What are colonic diverticula?
Colonic diverticula are small, pouch-like outpouchings that protrude from the wall of the large intestine.
A single pouch is called diverticulum, while diverticula is the plural form.
Diverticulum comes from Latin ‘divertere’, meaning ‘to turn aside or divert.” In anatomy it refers to a small structure that branches or bulges off from a main tube.
Where and why do they form?
Diverticula usually form at natural weak spots in the colon wall. The muscle layer of the colon isn’t continuous – it’s gathered into three bands called the taeniae coli.
The real weak points are where tiny blood vessels, called the vasa recta, pass through the muscle to reach the inner lining. These spots act like tiny ‘holes’ in the muscle.
When pressure inside the colon rises – such as during straining -the inner lining (mucosa) can push outward through these weak areas creating a small pouch: a diverticulum.
Several factors make this more likely. As we age, the connective tissue and muscle in the colon can weaken. A low-fiber diet can produce harder stools and higher pressure inside the colon. Changes in how the colon moves can also create areas of higher pressure.
In the West ,they are most common in the sigmoid colon, where pressure is highest.
Interestingly, in people of Asian descent, they are more often found on the right side of the colon, likely because of genetic and structural bowel differences.
Who gets colonic diverticula?
Diverticula are very common, especially as people get older. They become increasingly frequent with age, affecting most people over 60.
Certain factors make someone more likely to develop diverticula.
Low-fiber diets and chronic constipation are the biggest contributors.
Harder stools and straining raise pressure inside the colon, which makes it easier for pouches to form. Obesity and lack of exercise add to the problem, because being overweight or inactive can slow bowel movements, creating even harder, slower stools and more strain on the colon.
Genetics can also play a part, as some people are naturally more likely to have weak spots in their colon wall.
What are the symptoms?
Usually, diverticula cause no symptoms, though some may notice mild bloating, cramping, or occasional changes in bowel habits.
- Bloating.
- Cramping.
- Changes in bowel habits.
When someone has multiple diverticula in the colon, it’s called Diverticulosis. This just means the pouches are there – it doesn’t mean they’re causing problems.
Diverticulosis is very common, especially with age and most people don’t even know they have it. It’s often found by accident during a colonoscopy or imaging test.
Diverticulitis
Diverticulitis is when one or more diverticula become inflamed or infected.
This usually occurs if stool or bacteria get trapped in a pouch, irritating it.
When this happens, people usually feel pain in the lower left side of the tummy. They may also experience fever, nausea and changes in bowel habits, such as constipation or diarrhoea.
Most cases are mild and can be treated with rest, diet changes and sometimes antibiotics, but more severe cases may require hospital care.
To reduce the chance of recurrence, patients with diverticulitis should focus on a healthy diet, regular exercise, keeping a healthy weight and avoid smoking, which can increase the risk of complications.
Diverticula treatment
Once diverticula form, they don’t go away, which is why prevention is so important. Eating a high-fiber diet, staying hydrated, exercising regularly and avoiding chronic straining can all help reduce pressure in the colon and lower the risk of complications.
Treatment is usually only needed if a diverticulum becomes inflamed or infected, which is called diverticulitis. Mild cases can often be managed at home with bowel rest, a temporary change in diet and sometimes antibiotics. More severe cases may require surgery to remove the affected portion of the colon.
While diverticula stay for life, a healthy lifestyle can help prevent inflammation.
Diverticula and diet
A healthy lifestyle is key to keeping diverticula happy and reducing the risk of flare-ups. That means: staying active, avoiding constipation, eating a balanced diet and staying well hydrated. A Mediterranean-style diet, rich in fibre, fresh fruits and vegetables and low in processed foods, can help keep your bowels regular and ease pressure in the colon.
Interestingly, recent data suggest that nuts, seeds and even popcorn appear to be safe for people with diverticulosis – they don’t seem to trigger inflammation or diverticulitis as once thought. This is still an evolving area of research, but it’s a good reminder that overall healthy habits matter more than avoiding a few specific foods.
When things go wrong
Most of the time, diverticula don’t cause any problems. But sometimes complications can happen.
One possible complication is bleeding. A diverticulum can irritate a small blood vessel, which may cause bright red blood in the stool.
Most of the time, the bleeding stops on its own, but sometimes hospital care or a procedure to block the bleeding vessel is needed.
The bleeding can be a bit more serious or take longer to stop in people who take blood-thinning medications.
A more serious problem is perforation, which happens when an inflamed diverticulum develops a hole. This lets bacteria and stool leak into the belly, causing infection or peritonitis – a medical emergency. Treatment usually involves antibiotics and sometimes surgery. If the perforation is small and contained, it can form an abscess (a pocket of pus). Small abscesses may be treated with antibiotics alone, while larger ones often need drainage or surgery, depending on the person’s condition.
Occasionally, fistulas can form – abnormal connections between the colon and other organs, most commonly the bladder. Chronic inflammation can also lead to blockages from scarring. These complications usually require surgery.
Most diverticula are harmless, but problems can occur.
When is surgery required?
According to most international guidelines, surgery is typically considered for:
- Complicated diverticulitis – f there’s a perforation, large abscess, fistula or bowel blockage.
- Recurrent episodes – – if repeated attacks start to seriously affect a person’s quality of life.
- When medical treatment isn’t enough – if antibiotics and other measures fail to control the infection or inflammation.
The decision isn’t always straightforward, especially when there are no life-threatening complications. Your surgeon will discuss your individual circumstances to decide whether an operation is the best option for you.
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