GP specialist in gastroenterology Dr Kevin Barrett answers questions on the aetiology of diverticular disease and how it should be diagnosed and managed in primary care
Learning objectives
This module will enhance your understanding of:
- The prevalence and underlying pathology of diverticular disease and how it may present
- Key risks factors for diverticular disease including genetic contributors
- How to advise on the key dietary recommendations
- Best evidence-based approaches to managing mild flares, including appropriate antibiotic management
- Management options for ongoing symptoms including IBS-like symptoms, and when reinvestigation is appropriate
- When and what type of surgical interventions are indicated
Q1. How common is diverticular disease?
A. Diverticula are pouch-like protrusions of the mucosal wall of the gastrointestinal tract in weaker areas where the vasa recta infiltrate the circular muscular wall. Most are ‘false’ diverticula, being hernias through the muscular wall, whereas ‘true’ diverticula (for example Meckel’s diverticulum) involve all the layers of the intestinal wall and are much less common. They can occur in the large or small intestine but are usually found in the sigmoid colon: 95% of patients have diverticular disease in the sigmoid colon but only 7% have pan-colonic disease.1 Around 80-85% of patients are asymptomatic and diverticula in this situation are not considered pathological.2 Diverticula become more prevalent with age; only 20% of individuals aged under 40 have diverticula and this increases to 80% of those aged over 85. 1,2
Diverticulosis describes the presence of asymptomatic diverticula. The prevalence is increasing year-on-year;2 this is potentially due to increasing numbers of abdominal CT and MRI scans being performed although a change in diet may also be to blame. Many patients are concerned by an incidental finding of diverticula, but they can be reassured that asymptomatic disease is not dangerous. This can be used as an opportunity to discuss diet and lifestyle changes to reduce the likelihood of progression to diverticular disease. A small number of patients progress from diverticulosis to diverticular disease and then on to diverticulitis each year.3
Infected or inflamed diverticular disease is known as diverticulitis and is a common reason for consultations and antibiotic prescribing in primary care.4 The lifetime risk of diverticulitis is around 4%.2 Diverticulitis may occur because a faecalith obstructs the diverticula leading to micro- or macroscopic perforation.
Box 1 below outlines the definitions for diverticulosis, diverticular disease and diverticulitis.
Q2. How does it usually present and what, and how common, are the complications?
A. Although most patients are asymptomatic, diverticular disease describes symptoms associated with diverticula and occurs in 10-25% of patients.1,2 This can cause bleeding or inflammation (acute or chronic) which can be complicated by bowel perforation, obstruction, or the formation of an abscess or fistula. Pain, commonly in the left lower quadrant, is the most common symptom, although a rectal bleed can be the first presentation in 5-15% of patients.1 Bleeding occurs because of the proximity of the vasa recta to the intestinal lumen and this layer is exposed to more trauma by the herniation within the diverticula.
There is an overlap with the symptoms of colorectal cancer, inflammatory bowel disease (IBD), irritable bowel syndrome (IBS), endometriosis and ovarian cancer, so it is important to exclude these conditions in high-risk populations where the history or other symptoms indicate that these may be present.
Box 1. Definitions of diverticula conditions
Diverticulosis
- The presence of asymptomatic diverticula
Diverticular disease
- When diverticulosis becomes symptomatic
Diverticulitis
- When diverticula become inflamed or infected
Symptoms of diverticular disease may include diarrhoea, bloating and dysuria. A fever usually occurs if inflammation is present. Uncomplicated diverticulitis may cause pain, fatigue and rectal bleeding, but complicated diverticulitis which occurs in around 12% of cases can lead to an acute abdomen or sepsis if an abscess or perforation occurs;2 therefore a face-to-face assessment of a patient suspected of diverticulitis is important – measurement of blood pressure, temperature, pulse rate, and an abdominal examination are key. Occasionally a rectal examination will be useful as this may reveal pain or a mass associated with an abscess, or confirm the presence of blood in the rectum. Left-sided colonic diverticulitis occurs in 209 out of 100,000 people years based upon a Western population, and a perforation occurs in just under 10% of those cases. The death rate is low but still 0.9 per 100,000 adults.3
The Hinchey classification is sometimes used for staging of diverticulitis and uses Stages I through to IV. This has evolved with the addition of imaging,5 but is not often used outside of a secondary care or research settings.
Abdominal tenderness is almost always in the left lower quadrant although this may be located in other areas of the abdomen in patients with colonic diverticulosis or those of Asian origin.
Intestinal obstruction is uncommon (2.1%);3 patients may present with constipation, colicky abdominal pain and/or a distended abdomen.
Fistulae are about as common as abscesses (0.7-0.8%)3 but the presence of faecaluria (faeces in the urine), pneumaturia (air or bubbles in the urine), or the passage of faeces through the vagina would lead to this being suspected.
Click here to read and complete the full CPD module and download your certificate logging 2 CPD hours towards revalidation
Dr Kevin Barrett is a GPSI in gastroenterology in Hertfordshire and committee member of the Primary Care Society for Gastroenterology
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