Diverticulosis

What is diverticulosis?

Diverticulosis is the presence of small, bulging pouches (diverticula) that push outward through weak spots in the wall of your large intestine (colon). They most commonly form in the lower left side of the abdomen.

The condition exists on a spectrum:

• Asymptomatic diverticulosis: the most common form. The pouches are completely harmless, cause zero symptoms, and are usually found by accident during routine imaging.

• Symptomatic uncomplicated diverticular disease (SUDD): the pouches cause chronic discomfort, such as bloating, lower left belly pain, and altered bowel habits, but without any active infection.

• Acute diverticulitis (complication): this happens when one or more of the pouches become inflamed or infected, causing severe abdominal pain, fever, and nausea.

• Diverticular bleeding (complication): occurs when a blood vessel next to a pouch bursts, causing sudden, painless rectal bleeding.

Symptoms of diverticulosis

Asymptomatic diverticulosis causes no symptoms by definition. When symptoms occur they depend on whether inflammation or complications have developed:

Asymptomatic diverticulosis and SUDD:

• Intermittent lower left abdominal discomfort or cramping, often relieved by defecation

• Bloating and abdominal distension

• Altered bowel habits including constipation, diarrhoea, or alternating patterns

• Symptoms frequently overlap with irritable bowel syndrome, making structural imaging the only reliable way to distinguish the two

Acute diverticulitis:

• Acute left lower abdominal pain, typically persistent rather than cramping

• Fever and chills

• Nausea and vomiting

• Changed bowel habits

• In severe cases: peritonitis, abscess formation, or perforation requiring emergency surgery

Diverticular bleeding:

• Sudden painless rectal bleeding, often significant in volume

• Typically self-limiting but can require endoscopic or surgical intervention

What causes diverticulosis?

Diverticulosis develops from a combination of dietary, lifestyle, and constitutional factors that increase colonic pressure and reduce wall strength. Contributing causes include:

• Low dietary fibre intake is associated with diverticulosis and is an important modifiable factor for overall bowel health. Increasing fibre intake may help support normal bowel function and may reduce the risk of diverticular complications.

• Age diverticulosis is rare before 40 and affects approximately 50% of adults by age 60 and up to 70% by age 80, making it one of the most age-dependent structural conditions.

• Sedentary lifestyle reduces colonic motility and contributes to constipation-driven elevated intraluminal pressure.

• Obesity particularly central obesity, is independently associated with increased diverticulosis prevalence and diverticulitis risk.

• Red meat consumption is associated with increased diverticulosis risk and diverticulitis development through mechanisms that are not fully understood.

• Smoking is associated with increased diverticulitis risk and more severe complications.

• Non-steroidal anti-inflammatory drugs (NSAIDs) long-term NSAID use is associated with increased risk of diverticular bleeding and complicated diverticulitis.

• Genetic factors family history of diverticular disease significantly raises individual risk, suggesting a heritable component in colonic wall strength and motility.

How is diverticulosis detected?

Diverticulosis is detected through abdominal imaging, with blood tests assessing inflammatory markers when complications are suspected.

Abdominal MRI Elfcare's full body MRI images the colon and can identify diverticula, along with signs that may suggest inflammation, such as thickening of the colon wall or fat stranding around it. For most people, this is simply useful context, since diverticulosis on its own rarely needs any action. If your scan raises concern for active diverticulitis or a complication, CT remains the gold standard for confirming this and guiding treatment, and we arrange that follow-up promptly so you get a clear diagnosis and the right next step.

Blood tests cannot detect diverticulosis directly but identify active inflammation when diverticulitis is suspected and assess the broader metabolic and nutritional context. Relevant markers in Elfcare's panel include:

• CRP is the most important marker when acute diverticulitis is suspected, rising significantly with active colonic inflammation and correlating with disease severity. Also relevant for monitoring treatment response in acute diverticulitis managed with antibiotics.

• Full blood count and white cell count elevated white cells with left shift support active bacterial infection in acute diverticulitis.

• Albumin low albumin reflects poor nutritional status, particularly relevant in recurrent or complicated diverticular disease affecting dietary intake.

• HbA1c and glucose diabetes is associated with more severe diverticulitis and impaired immune response to colonic infection.

Why early detection matters

Most people with diverticulosis never develop significant complications. However, some may experience diverticulitis, while a smaller proportion may develop complications such as abscess, perforation, or fistula formation. Identifying diverticulosis early can help you understand your digestive health and make informed lifestyle choices. A high-fibre diet, adequate hydration, regular exercise, and avoiding unnecessary NSAID use may support bowel health and reduce the risk of complications. Early awareness also means that symptoms such as persistent lower-left abdominal pain, fever, or rectal bleeding can be recognized and investigated promptly rather than being attributed to routine digestive problems.

How Elfcare can help

Elfcare's full body MRI may visualize the colon and identify diverticula or other findings that may warrant further evaluation. It can provide useful structural information that may help put digestive symptoms or incidental findings into context.

Our blood panel includes markers such as CRP, full blood count, albumin, and metabolic markers, which can provide additional information about inflammation and overall health when clinically relevant.

If our MRI or blood tests identify findings that require further assessment, we help guide you toward the appropriate next step or specialist.