Snapshot A 65-year-old man with a long history of constipation presents with bright red blood per rectum for 1 day. He denies any straining, abdominal pain, diarrhea, or lightheadedness. He denies any recent trauma and family history is unremarkable. His last colonoscopy was about 12 years ago and patient reports he had some "blebs" in his colon. Physical exam was largely unremarkable and a rectal exam did not show any perianal fissures or hemorrhoids. Stool hemocult test is positive. (Diverticulitis) Introduction Overview diverticulosis condition of having multiple sac-like protrusions (diverticula) of the colonic wall that are not inflamed the diverticula are outpouchings of the colonic mucosa and submucosa through areas of weakness within the muscle layers of the colon wall diverticulitis is defined as inflammation of a diverticulum results from a microscopic or macroscopic perforation of a diverticulum due to diverticular inflammation and focal necrosis patients can present with repeated attacks Epidemiology demographics prevalence increases with age with a prevalence of 60% by age 60 location of the diverticula varies by geography sigmoid colon is the most common location in Western countries predominately at the right-side in Asian countries risk factors age low dietary fiber high fat and red meat intake physical inactivity obesity smoking positive family history nonsteroidal anti-inflammatory drugs (NSAIDs) Pathogenesis diverticulosis abnormal colonic motility leading to the colonic mucosa and submucosa to herniate through well-defined points of weakness at the muscle layer points of weakness correspond to where the vasa recta penetrate the circular muscle layer of the colon a typical colonic diverticulum is a “false diverticulum” and is only covered by serosa diverticulitis primary process is thought to be due to erosion of the diverticular wall by increased intraluminal pressure or inspissated food particles erosions of the wall then lead to inflammation and focal necrosis that may lead to micro- or macroscopic perforation the inflammation is frequently mild and often walled off by pericolic fat and mesentery this may lead to the formation of a localized abscess or a fistula (if adjacent organs are involved) poor containment of the inflamed diverticulum or abscess can result in free perforation and peritonitis Associated conditions collagen disorders e.g., Marfan and Ehlers-Danlos ADPKD Presentation Diverticulosis symptoms asymptomatic cramping bloating flatulence irregular defecation painless rectal bleeding physical exam left lower quadrant (LLQ) pain and tenderness Diverticulitis symptoms abdominal pain, most commonly at the LLQ nausea vomiting constipation diarrhea physical exam fever hypotension tender mass peritoneal signs (e.g., guarding, rigidity, and rebound tenderness) Imaging Colonoscopy gold standard allows for visualization of diverticula and rule out of differential (e.g., malignancy) not recommended during an acute diverticulitis attack recommended 4-6 weeks after resolution for evaluation and rule out of malignancy Computed tomography (CT) with contrast best for evaluation of acute diverticulitis positive findings include localized wall thickening (>4mm), pericolic fat stranding, and presence of colonic diverticula also allows for visualizations of complications such as abscess, obstruction, or perforation Plain abdominal radiograph may show signs of constipation rules out other causes of abdominal pain (e.g., small bowel obstruction) may be useful in detecting pneumoperitoneum and obstruction positive findings include air-fluid levels with bowel dilation or free air Studies CBC and iron studies for evaluation of anemia secondary to blood loss may see leukocytosis in diverticulitis Urinalysis may see sterile pyuria or colonic flora (if colovesical fistula) pregnancy test indicated in all women of childbearing age Differential Inflammatory bowel syndrome (IBD) differentiating factors will often present with more chronic clinical symptoms and will have positive biopsy findings Colon/rectal cancer differentiating factors may complain of symptoms (e.g., stool changes) and lesion will be present on colonoscopy Acute appendicitis differentiating factors will appear differently on abdominal CT imaging Treatment Diverticulosis lifestyle changes high-fiber diet to prevent constipation in the case of diverticular bleeding resuscitation (e.g., IV fluids and blood products) colonoscopy with cauterization if bleeding is not identified with colonoscopy, then angiography is indicated surgery is the last resort if the bleeding cannot be controlled with colonoscopy or angiography Diverticulitis outpatient treatment indicated for patients with uncomplicated diverticulitis and no signs of high fever, significant leukocytosis. Peritoneal signs, sepsis, immunosuppression, advanced age, intolerance of oral intake, or significant comorbidities oral antibiotics for 7-10 days with following 2-3 days after first visit inpatient medical management IV antibiotics with transition to oral antibiotics with improvement IV fluids Parenteral pain medications NPO if unable to tolerate oral intake surgery indicated for patients with perforated diverticulitis, hemodynamic instability, or peritonitis can be offered electively to patients with recurrent or chronic symptoms, patients who are immunosuppressed or with a prior episode of complicated diverticulitis Complications Anemia Bleeding/hemorrhage Exsanguination Abscess should be suspected in patients with uncomplicated diverticulitis showing no improvement despite 3 days of antibiotic treatment Bowel obstruction Diverticular fistula Perforation Peritonitis Shock