1. Diverticular Disease of the Colon
Jason Phillips, MD

2. Diverticulosis and the Simpsons

3. Nomenclature Diverticulum = sac-like protrusion of the colonic wall
Diverticulosis = describes the presence of diverticuli
Diverticulitis = inflammation of diverticuli

4. Epidemiology Before the 20th century, diverticular disease was rare
Prevalence has increased over time
First reported resection of complicated diverticulitis by Mayo % %

5. Epidemiology
Increases with age
Age 40 <5%
Age %
Age %

6. Epidemiology Gender prevalence depends on age
M>>F Age less than 40
M > F Age 40-50
F > M Ages 50-70
F>>M Ages > 70

7. Anatomic location of diverticuli varies with the geographic location
“Westernized” nations (North America, Europe, Australia) have predominantly left sided diverticulosis
95% diverticuli are in sigmoid colon
35% can also have proximal diverticuli
4% have only right sided diverticuli

8. Anatomic location of diverticuli varies with the geographic location
Asia and Africa diverticulosis in general is rare and usually right sided
Prevalence < 0.2%
70% diverticuli in right colon in Japan

9. What exactly is a diverticulum?
Colonic diverticulosis is actually not a true diverticulum but rather a pseudo-diverticulum

10. What exactly is a diverticulum?
True diverticulum contains all layers of the GI wall (mucosa to serosa)
Colonic pseudo-diverticulum more like a local hernia
Mucosa-submucosa herniates through the muscle layer (muscularis propria) and then is only covered by serosa

12. Pathophysiology
Diverticuli develop in ‘weak’ regions of the colon. Specifically, local hernias develop where the vasa recta penetrate the bowel wall

13. Mucosa
Submucosa
Muscularis
Vasa recta
Serosa

14. Pathophysiology Law of Laplace: P = kT / R
Pressure = K x Tension / Radius
Sigmoid colon has small diameter resulting in highest pressure zone

15. Pathophysiology
Segmentation = motility process in which the segmental muscular contractions separate the lumen into chambers
Segmentation  increased intraluminal pressure  mucosal herniation  Diverticulosis
May explain why high fiber prevents diverticuli by creating a larger diameter colon and less vigorous segmentation

17. Lifestyle factors associated with diverticular disease
Low fiber  diverticular disease
Not absolutely proven in all studies but strongly suggested
Western diet is low in fiber with high prevalence of diverticulosis
In contrast, African diet is high in fiber with a low prevalence of diverticulosis

18. Lifestyle factors associated with diverticular disease
Obesity associated with diverticulosis – particularly in men under the age of 40
Lack of physical activity

20. Uncomplicated diverticulosis
Usually an incidental finding at time of colonoscopy

23. Uncomplicated diverticulosis
Considered ‘asymptomatic’
However, a significant minority of patients will complain of cramping, bloating, irregular BMs, narrow caliber stools
IBS?
Recent studies demonstrate motility abnormalities in pts with ‘symptomatic’ uncomplicated diverticulosis

24. Uncomplicated diverticulosis
Treatment: Fiber
Bulk content reduces colonic pressure preventing underlying pathophysiology that lead to diverticulosis
20 to 30 g fiber per day is needed; difficult to get with diet alone

25. Do patients need to avoid foods with seeds or nuts?

26. NO! That is a myth.

27. Diverticulitis Diverticulitis = inflammation of diverticuli
Most common complication of diverticulosis
Occurs in 10-25% of patients with diverticulosis

28. Pathophysiology of Diverticulitis
Micro or macroscopic perforation of the diverticulum  subclinical inflammation to generalized peritonitis
Previously thought to be due to fecaliths causing increased diverticular pressure; this is really rare

29. Pathophysiology of Diverticulitis
Erosion of diverticular wall from increased intraluminal pressure  inflammation  focal necrosis  perforation
Usually inflammation is mild and microperforation is walled off by pericolonic fat and mesentery

30. Diagnosis of Diverticulitis
Classic history: increasing, constant, LLQ abdominal pain over several days prior to presentation with fever
Crescendo quality – each day is worse
Constant – not colicky
Fever occurs in % of cases
In one study, less than 17% of pts with diverticulitis had symptoms for less than 24 hours

31. Diagnosis of Diverticulitis
Previous of episodes of similar pain
Associated symptoms
Nausea/vomiting %
Constipation 50%
Diarrhea %
Urinary symptoms (dysuria, urgency, frequency) %

32. Diagnosis of Diverticulitis
Right sided diverticulitis tends to cause RLQ abdominal pain; can be difficult to distinguish from appendicitis

33. Diagnosis of Diverticulitis
Physical examination
Low grade fever
LLQ abdominal tenderness
Usually moderate with no peritoneal signs
Painful pseudo-mass in 20% of cases
Rebound tenderness suggests free perforation and peritonitis
Labs : Mild leukocytosis
45% of patients will have a normal WBC

34. Diagnosis of Diverticulitis
Clinically, diagnosis can be made with typical history and examination
Radiographic confirmation is often performed
Rules out other causes of an acute abdomen
Determines severity of the diverticulitis

40. Treatment of Diverticulitis
Complicated diverticulitis = Presence of macroperforation, obstruction, abscess, or fistula
Uncomplicated diverticulitis = Absence of the above complications

41. Uncomplicated diverticulitis
Bowel rest or restriction
Clear liquids or NPO for 2-3 days
Then advance diet
Antibiotics

42. Uncomplicated diverticulitis
Antibiotics
Coverage of fecal flora
Gram negative rods, anaerobes
Common regimens
Cipro + Flagyl x 10 days
Augmentin or Unsayn x 10 days

43. Uncomplicated diverticulitis
Monitoring clinical course
Pain should gradually improve several days (decrescendo)
Normalization of temperature
Tolerance of po intake
If symptoms deteriorate or fail to improve with 3 days, then Surgery consult

44. Uncomplicated diverticulitis
After resolution of attack  high fiber diet with supplemental fiber

45. Uncomplicated diverticulitis
Follow-up: Colonoscopy in 4-6 weeks
Flexible sigmoidoscopy and BE reasonable alternative
Purpose
Exclude neoplasm
Evaluate extent of the diverticulosis

46. Prognosis after resolution
30-40% of patients will remain asymptomatic
30-40% of pts will have episodic abdominal cramps without frank diverticulitis
20-30% of pts will have a second attack

47. Prognosis after resolution
Second attack
Risk of recurrent attacks is high (>50%)
Some studies suggest a higher rate (60%) of complications (abscess, fistulas, etc) in a second attack and a higher mortality rate (2x compared to initial attack)
After a second attack  elective surgery

48. Prognosis after resolution
Some argue in the elderly recurrent attacks can be managed with medications
Some argue elective surgery should be considered after a first attack in
Young patients under years of age
Immunosuppressed

49. Complicated Diverticulitis
Peritonitis
Resuscitation
Antibiotics
Ampicillin + Gentamycin + Metronidazole
Imipenem/cilastin
Zosyn
Emergency exploration
Mortality 6% purulent peritonitis and 35% fecal peritonitis

50. Complicated Diverticulitis: Abscess
Occurs in 16% of patients with acute diverticulitis
Percutaneous drainage followed by single stage surgery in 60-80% of patients

51. Complicated Diverticulitis: Abscess
CT guided drain
Leave in until drain output less than 10 mL in 24 hours
May take up to 30 days
Catheter sinograms helpful to show persistent communication between abcess and bowel

52. Complicated Diverticulitis: Abscess
Small abscesses too small to drain percutaneously (< 1cm) can be treated with antibiotics alone
These pts behave like uncomplicated diverticulitis and may not require surgery

53. Complicated Diverticulitis: Fistulas

54. Complicated Diverticulitis: Fistulas
Occurs in up to 80% of cases requiring surgery
Major types
Colovesical fistula 65%
Colovaginal 25%
Coloenteric, colouterine 10%

55. Complicated Diverticulitis: Fistulas - Symptoms
Passage of gas and stool from the affected organ
Colovesical fistula:
pneumaturia, dysuria, fecaluria
50% of patients can have diarrhea and passage of urine per rectum

56. Complicated Diverticulitis: Fistulas
Diagnosis
CT: thickened bladder with associated colonic diverticuli adjacent and air in the bladder
BE: direct visualization of fistula track only occurs in 20-26% of cases
Flexible sigmoidoscopy is low yield (0-3%)
Some argue cystoscopy helpful

57. Complicated Diverticulitis: Treatment of Fistulas
Surgery
Resection of affected colon (origin of the fistula)
Fistula tract can be “pinched off” most of the time
Suture closure for larger defects
Foley left in 7-10 days

58. Surgical Treatment of Diverticulitis
Elective single stage resection is ideal, ~6 weeks after episode
Two stage procedure (Hartmann procedure)

59. Surgical Treatment of Diverticulitis
Two stage procedure (Hartmann procedure)
Sigmoid resection
Colostomy
Rectal stump
3 months later  colostomy takedown and colorectal anastomosis

60. Diverticular bleeding
Most common cause of brisk hematochezia (30-50% of cases)
15% of patients with diverticulosis will bleed
75% of diverticular bleeding stops without need for intervention

61. Diverticular bleeding
Patients requiring less than 4 units of PRBC/ day  99% will stop bleeding
Risk of rebleeding  14-38%
After second episode of bleeding, risk of rebleeding  21-50%

62. Diverticular bleeding: Pathophysiology
Diverticulum herniates at site of vasa recta
Over time, the vessel becomes draped over the dome of the diverticulum separated only by mucosa
Over time, there is segmental weakening of the artery  ruptures and bleeds

63. Diverticular bleeding: Pathophysiology

64. Diverticular bleeding: Pathophysiology

65. Diverticular bleeding: Symptoms
Most only have symptoms of bloating and diarrhea but no significant abdominal pain
Painless hematochezia
Start – stop pattern; “water faucet”
Diverticulitis rarely causes bleeding

66. Diverticular bleeding: Management
Resuscitation
Localization
Supportive care with blood products

67. Diverticular bleeding: Localization
Right colon is the source of diverticular bleeding in 50-90% of patients
Possible reasons
Right colon diverticuli have wider necks and domes exposing vasa recta over a great length of injury
Thinner wall of the right colon

68. Diverticular bleeding: Localization
Colonoscopy after rapid prep
Can localize site of bleeding
Offers possible therapeutic intervention (cautery, clip, etc)
Often limited by either brisk bleeding obscuring lumen OR no active bleeding with clots in every diverticuli

69. Diverticular bleeding: Management

70. Diverticular bleeding: Localization
Tagged red blood cell scan
Can localize bleeding source
97% sensitivity
83% specificity
94% PPV
Can detect bleeding as slow as 0.1 mL/min
Often not particularly helpful

71. Diverticular bleeding: Localization
Angiography
Accurate localization
30-47% sensitive
100% specific
Need brisk active bleeding: mL/min
Offers therapy: embolization, vasopressin
20% risk of intestinal infarction

72. Diverticular bleeding: Surgery
Segmental resection
If site can be localized
Rebleeding rate of 0-14%
Subtotal colectomy
Rebleeding rate is 0%
High morbidity (37%)
High mortality (11-33%)

73. Questions?