstone

50
Q

Surgical intervention for a gallstone ileus

A

Laparotomy
Enterotomy
Removal of the stone

51
Q

Intussusception

A

Leading edge or intussusception is usually in an intraluminal lesion

52
Q

CT findings in intussusception

A

Intraluminal soft tissue “mass” with high attenuation peripherally and low attenuation centrally, known as “target sign”

53
Q

Volvulus

A

The twisting of a loop of bowel around the axis of a long narrow mesentery, often associated with malrotation or internal herniation

54
Q

What procedure should be done if there’s viable bowel in a volvulus?
If viable bowel and malrotation?

A

Enterolysis

Ladd procedure

55
Q

Ladd procedure

A

Counterclockwise reduction of the volvulus, division of Lad bands/adhesions and appendectomy

56
Q

What are Ladd bands?

A

Fibrous stalks or peritoneal tissue connecting the cecum to the abdominal wall, which creates the site of duodenal obstruction in malrotation

57
Q

What is required with a volvulus if the bowel appears nonviable?

A

A Ladd procedure and bowel resection is required

58
Q

Presentation of intestinal pseudo-obstruction

A

Mimics appendicitis
Pt may have a hx of repeated surgical procedures in attempt to detect a mechanical cause of these sx
Most commonly idiopathic but can be familial or associated with scleroderma, hypothyroidism, hypoparathyroidism or celiac dz

59
Q

Surgical options for intestinal pseudo-obstruction

A

Enterostomy
Bypass procedure
Bowel resection

60
Q

What is the most commonly involved site in Crohn’s dz?

A

The terminal ileum

61
Q

Who does Crohn’s dz more commonly affect?

A

Smokers
Ppl who reside in industrial areas
Ashkenazi Jews

62
Q

What may be found at the time of a Crohn’s surgical exploration?

A

Bowel perforation
Abscess formation
Enterovisceral fistula

63
Q

What may be present pathologically with Crohn’s dz?

A

Areas of thick grayish-white exudate or fibrosis and extension of the mesenteric fat around the circumference of the bowel may be present + fibrosis + ulceration

64
Q

Cobblestone appearance in Crohn’s

A

Linear ulceration with surrounding mucosal and submucosal edema

65
Q

60-70% of Crohn’s pts may have…

A

Noncaseating granulomas with Langerhans giant cells

66
Q

Clinical manifestations of Crohn’s dz

A 
Extraintestinal:
Arthralgias
Uveitis
Erythema nodosum
Pyoderma gangrenosum
Arthritis
Hepatitis
Pericholangitis
67
Q

Crohn’s complications requiring surgery

A 
Obstruction
Perforation
Fistula
Abscess
Perianal dz
68
Q

What is the incidence of colonic malignancy in Crohn’s?

A

6x greater than in the general population

69
Q

Diagnostic findings in Crohn’s dz

A

Granular, discrete, aphthous ulcerations surrounded by nl tissue and a cobblestone-like appearance of the mucosa, diffuse narrowing of bowel lumen, and asymmetric involvement of the bowel wall leading to nodular contour

70
Q

Nutritional considerations in Crohn’s

A

Protein-calorie malnutrition occurs in 80-90% of pts

71
Q

What is the MC indication for operation in Crohn’s?

A

Fistula

72
Q

EC fistulas in Crohn’s

A

Treated with resection of affected bowel and debridement of the fistula tract

73
Q

Enteroenteric fistulas in Crohn’s

A

May be left alone if asymptomatic; however if large segments are bypassed, significant malabsorption and fluid loss may ensure necessitating surgery.

74
Q

Surgery for enterovesical and enteroadnexal fistulas in Crohn’s

A

Involves resection of the affected bowel and fistula tract and closure of the bladder or adnexal defect

75
Q

Obstruction in Crohn’s

A

Healthy intervening segments of bowel flanked by diseased segments should only be resected if <5 cm
If a short stricture is the cause of the obstruction, then strictureplasty (Heineke-Mikulicz type) can be performed making a longitudinal incision through the stricture and closing it in a transverse fashion

76
Q

Contraindications to strictureplasty for Crohn’s

A

Small bowel perforation
Multiple strictures in a short segment
Concern for malignancy

77
Q

Prognosis of Crohn’s

A

The most common site of recurrence is the small bowel, just proximal to the prior site of resection

Surgery (30 decks)

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