Diverticulosis and Diverticular Disease

Clark Harrison MD Consultants definitions:

Diverticulosis-a sac-like protrusion of the colonic wall. Diverticular disease-clinically significant Diverticular Diverticular obstruction Segmental -SCAD Symptomatic uncomplicated diverticular disease- SUDD Diverticulitis

• Defined as of a • or chronic • Uncomplicated • Complicated: – – – 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 pulsion diverticulum 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 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 – ?alteration in gut microbiome Pathogenesis-SUDD

• SUDD is symptomatic uncomplicated diverticular disease • Features include: – – – 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 • • Occ N/V due to or obstruction • 50% report constipation • 25% to 35% report • 10% to 15% , frequency, or urgency • Pneumaturia = colovesical fistula Diverticulitis signs

• Peritoneal signs-tenderness, guarding, rebound, rigidity • Hypotension and are associated with perforation and peritonitis Diverticulitis complications

• Abscess-high suspicion if no improvement on • 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 Diverticulitis complications

• Obstruction due to inflammation or edema • Pyogenic -rare • Stricture from /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 -low sensitivity -contraindicated in acute diverticulitis Diverticulitis diagnosis

• Establish correct diagnosis • Exclude other entities • History and physical exam, pelvic in female patient Diverticulitis-

• -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% – is necessary after inflammation is treated Diverticulitis-differential diagnosis

• Acute -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 : -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 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 Diverticular bleeding clinical 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 bleed management • 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 bleed Surgery • Subtotal in patients with ongoing bleed which cannot be localized • 11%-33% mortality rates highest in elderly