Diverticular disease explained: symptoms and care

What diverticular disease is

The large bowel, or colon, is a muscular tube. Over time, small pouches called diverticula can bulge out through weak points in its wall, rather like tiny balloons pushed out under pressure. Simply having these pouches is called diverticulosis, and it is extremely common with age — many people have them and never notice. When the pouches cause symptoms such as tummy pain, bloating or changes in bowel habit, it is called diverticular disease. If a pouch becomes inflamed or infected, that is diverticulitis. Understanding these three terms — pouches present, pouches causing symptoms, and pouches inflamed — helps make sense of what can otherwise sound like a confusing condition.

Why it happens

Diverticula form where the bowel wall is weaker, and pressure inside the bowel pushes the lining out through these gaps. A diet low in fibre is thought to play a part: without enough fibre, stools can be smaller and harder, and the bowel has to squeeze more forcefully to move them along, raising the pressure inside. Ageing also weakens the bowel wall, which is why the condition becomes more common as people get older. Other factors that may increase the risk include being overweight, smoking, lack of physical activity and some medicines. Genetics play a role too, so it can run in families. For many people, several of these factors add up over the years.

Symptoms and flares

Many people with diverticula have no symptoms at all. When diverticular disease does cause problems, people may notice cramping tummy pain, often on the lower left side, bloating, and a change in bowel habit such as constipation or diarrhoea. A flare of diverticulitis is different and more intense: constant, often severe pain usually in the lower left tummy, a raised temperature, feeling generally unwell, and sometimes nausea or a change in bowel habit. Bleeding can also occur, sometimes suddenly and heavily, as fresh red blood from the back passage. Because these symptoms overlap with other bowel conditions, new or persistent changes should always be checked by a clinician rather than assumed to be diverticular disease.

When it becomes serious

Most diverticulitis flares are mild and settle, but complications can develop and need prompt care. An abscess (a collection of infection) can form, or a pouch can burst, leading to infection spreading in the abdomen, which causes severe pain and makes a person very unwell. Repeated inflammation can narrow the bowel or create an abnormal connection to another organ. Heavy bleeding from the bowel needs urgent assessment too. Warning signs to act on include severe or worsening tummy pain, a high fever, being unable to keep fluids down, a swollen tender abdomen, or significant bleeding from the back passage. These situations may need hospital treatment, and sometimes surgery, so they should never be ignored.

Living with diverticular disease

For most people, diverticular disease is managed with everyday measures rather than medicines. A diet high in fibre — plenty of wholegrains, fruit, vegetables, beans and pulses — helps keep stools soft and reduces pressure in the bowel, and drinking enough fluid is important as fibre increases. Fibre is best increased gradually to avoid bloating and wind. Staying active, keeping to a healthy weight and stopping smoking all help. The old advice to avoid nuts, seeds and popcorn is no longer thought necessary for most people. During a mild flare, a clinician may suggest resting the bowel briefly with lighter foods. Regular, uncomplicated symptoms can usually be managed at home with a GP's guidance.