Diverticulitis
Inflammation or infection of small pouches (diverticula) that form in the wall of the large bowel, causing lower-left abdominal pain, fever and altered bowel habit. Most cases settle with treatment, but complications like an abscess or perforation can be serious.
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What it is
Many people, especially over the age of 50, develop small out-pouchings called diverticula in the wall of the large bowel — a common and usually harmless condition called diverticulosis, linked to a low-fibre diet and ageing. Diverticulitis is what happens when one or more of these pouches becomes inflamed or infected. It typically causes a fairly constant pain in the lower-left abdomen (where the bowel most often has diverticula), often with a fever, a change in bowel habit (constipation or diarrhoea), nausea, and tenderness over the area. Most episodes are 'uncomplicated' and settle with rest, fluids and sometimes antibiotics. A minority become complicated, with an abscess (a walled-off collection of pus), a perforation (a hole in the bowel) leading to widespread infection (peritonitis), a blockage, or a bleed — which are serious and may need drainage or surgery. Blood tests showing raised inflammatory markers support the diagnosis, and a CT scan confirms it and detects complications.
Key lab markers
- White cell count (WBC) and neutrophils — usually raised, reflecting infection/inflammation.
- CRP — commonly raised; higher levels suggest more significant or complicated disease.
- CT scan of the abdomen — the main test to confirm diverticulitis and detect complications (abscess, perforation).
- Full blood count — checks for anaemia if there is bleeding.
- Colonoscopy — usually done after recovery (not during an acute attack) to confirm the diagnosis and exclude other causes.
Symptoms
- Fairly constant pain in the lower-left abdomen
- Fever
- A change in bowel habit — constipation or diarrhoea
- Nausea, sometimes vomiting
- Tenderness over the lower abdomen
- Bloating
- Sometimes blood in the stool
- Warning signs of complications: severe or spreading pain, high fever, a rigid abdomen, or heavy bleeding
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When to discuss with a doctor
See a doctor promptly for persistent lower-left abdominal pain with fever, especially with a change in bowel habit, so diverticulitis can be assessed and treated; mild uncomplicated cases are managed with rest, fluids, and sometimes antibiotics, and often improve within days. Seek urgent care for severe or spreading abdominal pain, a high fever, a rigid or very tender abdomen, being unable to pass wind or stool, or significant rectal bleeding — these can indicate a complication such as an abscess, perforation or obstruction. After recovery, a colonoscopy is usually arranged to confirm the diagnosis and rule out other bowel conditions, and a higher-fibre diet helps prevent recurrence. Mediora.AI can flag a raised white-cell and CRP pattern that fits diverticulitis, but the diagnosis is confirmed clinically and by CT; significant symptoms need prompt assessment.