Diverticular Disease and Diverticulitis: A Guide to Symptoms and Relief

Diverticular disease is an umbrella term for a common digestive condition where small, bulging pouches develop in the wall of the large intestine (colon). These pouches are known as diverticula. In the UK, this condition becomes increasingly common as people age, affecting a significant proportion of the population over 50.

It is important to distinguish between the two main stages of the condition. Diverticulosis is the presence of these pouches without any symptoms or inflammation. Diverticular disease occurs when the pouches cause symptoms like bloating or pain. Diverticulitis is a more serious state where the pouches become inflamed or infected, often requiring medical intervention to prevent complications.

The symptoms of diverticular disease can often mimic other gastrointestinal issues, such as Irritable Bowel Syndrome (IBS). However, the location and nature of the discomfort provide distinct clues. Most people with diverticula will never experience symptoms, but when they do occur, they include:

• Lower-left abdominal pain: This is the most common symptom, often described as a cramp or a persistent ache that may worsen after eating.
• Changes in bowel habits: You may notice alternating bouts of constipation and diarrhoea.
• Bloating and wind: A feeling of fullness or increased flatulence is common.
• Blood in the stool: Occasionally, diverticula can bleed, leading to bright red blood appearing in the toilet or mixed with the stool.

If the condition progresses to diverticulitis, the symptoms become more intense and may include a high temperature (fever), nausea, vomiting, and a sharp, severe pain that does not go away.

While the exact cause remains a subject of ongoing research, health professionals in the UK generally agree that diet and lifestyle play a primary role. The leading theory suggests that a low-fibre diet is a major contributing factor. Fibre helps soften the stool and increases its bulk, allowing it to pass through the colon easily.

When a diet lacks fibre, the colon must exert more pressure to move hard, small stools. This increased pressure can cause the inner layer of the intestine to push through weak spots in the outer muscular layer, forming the characteristic pouches. Other risk factors include aging, smoking, obesity, and a sedentary lifestyle. Genetic predisposition may also play a role, as the condition sometimes runs in families.

Dietary management is the cornerstone of treating diverticular disease and preventing flare-ups. In the UK, the National Institute for Health and Care Excellence (NICE) recommends a high-fibre diet for those with diverticulosis. Aim for approximately 30g of fibre per day from a variety of sources:

• Wholegrains: Brown rice, wholemeal bread, and oats.
• Legumes: Lentils, chickpeas, and beans.
• Fruit and Vegetables: Apples, pears, carrots, and leafy greens.

It is crucial to increase fibre intake gradually. A sudden jump in fibre can cause temporary wind and bloating. Alongside increased fibre, you must drink plenty of fluids—at least 1.2 to 2 litres of water daily—to help the fibre pass through your system efficiently. Contrary to old medical myths, there is no strong evidence that seeds, nuts, or popcorn trigger diverticulitis; most patients can enjoy these as part of a balanced diet.

When diverticula become infected (diverticulitis), the treatment approach shifts. For mild cases, your GP may prescribe a course of oral antibiotics and suggest a temporary clear-liquid diet to allow the bowel to rest. As symptoms improve over several days, you can gradually reintroduce solid foods, starting with low-fibre options before returning to a high-fibre maintenance diet.

Paracetamol is generally recommended for pain relief. It is usually advised to avoid non-steroidal anti-inflammatory drugs (NSAIDs) like ibuprofen or aspirin, as these may increase the risk of bowel complications such as perforation. Severe cases involving intense pain or the inability to keep fluids down may require hospitalisation for intravenous fluids and antibiotics.

If you are experiencing persistent changes in your bowel habits or recurring pain in your lower-left abdomen, consulting an online GP is an effective first step. A clinician can review your symptoms, provide advice on dietary modifications, and help differentiate between diverticular disease and other conditions like IBS or inflammatory bowel disease.

An online GP can also provide sick notes if your symptoms are currently preventing you from working, or offer a private referral for further diagnostic tests, such as a colonoscopy or CT scan, if your symptoms are persistent. Getting an early diagnosis helps you manage the condition proactively through lifestyle changes, reducing the risk of painful future infections.