Diverticulitis and Diverticular Disease " Part One"
A diverticulum (called diverticula if there are more than one of them) is a protrusion of the inner lining of the intestine through the outer muscular coat to form a small pouch with a narrow neck. The commonest site for diverticula to develop is the lower left part of the colon. The presence of diverticula is often referred to as diverticulosis.
What is the cause of diverticula?
Some people are born with a diverticulum, most often from the small intestine. Most diverticula develop during later life and are more common with increasing age. In Britain over half the well population aged more than 70 years have diverticula of the large intestine. In some rural areas of the world, particularly in Africa, diverticula are rarely seen. The difference from western countries is not fully understood but is thought to be due to diet. The colon exists to process otherwise indigestible plant foods known as dietary fibre.
In the west we eat less fibre than in other, primarily vegetarian, regions of the world. If the colon has plenty of fibre to deal with, the bulky soft contents keep the walls of the bowel apart. If little fibre is present, the stools tend to be smaller and harder, and they do not keep the walls of the tube-like colon apart when the muscles in the wall of the colon contract. These contractions form a ring-like narrowing to mix and push the contents along. Closed segments occur within which pressure is high and it is thought that this pressure pushes out the pouches.
Are diverticula risky or harmful?
We do not generally worry about our appendix which is a type of diverticulum. Diverticula are a common feature of many people's colons, projecting from the colon walls but not becoming troublesome. As with appendicitis where the appendix becomes inflamed or infected, diverticula can be subject to infection also and this can present as pain in the affected region, a feeling of illness and the danger of the diverticulum perforating or bleeding. If the diverticula become inflamed then the resulting condition is known as diverticulitis.
A description of diverticular disease
There is normal thickness and appearance of the intestinal musculature in most people who have diverticula, but some can have thicker and microscopically abnormal structure in this muscle. Muscle thickening makes the colon narrower and makes its outline more irregular. The changes in the muscle which occur do not have a clear cause but infection may not be the cause and diet may well be irrelevant. Even if very few or no diverticula are present in the colon this abnormality of the muscle can occur. Diverticular disease is the name given to the combination of diverticula and abnormal muscle. The word disease is used because the works diverticula and diverticular sound very similar.
What are the symptoms of diverticular disease?
The muscle abnormality is the reason for the symptoms of pain in the lower and left side of the abdomen, bloating, irregular timing of the bowel opening with stools like pellets and also bowel actions containing small amounts of blood. Irritable bowel syndrome has similar symptoms as both of these conditions are partly related in that there is abnormal function of muscle.
The necessity of investigation
Diverticula are not generally discovered on their own but secondarily when investigation for other conditions is occurring, such as x-ray or endoscopy for abdominal pain or rectal bleeding. As healthy older people very commonly have diverticula the doctor has to be certain they are the cause of symptoms and not just incidental. If there is blood test evidence of inflammation somewhere in the body and the area of the diverticula is tender then a diagnosis of diverticulitis is possible. If the lower left sigmoid colon has increased folding of its lining this is the muscular abnormality of diverticular disease.
Reassurance that a more serious disorder is not present helps people not to worry about the symptoms. An explanation of the difference between symptoms due to infection and those due to abnormal contraction of the muscle, without inflammation, helps people understand why one treatment may be advised and not another.