Diverticulosis is a condition in which small sacs (diverticula) form on the wall of the colon. The condition is generally symptom-free. Diverticulitis is a complication of diverticulosis in which the small sacs become infected. This then causes pain, changed bowel habit and often a feeling of being ill.
The colon (large intestine) is a long, tube-like structure that stores and then eliminates waste material. As a person ages and suffers with constipation and stress, pressure within the colon pushes bulging pockets or sacs (diverticula) outward from the colon walls. Diverticula can occur throughout the colon, but they are most common near the end of the colon, namely the sigmoid colon. If you have this condition (diverticulosis), you may have few or no symptoms.
Diverticulitis occurs if a diverticulum becomes infected. If you suffer from diverticulitis, you will have abdominal pain and tenderness, and fever. Sometimes the infection can cause an abscess which can bleed or rupture. This can be a serious complication requiring surgery.
When someone suffers symptoms associated with diverticulosis, it is referred to as diverticular disease.
Diverticular disease is common in the Western world, but rare in Asia and Africa. The incidence of diverticular disease increases with age. It rarely occurs before the age of 30, but occurs in about 50% of people by the age of 70.
Diverticula occur because of weaknesses in the bowel wall and increased pressure inside the bowel.
Connective tissue becomes weaker as a result of ageing, while the muscular wall of the colon grows thicker. This thickening may be a result of the increasing pressure required by the colon to eliminate faeces.
A diet low in fibre can lead to small, hard stools that are difficult to pass. Over time, vigorous contractions in the colon push the inner intestinal lining outwards through cracks in the muscle walls (herniation).
Uncomplicated diverticulosis is symptom free, and the condition may be found incidentally during tests for other intestinal problems.
The most common symptoms are related to the underlying cause of diverticulae which is constipation and the irritable bowel. They include:
- abdominal cramps
- mucous on the stool.
Symptoms usually occur due to a complication – most importantly, diverticulitis. About 20% of people with diverticulosis develop symptoms related to diverticulosis. This will cause continuous or cramping abdominal pain, usually in the lower left abdomen. Constipation and fever are common symptoms.
Pus may collect around the inflamed diverticulum, leading to the formation of an abscess, usually in the pelvis. On rare occasions, the inflamed diverticula can erode into the urinary bladder, causing bladder infection and passing of gas during urination. Inflammation in the colon may lead to bowel obstruction. Infrequently, a diverticulum ruptures into the abdominal cavity, causing a life-threatening infection (peritonitis).
Diverticular bleeding occurs when stool erodes into a blood vessel at the base of a diverticulum. Red, dark or maroon blood and clots are passed without any associated abdominal pain. Rarely, blood may be black in those bleeding from a diverticulum of the right-sided colon. Bleeding may be continuous or intermittent, lasting several days. In rare cases of brisk and severe bleeding, a drop in blood pressure may cause dizziness, shock and loss of consciousness.
How the condition develops
If diverticulitis is not treated, it may result in the formation of an abscess, which could lead to septic shock. A hole may develop in the wall of the bowel, leading to leakage of faeces into the abdomen and further infection. Small arteries may start to bleed (indicated by a change in stool colour), leading to iron-deficiency anaemia.
If there are no complications, keep in mind that there is nothing seriously wrong and that it is unlikely that complications will develop.
Your doctor may perform the following investigations if he or she suspects that you may have diverticulosis:
- Total blood count – to see if red blood cells have been lost and white blood cell count has increased
- Abdominal and chest X-rays – to look for gas under the diaphragm, which indicates leakage of colon contents into the abdomen
- Ultrasound examination – to detect an abscess
- Barium enema – introduction into the colon of a fluid that can be detected by X-ray. Diverticula are seen as barium-filled pouches protruding from the colon wall.
- Visual examination – a small tube is inserted through the rectum into the bowel. Short tubes (sigmoidoscopes) or longer ones (colonoscopes) may be used.
- Ultrasound and computerised axial tomography (CAT) scans – if persistent pain and fever indicate a possible diverticular abscess, these examinations may be performed on the abdomen and pelvis to detect collections of pus.
Many patients with diverticulosis have minimal or no symptoms, and do not require any specific treatment.
A high-fibre diet and fibre supplements are advisable to prevent constipation and the formation of more diverticula. Keep your colon healthy:
- Avoid dehydration
- Eat plenty of fruits, vegetables and whole-grain breads and cereals.
- Add three to four tablespoons (45 to 60 g) of wheat bran to your daily diet.
- Don’t strain during bowel movements.
- Avoid laxatives, including fruits that make the bowels work, such as prunes.
- Avoid drugs that slow down bowel action, such as painkillers containing codeine.
Some doctors have in the past recommended avoidance of nuts, corn and seeds to prevent complications of diverticulosis. It’s uncertain whether these diet restrictions are beneficial.
Patients with mild symptoms of bloating or abdominal pain may benefit from anti-spasmodic drugs such as mebeverne and hyoscyamine.
Antibiotics are usually needed in the presence of diverticulitis. Commonly prescribed antibiotics include ciprofloxacin, metronidazole, cephalexin and doxycycline. People with severe diverticulitis accompanied by high fever and pain are hospitalised and given a combination of drugs.
People with active bleeding are usually hospitalised for monitoring. Fluids are administered intravenously to maintain blood pressure. Blood transfusions are necessary for those with moderate to severe blood loss. Usually bleeding stops spontaneously and patients are sent home after several days in hospital.
Surgery is needed for people with persistent bowel obstruction or an abscess that does not respond to antibiotics. Most patients however, respond to a prolonged course of antibiotics.
Surgery is also indicated for severe bleeding, abscess drainage or when a hole has formed and colon contents are leaking into the rest of the abdomen. This often means that a part of the bowel has to be removed, but once healed; it normally does not cause additional problems, provided that the correct diet is followed.
Sometimes surgery may be suggested for people with frequent attacks of diverticulitis leading to multiple courses of antibiotics, hospitalisations and loss of workdays.
Once formed, diverticula are permanent, and there is no treatment available to prevent complications. However, the diet advised for home treatment may help prevent further diverticular formation or worsening of the condition.
When to see a doctor
Call your doctor if you have:
- Severe abdominal pain
- Pain that is localised to one area of the abdomen and lasts longer than four hours
- Abdominal pain accompanied by a fever
- Stools that are dark red, black or tarry – this usually means there is blood in the stool, which needs to be evaluated.
Reviewed by Dr John P Wright MBChB, MRCP (UK), PhD. Gastroenterologist in private practice, Cape Town. February 2015
Previously reviewed by Prof Don du Toit (MBChB) (D.Phil) (PhD) (FCS) (FRCS)