What Is It?
Diverticular disease is a condition where the large bowel wall develops small pouches. The bowel wall is like a muscular tube with a thin inside lining called the mucosa. The muscle in the wall contracts to squeeze and move the contents along. In diverticular disease, the muscle wall develops small holes, like weak spots. The inside lining or mucosa then bulges out. From the inside, this looks like the holes in Swiss cheese. Each one is a bit like a tiny cave or pocket. Sometimes there is just one diverticulum (singular) or there can be many diverticula (plural). It may affect only part of the large bowel or the entire large bowel (colon) could be affected.
In the West, the commonest site affected by diverticular disease is the sigmoid colon. However, in the East the right colon and caecum are more commonly affected.
What is the cause?
Diverticular disease is related to constipation. Hard stools make the job of the large bowel more difficult. The muscle has to work much harder to push the contents along. Pressure builds up and eventually the muscle develops areas of weakness that become diverticula.
What trouble can diverticular disease cause?
Many patients with diverticular disease have no trouble or symptoms whatsoever. Problems arise usually because faeces gets lodged inside the diverticulum, obstructing the opening. The diverticulum becomes inflamed, rather like appendicitis. This is called diverticulitis. This can affect a whole segment of large bowel leading to a big inflamed mass. The patient complains of pain and a tender lump. This mass can cause bowel obstruction and surgery becomes necessary.
The inflamed diverticulum can also perforate, leading to a collection of pus or abscess next to the bowel. The patient becomes ill with severe abdominal pain and fever. Sometimes it can perforate into a nearby organ like the urinary bladder or vagina. An abnormal passage called a fistula is created and this can lead to leakage of faeces into the urine or vagina.
Sometimes, the inflamed diverticulum causes bleeding instead of perforation. Diverticular disease is the commonest cause of massive rectal bleeding. Thankfully, most of these cases stop bleeding by itself but if it continues to bleed, surgery may be needed.
This 66 year old patient had severe bleeding from diverticular disease of the right colon. Note the puddle of dye (arrow) indicating the location of active bleeding.
This patient had to be rushed from the X-Ray department straight to the operating theatre as his blood pressure was low due to bleeding. His blood pressure recovered immediately the moment the vessel was ligated and the affected bowel removed, saving his life.
Can it cause cancer?
However, if the diverticular disease is extensive, it can make it harder for your doctor to diagnose a small cancer hiding amongst the diverticula. Moreover, a diverticular mass can cause symptoms very similar to cancer like obstruction, rectal bleeding and an abdominal mass.
I’ve just been told I have diverticular disease. What should I do?
Nothing, if it is not causing any trouble.
If your diverticular disease is uncomplicated, you do not need surgery.
Just make sure you don’t get constipation.
Traditional medical advice is to eat lots of dietary fibre – all the usual stuff: fruits, vegetables, brown bread cereal etc. However, the benefit of fibre has been questioned recently. Avoid stimulant laxatives that increase pressure in the colon.
If your diverticular disease has led to bleeding, obstruction, perforation or a mass you will need to be admitted.
Obstruction or perforation requires emergency surgery. You may need to have a temporary colostomy (wear a bag, see my article on Colostomy).
Bleeding often settles eventually but requires medication and maybe blood transfusion. It is important to be observed on the ward as diverticular bleed can occasionally be a really, really BIG bleed!
A diverticular mass or diverticulitis without perforation can be treated with iv antibiotic injections. As Malaysians commonly get diverticulitis in the right colon (near the appendix) this can cause symptoms virtually identical to appendicitis. Nowadays, a CT scan should be able to tell the difference, thereby avoiding an unnecessary operation to look at a normal appendix. If the diverticulitis fails to settle on antibiotics or if there is perforation, surgery will be necessary.
Can the bowel be repaired?
In general, no. If there is no bleeding, obstruction or perforation the diverticular disease can be left alone. If surgery is required, the affected part of the large bowel is resected and removed. The bowel is then either joined back up or brought out as a colostomy.
How do I find out if I have diverticular disease?
We would need to look at your bowel. This could be a colonoscopy, CT scan, gastrografin enema study or at operation.
If there are many large diverticula, colonoscopy becomes more difficult and there is a small risk of bowel perforation.
Most of the time, we discover diverticular disease during colonoscopy for patients with bleeding or other symptoms.