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Diverticular disease of the colon is a very common condition in western
societies, allegedly affecting more than one third of the population after the
age of 60. It is not however a disease that affects exclusively the elderly. Often
younger patients in their forties or even their thirties, present to the surgeon
with symptoms or complications of diverticular disease. It is believed that
younger male patients may be more at risk of suffering from complications of
diverticular disease.

A “diverticulum” is a small pouch which is created on the external side of the
colon wall. It consists only of “mucosa” which is the inner layer of the bowel.
The mucosa herniates through the two other more external layers and creates
a number of small pouches or diverticula which occupy usually the left colon
(sigmoid colon) but sometimes may extend to the whole of the colon.

Most of the patients with diverticula do not have any symptoms and become
aware of them only if they happen to have a colonoscopy or a barium enema.
In that case the patient is said to have “diverticulosis” which is not
considered a disease when it gives no symptoms. The vast majority of people
with diverticulosis will never have any symptoms. Those who do more
commonly develop an inflammation of the colon which is called
“diverticulitis”. The presence of diverticulitis or any other symptoms or
complications arising from a colon with diverticulosis is called diverticular
disease.

What causes diverticular disease?
Traditional teaching arising from studies performed more than 30 years ago
states that low fibre diet (diet poor in fruits and vegetables) is mainly
responsible. The argument for that cause is that diverticular disease was not
common before the beginning of the 20th century when modern methods of
refining flour, sugar and other foods was applied in the West. Also it is known
that diverticulosis occurs more rarely in the developing world and that
immigrants from the developing world who adopt the diet and habits of the
westerners start developing the disease after some years of immigration.

The theory behind the low fibre diet is that fibre gives bulk to the stools and
less effort is required for the transit of the stoos through the colon. Low fibre
creates stools of smaller quantity and harder consistence which require more
effort (constipation) – this results in higher colonic pressures which in turn
creates “herniation” of the mucosa through the bowel wall and creation of
diverticula.

However, more recent research raises doubts as to whether diet and
constipation is the primary cause (although, once established, patients with
diverticulosis benefit from high fibre diet). There are theories that the primary
disorder in diverticular disease maybe an abnormal “motility” of the colon
which results in repeat, irregular spasmodic movements and “hypertrophy”
(overgrowing) of the colonic wall.

Clinical presentation of diverticular disease

The symptoms are non specific and can be confused with other conditions of
the colon and even small bowel. Because the diverticula are usually located at
the left colon the more common type of pain is left lower abdominal pain.
There might be disturbance of the bowel movements, usually in the form
of increased frequency of motions, non formed stools or diarrhoea. A
phlegmon may be formed which is a swollen and inflamed mass arising from
the diseased colon, this can be felt as a tender mass on palpation of the
abdomen.
The pain can be localised or, if a perforation of a diverticulum occurs, it can
become generalised and be accompanied by symptoms of peritonitis which is
very severe and potentially life threatening condition.

Bleeding can sometimes happen because the inflamed diverticula can erode
through neighbouring blood vessels. The bleeding from diverticulitis is usually
heavy and requires admissison to the hospital (which distinguishes from the
minor bleeding caused by haemorrhoids).
The treatment of bleeding is with transfusions (in most cases it stops
spontaneously), angiogram and embolisation of the bleeding vessel or, as the
last resort, emergency surgery.

Perforation of a diverticulum can give rise to an abdominal abscess. This
may cause symptoms of abdominal pain and fever. The abscess can be
treated with antibiotics and often has to be drained by a percutaneous needle
under CT scan guidance. If drainage fails then sometimes an operation has to
be performed.

An abscess from a diverticulum can sometimes erode into nearby organs
establishing and abnormal communication (a track) which is called a fistula. If
the communication is with the bladder it is called a colo-vesical fistula.
Colovesical fistula presents with a typical symptom called pneumaturia which
means the presence of wind in the urine. The patient notices passing bubbles
in their urine and in later stages they can develop faecaluria which means
faeces in the urine. A communication between the bladder and the bowel
always leads to urine infection and possibly life-threatening sepsis so it always
requires an operation. The operation consists of excision of the fistula
together with the diseased part of the bowel. Repair of the bladder is often
necessary.

Abnormal communication of the colon with the vagina creates a colovaginal
fistula which presents with discharge of faeces in the vagina. The treatment is
surgical.

Who needs surgery?

Obviously, most people who develop severe complications of diverticular
disease will need some form of emergency or urgent surgery. Many
diverticulitis cases or even abscess cases can be managed with admission to
the hospital and antibiotics. However the main dilemma is what is the best
policy regarding patients who develop frequently symptoms from
diverticular disease to the point that it affects their quality of life. It has been
recommended that patients who have more than two admissions for
diverticular disease should be candidates for elective surgery. However
surgery for diverticular disease is quite major and has a certain risk of
complications. The decision to proceed to surgery should balance the risks
against the benefits. Nowadays laparoscopic colorectal surgery for
diverticular disease is reported to have good results with relatively short
hospitalisation and early recovery. The number of elective laparoscopic
colectomies for diverticular disease may be increasing, particularly as the
condition often affects younger people who are at greater cumulative risk of
complications.

Non surgical options

Sadly, non surgical options are limited. During the acute attack of diverticulitis
a short course of intravenous or oral antibiotics helps the attack to settle.
Studies from Italy claim that long term administration of oral, non absorbable,
antibiotics such as rifaximin may reduce the number of new attacks, however
this practice has not been followed in other countries. The standard advice is
a high fibre diet with fibre supplements because studies show that this
may decrease the severity of pain. However there is no evidence that high
fibre diet has a beneficial effect on the progress of the condition.

There are a couple of randomized controlled trials which show that a 5-ASA
medication, mesalazine, can help in settling the acute attack of diverticulitis
and reduce the risk of early relapse. Mesalazine is used extensively in
Inflammatory Bowel Disease and it is well tolerated drug. It is still not clear if
mesalazine would be able to help all patients with diverticular disease or only
certain patients.

The good news is that more than 75% of acute attacks of diverticular disease
do not recur. For most patients long term follow-up is not necessary if there
are no further symptoms. For those patients who get recurrent or persistent
symptoms a follow up scheme with CT scan might be useful but studies on this
area are still lacking.

Research directions

Very little research has been done in diverticular disease in relation to other
bowel conditions. It has been largely a neglected condition thought to affect
the elderly -this is not true since there are quite a few patients in their forties
or even thirties. It has also been thought to be a condition which can be
managed only when it presents as an emergency and little advice is available
for prevention.

At King's College Hospital we have a special clinic for diverticular disease and
research done at our institution has so far shown:

that smokers with diverticular disease have a much higher chance of
developing complications. This may have to do with an
immunosuppressive effect of smoking on the colon mucosa and we
advise smokers to quit in order to prevent complications.
we have shown that diverticular disease has a high hospital
prevalence and a high financial impact - we spend 4% of the budget
of a surgical department in managing it, which is quite a high
percentage for a single condition.
we have looked into the quality of life of patients with diverticular
disease and this has been shown to be affected long term. It should not
therefore be managed only as an emergency.
we have shown that serotonin, a molecule which is a neuroendocrine
transmitter in the brain and the gut, has increased activity in colons with
diverticular disease. A long term serotonin disorder may be one of the
causes of abnormal motility of the colon in diverticular disaese but this
hypothesis needs more research to be proven. It is interesting that
serotonin has been proven by other researchers to be implicated in
Irritable Bowel Syndrome and this molecule may be a link between the
two conditions.

Our "Diverticular Disease Clinic" at King's College Hospital is open
to referrals or patient self-referrals by fax: 0207 346 4869.

Endoscopic appearance
of colon with diverticular
disaese where the large
diverticula openings give
the impression of
multiple lumens.

Diverticular Disease