Recommendations
Key Recommendations
Suspect complicated acute diverticulitis in patients with uncontrolled abdominal pain plus any of the following:[39]
Abdominal mass or perirectal fullness noted on examination, which may indicate an intra-abdominal abscess
Abdominal rigidity or guarding, which may indicate bowel perforation or peritonitis
Signs of sepsis
Think ‘Could this be sepsis?’ based on acute deterioration in a patient in whom there is clinical evidence or strong suspicion of infection.[45][46][47] See Sepsis in adults.
Signs of a fistula into the bladder or vagina, such as faecaluria, pneumaturia, pyuria, or the passage of faeces through the vagina
Colicky abdominal pain, constipation, vomiting, or abdominal distention
These may be symptoms of large bowel obstruction. See Large bowel obstruction.
See Complications section and Assessment of acute abdomen for more information.
Suspect acute diverticulitis in patients with constant severe abdominal pain in the left lower quadrant plus any of the following:[39]
Fever
Sudden change in bowel habit with significant rectal bleeding or passage of mucus from the rectum
Tenderness in the left lower quadrant
Palpable abdominal mass or distension on examination with a history of diverticular disease.
Consider diverticular disease in patients presenting with intermittent abdominal pain with constipation, diarrhoea, or rectal bleeding, and/or tenderness in the left lower quadrant.[39]
Request a contrast computed tomography scan in a patient with suspected acute diverticulitis and raised inflammatory markers.[39][48]
In primary care, refer a patient with suspected complicated acute diverticulitis for same-day hospital assessment.[39]
Consider diverticular disease in patients with one or both of the following, in the left lower quadrant:[6][39]
Intermittent abdominal pain presenting with constipation, diarrhoea, or rectal bleeding
Tenderness.
In uncomplicated diverticular disease blood tests are usually normal. Symptoms may overlap with those of irritable bowel syndrome, colitis, and malignancy. See Differentials.
Suspect acute diverticulitis in patients with constant severe abdominal pain in the left lower quadrant plus any of the following:[39]
Fever
Sudden change in bowel habit with significant rectal bleeding or passage of mucus from the rectum
Tenderness in the left lower quadrant
Palpable abdominal mass or distension on examination with a history of diverticular disease.
Suspect complicated acute diverticulitis in patients with uncontrolled abdominal pain plus any of the following:[39]
Abdominal mass or perirectal fullness noted on examination, which may indicate an intra-abdominal abscess
Abdominal rigidity or guarding, which may indicate bowel perforation or peritonitis
Signs of sepsis
Signs of a fistula into the bladder or vagina, such as faecaluria, pneumaturia, pyuria, or the passage of faeces through the vagina
Colicky abdominal pain, constipation, vomiting, or abdominal distention
These may be symptoms of large bowel obstruction. See Large bowel obstruction.
See Complications section and Assessment of acute abdomen for more information.
Practical tip
Sepsis
Think ‘Could this be sepsis?’ based on acute deterioration in a patient in whom there is clinical evidence or strong suspicion of infection.[45][46][47] See Sepsis in adults.
Use a systematic approach (e.g., National Early Warning Score 2 [NEWS2]), alongside your clinical judgement, to assess the risk of deterioration due to sepsis.[46][47][49][50] Consult local guidelines for the recommended approach at your institution.
Arrange urgent review by a senior clinical decision-maker (e.g., ST3 level doctor in the UK) if you suspect sepsis:[45][51]
Within 30 minutes for a patient who is critically ill (e.g., NEWS2 score of 7 or more, evidence of septic shock, or other significant clinical concerns)
A patient is also at high risk of severe illness or death from sepsis if they have a NEWS2 score below 7 and a single parameter contributes 3 points to their NEWS2 score and a medical review has confirmed that they are at high risk.
Within 1 hour for a patient who is severely ill (e.g., NEWS2 score of 5 or 6) or within 1 hour of any intervention for suspected sepsis (antibiotics/fluid resuscitation/oxygen) if there is no improvement in the patient’s condition.
Follow your local protocol for investigation and treatment of all patients with suspected sepsis, or those at risk. Start treatment promptly. Determine urgency of treatment according to likelihood of infection and severity of illness, or according to your local protocol.[50][51]
In the community and in custodial settings: refer for emergency medical care in hospital (usually by blue-light ambulance in the UK) any patient who is acutely ill with a suspected infection and is:[45]
Deemed to be at high risk of deterioration due to organ dysfunction (as measured by risk stratification)
At risk of neutropenic sepsis.
Asymptomatic patients
Asymptomatic diverticulosis is often diagnosed incidentally during screening colonoscopy or radiological investigation for other indications. Physical examination and blood tests are usually normal in asymptomatic patients.
A patient with uncontrolled abdominal pain and systemic symptoms may have complicated acute diverticulitis. See Complications.
In primary care, refer the patient with suspected complicated acute diverticulitis for same-day hospital assessment.[39]
Reassess the patient with uncomplicated acute diverticulitis if symptoms worsen and refer to secondary care for further assessment.[39]
Refer patients with suspected diverticular disease to secondary care if:[39]
Routine endoscopic and/or radiological investigations cannot be organised from primary care
Colitis is suspected
The patient meets the criteria for a suspected cancer pathway.[52]
Acute diverticulitis
In patients with acute diverticulitis, tenderness, rebound, and guarding may be present in the left lower quadrant of the abdomen. Patients with free perforation and generalised peritonitis may have diffuse abdominal tenderness. A mass may be palpable in patients with abscess formation. Pelvic tenderness on digital rectal examination is also a helpful sign.
Right-sided diverticulitis may mimic acute appendicitis, but patients are unlikely to describe prodromal symptoms typical of appendicitis.[53]
Request a full blood count (FBC), looking for neutrophilia or anaemia, urea and electrolytes, and C-reactive protein.[39] Non-specific inflammatory markers are often elevated; an initial C-reactive protein concentration above 170 mg/L (17 mg/dL) can predict complicated diverticulitis, although a low C-reactive protein does not rule out complicated diverticulitis.[6][54] Assessing kidney function helps to determine whether a contrast computed tomography scan can be performed.[39]
Consider alternative diagnoses if inflammatory markers are not raised.[39]
In acute diverticulitis, an FBC with differential usually reveals polymorphonuclear leukocytosis.[55]
Practical tip
Abdominal pain and leukocytosis
Consider diverticulitis in older patients with abdominal pain and leukocytosis, because the presentation can be atypical in this group.
Request a blood culture and arterial blood gas with lactate in patients with signs or symptoms of systemic sepsis, those who are severely ill, or those who have complications (e.g., perforation, fistula, phlegmon).
Request a contrast computed tomography (CT) scan of the abdomen as the imaging modality of choice for a patient with suspected acute diverticulitis and raised inflammatory markers.[6][39][48]
Findings in patients with acute diverticulitis may show diverticulosis with associated colon wall thickening, fat stranding, phlegmon, extraluminal gas, abscess formation, or intra-abdominal free fluid.[6]
CT may also exclude other diagnoses, such as ovarian pathology or leaking aortic or iliac aneurysm.[6]
Consider non-contrast CT, magnetic resonance imaging, or an ultrasound scan if contrast CT is contraindicated.[39] Discuss with the radiology team.
Consider an early colonoscopy or flexible sigmoidoscopy in patients presenting with rectal bleeding (see below). A limited flexible sigmoidoscopy without air insufflation will help identify a locally perforated rectosigmoid carcinoma mimicking acute diverticulitis. Flexible sigmoidoscopy or colonoscopy can be considered when diagnosis of diverticular disease is unclear or when cancer or bowel ischaemia is suspected. Great care is necessary during these endoscopic procedures to avoid perforation. See Colorectal cancer and Ischaemic bowel disease.
Consider chest x-ray to assess for possible pneumoperitoneum in the patient with suspected perforation. Chest x-rays are useful to exclude other conditions mimicking an acute abdomen.
Acute bleeding
Diverticular bleeding is usually abrupt, painless, profuse arterial lower gastrointestinal (GI) bleeding.
The incidence of diverticular bleeding increases with age. The right colon is the source of diverticular bleeding in more than 50% of patients in Western countries. In Asian countries, age greater than 70 years and both-sided diverticulosis increase the bleeding risk.[8]
Consider using the ‘shock index’ (heart rate/systolic blood pressure) as a marker for active bleeding. For haemodynamically unstable patients or those with a shock index of >1 after initial resuscitation, use CT angiography (CTA) to locate the site of blood loss, prior to endoscopic or radiological therapy (see Management recommendations for more information on stratification of patients with acute bleeding).[56][57]
Colonoscopy or sigmoidoscopy can also be used for accurate diagnosis during acute bleeding.[58] However, the US guidelines suggest lower GI endoscopy on a non-urgent basis after 24 hours following presentation.[57]
Isotope-labelled red blood cell nuclear scan is another option; however, this is rarely used in this context as it has largely been superseded by CTA; this should be discussed with radiology.[56][57]
Typically diagnostic laparoscopy is not a recommended investigation to diagnose colonic diverticular disease. However, it has a role if the primary diagnosis remains unclear after investigations and imaging, and if other investigations, such as CT scan, show complications of diverticular disease (e.g., intra-abdominal collections, abscess, suspicious mass or fistulation). Laparoscopy may also provide therapeutic options.
Diverticular disease may also be detected incidentally at the time of laparoscopy performed for another indication.
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