|
Diverticulitis
Diverticulosis
General Considerations
- Herniation of mucosa and submucosa through muscular layers–pseudodiverticulum=false diverticulum=pulsion type
- Diverticula are reducible; they may be seen on one but not another BE
- Only proven association is with Marfan’s syndrome (20% get diverticulitis)
Location
- Almost always involves sigmoid; never rectum; more common on left
- In about 17%, the tics cover the entire colon
- In another 12%, they are isolated to right colon
Prediverticular Disease
- Saw-tooth appearance to the colon, usually sigmoid, with shortening of bowel, crowding of haustra and picket-fencing of folds
- Muscle spasm is present-may be relieved with glucagon
- Controversial as to whether this form can be symptomatic, i.e. pain
Diverticulosis
- May be due to low roughage, high refined-fiber diet
- More common in industrialized nations
- Arise between the mesenteric and anti-mesenteric teniae of the colon and project between circular muscle rings–not through them
- May vary in size from tiny projections to several cm in size
- Have variable filling
- Associated spasm and numerous tics in sigmoid may make it impossible to see polyp in this region–even difficult with colonoscopy
- On AC BE tics have sharp outer and fuzzy inner margins viewed en-face
- Giant sigmoid diverticulum–huge gas-containing cyst-like structure arising in left iliac fossa
Diverticulitis
- Perforation of diverticulum with pericolic abscess of varying size; not simply inflammation of a tic
Clinical Findings
- Pain and tenderness, mass in LLQ
- Fever, leukocytosis
Imaging Findings
CT
- Infiltration of pericolonic fat
- Bowel wall thickening >1cm
- Abscess
- Fluid or free air in peritoneal cavity
- Colovesical or colovaginal fistula
- Intramural sinus tracts
BE
- Extraluminal contrast
- Pericolonic abscess produces mass effect
- Double-tracking=barium in longitudinal sinus tract in wall
- Spasm is an indirect sign of diverticulitis
- Fistula to bladder (diverticulitis is most common cause of non-traumatic fistula here) or small bowel or vagina (diverticulitis causes 1/3 of fistulae to vagina)
![diverticulitis](../../images/giimages1/diverticulitis-ann.jpg)
Diverticulitis, Barium Enema. There is an abscess in the left lower quadrant which is producing compression on the barium-filled sigmoid (red arrow), and there is evidence of extraluminal contrast (red arrow) from a perforated diverticulum,
Conventional Radiography
- Sentinel loop or, less likely, LBO
- Air bubbles in abscess
- Pneumoperitoneum (rare)
Differential Diagnosis
- Colon ca-but mucosa is left intact in diverticulitis
- Crohn’s disease-may be indistinguishable if TI not involved in Crohn’s
- Ischemic colitis–only if sigmoid is involved
- Radiation colitis
Complications
- Peritonitis–usually the perforation is walled off but it may spread throughout the peritoneal cavity or the retroperitoneum
- If a ruptured diverticulum is a strong clinical consideration prior to contrast study, water soluble contrast should be used rather than barium
- Obstruction–is rare
- Bleeding–see below
Hemorrhage from Diverticulosis
- Does't involve Diverticulitis
- 75% of those that bleed are in right colon
- Clinically, massive rectal hemorrhage without pain
- May be diagnosed with nuclear med bleeding scan or angiography
![diverticulitis](../../images/giimages1/diverticultis-ann.JPG)
Diverticulitis. There is an abscess in the left lower quadrant (red arrow), with thickening of the bowel wall, infiltration of the pericolonic fat (yellow arrow) and multiple areas of extraluminal air.
|
|
|