Colorectal Cancer, Polyps, and Diverticular Disease: Diverticular Disease: Diagnosis to Follow-Up

0:00Welcome to Board Pearls. This is episode two of two of the Colorectal Cancer, Polyps, and Diverticular Disease chapter, in the Colorectal and Pelvic Floor Disorders module. This episode is diverticular disease. A man with a first attack of diverticulitis is followed through the attack and the years after it, and his case shows how the diagnosis is confirmed and graded, why he may not need antibiotics, what follows the attack, and why repeated attacks no longer mean an operation. A woman with a pelvic abscess shows when a drain or surgery is needed, and later what air in the urine means. And a man with rectal bleeding has a colitis that spares the rectum.

0:38Here's the first patient. A sixty-three-year-old man has had left lower abdominal pain for two days, with a temperature of thirty-seven point nine and a white count of thirteen thousand. He's otherwise healthy, takes no immunosuppressants, and is eating and drinking. His heart rate is eighty-four and his blood pressure is normal. He takes ibuprofen for back pain, and he smokes. His last colonoscopy, nine years ago, was normal apart from diverticula.

1:03Left lower abdominal pain with a low fever and a raised white count, in a man known to have diverticula, suggests acute diverticulitis, inflammation of a colonic diverticulum, most often in the sigmoid. The disease starts with the diverticula themselves. A diverticulum is a herniation of the colon's mucosa and submucosa through the muscularis propria, at the weak points where small arteries, the vasa recta, pierce the muscle layer. Because only the inner layers push through, without the muscle, these are false diverticula, and they sit at the antimesenteric border.

1:34His age and his sigmoid disease are typical. Diverticulosis is the single most common colonoscopy finding in the United States. It's uncommon under thirty, and by eighty it's present in over seventy percent of adults. In Western patients it's mostly in the sigmoid, on the left, while in Asian populations the right colon is more often involved, which is why right lower quadrant pain doesn't rule it out.

1:59His diverticula had been silent for years, and that's the usual course. Most diverticulosis never causes symptoms, and only one to four percent of people with it develop a complication in their lifetime. Diverticulitis is the most common complication. Diverticular bleeding is the second, and it's one of the main causes of lower gastrointestinal, GI, bleeding.

2:20His symptoms suggest diverticulitis, but they don't confirm it. The diagnosis combines typical pain, left lower quadrant for sigmoid disease or right lower quadrant for right-sided disease, with fever, a raised white count, and computed tomography, CT, showing diverticula with surrounding fat stranding and inflammation.

2:40CT is the imaging study of choice, for three reasons. It confirms the diagnosis. It grades the severity. And it finds the complications that change management: abscess, perforation, fistula, and obstruction. None of those can be seen from the bedside, which is why a clinical diagnosis alone isn't enough.

3:01The grade CT assigns decides his management, and complicated disease is graded by the Hinchey classification, on CT or at surgery. Stage one is a pericolic abscess, split into one-A, a phlegmon, and one-B, an abscess next to the colon. Stage two is a pelvic or distant abscess. Stage three is purulent peritonitis, and stage four is feculent peritonitis. The grade drives the choice between medical management, percutaneous drainage, and surgery.

3:31His CT shows sigmoid diverticulitis with fat stranding, and no abscess, free air, fistula, or obstruction. That's acute uncomplicated diverticulitis.

3:43With uncomplicated disease confirmed, the next decision is whether he needs antibiotics, and that answer has changed. A randomized trial of more than five hundred patients with uncomplicated diverticulitis compared observation with antibiotics. It found no difference in time to recovery, complications, recurrence, or need for surgery. That reframed uncomplicated diverticulitis in an immunocompetent patient as more an inflammatory process than an infectious one.

4:10The twenty twenty-two American College of Physicians guideline put that finding into practice for a specific group. It recommends supportive care, with selective rather than universal antibiotics, for immunocompetent outpatients with acute uncomplicated left-sided diverticulitis. They must have no systemic inflammatory response, not be medically frail, not need admission, and have adequate outpatient follow-up.

4:35Every part of that description has to fit, because missing one puts a patient in the wrong group. He's immunocompetent. His disease is left-sided and uncomplicated. His heart rate and blood pressure are normal, so he has no systemic inflammatory response. He isn't frail. He can eat and drink at home, and he can be seen again in a few days. He fits every part, so he's managed at home with supportive care and no antibiotics, and he's better in four days.

5:03Antibiotics remain standard for everyone outside that group. That means patients who are immunocompromised, frail, septic, or need admission, and anyone with complicated disease. When they're given, the oral regimens are ciprofloxacin plus metronidazole, or amoxicillin-clavulanate, which cover the usual gram-negative and anaerobic bacteria. Admitted patients get intravenous regimens.

5:26Once he's better, his colon still has to be examined, because the attack could have been hiding a cancer. Colonoscopy six to eight weeks after a first episode is recommended to exclude an underlying colorectal cancer. The symptoms overlap, and CT can't reliably tell acute diverticulitis from a perforating sigmoid cancer. The false-negative rate of CT for a cancer hidden in the inflamed segment is meaningful, and cancers are missed this way.

5:53A recent normal exam is the one exception. A patient who's had a recent high-quality colonoscopy without findings can defer it. His last one was nine years ago, so it isn't recent. He has a colonoscopy at seven weeks, and it shows diverticula and nothing else.

6:10He then needs counseling about recurrence, because the risk persists and part of it is his to change. After a first attack, recurrence is roughly eight percent at one year, rising to seventeen percent at five years and twenty-two percent at ten. The risk rises with each further episode, but most recurrences are uncomplicated.

6:30The modifiable risk factors are smoking, obesity, nonsteroidal anti-inflammatory drugs, NSAIDs, corticosteroids, and opiates. He smokes and takes ibuprofen, so those are the targets, because they're the parts of his risk that can actually change. He's offered help to quit, and his back pain gets a different plan. Aspirin doesn't appear to drive first or recurrent diverticulitis. Mesalamine, rifaximin, and probiotics have been studied to prevent recurrence, with insufficient and conflicting evidence, so none is recommended.

7:03The second patient shows what happens when CT finds a complication. A seventy-year-old woman with sigmoid diverticulitis has a five-centimeter pelvic abscess on CT. She has complicated diverticulitis, Hinchey two.

7:17Complicated diverticulitis is managed by combining antibiotics with an anatomic intervention, and abscess size decides which. Pericolic abscesses under four centimeters usually resolve with antibiotics alone. At four centimeters or more, antibiotics don't penetrate the cavity well enough, so the abscess is drained percutaneously under CT or ultrasound guidance. Hers is five centimeters, so she gets a percutaneous drain plus intravenous antibiotics. An abscess that can't be drained is an indication for urgent surgery.

7:49A higher grade would have meant an operation. If her CT had instead shown free perforation with diffuse peritonitis, Hinchey three or four, she'd need urgent surgery. That's a sigmoid resection, done either with a primary anastomosis or as a Hartmann procedure, a sigmoid resection with an end colostomy and a closed rectal stump. The choice depends on how stable she is and how much contamination there is.

8:13Her drain works, but months later a different complication appears. She notices air in her urine and has repeated urinary tract infections. That's a colovesical fistula, the most common diverticular fistula, which classically presents with pneumaturia and recurrent infections. Colovaginal, coloenteric, and colocutaneous fistulas are the others. Fistulas are elective surgical indications, and hers is repaired with a planned sigmoid resection. Strictures from chronic inflammation can also cause obstruction and need resection.

8:45The first patient's later course raises the question that used to end in surgery. Over the next four years, he has three more uncomplicated attacks, each brief, and he asks whether he should have his sigmoid removed.

8:58Surgery is no longer tied to the number of attacks. Prophylactic surgery after a fixed number of episodes isn't recommended, because the risk of complicated disease doesn't rise enough to justify an elective resection in immunocompetent patients. Elective resection is now reserved for three groups: patients with multiple debilitating recurrences, patients with complicated attacks such as abscess, fistula, or stricture, and immunocompromised patients, in whom recurrent disease carries higher risk.

9:27His attacks are mild and brief, and he's immunocompetent, so none of the three reasons applies, and he isn't offered surgery. Instead, his modifiable risks are revisited. He's still on ibuprofen, and that's where the next change starts.

9:41The third patient has known diverticulosis too, but his symptoms are colitis, not diverticulitis. A sixty-six-year-old man has rectal bleeding, mild diarrhea, and crampy left lower abdominal pain. His colonoscopy shows redness, friability, and inflammation in the sigmoid segment that carries the diverticula, with normal mucosa below in the rectum and normal mucosa above.

10:04That's segmental colitis associated with diverticulosis, SCAD, a chronic inflammation of the mucosa between the diverticula. The distribution makes the diagnosis. Sparing of the rectum separates it from ulcerative colitis, which always starts in the rectum. Sparing of the proximal colon separates it from Crohn disease. The biopsies show a chronic inflammatory infiltrate that can mimic inflammatory bowel disease, IBD, so the diagnosis rests on the segmental distribution rather than the histology alone.

10:34His treatment follows the approach to mild distal ulcerative colitis. It's mesalamine, oral or topical, and most patients respond. Refractory disease may need oral budesonide or systemic steroids, and sigmoidectomy is reserved for disease that fails medical therapy.

10:51Here are the traps the boards set in these patients. Diverticulitis isn't diagnosed or graded without CT. A stable, immunocompetent outpatient with uncomplicated disease doesn't need antibiotics, but a patient who's immunocompromised, frail, septic, or admitted does. And an abscess of four centimeters or more isn't treated with antibiotics alone.

11:14The follow-up traps come next. Surgery isn't recommended after a set number of attacks. Colonoscopy after a first attack isn't skipped without a recent high-quality exam. Mesalamine and rifaximin aren't used to prevent recurrence. NSAIDs and smoking are modifiable risks that shouldn't be overlooked. And rectum-sparing sigmoid colitis in a patient with diverticula isn't ulcerative colitis.

11:38So, start to finish. Diverticula are false herniations at the vasa recta, common with age, and rarely complicated. Diagnose and grade diverticulitis with CT and the Hinchey stages. Uncomplicated disease in a stable, immunocompetent outpatient can be managed without antibiotics, while immunocompromised, frail, septic, or admitted patients and anyone with complicated disease get them.

12:03Drain abscesses of four centimeters or more. Free perforation or an undrainable abscess goes to surgery, and fistulas are repaired electively. Elective resection isn't tied to the number of attacks, and it's for debilitating recurrences, complicated disease, and immunocompromised patients.

12:21Colonoscopy after a first attack excludes cancer unless a recent high-quality exam was normal. Counsel on smoking, NSAIDs, and the other modifiable risks. And SCAD is segmental sigmoid colitis that spares the rectum, treated with mesalamine.

12:36That completes the Colorectal Cancer, Polyps, and Diverticular Disease chapter. The next chapter is pelvic floor and anorectal disorders, starting with chronic constipation.

12:48For the full chapter, the practice vignettes, and the topic-tagged question bank, head to board pearls dot com. You'll find the rest of the series on Apple Podcasts, Spotify, or wherever you listen to podcasts. That brings us to the end of episode two of two of chapter fifteen, and I'll see you in the next one.