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Diverticulosis/Diverticulitis Glos Care Pathway Overview

This pathway has been published with the aim of supporting Primary Care in providing best practice care to their diverticulitis patients.  The aim of the pathway is to ensure that patients are referred appropriately, and that all primary care assessments have taken place prior to referral. 

Please click the relevant flowchart box to be taken directly to textual information


Red Flags
In instances where there is a suspicion of lower GI cancer please refer to the Lower GI Cancer-suspected - 2ww Referral form and pathway.
Arrange urgent hospital admission for specialist investigations and management if there is suspected acute diverticulitis and the person:
  • Has a suspected complication, such as rectal bleeding that may require urgent blood transfusion; bowel perforation; peritonitis; or abscess.
  • Has symptoms such as severe abdominal pain which cannot be managed in primary care.
  • Is dehydrated or at risk of dehydration and is unable to take or tolerate oral fluids at home.
  • Is unable to take or tolerate oral antibiotics (if needed) at home.
  • Is frail and/or has significant co-morbidities and/or is immunocompromised (for example has diabetes mellitus, end-stage chronic kidney disease, malignancy, cirrhosis, or is taking immunosuppressive drugs).

Diverticula are sac-like protrusions of mucosa through the muscular wall of the colon. They are usually multiple, 5–10 mm in diameter, and occur in the sigmoid colon.  The exact cause of diverticulosis and diverticulitis is not known, but diverticulum formation may be associated with a low-fibre diet. This lowers stool bulk, slows transit times, and increases intraluminal pressure.

  • Diverticulosis is a condition where diverticula are present without symptoms.
  • Diverticular disease is a condition where diverticula cause symptoms, such as intermittent lower abdominal pain, without inflammation and infection.
  • Diverticulitis is a condition where diverticula become inflamed and infected, typically causing severe lower abdominal pain, fever, general malaise, and occasionally rectal bleeding.
    • 'Uncomplicated' diverticulitis refers to localised diverticular inflammation that does not extend to the peritoneum.
    • 'Complicated' diverticulitis refers to diverticulitis associated with complications, such as abscess, peritonitis, fistula, obstruction, or perforation.

The exact cause for the development of diverticular disease and diverticulitis is not known, but the following risk factors may be involved:

  • Genetic
  • Low-fibre diet
  • Smoking
  • Obesity
  • Drugs, such as nonsteroidal anti-inflammatory drugs (NSAIDs), opioids, and corticosteroids
Differential Diagnosis

  • Irritable bowel syndrome
  • Gastroenteritis
  • Appendicitis
  • Ischaemic colitis
  • Inflammatory bowel disease
  • Bowel obstruction  
  • Colorectal cancer
    • Frequent small or continual rectal bleeds are unlikely to be caused by diverticular disease and require further investigation, even in a person known to have diverticula. In addition, the diverticulitis complication of bowel obstruction may mimic symptoms of colorectal cancer

  • Pelvic inflammatory disease
  • Ovarian cyst or torsion — suggested by sharp, stabbing lower abdominal or pelvic pain with nausea and vomiting.
  • Ectopic pregnancy

Initial Primary Care Assessment

Consider an alternative cause for symptoms before making a working diagnosis of diverticular disease or diverticulitis.

It may present with a large, painless rectal bleed, or be found incidentally during investigation for other symptoms.

  • 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
  • Constipation, diarrhoea, or occasional large rectal bleeds
  • Bloating and the passage of mucus rectally
  • Tenderness in the left lower quadrant on abdominal examination

  • 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 localised in the right lower quadrant
  • Change in bowel habit, and possible significant rectal bleeding
  • Possible nausea, vomiting, dysuria, and urinary frequency
  • A previous history of diverticulosis or diverticulitis
  • Tenderness in the left lower quadrant, palpable abdominal mass or distention on abdominal examination

  • 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 and fistula formation — the presence of faecaluria, pneumaturia, or pyuria may suggest colovesical fistula
  • Intestinal obstruction — suggested by colicky abdominal pain, constipation, vomiting, inability to pass flatus, and abdominal distention
Management of diverticulosis

Age from 18 years onwards

If a person has confirmed diverticulosis, provide the following advice:

  • If asymptomatic diverticulosis has been found incidentally while investigating other symptoms, no further investigations are needed.
  • Recommend eating a healthy, balanced diet and having regular meals:
    • The person's diet should contain whole grains, fruits, and vegetables.
    • Fibre intake should be increased gradually (to minimise flatulence and bloating) — adults should aim to consume 30 g of fibre per day to reduce the risk of developing symptomatic diverticular disease.
    • Advise the person that the beneficial effects of increasing dietary fibre may take several weeks.
    • Advise that a high-fibre diet should be maintained for life.
  • Recommend drinking an adequate fluid intake with a high-fibre diet, especially if there is a risk of dehydration.

Routine follow-up is not necessary if there is no progression to symptomatic diverticular disease or diverticulitis.

Management of acute diverticulitis

Manage the person in primary care if there is suspected mild, uncomplicated diverticulitis, depending on clinical judgement:

  • Consider prescribing oral antibiotics if there is suspected infection.
    • If needed, prescribe at least one week of amoxicillin 500mg three times daily and metronidazole 400mg three times daily.
  • Consider watchful waiting if the person is systemically well, has no co-morbidities, and there is no suspected infection.
  • Advise on the use of analgesia, such as paracetamol as-needed.
    • Advise the person to avoid nonsteroidal anti-inflammatory drugs (NSAIDs) and opioid analgesia (such as codeine) if possible, due to the potential increased risk of diverticular perforation.
  • Recommend clear liquids only, with a gradual reintroduction of solid food if symptoms improve over the following 2–3 days.
  • Consider checking bloods for raised white cell count and C-reactive protein (CRP), which may suggest infection.

If the person is managed in primary care, arrange a review within 48 hours, or sooner if symptoms worsen.

  • Arrange urgent hospital admission if symptoms persist or deteriorate despite management in primary care.
  • Consider arranging referral to a specialist in colorectal surgery if a person is managed in primary care and has frequent or severe recurrent episodes of acute diverticulitis.
When to Refer
  • See Red Flags section
  • If the person is managed in primary care, arrange a review within 48 hours, or sooner if symptoms worsen.
  • Arrange urgent hospital admission if symptoms persist or deteriorate despite management in primary care.
  • Consider arranging referral to a specialist in colorectal surgery if a person is managed in primary care and has frequent or severe recurrent episodes of acute diverticulitis.
Secondary Care Management

  • Computed tomography (CT) scan of the abdomen and pelvis to establish the diagnosis, determine the extent and severity of disease, and exclude any complications
  • Planned colonoscopy or CT colonography/Virtual Colonscopy in selected patients after resolution of acute complicated diverticulitis symptoms, to exclude alternative diagnoses such as inflammatory bowel disease, ischaemic colitis, or colorectal cancer

  • Intravenous antibiotics, fluid replacement, and analgesia
  • Urgent surgery for people with acute complicated diverticulitis (for example with peritonitis and sepsis), and for people who do not improve with medical treatment. Surgical options include:
    • Percutaneous drainage of large abscesses
    • Peritoneal lavage
    • Simple colostomy formation
    • Sigmoid resection with colostomy (Hartmann's procedure)
    • Sigmoid resection with a primary colocolic or colorectal anastomosis with or without a diverting colostomy or ileostomy
  • Elective surgery may be considered for people with recurrent complicated diverticulitis (for example stricture or fistula formation) or immunocompromised people at high risk of complications
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