Diverticulosis, diverticular disease and diverticulitis

The prevalence of diverticula Is unknown as most are asymptomatic. However, it is rare before the age of 40 and increases with age.

  • Diverticulosis occurs in 5–10% of people aged 45 years and older.
  • Diverticulosis occurs in about 80% of people aged 85 years and older.

For people with diverticulosis, the lifetime risk of developing acute diverticulitis is about 4–25%



  • Diverticula are herniations of bowel mucosa through the bowel wall
  • DIVERTICULOSIS (or DIVERTICULAR DISEASE) simply means the presence of diverticulae
  • They can be present in any part of the gastro-intestinal tract but most commonly are found in the colon and, most commonly, in the left sided colon (sigmoid and descending colon)
  • Diverticular Disease tends to be asymptomatic and is relatively rare before the age of 40 although cases in younger patients are becoming increasingly common
  • Diverticulosis is present in around 80% of people aged 85 years and older

Symptomatic Diverticular disease:

When diverticulosis becomes symptomatic. Symptoms may include:

  • Intermittent abdominal pain in the left lower quadrant: Pain may be triggered by eating and may be relieved by the passage of stool or flatus.
  • Tenderness in the left lower quadrant on abdominal examination.
  • Change in Bowel habit: Constipation, diarrhoea, or occasional large rectal bleeds.
  • Bloating and the passage of mucus rectally.


This is when diverticula become inflamed/infected (see image below) and can present with the following symptoms:

  • Constant abdominal pain: usually severe and starting in the hypogastrium before localising in the left lower quadrant, with fever.
    • Note: in a minority of people and in people of Asian origin, pain may be localized in the right lower quadrant.
  • Tenderness in the left lower quadrant: palpable abdominal mass or distention on abdominal examination.
  • Change in bowel habit: and possible significant rectal bleeding.
  • Generalised symptoms: nausea, vomiting, dysuria, and urinary frequency.
  • PMH: diverticulosis or diverticulitis.

Complications of diverticulitis:

  • Rectal Bleeds: Occur in 15% of patients, 1/3 are massive, and 70-80% stop spontaneously
  • Intra-abdominal abscess formation: suggested by an abdominal mass on examination or peri-rectal fullness on internal rectal examination (for example due to a low-lying pelvic abscess).
  • Perforation and peritonitis: suggested by abdominal rigidity, guarding, and rebound tenderness on examination.
  • Sepsis: suggested by skin discolouration, raised or lowered temperature, rigors, change in conscious level or confusion, rapid pulse, and reduced urination.
  • Stricture: suggested by symptoms of colonic obstruction (colicky abdominal pain, constipation, vomiting, an inability to pass flatus and abdominal distension (beware the signs and symptoms of closed loop large bowel obstruction)
  • Fistula formation: the presence of faecaluria, pneumaturia, or pyuria may suggest colovesical fistula.
Noha Ahmed Nasef
/ Sunali Mehta


  • Bloods: VBG, FBC, U&E, CRP, Clotting, G&S (if bleeding), Culture (if requires IV Antibiotics)
  • Imaging:
    • Erect CXR: if considering perforation (but remember this misses approx 25% of perforations)
    • AXR: if considering obstruction
    • CT Abdo/Pelvis: This may be the most appropriate 1st line modality if the patient is significantly unwell (liaise with the surgical team)


Admission Criteria:

  • Complications of diverticulitis: Sepsis, Perforation, Peritonitis, Fistulae, Strictures, Obstruction
  • Significant rectal bleeding: for example, >200ml OR if the person is haemodynamically unstable
  • Severe Pain: that is uncontrollable with simple analgesia.
  • Dehydration: ensure IV fluids commenced
  • Requires IV Antibiotics (if needed) – Commence ASAP (<60min in Red-Flag Sepsis)
  • Frail or significant Co-morbidities

***If evidence of SEPSIS ensure SEPSIS-6 complete***

None of the above – Consider discharge and:

  • Oral antibiotics if there is suspected infection


    • If needed, prescribe at least one week of co-amoxiclav (or a combination of cefalexin with metronidazole or trimethoprim with metronidazole or ciprofloxacin and metronidazole if the person is allergic to penicillin).
  • Follow-Up (depending on severity)
      • Always contact the on-call surgical team for advice prior to discharge
      • Patient may require SDEC for repeat bloods
      • May require OP flexible sigmoidoscopy



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