Small Bowel Obstruction Flashcards
What percentage of all small bowel obstruction (SBO) cases are due to postoperative adhesions?
75% to 80%
Name some congenital anatomic abnormalities that can cause SBO.
Midgut volvulus
Ileal atresia
De novo adhesions
What are some disorders of the bowel wall that can lead to SBO?
Intussusception
Stricture
Tumor
List examples of extrinsic compression causes of SBO.
Compression from a mass
What are some intraluminal disorders that can cause SBO?
Meconium ileus
Gallstones
Foreign body
Bezoar
What is the most common cause of SBO in undeveloped countries?
Strangulated hernias
Give examples of foreign bodies that can cause SBO.
Bezoars
Swallowed objects
Gallstones
Name additional causes of SBO not related to adhesions or hernias.
Radiation
Endometriosis
Infection (e.g., tuberculosis)
In the absence of prior intraabdominal surgery, what is the most common cause of SBO?
Abdominal wall hernia with small bowel incarceration
What should be considered in older patients with suspected SBO, no prior abdominal surgery, and no hernia on examination?
Evaluation for malignancy
Leukocytosis with a left shift in SBO
nonspecific indicator of inflammation and/ or infection
does not correlate with disease severity.
The typical gas pattern for SBO on plain film demonstrates
dilated gas- or fluid-filled loops of small bowel in the setting of a gasless or nondistended colon
what may be given in partial adhesive SBO at a later point to expedite resolution of the obstruction
Gastrografin
Ct Findings concerning for bowel wall compromise include
bowel wall edema or hemorrhage
altered bowel wall enhancement (Decreased,Absent or Delayed hyperenhancement)
interloop ascites
mesenteric edema/ fat stranding
vascular engorgement
vessel occlusion
late signs of bowel wall compromise and indicate bowel wall necrosis in the setting of SBO.
pneumatosis of the bowel wall
mesenteric and/ or portal venous gas,
extraluminal free air
When to use MRI ?
Pregnant
Children
the three CT patterns of closed-loop small bowel obstruction
1- typical closed-loop obstruction, the afferent loop and closed loop are dilated and the efferent loop is collapsed.
2- collapsed closed-loop obstruction, the closed loop is collapsed, the afferent loop is dilated, and the efferent loop is collapsed
3- flat-belly closed-loop obstruction, the closed loop is dilated and the afferent and efferent loops are collapsed.
partial small bowel obstruction (pSBO)
contents continue to pass through the intestine.
Patient exhibit a benign abdominal examination and continue to pass bowel movements and flatus.
Concerning Radiographic Signs other than Previous mentioned
-Multiple transition zones: Closed-loop obstruction demonstrates radial small bowel arrangement with a U- or C-shaped configuration, converging at the site of obstruction.
-Swirling of mesenteric vessels (also known as the swirl sign or whirl sign) may indicate volvulus and/ or closed-loop obstruction.
When to do Expectant therapy for SBO
recommended for patients without peritonitis or hemodynamic instability
Patients with partial adhesive SBO without strangulation are good candidates for
-Gastrografin (diagnostic and therapeutic)
-Doses of 100 mL in 50 mL of water
-Either immediately at admission, or if conservative therapy with decompression fails, after 48 hours.
-Gastrografin appearing in the colon within 24 hours on x-ray study predicts resolution without surgical intervention.
-The radiograph can be repeated every 8 to 12
Nonoperative techniques can be utilized for how long ?
2 to 3 days
spontaneous resolution decreases after the third day
Predictors for successful laparoscopic treatment
history of ≤ 2 laparotomies
appendectomy as the sole previous operation and cause of the obstruction
no previous median laparotomy incision
and a single adhesive band.
Patient with irreducible hernia SBO
You can reduce the bowel and monitor post– hernia reduction (typically at least 24 hours) if there are no concerns for bowel compromise.
One-half of reported SBO cases during pregnancy are
caused by adhesions.
Fetal mortality averages 21% and is more likely with surgery in the (Which Trimester ?)
first trimester
Obstruction Due to Inflammatory Bowel Disease
-Early CT enterography is essential
-The team should determine early surgery versus neoadjuvant antiinflammatory therapy and the need for antibiotics and/ or abscess drainage.
Malignancy Causing SBO like ?
neuroendocrine tumors
adenocarcinomas
lymphomas
gastrointestinal stromal tumors.
How would you Treat the Previous ?
oncologic principles > resection of the involved segment of bowel along with a 5- to 10-cm margin proximally and distally as well as removal of all associated mesentery.
When to Consider A small bowel bypass
If the tumor causing the obstruction cannot be completely resected and multiple sites of bowel obstruction exist
SBO in virgin abdomen (VA) Benign or Malignant ?
-mostly benign cause; in contrast with older literature and surgical textbooks that suggest malignancy as the main cause of obstruction in VA patients.
How would you Tx the Previous
can be treated by nonoperative trial initially.
Nevertheless, a laparotomy remains indicated in case of a nonresolving obstruction.
Post Bariatric Surgery at risk of What ?
same causes as all other patients +
risk of internal hernia
intussusception
and closed-loop obstructions resulting from surgical creation of mesenteric defects.
Findings for patient post Bariatric Sx
-significantly dilated small bowel with a transition point is often a late finding.
-Elevated amylase and/ or lipase may be a significant finding , especially with acute obstruction of the biliopancreatic limb.
lower threshold to proceed to the operating room for any suspicious findings is recommended.
