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Diagnosing Diverticular Disease

NYU Langone gastroenterologists, who specialize in diseases of the digestive tract, have extensive experience diagnosing and managing diverticular disease. This condition affects the colon, or large intestine, and occurs when small pouches called diverticula form in weak spots on the colon wall. When you have these pouches, or sacs, the condition is referred to as diverticulosis. 

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Doctors believe that diverticula develop when increased pressure in the colon exacerbates small weaknesses in the layers of muscle, blood vessels, and connective tissue in the colon wall. Over time, the colon wall may bulge outward at these weak spots, forming pouches. This may occur as a result of frequent constipation and straining during bowel movements. Doctors also theorize that abnormal muscle movements in the colon wall may increase pressure in some areas, causing pouches to form.

Diverticulosis is more common in people who eat a diet high in red meat and fat, and it is most frequently diagnosed in people over age 60. Most people don’t experience any symptoms. Sometimes, the condition causes cramping, bloating, or changes in bowel habits. Those who experience symptoms are more likely to be obese, exercise infrequently, or smoke. Less commonly, long-term use of certain medications, including corticosteroids and opiates, may increase the risk of complications of diverticulosis. 

Complications of Diverticular Disease

Some people who have diverticulosis experience complications. One of the most common is diverticulitis, in which the diverticula become inflamed and infected. This may occur when particles of food or bacteria get stuck in the pouches, causing tiny perforations and inflammation. Because the colon is teeming with bacteria, these microperforations can become infected easily. 

Without treatment, diverticulitis can lead to serious problems that require hospitalization. They include an infection in the abdominal cavity, called peritonitis; a pocket of infection in the wall of colon, called an abscess; a connection that forms between the colon and another organ, called a fistula; or a bowel obstruction. 

Symptoms include abdominal pain, commonly on the lower left side, as well as fever, chills, nausea, vomiting, and constipation.

Another possible complication is diverticular bleeding. This can occur at the same time as an infection or on its own. Increased pressure or weaknesses in the walls of blood vessels in the pouches can lead to erosion and perforations, which cause bleeding. If this occurs, bright red blood passes through the colon and the rectum. 

Bleeding is often painless and may be accompanied by a feeling of lightheadedness or dizziness. If you experience any rectal bleeding, seek immediate medical care. Even if it is not associated with diverticular disease, an NYU Langone specialist can determine the cause and recommend the appropriate treatment. 

Diagnostic Tests

To diagnose diverticular disease, your NYU Langone gastroenterologist asks about your symptoms and takes a medical history. He or she asks if you’ve had diverticular disease in the past. 

The doctor may also perform a physical exam to check for abdominal tenderness, which is common in diverticulitis. Next, he or she may conduct one or more of the following tests. 

Blood Test

Your doctor may perform a blood test to look for signs of infection, such as an increase in the number of disease-fighting immune cells called leukocytes.

Abdominal CT Scan 

An abdominal CT scan is the most precise tool doctors use to diagnose diverticular disease. A CT scan provides cross-sectional, two- and three-dimensional images of structures in the gastrointestinal tract. It enables your doctor to identify any abnormalities in the colon and the area around it, such as an abscess or a fistula, an abnormal opening in the intestines that connects to another organ.


A colonoscopy is a procedure that allows the gastroenterologist to examine the lining of the colon and rectum wall for any problems, including diverticula. Your doctor may also use this test to identify inflammation or bleeding in the colon. The test can be used to diagnose diverticular disease in people who have symptoms. 

Colonoscopies are also commonly used as a screening tool for colon cancer. In fact, many people are unexpectedly diagnosed with diverticular disease as a result of a routine colonoscopy. 

Your NYU Langone doctor may recommend a colonoscopy if he or she suspects you have diverticulosis. However, if you have symptoms of an infection, such as fever, chills, or nausea, your doctor does not need to perform this test until those symptoms resolve. The blood test and abdominal CT scan are all that are needed to confirm the diagnosis.

To perform a colonoscopy, a specialist gives you a sedative. While you lie on your side, he or she inserts a colonoscope—a flexible tube with a tiny camera on the end—into the anus and through the rectum. The camera on the colonoscope transmits images to a video monitor, enabling the doctor to view the colon wall. After your doctor examines the area and photographs it, you are taken to a recovery room. 

A colonoscopy takes about 20 minutes. Before the procedure, your colon must be clean. Your doctor gives you instructions on how to prepare, which typically begins one day before the procedure and involves consuming a clear liquid diet and taking laxatives. 

Because a colonoscopy is usually performed using sedation, you need someone to pick you up and take you home after the procedure.

Our Research and Education in Diverticular Disease

Learn more about our research and professional education opportunities.