Diagnostic Ultrasound - Abdomen and Pelvis

Intussusception
658
Diagnoses: Bowel
Inflammatory
• Appendicular mass
○ Right iliac fossa mass ± inflamed appendix/appendicolith,
inflamed periappendiceal fat ± fluid
• Inflammatory bowel disease
○ Thickened bowel wall with preservation of gut signature
and creeping fat
Infection
• Enteritis/colitis
○ Long segment involvement
○ Clostridium difficile colitis particularly, because of degree
of thickening and submucosal edema
PATHOLOGY
General Features
• Etiology
○ Children
– Idiopathic (95%)
□ Enlarged lymphoid tissue post infection; rare
before 3 months of age (passive immunity)
□ Other causes: Abnormal motility, early weaning,
prematurity, hyperperistalsis, hypertrophied Peyer
patches
– Lead point (5%)
□ Meckel diverticulum, polyp, enteric duplication cyst,
appendicitis, Henoch-Schönlein purpura,
inspissated meconium, gastrojejunal feeding tubes
○ Adults: Identifiable etiology in 90%
– Lead point
□ Malignant: Primary polypoid adenocarcinoma
(more commonly colon), metastases (melanoma,
breast, lung), and lymphoma (more commonly
small bowel)
□ Benign: GIST, polyp, lipoma, leiomyoma, adenoma
of appendix, appendiceal stump granuloma
□ Higher incidence of malignant lesions in large
bowel and benign lesions in small bowel
□ Congenital: Meckel diverticulum, duplication cyst,
ectopic pancreas
□ Inflammatory: Colitis, chronic ulcers, epiploic
appendagitis, cystic fibrosis
□ Trauma: Mural hematoma
□ Postoperative: Suture lines, ostomy closure sites,
submucosal edema
□ Long intestinal tubes
– Nonlead point intussusception
□ Abnormal bowel motility, electrolyte imbalance,
fasting, chronic dilated loop
□ Miscellaneous: Scleroderma, celiac and Whipple
disease
– Transient intussusception
□ Often incidental finding in asymptomatic patient
□ No lead point identified, dysrhythmic peristalsis
□ Usually short segment, no proximal dilatation or
obstruction
□ Spontaneous resolution, rarely requiring surgical
treatment
Gross Pathologic & Surgical Features
• Invaginated bowel ± lead point
CLINICAL ISSUES
Presentation
• Most common signs/symptoms
○ Adults (5%): Accounts for < 2% adult obstructions
– Insidious, vague abdominal symptoms to intermittent
pain, vomiting, red blood in stool
○ Children (95%): Accounts for 80% cases of infantile
obstruction, most common pediatric abdominal surgical
emergency
– Triad: Acute pain, palpable mass, "red currant jelly"
stools
Natural History & Prognosis
• Complications: Obstruction, bowel ischemia/infarction,
perforation, & peritonitis
• Option to rescan after few hours if pain subsiding
• Prompt treatment (reduction or surgery) associated with
good prognosis and low recurrence rate
• Poor prognosis if vascular compromise (ischemia &
perforation)
Treatment
• Surgery indicated where lead point identified or
complications evident on CT
• Children
○ Hydrostatic or pneumatic reduction (US/fluoroscopy)
○ If nonreducible, consider open surgical reduction or
resection
• Adults
○ Surgery usually indicated as high incidence of underlying
lesion
○ Intraoperative reduction may minimize extent of bowel
resection, reducing risk of short bowel syndrome
○ No treatment for transient intussusception as
spontaneous resolution
DIAGNOSTIC CHECKLIST
Consider
• Intussusception: When classical target or doughnut sign is
seen on US or CT in appropriate clinical setting
• Exclude lead point lesion, vascular compromise, and
complications of ischemia
SELECTED REFERENCES
1. Aref H et al: Transient small bowel intussusception in an adult: case report
with intraoperative video and literature review. BMC Surg. 15(1):36, 2015
2. Kim JS et al: [Conservative management of adult small bowel
intussusception detected at abdominal computed tomography.] Korean J
Gastroenterol. 65(5):291-6, 2015
3. Hannon E et al: UK intussusception audit: a national survey of practice and
audit of reduction rates. Clin Radiol. 69(4):344-9, 2014
4. Potts J et al: Small bowel intussusception in adults. Ann R Coll Surg Engl.
96(1):11-4, 2014
5. Park NH et al: Ultrasonographic findings of small bowel intussusception,
focusing on differentiation from ileocolic intussusception. Br J Radiol.
80(958):798-802, 2007
6. Choi SH et al: Intussusception in adults: from stomach to rectum. AJR Am J
Roentgenol. 183(3):691-8, 2004