Colon diverticula: how to recognize and treat them

“Diverticula develop most frequently in the digestive tract and particularly in the large intestine, especially in its left-sided segment known as the sigmoid colon,” explains Professor Vecchi.

When discussing colonic diverticula, it is important to distinguish between diverticulosis, diverticular disease, and diverticulitis:

• The term diverticulosis refers simply to the presence of diverticula (an anatomical finding), regardless of whether symptoms are present.
• Diverticular disease, on the other hand, refers to the clinical condition associated with diverticula.
• Diverticulitis, an acute inflammation of diverticula accompanied by pain and other symptoms, is one manifestation of diverticular disease.

In addition to diverticulitis, diverticular disease may present as:

• Diverticular bleeding: because diverticula often form near small blood vessels that cross the intestinal wall, these vessels may rupture and cause acute rectal bleeding. If the bleeding does not stop spontaneously, urgent evaluation in the emergency department is required.
• Symptomatic uncomplicated diverticular disease (SUDD): characterized by chronic, fluctuating, and variable symptoms without episodes of acute diverticulitis.

In most cases, diverticula cause no symptoms, which is why many people discover them incidentally during diagnostic investigations. When symptoms occur, they may include:

Acute symptoms

• cramping and persistent abdominal pain, often in the lower left abdomen;
• fever;
• bowel habit changes, including diarrhea or constipation, potentially progressing to complete bowel obstruction;
• nausea and vomiting;
• visible blood in the stool (rectal bleeding), often abundant and bright red or dark red in color, requiring emergency evaluation if not self-limited.

Chronic symptoms

• recurrent chronic abdominal pain, often localized in the lower left abdomen;
• bloating and excessive gas;
• altered bowel habits, including constipation, diarrhea, or alternating episodes of both;
• sensation of incomplete bowel evacuation.

Colonic diverticula or irritable bowel syndrome?

While diverticula are physical pouches in the wall of the colon, Irritable Bowel Syndrome (IBS) is a functional gastrointestinal disorder not associated with structural disease or visible anatomical abnormalities such as diverticula.

Abdominal discomfort caused by IBS may overlap with symptoms of diverticular disease in many respects. However, IBS generally does not cause fever, nausea, vomiting, or bleeding.

Mild to moderate diverticular disease can often be treated with medical therapy, including antibiotics. More severe cases may lead to complications, including:

• bleeding, which is often self-limited but may occasionally be severe;
• abscesses and fistulas, particularly when inflammation extends to nearby organs such as the bladder;
• microperforations of the intestine, which in rare cases may progress to peritonitis.

In some cases, diverticulitis can cause bowel obstruction due either to swelling of the colonic wall during the acute phase or to narrowing caused by scar tissue resulting from previous episodes. This may partially or completely block the passage of stool and intestinal gas.

In such situations, prompt medical intervention is often necessary, and patients with suspected obstruction should seek emergency care immediately.

Diverticula are believed to be associated with weakening of the walls of the affected organ, which become less elastic over time, particularly with aging. In younger individuals, hereditary factors may contribute to this weakness.

For colonic diverticula, another contributing factor may be the high pressure generated by the colon in patients with chronic constipation when hard, dehydrated stool passes through the intestine. Constipation itself is often associated with a low-fiber diet. Fiber from fruits, vegetables, and legumes helps retain water in stool, making it softer and easier to pass through the colon. Physical inactivity may also slow intestinal motility and reduce the propulsion of stool through the bowel.

The clinical manifestations of diverticular disease are generally caused by:

• Diverticulitis, when fecal material becomes trapped within diverticula, promoting bacterial growth and infection;
• Diverticular bleeding, resulting from rupture of small blood vessels adjacent to diverticula due to wall fragility and pressure fluctuations within the bowel;
• Symptomatic uncomplicated diverticular disease, where chronic symptoms are likely related to altered intestinal motility, increased visceral sensitivity, and elevated intraluminal colonic pressure even in the absence of acute inflammation.

Early diagnosis is important to prevent complications such as abscesses or bowel perforation. Colonic diverticula are diagnosed through imaging and endoscopic investigations, including:

• Colonoscopy, which allows direct visualization of the inner lining of the colon and can be performed safely except during episodes of acute diverticulitis;
• Abdominal CT scan, used to identify diverticula, assess inflammation, and detect complications;
• Abdominal ultrasound, which can evaluate intestinal loops and surrounding structures.

Treatment depends on disease severity, which can vary considerably.

During acute episodes

Management may include:

• antibiotics and pain relievers;
• a liquid or low-residue diet consisting of easily digestible, low-fiber foods such as white bread, white rice, lean meats, and dairy products, while avoiding fruits, nuts, vegetables, legumes, and whole grains;
• hospitalization and/or surgery in cases of severe bleeding, widespread infection, perforation, fistulas, abscesses, or bowel obstruction.

Surgical treatment involves removal of the affected segment of the colon (resection) and reconnection of the healthy bowel to restore normal passage of stool. In very severe cases, a temporary stoma (colostomy) may also be required, allowing stool to be diverted into an external collection bag while the bowel heals.

Diverticular disease without inflammation

Numerous strategies have been studied to prevent episodes of acute diverticulitis. Although some may be beneficial, none has been conclusively proven effective. These strategies include:

• a high-fiber diet rich in fresh fruits and vegetables, with or without fiber supplements;
• adequate hydration (at least 1.5–2 liters of water per day unless otherwise advised by a physician);
• regular physical activity;
• periodic short courses of non-absorbable antibiotics.

“Ultimately, the most important message for patients is to maintain bowel function that is as regular and consistent as possible, thereby reducing the likelihood of diverticular blockage,” explains Professor Vecchi.

During an acute inflammatory episode, fiber intake should be reduced, particularly foods that are more irritating or difficult to digest, such as:

• insoluble fiber (bran and whole grains);
• raw vegetables;
• fruit skins and seeds;
• legumes.

Patients are also advised to follow a light diet and avoid:

• fatty and fried foods;
• processed meats and cured meats;
• alcohol;
• irritating spices;
• seeds and nuts, whose consumption should be discussed with a physician.

“Once diverticula have formed, they do not disappear or regress,” concludes Professor Vecchi. “They can be treated when they become inflamed, but outside acute episodes it is essential to maintain a balanced diet, proper hydration, and a healthy lifestyle.”

Prevention plays a key role in reducing the risk of complications and improving quality of life through daily habits that promote regular bowel function and overall well-being.