Diverticulosis is the presence of diverticula in the large intestine. Diverticula are sac-like protrusions of the colonic wall. As infants and children, we do not possess these sac-like protrusions. Rather, the incidence of diverticulosis increases with age. In fact, by age 60, approximately 60% of persons will have diverticulosis, whereas less than 20% of persons will have diverticulosis prior to age 40.
The exact cause for the formation of diverticulosis is unclear, but is thought to be due to a combination of factors, including colonic wall structure, motility, and diet. Due to the fact that diverticulosis is rare in rural Africa, but common in developed countries, it was initially hypothesized that low fiber diets are associated with the formation of diverticulosis. Studies comparing patients with low fiber diets and high fiber diets have failed to consistently support this theory, but it does seem to play a role.
As far as symptoms of diverticulosis are concerned, most patients with diverticulosis remain asymptomatic. However, as discussed below, there are a few complications of diverticulosis which may result in symptoms.
Diverticulitis affects approximately 10-25% of people with diverticulosis. Diverticulitis is caused by a small perforation of a diverticulum, resulting in inflammation around the site of the perforated diverticulum, which in turn causes abdominal pain. In the Westernized world, diverticulosis is most common on the left side of the abdomen. Therefore, patients with diverticulitis most commonly present with left lower quadrant abdominal pain. Commonly, patients may also experience a concurrent change in bowel habits, fever, nausea, vomiting, or decreased appetite.
The diagnosis of diverticulitis can often be suspected with symptoms and physical exam findings below. However, CT scans are often used to confirm the diagnosis and to exclude possible complications of diverticulitis, which may require additional attention to treatment. Uncomplicated diverticulitis is generally treated with oral antibiotics. Most patients can be treated as an outpatient, but some may require hospital admission. Complicated diverticulitis generally requires treatment with IV antibiotics as an inpatient, with the potential for surgery.
Diverticular Hemorrhage (bleed)
Diverticula form where arteries pierce the large intestine, because it is in this area that the wall of the large intestine is weakest. As a result, the only thing that separates the blood vessel from the lumen of the intestine is thin tissue. If this thin tissue erodes, then the result is quite significant bleeding from the blood vessel into the large intestine. This results in painless passage of large amounts of red blood from the rectum. In some cases, the bleeding may be so profuse that blood transfusion is necessary. Therefore, patients suspected of having a diverticular bleed are generally admitted to the hospital for close observation. In most cases, the bleeding resolves on its own. However, colonoscopy is generally performed to help assess the cause for bleeding and possibly to intervene, if able. If the bleeding persists and is profuse, then other modalities may also be considered, such as a tagged red blood cell scan or CT angiography, which allow radiologists to find the source for the bleeding. With this knowledge, interventional radiologists may be able to stop the bleeding at its source.
Chronic diverticulitis can manifest as chronic recurrent infections requiring treatment similar to acute diverticulitis or as a chronic low-grade inflammation called segmental colitis associated with diverticulosis (SCAD). Unlike typical diverticulitis, this is an inflammatory condition which is stumbled upon during colonoscopy with or without prior diverticulitis. Colonic lining shows inflammatory changes confirmed on biopsy. Symptoms of abdominal pain and diarrhea are often present. This condition occurs only in small minority of patients with diverticulosis. While there is no specific treatment, improvement is often noted spontaneously, with bowel rest, or antibiotics or rarely anti-inflammatory medications. Surgical resection of the affected segment of colon may be needed in rare situations for symptomatic relief.
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