Diverticular Disease

What diverticula are

The colon wall has weak spots where blood vessels pass through the muscle. Over time, pressure inside the colon can push the inner lining out through these spots, forming pea-sized pouches. They are most common in the sigmoid colon on the lower left side in Western countries, and on the right side in East Asian populations.

Types of diverticular disease

Causes and risk factors

• age: pouches become more common with each decade
• low-fiber diet
• obesity, especially abdominal fat
• physical inactivity
• smoking
• high intake of red and processed meat
• medicines: NSAIDs, aspirin, steroids and opioids increase the risk of complications and bleeding
• genetics: family history plays a significant role
• connective tissue disorders in younger people

Symptoms

Diverticulosis

Usually none. Many people learn they have pouches from a colonoscopy or CT done for another reason.

Symptomatic diverticular disease

• cramping lower abdominal pain, often on the left, eased by passing gas or stool
• bloating
• constipation, diarrhea or both

Diverticulitis

• constant pain, usually in the lower left belly, lasting days
• fever and chills
• nausea and loss of appetite
• tenderness when the belly is pressed
• change in bowel habit
• urinary symptoms if the inflamed colon touches the bladder

Diverticular bleeding

• sudden, painless passage of red or maroon blood from the rectum, sometimes large amounts
• most episodes stop on their own

Diagnosis

• History and examination, including belly tenderness and temperature
• Blood tests: white cell count and C-reactive protein for inflammation
• CT scan of the abdomen and pelvis: the main test for diverticulitis, showing inflammation, abscesses and perforation
• Colonoscopy: not done during acute diverticulitis, but often recommended 6 to 8 weeks after a first episode, if not done recently, to rule out colorectal cancer
• For bleeding: colonoscopy, CT angiography or other imaging to find the source

Treatment

Diverticulosis and symptomatic disease

• Fiber: aim for 25 to 35 g a day from fruits, vegetables, whole grains, beans and lentils, increasing gradually. A psyllium supplement can help.
• Fluids and regular exercise.
• Antispasmodics for cramping.
• Seeds, nuts and popcorn do not need to be avoided. Studies have not shown that they cause diverticulitis.

Uncomplicated diverticulitis

• Many people with mild disease can be treated at home.
• Clear liquids or a low-residue diet for a few days, then gradual return to normal food.
• Antibiotics are no longer required for every case. Guidelines suggest they can be used selectively, for example with fever, high inflammatory markers, a weakened immune system, other serious illness, or failure to improve.
• Pain relief: acetaminophen (paracetamol) is preferred. Avoid NSAIDs, which raise the risk of complications.
• Follow-up within a few days to make sure symptoms are improving.

Complicated diverticulitis

• hospital admission with IV fluids and IV antibiotics
• drainage of an abscess through the skin, guided by CT
• surgery for perforation, peritonitis, fistula, obstruction or abscesses that cannot be drained

Surgery

Removing the affected part of the colon (sigmoid colectomy), often by keyhole surgery, may be recommended after complicated diverticulitis or for frequent attacks that affect quality of life. The number of past attacks alone is no longer the main deciding factor. Some emergency operations require a temporary colostomy.

Diverticular bleeding

Most bleeding stops without treatment. Persistent bleeding is treated with colonoscopic clips, embolization through blood vessels, or, rarely, surgery. Blood transfusions may be needed.

Complications

• abscess
• perforation and peritonitis
• fistula to the bladder, vagina or skin
• bowel narrowing (stricture) and obstruction
• recurrence of diverticulitis in some patients
• gastrointestinal bleeding

Prevention

• eat a high-fiber diet
• stay active: vigorous exercise is linked to lower risk
• reach and maintain a healthy weight
• don't smoke
• limit red and processed meat
• avoid regular NSAID use if possible

Frequently asked questions

What is the difference between diverticulosis and diverticulitis?

Diverticulosis means having pouches in the colon wall, usually without symptoms. Diverticulitis means one or more pouches have become inflamed or infected, causing constant belly pain, often on the lower left, with fever and tenderness. Diverticular disease covers both and related problems.

What are the symptoms of diverticulitis?

Typical symptoms are steady pain in the lower left belly lasting more than a day, fever, nausea, loss of appetite and changes in bowel habit. The belly is tender when pressed. Severe pain, high fever or vomiting can signal complications needing urgent care.

Do I need antibiotics for diverticulitis?

Not always. Current guidelines say mild, uncomplicated diverticulitis in otherwise healthy people can often be managed without antibiotics, using rest, clear fluids and pain relief. Antibiotics are used for more severe illness, complications or if symptoms do not improve.

What foods should I avoid with diverticular disease?

There is no need to avoid nuts, seeds, corn or popcorn, as research has not linked them to diverticulitis. A high-fiber diet helps prevent symptoms. During a flare, a short period of clear liquids or low-fiber food may be advised, then fiber is reintroduced gradually.

Can diverticular disease turn into cancer?

No. Diverticular disease does not cause colon cancer. However, the symptoms and CT appearance can overlap, so a colonoscopy is often recommended after a first episode of diverticulitis to check for cancer if one has not been done recently.