What is diverticular disease?
It is an acquired condition, in which there are small out-pouchings of the mucosa of the large intestine, known as diverticulae.
Definitions:
Diverticulosis – the presence of diverticulae in the large intestine
Diverticular Disease – the presence of symptoms resulting from the existence of diverticulae in the large intestine
(Acute) diverticulitis – ongoing inflammation of one or more diverticulae
Epidemiology
- Primarily a disease of the elderly, very uncommon in those under 40
- 50% of the over 70’s have diverticulae
- Most commonly occurs in the sigmoid colon
- 75-90% of cases of diverticulosis are asymptomatic
- Diverticular disease is present in 10-25% of cases, and of these, about 20% will develop acute diverticulitis at some stage.
- Slightly more common in females
- Associated with a western lifestyle
Aetiology
- Lack of fibre in the diet (particularly in processed foods)
Pathology
It is thought that in the presence of a lack of fibre, the muscles of the colon must work harder to move faeces along. This causes very high pressures in the colon, and as a result, some parts of the mucosa will form out-pouchings.
- This can occur, because the muscle coverage along the outside of the colon (the taeniae coli) do not entirely encircle the whole of the intestine, but instead are present in bands. The herniation of the mucosa occurs inbetween these bands.
- There may also be muscle changes, whereby the taeniae coli become thickened and fibrosed, pre-disposing the formation of diverticulae
Clinical features
- Up to 95% symptomless
- Diverticular disease can cause erratic bowel habits (constipation or diarrhoea) and left iliac fossa pain, which may or may not be colicky
- Complications of diverticular disease:
o Acute diverticulitis
§ Left iliac fossa pain
§ Malaise / fever
§ Palpable mass
§ Abdominal distension
§ Tachycardia
§ These symptoms are similar to appendicitis, but usually occur on the left hand side.
§ This inflammation will often spontaneously resolve, but in some cases it can progress to:
· Fistulation
· Abscess
· Peritonitis
· Perforation
· Haemorrhage
· In some cases, acute diverticulitis can be life threatening (e.g. in cases of perforation)
o Perforation
o Large bowel obstruction
o Fistula (to bladder)
o Fistula to small intestine
o Lower GI bleed
Investigations
- Clinical Examination – the sigmoid colon may be palpable
- Barium Enema – the investigation of choice, but should not be used if there are active complications.
- Ultrasound – can asses bowel wall thickness, and rule out other differentials
- Sigmoidoscopy – if other investigations have been inconclusive
- Diverticular disease is notorious for concealing colon carcinoma
Investigations for Acute Diverticulitis
- CRP and ESR – usually raised
- Ultrasound / CT – can show wall thickening, diverticulae, and also abscess or perforation
Treatment for Acute Diverticulitis
- Antibiotics (usually metronidazole)
- Fluids
- Analgesia – but be careful! You don’t want to give a constipating analgesic (i.e. many opioids, particularly morphine as this also raises intra-luminal pressure)
Often patients can be managed at home, but in severe cases, hospitalisation may be required, in which case fluids may be given IV
Long term management of Diverticular Disease
- Asymptomatic disease – no direct treatment – recommend high fibre diet and high fluid intake
- Symptomatic disease –
o Analgesics – again, avoid opioids
o Laxatives, if necessary – but avoid stimulant laxatives
o Anticholinergics – may be useful in patients with over-active sigmoid colon
o Surgery – to resect the sigmoid colon – in severe cases
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