GIT IV (SBO) Flashcards
Congenital causes
Jejunal atresia
Meckel diverticulum
Midgut volvulus
Enteric duplication
Mesenteric cyst
Meconium ileus
Acquired causes of SBO
Extrinsic (complression):
Adhesion, hernia, mass
Intraluminal:
FB, galls stone ileus, bezoar, migration of gastric ballon.
Intrinsic:
Inflammation(crohn’s), TB, Tumor, Intussusception, ischemia, radiation
Features on abdominal Radiograph:
• Central dilated loops
• Dilated loops of SB proximal to the obstruction > 3cm
Valvulae conniventes are visible
Gas-fluid levels if the study is erect.
What is the rule of 3-6-9
Small bowel: < 3 cm
Large bowel TC: < 6 cm
Cecum: < 9 cm
Appendix: <6 mm
High-grade mechanical obstruction may also present with the following features:
Gasless abdomen
String of pearls sign
Signs of SBO secondary to adhesion:
• Dilated small bowel loops proximally
• Thickened mucosa (valvulae conniventes)
• Cut-off sign distally
• ++++ diameter of bowel
• don’t forget that the upper limit is 3 cm of diameter
SBO on US:
• Dilated bowel loop (>3cm)
• Decrease of absent peristalsis
• Prominence valvulae conniventes
US findings suggestive of bowel ischemia
• Extra luminal free fluid
• Loss of peristalsis
• Bowel wall thickening >3mm
• Mural gas
Which sensitive for SBO radiograph or CT
CT, and will demonstrate the cause in ~80% of cases
Meconium ileus onAXR
• Small bowel obstruction
• Dilated loops proximal to impaction
• Soap-bubbly pattern of impaction
• No Air-fluid level
Meconium ileus on FL enema shows:
Small unused microcolon
Filling defects representing meconium pellets in the terminal ileum
Is AXR good for intussusception?
No, it is not sensitive or specific
Intussusception on AXR 🤷♂️
May be normal or:
• Soft tissue mass surrounded by a crescent of gas
• Evidence of distal small bowel obstruction
• Absence of or decreased gas in the colon
• Pneumoperitoneum may seen
Adults usually normal bowel gas pattern
Gold standard diagnostic and therapeutic of intussusception
Barium enema
What are two signs of intussusception on barium enema
• Meniscus sign
• Coiled spring appearance
Signs of intussusception on US (for pediatric):
Transverse: Target or duoghnut sign
Oblique: pseudo kidney sign
Longitudinal: Sandwich, trident
Doppler may help determine viability of the tissue
Intussusception on US (for adult)
Less useful
It is useful when an abdominal mass is palpated
Intussusception on CT
Most commonly done for adult, and pathognomonic:
Axial: Target sign, with layers kf fat and bowel wall visible.
Coronal: Elongated, sausage-shaped mass with visible layers.
