How is acute diverticulitis treated?

Uncomplicated diverticulitis is always treated conservatively – in other words, without surgery. In the past, doctors tended to prescribe antibiotics for the treatment of acute diverticulitis. Nowadays clinical guidelines have shifted away from the routine use of antibiotics here. But it's important to have regular check-ups. Sometimes a temporary change in diet is recommended.

The use of antibiotics can sometimes be avoided in uncomplicated diverticulitis – but only if an ultrasound or CT scan has been done and no abscesses were found. Then antibiotics probably wouldn’t reduce the risk of complications. About 1 out of 100 people in studies had an abscess or an intestinal perforation, regardless of whether or not they had taken antibiotics. In rare cases, though, these scans may fail to discover abscesses or perforations.

Antibiotics are generally only recommended for the treatment of uncomplicated diverticulitis if there’s an increased risk of complications – for instance, if someone has chronic kidney disease, a weakened immune system, high blood pressure or allergies. But there's a lack of research on treatment with antibiotics in high-risk patients so it’s not yet possible to say how effective antibiotics really are in those cases.

In uncomplicated diverticulitis, it’s important to see a doctor regularly – particularly in the first few days – in order to detect any complications early on. Your blood can be tested to check for signs of inflammation or infection, for instance. This is often possible on an outpatient basis (without a hospital stay).

Serious complications like an intestinal perforation are rare in uncomplicated diverticulitis, but still possible. So it’s important to look out for warning signs anyway, such as severe belly pain, fever, a hard and tense belly, and nausea. Symptoms like this should be checked out by a doctor as soon as possible.

Some doctors advise people to try to carry on eating normally – or to eat easily digestible foods for a while. Others recommend mainly eating soups or other non-solid foods, having a low-fiber diet, and drinking enough fluids, in the first few days. But it's not clear whether it really is better to avoid solid foods for a while. There is a lack of good research in this area.

In about 95 out of 100 people, uncomplicated diverticulitis goes away on its own within a week. In about 5 out of 100 people, the symptoms stay and treatment is needed. Surgery is only rarely necessary.

Complicated diverticulitis is treated with antibiotics. People often switch to a liquid diet for a while, too. Sometimes surgery is needed.

Complicated diverticulitis is treated in the hospital. Antibiotics are needed in order to stop the infection from spreading further. They can be used in the form of a syrup, tablets, or an infusion (drip).

Whether or not people with complicated diverticulitis should avoid solid foods will depend on their symptoms and the results of diagnostic tests. They are often given water, tea and soup for a few days, and then gradually start eating normally again. If they aren’t able to drink enough, they are given fluids through a drip.

People who have complicated diverticulitis have an abscess with pus in it. If the abscess is quite big, the pus can be drained out of it through a thin tube that is inserted into the belly.

If the symptoms don’t improve within a few days, the risk of serious complications increases. Surgery is then recommended. People who have an intestinal perforation or peritonitis need to have surgery immediately. Both of these conditions are medical emergencies.

Even if a long-lasting infection with pus goes away after treatment with antibiotics, doctors still often recommend operating on the bowel. The aim of this surgery is to prevent people from developing complicated diverticulitis again. Research has shown that almost 1 in 3 people who have previously had successful treatment with antibiotics go on to develop diverticulitis again within a few years – and new episodes sometimes lead to serious complications. People who have a weakened immune system or chronic kidney disease are also at higher risk of serious complications.

In about 80 out of 100 people, complicated diverticulitis clears up within a few weeks of having treatment with antibiotics. About 20 out of 100 people have surgery.