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.
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
Related symptoms
Related lab panels
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.