Diverticulosis and Diverticular Disease

Clark Harrison MD

Gastroenterology Consultants

Diverticulosis definitions:

Diverticulosis-a sac-like protrusion of the colonic wall.

Diverticular disease-clinically significantDiverticulitis

Diverticular bleeding

Diverticular obstruction

Segmental colitis-SCAD

Symptomatic uncomplicated diverticular disease-SUDD

Diverticulitis

• Defined as inflammation of a diverticulum

• Acute or chronic

• Uncomplicated

• Complicated:

– Abscess

– Fistula

– Free perforation

– obstruction

Diverticulosis epidemiology

• 50% to 60% by age 60

• < 2% at age 40

• More common in Western countries

• Less common in Asia 1-5 per million

Diverticulitis epidemiology

• Occurs in 5-15% of patients with diverticulosis

• Mean age for admission is 63

• 16% of admissions are for patients < 45

• Usually left sided

• Right sided diverticulitis accounts for only 1.5%

Diverticulosis pathogenesis

• Diverticuli develop at points of weakness in the colonic wall where the vasa recta penetrate the muscular wall.

• A colonic diverticulum is a false or pulsiondiverticulum consisting only of mucosa and submucosa

Diverticulitis pathogenesis

• Occurs due to perforation of a diverticulum with contamination

• Contamination is usually walled off or contained resulting in localized inflammation

• Abscess or fistula may occur

• Free perforation results in peritonitis

Diverticular bleed pathogenesis

• As a diverticulum develops the penetrating vessel becomes draped and distorted over the diverticulum

• Injury to the artery wall over time results in weakness which can rupture and bleed

• Diverticular bleeding with concurrent diverticulitis is extremely rare.

Pathogenesis-SCAD

• SCAD is segmental colitis associated with diverticulosis

• A rare complication

• Not completely understood

– ?mucosal prolapse

– ?fecal stasis

– ?localized ischemia

– ?alteration in gut microbiome

Pathogenesis-SUDD

• SUDD is symptomatic uncomplicated diverticular disease

• Features include:

– Abdominal pain

– Constipation

– Irregular stool caliber or consistency

– Often improves with increased fiber

Acute diverticulitis

• Inflammation due to microperforation of a diverticulum

• Complicated diverticulitis defined as acute diverticulitis with abscess, perforation, fistula, or obstruction

Diverticulitis-clinical presentation

• Abd pain usually LLQ

• Fever

• Occ N/V due to ileus or obstruction

• 50% report constipation

• 25% to 35% report diarrhea

• 10% to 15% dysuria, frequency, or urgency

• Pneumaturia = colovesical fistula

Diverticulitis signs

• Peritoneal signs-tenderness, guarding, rebound, rigidity

• Hypotension and sepsis are associated with perforation and peritonitis

Diverticulitis complications

• Abscess-high suspicion if no improvement on antibiotics

• Fistula-seen in 20% who undergo surgery. Men > women

• Perforation-1%-2%

– Peritonitis due to free rupture of a diverticulum

– Rupture of a diverticular abscess with contamination of the abdomen

Diverticulitis complications

• Obstruction due to inflammation or edema

• Pyogenic liver abscess-rare

• Stricture from fibrosis/scarring-rare

Diverticulitis-imaging

• CT 94%-99% sensitivity and specificity

• CT findings:

– Inflammation/Fat stranding

– Diverticuli

– Abscess

– Obstruction

– Air collections/free air

• *Avoid IV contrast in CKD

Diverticulitis-imaging

• US-low sensitivity

• Barium enema

-low sensitivity

-contraindicated in acute diverticulitis

Diverticulitis diagnosis

• Establish correct diagnosis

• Exclude other entities

• History and physical exam, pelvic in female patient

Diverticulitis-differential diagnosis

• Ischemic colitis-assoc with pain and bloody diarrhea.

– Due to non-occlusive ischemia

– CT shows bowel wall thickening more extensive than localized

– Pericolonic inflammation is usually absent

Diverticulitis-differential diagnosis

• CRC

– May look similar to diverticulitis on CT scan

– Pericolonic inflammation, mesenteric inflammation, >10cm involvment, absence of enlarged nodes more suggestive of diverticulitis

– Impossible to discern on CT in 10%-20%

– Colonoscopy is necessary after inflammation is treated

Diverticulitis-differential diagnosis

• Acute appendicitis-CT very sensitive and specific

• IBD-predominant sx is diarrhea

-onset sx is over days to weeks

• Infectious colitis-diarrhea predominates

Diverticulitis-role of colonoscopy

• No role in acute setting

• May be done 6-8 weeks after resolution of symptoms both to establish diagnosis and for screening

• Not necessary if patient has had colonoscopy which showed diverticulosis within the last few years

Diverticulitis-clinical course

• 75% uncomplicated

• 20%-40% recurrent episodes

• 20% chronic abdominal pain

• 5% diverticular colitis

Diverticulitis-mortality

• Up to 20% with emergency surgery

• Negligible in uncomplicated diverticulitis

Acute diverticulitis treatment

• Uncomplicated-criteria for inpatient care:

– Elderly

– Immunosuppressed

– Significant co-morbidities

– High fever

– Severe abdominal pain

Acute diverticulitis-inpatient care

• Broad spectrum antibiotic:

-Quinolone + metronidazole

-Piperacillin/tazobactam (Zosyn)

-Ampicillin/sulbactam (Unasyn)

• Transition to oral antibiotics

• Colonoscopy after resolution if not already done

Acute diverticulitis-outpatient care

• Outpatient antibiotics:– Quinolone + metronidazole* x 10 days– Amox/clavulanate x 10 days– TMP/SMX + metronidazole* x 10 days

• Outpatient criteria– No high fever– Reliable/compliant– Able to tolerate PO

Complicated diverticulitis

• Peritonitis due to perforation

• Treatment-

– Resuscitation

– Empiric broad spectrum antibiotics

– Emergency surgery – 2 stage

– Mortality = 6% for purulent peritonitis and 35% for fecal peritonitis

Complicated diverticulitis-obstruction

• Less common

• Resection is mandatory when there is concern for colon cancer

• Severe diverticulosis can make it impossible to safely traverse the sigmoid colon at colonoscopy

Complicated diverticulitis-abscess

• Occurs in 16%

• 30%-50% will require surgery

• IR catheter drainage may be definitive treatment

• Abscess < 3cm too small a target for IR

• Failure to improve 24-48 hrs mandates surgery

• Free air is an indication for surgery

Complicated diverticulitis-surgery

• Complicated diverticulitis

• Failed medical management

• Recurrent episodes-indications are somewhat arbitrary

Diverticular bleeding

• Most common cause of LGI bleed in adults

• Bleeding occurs in ~15%

• Massive in 1/3 of patients

• Rarely associated with diverticulitis

• Symptoms are painless hematochezia

Diverticular bleedingclinical course

• Stops spontaneously in 75%

• Stops in 99% of patients transfused < 4U

• Rebleed rate after first bleed is 15%-38%

• Rebleed rate after second episode is 20%-50%

• Surgery should be considered after second bleed

• Mortality rate is as high as 10% especially in the elderly

Diverticular bleedmanagement

• Resuscitation

• Correct coagulopathy if present

• CT angio in brisk bleeding

• ?Nuc med RBC scan-does not localize bleed

• Colonoscopy can be diagnostic and therapeutic but bleeding diverticulum hard to find

• IR or surgery if uncontrolled bleeding

Diverticular bleedSurgery

• Subtotal colectomy in patients with ongoing bleed which cannot be localized

• 11%-33% mortality rates highest in elderly