Guidance

Recommendations

Recommendations

People have the right to be involved in discussions and make informed decisions about their care, as described in NICE's information on making decisions about your care.

Making decisions using NICE guidelines explains how we use words to show the strength (or certainty) of our recommendations, and has information about prescribing medicines (including off‑label use), professional guidelines, standards and laws (including on consent and mental capacity), and safeguarding.

1.1 Diverticulosis

Management and advice

1.1.1

Tell people with diverticulosis that the condition is asymptomatic and no specific treatments are needed.

1.1.2

Advise people to eat a healthy, balanced diet including whole grains, fruit and vegetables. Tell them that:

  • there is no need to avoid seeds, nuts, popcorn or fruit skins

  • if they have constipation and a low-fibre diet, increasing their fibre intake gradually may minimise flatulence and bloating.

1.1.3

Advise people to drink adequate fluid if they are increasing their fibre intake, especially if there is a risk of dehydration.

1.1.4

Consider bulk-forming laxatives for people with constipation.

1.1.5

Tell people about the benefits of exercise, and weight loss if they are overweight or obese, and stopping smoking, in reducing the risk of developing acute diverticulitis and symptomatic disease.

For a short explanation of why the committee made these recommendations and how they might affect practice, see the rationale and impact section on diverticulosis management and advice.

Full details of the evidence and the committee's discussion are in evidence review A: prevention of diverticular disease in patients with diverticulosis.

1.2 Diverticular disease

Symptoms and signs

1.2.1

Suspect diverticular disease if a person presents with one or both of the following:

  • intermittent abdominal pain in the left lower quadrant with constipation, diarrhoea or occasional large rectal bleeds (the pain may be triggered by eating and relieved by the passage of stool or flatus)

  • tenderness in the left lower quadrant on abdominal examination.

    Be aware that:

  • in a minority of people and in people of Asian origin, pain and tenderness may be localised in the right lower quadrant

  • symptoms may overlap with conditions such as irritable bowel syndrome, colitis and malignancy.

For a short explanation of why the committee made these recommendations and how they might affect practice, see the rationale and impact section on symptoms and signs of diverticular disease.

Full details of the evidence and the committee's discussion are in evidence review B: symptoms and signs of diverticular disease.

Investigations and referral

1.2.2

Do not routinely refer people with suspected diverticular disease unless:

  • routine endoscopic and/or radiological investigations cannot be organised from primary care or

  • colitis is suspected or

  • the person meets the criteria for a suspected cancer pathway.

For a short explanation of why the committee made these recommendations and how they might affect practice, see the rationale and impact section on investigations and referral.

Full details of the evidence and the committee's discussion are in evidence review C: diagnosis of diverticular disease.

Management and advice

1.2.5

Advise people to avoid non-steroidal anti-inflammatory drugs and opioid analgesia if possible, because they may increase the risk of diverticular perforation.

1.2.6

For advice on diet, fluid intake, stopping smoking, weight loss and exercise, follow the recommendations in section 1.1 on diverticulosis.

1.2.7

Advise people that:

  • the benefits of increasing dietary fibre may take several weeks to achieve

  • if tolerated, a high-fibre diet should be maintained for life.

1.2.8

Consider bulk-forming laxatives if:

  • a high-fibre diet is unacceptable to the person or it is not tolerated or

  • the person has persistent constipation or diarrhoea.

1.2.9

Consider simple analgesia, for example paracetamol, as needed if the person has ongoing abdominal pain.

1.2.10

Consider an antispasmodic if the person has abdominal cramping.

1.2.11

If the person has persistent symptoms or symptoms that do not respond to treatment, think about alternative causes and investigate and manage appropriately.

For a short explanation of why the committee made these recommendations and how they might affect practice, see the rationale and impact section on diverticulosis management and advice.

Full details of the evidence and the committee's discussion are in evidence review D: management of diverticular disease.

Recurrent diverticular disease

The committee were unable to make recommendations for practice in this area.

For a short explanation of why the committee made these recommendations and how they might affect practice, see the rationale and impact section on recurrent diverticular disease.

Full details of the evidence and the committee's discussion are in evidence review evidence review E: management of recurrent diverticular disease.

1.3 Acute diverticulitis

Symptoms and signs of acute diverticulitis

1.3.1

Suspect acute diverticulitis if a person presents with constant abdominal pain, usually severe and localising in the left lower quadrant, with any of the following:

  • fever or

  • sudden change in bowel habit and significant rectal bleeding or passage of mucus from the rectum or

  • tenderness in the left lower quadrant, a palpable abdominal mass or distention on abdominal examination, with a previous history of diverticulosis or diverticulitis.

    Be aware that in a minority of people and in people of Asian origin, pain and tenderness may be localised in the right lower quadrant.

For a short explanation of why the committee made these recommendations and how they might affect practice, see the rationale and impact section on symptoms and signs of acute diverticulitis.

Full details of the evidence and the committee's discussion are in evidence review evidence review F: referral criteria for acute diverticulitis.

Symptoms and signs of complicated acute diverticulitis

1.3.2

Suspect complicated acute diverticulitis and refer for same-day hospital assessment if the person has uncontrolled abdominal pain and any of the features in table 1.

Table 1 Symptoms and signs that suggest complicated acute diverticulitis
Symptom or sign Possible complication

Abdominal mass on examination or peri-rectal fullness on digital rectal examination

Intra-abdominal abscess

Abdominal rigidity and guarding on examination

Bowel perforation and peritonitis

Altered mental state, raised respiratory rate, low systolic blood pressure, raised heart rate, low tympanic temperature, no urine output or skin discolouration

Sepsis (see the NICE guideline on sepsis)

Faecaluria, pneumaturia, pyuria or the passage of faeces through the vagina

Fistula into the bladder or vagina

Colicky abdominal pain, absolute constipation (passage of no flatus or stool), vomiting or abdominal distention

Intestinal obstruction

For a short explanation of why the committee made these recommendations and how they might affect practice, see the rationale and impact section on symptoms and signs of complicated acute diverticulitis.

Full details of the evidence and the committee's discussion are in evidence review I: indications for surgery.

Investigation of suspected acute diverticulitis

Primary care
1.3.3

For people with suspected uncomplicated acute diverticulitis who are not referred for same-day hospital assessment:

  • reassess in primary care if their symptoms persist or worsen and

  • consider referral to secondary care for further assessment.

Secondary care
1.3.4

For people with suspected complicated acute diverticulitis who have been referred for same-day hospital assessment, offer a full blood count, urea and electrolytes test and C‑reactive protein test.

1.3.5

If the person with suspected complicated acute diverticulitis has raised inflammatory markers, offer a contrast CT scan within 24 hours of hospital admission to confirm diagnosis and help plan management. If contrast CT is contraindicated, perform one of the following:

  • a non-contrast CT or

  • an MRI or

  • an ultrasound scan, depending on local expertise.

1.3.6

If inflammatory markers are not raised, think about the possibility of alternative diagnoses.

For a short explanation of why the committee made these recommendations and how they might affect practice, see the rationale and impact section on investigation of suspected acute diverticulitis.

Full details of the evidence and the committee's discussion are in evidence review G: diagnostic tests for acute diverticulitis.

Non-surgical management of acute diverticulitis

1.3.7

For people with acute diverticulitis who are systemically well:

  • consider a no antibiotic prescribing strategy

  • offer simple analgesia, for example paracetamol

  • advise the person to re‑present if symptoms persist or worsen.

1.3.8

Offer an antibiotic prescribing strategy if the person with acute diverticulitis is systemically unwell, is immunosuppressed or has significant comorbidity.

1.3.9

Offer oral antibiotics if the person with acute diverticulitis is systemically unwell but does not meet the criteria for referral for suspected complicated acute diverticulitis.

1.3.11

Review intravenous antibiotics within 48 hours or after scanning if sooner (see recommendation 1.3.5) and consider stepping down to oral antibiotics where possible.

1.3.12

If the person has CT-confirmed uncomplicated acute diverticulitis, review the need for antibiotics and discharge them depending on any co-existing medical conditions.

1.3.13

When prescribing an antibiotic for suspected or confirmed acute diverticulitis, follow the advice in table 2.

Table 2 Antibiotics for adults aged 18 years and over with suspected or confirmed acute diverticulitis
Treatment Antibiotic, dosage and course length
First-choice oral antibiotic for suspected or confirmed uncomplicated acute diverticulitis

Co-amoxiclav:

500/125 mg three times a day for 5 days
Alternative first-choice oral antibiotics if penicillin allergy or co‑amoxiclav unsuitable

Cefalexin (caution in penicillin allergy) with metronidazole:

Cefalexin:500 mg twice or three times a day (up to 1 to 1.5 g three or four times a day for severe infection) for 5 days

Metronidazole: 400 mg three times a day for 5 days

Trimethoprim with metronidazole:

Trimethoprim: 200 mg twice a day for 5 days

Metronidazole: 400 mg three times a day for 5 days

Ciprofloxacin (only if switching from IV ciprofloxacin with specialist advice) with metronidazole:

Ciprofloxacin: 500 mg twice a day for 5 days

Metronidazole: 400 mg three times a day for 5 days

See the MHRA January 2024 advice for restrictions and precautions on using fluoroquinolone antibiotics because of the risk of disabling and potentially long-lasting or irreversible side effects. Fluoroquinolones must now only be prescribed when other commonly recommended antibiotics are inappropriate
First-choice intravenous antibiotics for suspected or confirmed complicated acute diverticulitis

Co-amoxiclav:

1.2 g three times a day

Cefuroxime with metronidazole:

Cefuroxime:750 mg three or four times a day (increased to 1.5 g three or four times a day if severe infection)

Metronidazole: 500 mg three times a day

Amoxicillin with gentamicin and metronidazole:

Amoxicillin: 500 mg three times a day (increased to 1 g four times a day if severe infection)

Gentamicin: Initially 5 to 7 mg/kg once a day, subsequent doses adjusted according to serum gentamicin concentration.Therapeutic drug monitoring and assessment of renal function is required (see the BNF information on gentamicin)

Metronidazole: 500 mg three times a day

Ciprofloxacin (only in people with allergy to penicillins and cephalosporins) with metronidazole:

Ciprofloxacin: 400 mg twice or three times a day

Metronidazole: 500 mg three times a day

See the MHRA January 2024 advice for restrictions and precautions on using fluoroquinolone antibiotics because of the risk of disabling and potentially long-lasting or irreversible side effects. Fluoroquinolones must now only be prescribed when other commonly recommended antibiotics are inappropriate
Alternative intravenous antibiotics

Consult local microbiologist

See BNF for appropriate use and dosing in specific populations, for example, hepatic impairment, renal impairment, pregnancy and breastfeeding, and administering intravenous (or, where appropriate, intramuscular) antibiotics.

Longer courses may be needed based on clinical assessment. Continue antibiotics for up to 14 days in people with CT-confirmed diverticular abscess.

Review intravenous antibiotics within 48 hours or after scanning if sooner and consider stepping down to oral antibiotics where possible.

Emergency management of complicated acute diverticulitis

For a short explanation of why the committee made these recommendations and how they might affect practice, see the rationale and impact section on the non-surgical management of acute diverticulitis.

Full details of the evidence and the committee's discussion are in evidence review H: non-surgical management of acute diverticulitis.

Management of abscesses
1.3.16

Offer intravenous antibiotics to people with acute diverticulitis and suspected diverticular abscess.

1.3.17

When prescribing an antibiotic for diverticular abscess, follow the advice in table 2.

1.3.18

Offer a contrast CT scan to people with acute diverticulitis and suspected diverticular abscess. If contrast CT is contraindicated, perform one of the following:

  • a non-contrast CT or

  • an MRI or

  • an ultrasound scan, depending on local expertise.

1.3.19

Review intravenous antibiotics within 48 hours or after scanning if sooner and consider stepping down to oral antibiotics where possible.

1.3.20

Use the scan results to guide treatment based on the size and location of the abscess.

1.3.21

If a person does not have confirmed diverticular abscess, review their need for antibiotics.

1.3.22

Consider either percutaneous drainage (if anatomically feasible) or surgery (see recommendation 1.3.27) for abscesses greater than 3 cm.

1.3.23

Send samples of pus from the abscess (if it has been drained) to the microbiology laboratory to enable antibiotic treatment to be tailored to sensitivities.

1.3.24

For abscesses less than 3 cm switch to oral antibiotics where possible.

1.3.25

In people with a CT-confirmed diverticular abscess, if the condition does not improve clinically or there is deterioration, consider re-imaging to inform the management strategy.

For a short explanation of why the committee made these recommendations and how they might affect practice, see the rationale and impact section on the management of abscesses in complicated acute diverticulitis.

Full details of the evidence and the committee's discussion are in evidence review N: percutaneous drainage versus resectional surgery for the management of abscesses.

Management of bowel perforations
1.3.26

Offer either laparoscopic lavage or resectional surgery (see recommendation 1.3.27) to people with diverticular perforation with generalised peritonitis after discussing the risks and benefits of the 2 options with them (see table 3). If faecal peritonitis is identified intraoperatively, proceed to resectional surgery.

Table 3 Factors to take into account when deciding whether to have lavage or resection for diverticular perforation with generalised peritonitis
Factor Laparoscopic lavage Resectional surgery

What the procedure involves

In diverticulitis this involves washing the abdominal cavity and colon using keyhole surgery

The surgical removal of the diseased colon followed by either reattaching the remaining segments of the colon or forming an end stoma

Effect on quality of life

There was no significant difference in quality of life scores reported for lavage and surgery

There was no significant difference in quality of life scores reported for lavage and surgery

Mortality

Although there was some benefit seen in mortality for lavage, this evidence was very uncertain

Although there was some benefit seen in mortality for lavage, this evidence was very uncertain

Needing a stoma (where the bowel is connected surgically to an opening in the abdomen and stools are collected in a bag or pouch)

A stoma is not needed

A stoma may be needed

Pain

Less likely to relieve pain than resectional surgery

More likely to relieve pain than lavage because the damaged bowel has been removed

Recurrent diverticulitis

Fewer people had recurrent diverticulitis after surgery than after lavage because the diseased bowel is removed. However, the evidence was very uncertain

Fewer people had recurrent diverticulitis after surgery than after lavage because the diseased bowel is removed. However, the evidence was very uncertain

Needing more operations

Evidence comparing unplanned surgery with lavage showed that fewer people needed reoperations after surgery than after lavage

Evidence that included unplanned surgery and planned surgery (scheduled stoma reversal after resectional surgery) showed that fewer people needed reoperations after lavage

However, in both cases the evidence was very uncertain

Evidence comparing unplanned surgery with lavage showed that fewer people needed reoperations after surgery than after lavage

Evidence that included unplanned surgery and planned surgery (scheduled stoma reversal after resectional surgery) showed that fewer people needed reoperations after lavage

However, in both cases the evidence was very uncertain

Postoperative complications

There was no meaningful difference in the number of infections or in the need for further intervention between lavage and surgery. People who had surgery had a greater reduction in post-surgical abscesses than those who had lavage, but this evidence was of low quality

There was no meaningful difference in the number of infections or in the need for further intervention between lavage and surgery. People who had surgery had a greater reduction in post-surgical abscesses than those who had lavage, but this evidence was of low quality

For a short explanation of why the committee made these recommendations and how they might affect practice, see the rationale and impact section on the management of bowel perforations in complicated acute diverticulitis.

Full details of the evidence and the committee's discussion are in evidence review O: laparoscopic lavage for the management of bowel perforations.

Anastomosis and bowel resection for people with complicated acute diverticulitis (elective and emergency surgery)

1.3.27

Offer people with complicated acute diverticulitis who are having surgery (either elective or emergency):

  • primary anastomosis (join in the bowel) with or without diverting stoma or

  • Hartmann's procedure (resection of the bowel with an end stoma).

    Take into account the person's age, any other conditions they have and how well they can carry out everyday activities (WHO performance status).

For a short explanation of why the committee made these recommendations and how they might affect practice, see the rationale and impact section on anastomosis for people with complicated acute diverticulitis.

Full details of the evidence and the committee's discussion are in evidence review M: primary versus secondary anastomosis (timing of anastomosis) in complicated acute diverticulitis.

1.3.28

In people undergoing bowel resection, consider resecting back to the compliant bowel (that is, bowel that is soft, unthickened and unaffected by inflammation).

For a short explanation of why the committee made these recommendations and how they might affect practice, see the rationale and impact section on bowel resection for people with complicated acute diverticulitis.

Full details of the evidence and the committee's discussion are in evidence review L: management of complicated acute diverticulitis – extent of colectomy.

Elective surgical management after resolution of complicated acute diverticulitis

1.3.29

Consider open or laparoscopic resection for elective surgery for people who have recovered from complicated acute diverticulitis but have continuing symptoms, for example in people with stricture or fistula.

For a short explanation of why the committee made these recommendations and how they might affect practice, see the rationale and impact section on elective surgical management after resolution of complicated acute diverticulitis.

Full details of the evidence and the committee's discussion are in evidence review K: laparoscopic versus open sigmoid resection for acute diverticulitis.

Timing of surgery for complicated acute diverticulitis

The committee were unable to make recommendations for practice in this area. They made a recommendation for research on timing of surgery for complicated acute diverticulosis.

For a short explanation of why the committee made these recommendations and how they might affect practice, see the rationale and impact section on timing of surgery for complicated acute diverticulitis.

Full details of the evidence and the committee's discussion are in evidence review J: timing of surgery for complicated acute diverticulitis.

Management of recurrent acute diverticulitis

For a short explanation of why the committee made these recommendations and how they might affect practice, see the rationale and impact section on the management of recurrent acute diverticultitis.

Full details of the evidence and the committee's discussion are in evidence review P: management of recurrent acute diverticulitis.

1.4 Information

Diverticulosis

1.4.1

Give people with diverticulosis, and their families and carers where appropriate, verbal and written information on:

  • diet and lifestyle

  • the course of diverticulosis and the likelihood of progression

  • symptoms that indicate complications or progression to diverticular disease.

Diverticular disease

1.4.2

Give people with diverticular disease, and their families and carers where appropriate, verbal and written information on:

  • diet and lifestyle

  • the course of diverticular disease and the likelihood of progression

  • symptoms and symptom management

  • when to seek medical advice.

Acute diverticulitis

1.4.3

Give people with acute diverticulitis, and their families and carers where appropriate, verbal and written information on:

  • diet and lifestyle

  • the course of acute diverticulitis and likelihood of complicated disease or recurrent episodes

  • symptoms

  • when and how to seek further medical advice

  • possible investigations and treatments

  • risks of interventions and treatments, including antibiotic resistance, and how invasive these are

  • role of surgery and outcomes (postoperative bowel function and symptoms).

For a short explanation of why the committee made these recommendations and how they might affect practice, see the rationale and impact section on information for people with diverticulosis, diverticular disease and acute diverticulitis.

Full details of the evidence and the committee's discussion are in evidence review Q: information and support.

Terms used in this guideline

Acute diverticulitis

Sudden inflammation or infection associated with diverticula. Symptoms include constant abdominal pain, usually severe and localising in the left lower quadrant. Other features, including fever, may also be present.

Colitis

Inflammation of the bowel related to Crohn's disease, ulcerative colitis, ischaemia or microscopic colitis. Symptoms may include abdominal pain and change in bowel habits with passage of blood.

Complicated acute diverticulitis

The presence of complications associated with inflamed or infected diverticula. These complications may include abscess, fistula, stricture perforation and sepsis.

Diverticular disease

The presence of diverticula with mild abdominal pain or tenderness and no systemic symptoms.

Diverticulosis

The presence of diverticula without symptoms.