DIVERTICULITIS

I. Epidemiology

1. 20% of pts with diverticulosis will develop symptomatic diverticulitis
2. 20% are < 50yo
3. Male:Female about 1:1
4. 2/3 of pts < 50yo with diverticulitis will remain disease-free for up to 9y after initial attack

II. Pathophysiology

1. Formation of diverticula related to increased intraluminal pressure + weakening of bowel wall
2. Particles of food become stuck in diverticulum, obstructing and allowing for bacterial overfrowth, and eventually abcess formation or perforation + peritonitis
3. Can also form colovesical, colovaginal, and colocutaneous fistulae

III. Clinical features

1. Fever & leukocytosis
2. Abdominal pain us. initially hypogastric but then LLQ, can be RLQ if right-sided diverticulitis OR if redundant descending colon is lying in the RLQ
3. Urinary sx may occur if affected colonic segment is close to the bladder
4. The infected tic can sometimes be felt as a LLQ or rectal mass
5. Rectal bleeding is very uncommon
6. 85% of cases involve descending or sigmoid colon, but right-sided disease may occur--more frequent in people of Asian descent
7. Right-sided diverticulitis
   1. Unlike sigmoid diverticuli which tend to be outpouchings of mucosa through the muscularis, right-sided diverticuli tend to involve all layers of the colonic wall. In one case series of right-sided diverticulitis, ultrasound provided the dx in 91% of cases; CT was diagnostic in 93%. Most pts were successfully tx'd nonoperatively, with antibiotics (Radiology 208:611, 1998--JW)

IV. Diagnosis

1. Barium enema, the traditional method, can cause bowel perforation
2. CT is diagnostic procedure of choice as of 1998
   1. Can't distinguish diverticulitis from Ca on CT
   2. CT can also be used to assist percutaneous drainage of an abcess
3. Ultrasound can also be used but is highly operator-dependent

V. Treatment

1. Outpatient tx--if stable and tolerating PO's
   1. Liquid diet
   2. 7-10d of broad-spectrum abx, e.g. metronidazole + ciprofloxacin
2. Inpt Tx
   1. NPO
   2. IV triple abx: ampicillin, gentamicin, metronidazole (alt: piiperacilin monotherapy, tazobactam monotherapy)
   3. For analgesia, meperidine better than morphine which can cause colonic spasm
   4. Surgical tx
      1. Required in 20%
      2. Recc'd if recurrent episodes or fistulae are present
      3. Unless generalized peritonitis is present, primary anastomosis rather than colostomy can be done
      4. 27% of pts will have recurrence even after surgery
3. Re-image if not responding to tx in < 3d (decrease in pain, fever, leukocytosis
4. Authors of NEJM article recommend colonoscopy to r/o neoplasm for all those who don't get surgery

(Source: NEJM 338:1521, 1998--JW)