Ep 182: A 64-Year-Old with Abnormal Colonoscopy

This is Katerina Heidhausen, Executive Editor of Harrison's Principles of Internal Medicine. Harrison's podcast is brought to you by McGraw Hills Access Medicine, the online medical resource that delivers the latest content from the best minds in medicine. And now, onto the episode. Hi everyone. Welcome back to Harrison's Podcast. We're your co-hosts. I'm Dr. Kathy Handy. And I'm Dr. Charlie Wiener, and we're joining you from the Johns Hopkins School of Medicine.

Welcome to today's episode, a sixty-four year old with an abnormal colonoscopy.

So Kathy, today's patient comes to see you because at his recent screening colonoscopy, he was told that while he did not have any worries in polyps, they did see signs of direticulosis. Okay, well that's important. In the United States, diverticulosis affects one half of the population over the age of sixty, and the majority of affected individuals will have no associated symptoms.

Diverticular disease has become the fifth most costly GI disorder in the United States and is the leading indication for elective colon resection. The incidence of diverticular disease is on the rise and most prevalent among middle-aged individuals. Diverticular disease used to be confined to developed countries. However, with the adoption of westernized diets in other countries, diverticulosis is on the rise really across the globe.

and immigrants to the United States develop diverticular disease at the same rate as US natives. Wow, this is a good topic then. Uh are there known risk factors for uh other than Western diet? Other risk factors include the use of NSAIDs or aspirin, steroids, opioids, smoking, and a sedentary lifestyle. Tell me more about our patient. Well, he's 64 years old and he has a past history only of hyperlipidemia on a torvostat.

He works as a vice president at a venture capital firm, and he has that sedentary lifestyle you mentioned. He's never been hospitalized and is diligent with his medical screening, including that recent colonoscopy. His physical examination is totally unremarkable other than being overweight with a BMI of about twenty eight. Okay, what's our question? So the question asks In discussing diverticulosis with this patient, all of the following statements are true except

Option A is that he has an approximately 5% risk of acute diverticulitis. Option B is that he should avoid eating nuts and seeds. Option C is that his asymptomatic diverticulosis is best managed with lifestyle changes. Option D is that his diverticula are most likely localized to the sigmoid colon. Option E says his risk of acute lower GI bleed is less than twenty five percent. Well let me take these out of order. Option D is true.

Diverticula are most commonly encountered in the sigmoid colon and specifically at the point where the nutrient artery or vasorecta penetrates through the muscularis propria. That results in a break in the integrity of the colonic wall. The rectum is always spared. They are also common in the descending left colon. Interestingly, in Asian populations, seventy percent of diverticula are seen in the right colon and ceca. The reasons for that distinction are not clear.

Okay, well let's discuss options A and E,'cause they relate to the complications of diverticulosis. Yes, the two main complications of asymptomatic diverticulosis are the development of hematochesia or diverticulitis. Option E is true also. Hemorrhage from a colonic diverticulum is the most common cause of hematochesia in patients over sixty. But fewer than twenty five percent of patients with diverticulosis will have gastrointestinal bleeding.

Patients at increased risk for bleeding tend to be those who have hypertension, have atherosclerosis, and regularly use anticoagulants and NZES. Additional risk factors include obesity and a history of diabetes malady. Of note, due to increased use of anticoagulants in our aging population, there has been a rise in the incidence of diverticular bleeding. Most bleeds are self limited and stop spontaneously with bowel rest, but the lifetime risk of rebleeding is about twenty five percent.

Okay, well what about diverticulitis as opposed to diverticulosis? Option A is also true. Studies have shown that about five percent of individuals with diverticulosis will develop acute diverticular disease. Previous understanding of the pathogenesis of diverticulosis attributed the disease to poor dietary choices, and the onset of diverticulitis would occur acutely when these diverticula became obstructed.

However, evidence now suggests that the pathogenesis is more complex and multifactorial. It appears that gut dysbiosis and chronic inflammation are part of the pathogenesis. There's ongoing research on those causes, plus the role of genetic risk. Acute uncomplicated diverticulitis characteristically presents with fever, anorexia, left lower quadrant, abdominal pain, and obstipation. I assume that uh CT is the best diagnostic study.

Yes, the diagnosis of diverticulitis is best made on a contrast enhanced abdominal and pelvic CT scan demonstrating the sigmoid diverticula, thickened colonic wall and inflammation within the pericolic fat without the collection of contrast material or fluid. The CT may also distinguish between uncomplicated diverticulitis and complicated diverticulitis, which is characterized by diverticular disease associated with an abscess or perforation, and less commonly with the fistula.

Okay, so we're down to the last two choices, both of which deal with therapy. One of them is right, one of them's wrong. Asymptomatic diverticular disease discovered on colonoscopy or incidentally on an imaging study is best managed by lifestyle changes. Although the data regarding dietary risks and symptomatic diverticular disease are limited, patients may benefit from a fiber enriched diet or supplements that include thirty grams of fiber each day.

The use of fiber decreases colonic transit time and therefore prevents increased intraluminal pressure, leading to the development of diverticulosis. The incidence of complicated diverticular disease appears to also be increased in patients who smoke and are obese, so more reasons to quit smoking and lose weight. Okay, so option C is true. That means it is okay for him to eat nuts and seeds.

Correct. Option B is not true. The historical recommendation to avoid eating nuts is based on no more than anecdotal data. We're not want to take that away from him if it's part of his aspiration for a healthy diet. Okay. Any final words? The routine use of antibiotics and uncomplicated diverticular disease does not appear to reduce time-to-symptom resolution or reduce the risk of complications or recurrence.

Two large randomized trials and a large meta-analysis demonstrated that immunocompetent patients with uncomplicated diverticular disease had no difference in time to symptom resolution, recurrence rates, Development of complicated diverticular disease or surgery if treated with or without antibiotics.

Currently, patients who are immunocompromised, have findings of extensive inflammation on radiographic studies, are at risk for disease progression, or have CT findings of complicated diverticular disease should be treated with antibiotics. And if you want to treat with antibiotics, which ones, how long and do they have to be inpatient or can you use outpatient therapy?

The current recommended coverage for uncomplicated acute diverticulitis is a third generation cephalosporin or ciprofloxicin and metronidazole. The usual course of antibiotics is five days. One study compared the use of IV versus oral antibiotics in uncomplicated diverticular disease and noted no difference in recovery time or progression of the disease. and recommended that safe home treatment on oral antibiotics after a six hour observation in the emergency department is reasonable.

So in a low risk patient, that may also be an option. Great. So the teaching points of today's case are that diverticulosis is remarkably common in our country, and while the risks of acute bleeding or diverticulitis in any individual is not high. Given the prevalence, you are likely to see it. Most diverticula occur in the sigmoid or descending colon and are best treated with lifestyle and diet changes.

GI bleeding is usually self-limited. Uncomplicated acute diverticulitis may not require antibiotics or may be treated as an outpatient. You can find this question and other questions like it in the Harrison Self-Review book, and you can also learn more about this topic in the Harrison's chapter on diverticular disease and common anorectal disorders.

Visit the show notes for links to helpful resources, including related chapters and review questions from Harrisons, available exclusively on Access Medicine. If you enjoyed this episode, please leave us a review so we can reach more listeners just like you. Thanks so much for listening.