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VilleSallinen

Diverticulitis and Diverticulosis

Essentials

  • Diverticulosis describes the presence of pouches (diverticula) in the intestine. These are quite common and become significantly more so with age.
  • Most diverticula occur in the large intestine, particularly in the sigmoid colon, on which this article concentrates.
  • The most common complication of diverticulosis is diverticulitis, where a diverticulum becomes inflamed and may burst.
  • Diverticulitis is divided into uncomplicated and complicated types.
    • Uncomplicated diverticulitis is inflammation in an area of the intestine with diverticula, where the intestinal wall is intact and there are no signs of complications (such as an abscess or air outside the intestine).
    • In complicated diverticulitis, the intestinal wall is perforated. If the resulting faecal contamination is localized, an abscess forms. If faecal contamination spreads more widely, peritonitis develops.
  • Diverticulitis varies in severity from uncomplicated disease healing spontaneously (> 90%) to life-threatening peritonitis.
  • Computerized tomography (CT) is recommended to diagnose the first episode of diverticulitis. Subsequently recurring mild disease with typical symptoms can be treated in primary health care based on the clinical picture.
  • See also Acute Abdomen in the Adult.

Symptoms and findings

Diverticulosis

  • Diverticulosis is usually asymptomatic, with no findings other than diverticula; this type of condition is called uncomplicated.
  • Symptomatic uncomplicated diverticular disease (SUDD) is diverticula with abdominal symptoms but without macroscopic changes visible on colonoscopy.
    • The diagnosis requires excluding other causes of abdominal symptoms by appropriate investigations.
    • The symptoms resemble those of irritable bowel syndrome, and the two diseases probably overlap.
  • Complications of diverticulosis include diverticulitis, strictures, haemorrhages and fistulas.
    • Diverticulitis itself may be uncomplicated or complicated.
    • A stricture will cause the clinical picture of intestinal obstruction, which may develop gradually.
    • Bleeding from a diverticulum usually causes bright red rectal bleeding (haematochezia).
    • A fistula is a tunnel developing from the intestine to an adjacent organ, such as the bladder or the vagina. Its symptoms may include passage of air in urine (pneumaturia) or the occurrence of faeces in the vagina.

Diverticulitis

  • The clinical picture of acute diverticulitis includes pain in the left lower quadrant of the abdomen (sigmoid diverticulitis) and fever.
  • Even in uncomplicated diverticulitis, CRP may be significantly elevated (as high as > 100).
  • In uncomplicated diverticulitis, abdominal tenderness and any guarding are local (in the left lower quadrant) but more extensive peritoneal irritation or peritonism suggests a more severe form of disease.
  • The severity of the disease can be assessed based on the staging presented in table T1.

Staging of diverticulitis based on clinical findings and imaging according to Sallinen et al., 2015 7. Uncomplicated diverticulitis diagnosed by clinical examination alone belongs to stage 1.

StageComplicated (abscess, extraluminal gas)Abscess > 6 cm or gas in the abdominal cavity*Clinical peritonitisOrgan dysfunction
* CT showing more extensive gas in the abdominal cavity
1NoNoNoNo
2YesNoNoNo
3YesYesNoNo
4YesYesYesNo
5YesYesYesYes

Diagnosis

Diverticulosis

  • Diverticulosis is usually detected incidentally during colonoscopy done as screening or due to abdominal symptoms.
  • Diverticulosis may also be an incidental imaging finding.

Diverticulitis

  • The first episode of acute diverticulitis should be diagnosed by CT because the clinical picture is not sufficiently specific for making a diagnosis.
  • If acute diverticulitis has previously been diagnosed by CT, diverticulitis with mild symptoms recurring with a typical clinical picture can be diagnosed and treated based on the clinical picture alone.
  • A typical clinical picture with mild symptoms consists of pain in the left lower quadrant of the abdomen, possibly local tenderness on palpation, fever and increased inflammatory markers (CRP elevated, even to levels > 100). If there is more extensive peritoneal irritation or impaired general condition the disease can no longer be called mild.
  • If there is a suspicion of a condition other than uncomplicated diverticulitis with mild symptoms, the diagnosis should be further confirmed by CT.

Treatment

Diverticulosis

  • There is no specific treatment available for diverticulosis.
  • Uncomplicated diverticulosis (with or without symptoms) can be treated and complications prevented by following healthy habits.
    • Sufficient dietary fibre: whole-grain products, fruit, vegetables
    • Aiming at normal weight
    • Exercise
    • Avoidance of smoking
    • Use of bulk laxatives, as necessary if there is constipation
  • Complicated diverticulosis with intestinal stenosis (stricture) or a passageway to outside the intestine (fistula) requires surgical treatment.
    • Intestinal obstruction should be treated by emergency surgery because it involves a risk of perforation of the caecum.
  • Bleeding from a diverticulum is usually self-restricted but normally requires follow-up and emergency investigation in specialized care. Bleeding can be stopped either endovascularly, by an endoscopic procedure or by surgery, as necessary.
  • For diverticulosis with severe symptoms, particularly pain that has become chronic following diverticulitis (> 3 months), treatment by sigmoid resection can be considered.

Diverticulitis

  • Stage 1 diverticulitis can be treated in primary health care, but other stages require assessment in specialized care.
  • The first episode of diverticulitis should be confirmed by a CT scan.
  • Uncomplicated diverticulitis with mild symptoms in a patient with diverticulosis can be treated symptomatically with analgesic and antipyretic medication.
  • Fasting or other dietary restrictions are not necessary.
  • Antimicrobial medication is indicated in immunosuppressed patients (such as those with poorly controlled diabetes, liver cirrhosis, immunosuppressive medication, pregnancy, cytostatic chemotherapy). Depending on the patient's general condition, medication can be given orally to begin with (cephalexin 500 mg 3 times daily and metronidazole 400 mg 3 times daily) or started intravenously. Treatment for a total of 7 days is usually sufficient.
  • If the symptoms do not subside within a few days or if the patient's condition gets otherwise worse, the diagnosis should be further clarified by CT.
  • Complicated disease (abscess, gas in the abdominal cavity, peritonitis) requires antimicrobial treatment in a hospital.
    • A combination of intravenous cefuroxime and metronidazole is used in most cases.
    • Any abscess should be treated in specialized care, by antimicrobial treatment alone, by drainage or by surgery, depending on its location and size.
    • Peritonitis represents an emergency requiring immediate surgical treatment.

Follow-up management

  • Typical uncomplicated diverticulitis confirmed by CT (or subsequent clinically mild diverticulitis) does not need to be followed up by colonoscopy.
    • Keep in mind other indications for colonoscopy, such as faecal blood, any screening programme, persistent symptoms.
    • Colonoscopy should also be performed if diverticulitis has never been diagnosed by CT.
  • If complicated diverticulitis has been treated conservatively (without surgery), the diagnosis should always be confirmed by colonoscopy e.g. about one month after the acute inflammation (to exclude intestinal cancer).
  • In frequently recurring episodes of diverticulitis (> 3 within 2 years), or if severe symptoms persist for more than 3 months after diverticulitis, elective sigmoid resection can be considered. To assess this, the patient should be referred to specialized care.

    References

    • Santos A, Mentula P, Pinta T, et al. Quality-of-Life and Recurrence Outcomes Following Laparoscopic Elective Sigmoid Resection vs Conservative Treatment Following Diverticulitis: Prespecified 2-Year Analysis of the LASER Randomized Clinical Trial. JAMA Surg 2023;158(6):593-601. [PubMed]
    • Hall J, Hardiman K, Lee S, et al. The American Society of Colon and Rectal Surgeons Clinical Practice Guidelines for the Treatment of Left-Sided Colonic Diverticulitis. Dis Colon Rectum 2020;63(6):728-747. [PubMed]
    • van Dijk ST, Chabok A, Dijkgraaf MG, et al. Observational versus antibiotic treatment for uncomplicated diverticulitis: an individual-patient data meta-analysis. Br J Surg 2020;107(8):1062-1069. [PubMed]
    • Sartelli M, Weber DG, Kluger Y, et al. 2020 update of the WSES guidelines for the management of acute colonic diverticulitis in the emergency setting. World J Emerg Surg 2020;15(1):32. [PubMed]
    • NICE. Diverticular disease: diagnosis and management. NICE Guideline 2019. www.nice.org.uk/guidance/ng147
    • Rottier SJ, van Dijk ST, van Geloven AAW, et al. Meta-analysis of the role of colonoscopy after an episode of left-sided acute diverticulitis. Br J Surg 2019;106(8):988-997. [PubMed]
    • Sallinen VJ, Leppäniemi AK, Mentula PJ. Staging of acute diverticulitis based on clinical, radiologic, and physiologic parameters. J Trauma Acute Care Surg 2015;78(3):543-51. [PubMed]