Diverticulitis

What is diverticulitis?

Diverticulitis is inflammation or infection of small pouches, called diverticula, that form in the wall of the colon. The pouches are common with age and usually cause no trouble. Diverticulitis develops when one becomes inflamed, causing lower left abdominal pain, fever and a change in bowel habit.

Diverticulosis means small pouches have formed in the colon wall, a common change with age. It usually causes no trouble. Diverticulitis is when one of these pouches becomes inflamed, leading to pain and sometimes complications such as an abscess, blockage, or a small tear.

What causes diverticulitis?

Diverticulitis follows the formation of diverticula, which is linked to a low-fibre diet, constipation and ageing. An attack starts when stool or bacteria become trapped in a pouch and it becomes inflamed. Obesity, inactivity and long-term use of some painkillers are also linked to a higher chance of attacks.

• A low-fibre diet leading to constipation and pressure
• Ageing
• Stool getting trapped in a pouch
• Obesity and inactivity
• Certain medicines such as long-term painkillers

What are the symptoms?

Diverticulitis typically causes constant pain in the lower left abdomen, often with fever and chills. Nausea, bloating, tenderness and a change in bowel habit are common. Some people have urinary symptoms, because the inflamed bowel can lie against the bladder, and a few notice gas when passing urine.

• Constant pain, often in the lower left abdomen
• Fever and chills
• Nausea and a change in bowel habits
• Tenderness and bloating
• Urinary symptoms, and occasionally gas passed when urinating

When should I see a colorectal surgeon?

Lower abdominal pain with fever needs prompt assessment for diverticulitis. Go to an emergency department for severe or worsening pain, a high fever, being unable to keep fluids down, a rigid abdomen, or signs of a bowel blockage. Repeated attacks also need review by a colorectal surgeon.

The warning signs below need prompt attention.

• High fever or worsening pain
• Inability to keep fluids down
• A large abscess or perforation
• Repeated attacks
• Signs of a bowel blockage

How is it diagnosed?

Diverticulitis is diagnosed from your symptoms, an abdominal examination, blood tests and usually a CT scan of the abdomen, which shows the inflamed bowel and any abscess. Urine tests rule out other causes. A colonoscopy is arranged after the attack settles to check the colon, because other conditions can look similar.

• Examination and blood tests
• CT scan of the abdomen
• Urine tests
• Colonoscopy later, once the attack settles
• Imaging for complications

How is diverticulitis treated?

Mild diverticulitis is often treated at home with pain relief, fluids and a temporary light diet, with antibiotics when you are unwell or the attack is more severe. An abscess may need drainage. Surgery to remove the affected bowel is kept for complications or repeated attacks, and is decided case by case.

• Bowel rest and a clear or low-fibre diet during the attack
• Antibiotics when you are unwell or the attack is more severe
• Pain relief and fluids
• Drainage of an abscess if needed
• Surgery to remove the affected bowel for repeated or complicated disease

What are the risks and complications?

Diverticulitis can lead to an abscess, a perforation of the bowel wall, a channel called a fistula to another organ, or bowel narrowing and blockage. These complications are the main reason some people need surgery. Surgery has its own risks, and a temporary stoma is occasionally needed.

• Abscess and perforation
• A channel forming to another organ
• Bowel narrowing and blockage
• Surgery risks and, rarely, a temporary stoma