3. Epidemiology
Most frequent surgical disorder of the small intestine
Etiologies according to their relationship to intestinal wall:
1. Intraluminal (e.g., foreign bodies, gallstones, or meconium)
2. Intramural (e.g., tumors, Crohn's disease–associated inflammatory
strictures)
3. Extrinsic (e.g., adhesions, hernias, or carcinomatosis)
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75% of cases is caused by intra-abdominal adhesions
related to prior abdominal surgery
Less prevalent etiologies include:
hernias
malignant bowel obstruction
(extrinsic compression or invasion from neoplasms arising
in organs other than the intestine)
and Crohn's disease
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Congenital abnormalities
Usually become evident during childhood
intestinal malrotation and midgut volvulus should not be
forgotten in adult patients
especially in those without history of prior abdominal
surgery
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8. Pathophysiology
In the onset, gas and fluid accumulate within the intestinal
lumen proximal to the site of obstruction
Intestinal activity increases Colicky pain & Diahrrea
Where does the gas & fluid come from?
Bowel distends and intraluminal and intramural pressures rise
Impair of intestinal microvascular perfusion Ischemia
Necrosis
strangulated bowel obstruction
9. Continues
partial small bowel obstruction
only a portion of the intestinal lumen is occluded
pathophysiologic events occur more slowly & strangulation is
less likely
closed loop obstruction
accumulating gas and fluid cannot escape
Leading to a rapid rise in luminal pressure, and a rapid
progression to strangulation
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11. Clinical Presentation
colicky abdominal pain, nausea, vomiting, and obstipation
Vomiting is more seen with proximal obstructions than distal
In established obstructions you see vomitus more feculent
Continued passage beyond 6 to 12 hours after onset of
symptoms is characteristic of partial obstruction
Abdominal Distention is another sign, esp. if the obstruction is
in distal ileum, absent if in proximal small intestine
Bowel sounds
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Laboratory findings intravascular volume depletion consist of:
hemoconcentration and electrolyte abnormalities
Mild leukocytosis is common
Features of strangulated obstruction include:
Odd abdominal pain, suggestive of intestinal ischemia
tachycardia, localized abdominal tenderness, fever, marked
leukocytosis, and acidosis
Any of these findings must alert you to the possibility of
strangulation Surgery
13. example
Chronic partial small bowel
obstruction
several months' history of chronic
abdominal pain, and intermittent
vomiting
dilated segment shows evidence of
fecalization
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15. Diagnosis
Focus on the following goals:
(a) distinguish mechanical obstruction from ileus
(b) determine the etiology of the obstruction
(c) discriminate partial from complete obstruction
(d) discriminate simple from strangulating obstruction
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Important elements to obtain on history:
prior abdominal operations (suggesting the presence of
adhesions)
abdominal disorders (e.g., intra-abdominal cancer or
inflammatory bowel disease)
hernias (esp. in inguinal & femoral regions)
Blood in Stool (Strangulation)
18. Radiographic Examination
Abdominal series in X-ray:
(1) Abdomen Supine,
(2) Abdomen Upright,
(3) Chest Upright.
most specific triad for small bowel obstruction:
dilated small bowel loops (>3 cm in diameter)
air-fluid levels
a paucity of air in the colon
Specificity of plain Radiography is low (ileus and colonic obstruction)
False-negative (proximal of small intestine OR filled with fluid but no
gas)
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22. CT-Scan
a discrete transition zone with:
dilation of bowel proximally, decompression of bowel distally,
intraluminal contrast that does not pass beyond the transition
zone,
and a colon containing little gas or fluid
Closed-loop obstruction
U-shaped or C-shaped dilated bowel loop
mesenteric vessels converging toward a torsion point
Strangulation (thickening of the bowel wall, pneumatosis
intestinalis)
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28. Therapy
marked depletion of intravascular volume decreased
oral intake, vomiting, and sequestration of fluid in bowel
lumen and wall
IV fluid and bladder catheter(urine output)
Broad-spectrum antibiotics
NG tube (decreases nausea, distention, and the risk of
vomiting & aspiration)
Stricture: an abnormal narrowing of a bodily passage (as from inflammation, cancer, or the formation of scar tissue) <esophageal stricture>; also : the narrowed part
Carcinomatosis: a condition in which multiple carcinomas develop simultaneously usually after dissemination from a primary source
Simultaneous: happening or done at the same time as sth else
Meconium : a dark greenish mass of desquamated cells, mucus, and bile that accumulates in the bowel of a fetus and is typically discharged shortly after birth
Asthenic : of, relating to, or exhibiting asthenia : debilitated
Asthenia : lack or loss of strength : debility
Hematemesis ˌhē-mə-ˈtem-ə-səs: the vomiting of blood
Intestinal Malrotation: Many authors define intestinal malrotation as intestinal nonrotation or incomplete rotation around the superior mesenteric artery (SMA). Interruption of typical intestinal rotation and fixation during fetal development can occur at a wide range of locations; this leads to various acute and chronic presentations of disease. The most common type found in pediatric patients is incomplete rotation predisposing to midgut volvulus, which can result in short-bowel syndrome or even death. Presentations: Acute & Chronic midgut volvulus-Acute & Chronic duodenal obstruction-Internal herniation
Midgut Volvulus: Intestinal volvulus is defined as a complete twisting of a loop of intestine around its mesenteric attachment site. It is related to but not precisely synonymous with malrotation. Presentations: In the first month of life, the most typical presentation includes feeding intolerance with bilious (ie, yellow or green) vomiting and sudden onset of abdominal pain.
Internal hernias are protrusions of the viscera through the peritoneum or mesentery but remaining within the abdominal cavity.
Most common presentation is an acute intestinal obstruction of small bowel loops that develops through normal or abnormal apertures.
Intussusception is caused by part of the intestine being pulled inward into itself. This can block the passage of food through the intestine. If the blood supply is cut off, the segment of intestine pulled inside can die. Decreased blood flow, Irritation & Swellings are clinical presentations. The intestine can die, and the patient can have significant bleeding. If a hole occurs, infection, shock, and dehydration can take place very rapidly.
Diverticulits happens when pouches (diverticula ) form in the wall of the colon . If these pouches get inflamed or infected, it is called diverticulitis. Diverticulitis can be very painful.
Meticulous : paying careful attention to every detail SYN fatidious, thorough
Paucity : a small amount of sth; less than enough of sth
Discrete : independent of other things of the same type SYN separate
Small bowel obstruction. A computed tomographic scan of a patient presenting with signs and symptoms of bowel obstruction. Image shows grossly dilated loops of small bowel, with decompressed terminal ileum (I) and ascending colon (C), suggesting a complete distal small bowel obstruction. At laparotomy, adhesive bands from a previous surgery were identified and divided.
Intestinal pneumatosis. This computed tomographic scan shows intestinal pneumatosis (arrow). The cause of this radiologic finding was intestinal ischemia. Patient was taken emergently to the operating room and underwent resection of an infarcted segment of small bowel.
The CT-presentation of a closed loop obstruction in the small bowel depends on two things:
length of the bowel segment that forms the closed loop
orientation of the loop in relation to the imaging plane
If we have a short closed loop oriented within the plane of imaging, we will see a U- or C-shaped loop of bowel.
Another important appearance of a closed loop obstruction is that of a radial array of dilated small bowel loops with the mesenteric vessels converging to a central point. This is almost always due to a small bowel volvulus.
If the closed loop is longer and is oriented perpendicular to the plane of section, we will see a clump of bowel loops as shown in the case on the left. Sometimes this is difficult to appreciate on just the axial images and coronal or sagittal reconstructions can be helpful. In this case there is also mesenteric edema and localised ascites in combination with dilated loops with wall thickening indicating strangulation and risk of infarction.
