Diverticular Diseases of the Colon

DIVERTICULAR DISEASES OF THE COLON

V N Shrikhande
Bombay Hospital Institute of Medical Sciences and Post-Graduate Studies and Shrikhande Clinic, Mumbai, India.
INTRODUCTION
Diverticuli are mucosal pouches which protrude through defects in the colonic wall at the point of entry of blood vessels. The commonest are the acquired diverticuli in the sigmoid colon of the elderly. It's a disease of the past century common in the developed world. Like many other colonic diseases, it is associated with constipation due to a diet lacking in fibres. Increased intra colonic pressure and presence of weak spots lead to development of diverticuli. With increasing longevity, the incidence will continue to rise, but less than 10% become intractable. There is no sex predisposition.

Pathology

If the neck is wide there will be no obstruction, infection or symptoms. Obstruction at the neck leads to infection just the way an impacted faecolith leads to appendicitis.

An obstructed diverticulum may develop micro perforations and cause tiny abscesses. If the perforations are large, abscesses are formed with clinical picture of sepsis. Fortunately free perforations are rare. Localised minor infections may settle down with conservative measures, but abscesses and obstruction need surgical intervention. Some patients develop internal fistulae with the urinary bladder or the vagina. These fistulae never heal spontaneously.

Subacute obstruction is common. It is caused by luminal narrowing due to inflammation, fibrosis or compression by the pus. Complete obstruction is rare.

Majority of bleedings stop on their own; only occasionally resection of the affected segment may have to be performed if endoscopy and angiography fails to find the source of bleeding or if endoscopic therapy fails.

Clinical features

Diverticulosis is asymptomatic and is often an incidental finding on barium studies done for GI symptoms.

Diverticulitis presents a clinical picture aptly described as left sided appendicitis. Presence of a lump in the lower abdomen is one presentation typically seen in patients admitted as emergencies. There is a history of repeated attacks of pain either due to infection or narrowing of the colon with subacute obstruction. In almost every case of colo-vesical fistula, the patients are treated for a long time for recurrent episodes of urinary tract infections. H/o pneumaturia leaves no doubt about the diagnosis. In cases of colo-vaginal fistula, there is a history of faecal fluid and gases leaking out from vagina.

When massive bleeding from the lower GI tract occurs in patients with diverticular disease, it is wise to remember that angiodysplasia is a more likely cause than diverticulosis.

Diagnosis

Demonstrating diverticuli in a patient with nonspecific symptoms in this era of functional bowel disturbances, is of no help in management. It is akin to finding asymptomatic gall stones on ultrasound. Occult blood in stools should never be attributed to diverticuli. Cancer of colon must be excluded.

Barium studies are good for demonstrating diverticuli. They should not be used for diverticulitis because not only are they unreliable, but they also carry a danger of spilling barium in the pericolic region. CT Scan, which is a great help, shows both intra and per-luminal disease and can play a significant role in draining abscesses.

Colonoscopy may not be always possible either because of stenosis or presence of perforation.

Management

Asymptomatic diverticuli should be left alone. Once diverticuli develop, no treatment can help to regress them.

If diagnosis is confirmed and the symptoms are mild, conservative management with plenty of fruits and vegetables in the diet may keep the patient symptom free. However, repeated attacks of infection demands surgery.

Patients who need surgery are seen in two clinical situations.

1. Elective intervention : The indications are -

Subacute obstruction

Repeated attacks of diverticulitis

Urinary symptoms

Development of fistulae

Suspicion of malignancy

The treatment is by resection of the involved segment and end to end anastomosis. In the majority of planned operations, proximal colostomy is not necessary. Recurrence after resection can be avoided with colo-rectal anastomosis. No segment of the sigmoid should be left behind.

The standards of safe colonic surgery have been established several decades ago and need no repetition.

Internal fistulae, in addition to resection of the colon, need excision of the tract and of the involved portions of the urinary bladder or vagina.

2. The emergency situations

Localised abscess

General peritonitis, which is fortunately rare.

Intestinal obstruction

Severe bleeding

In the past the standard treatment was a staged procedure.

Draining of the pus and faecal material and establishing a proximal colostomy.

Removal of the affected segment after an interval of 10 days or more.

Closure of colostomy

The usual hospital stay was about five weeks. This will surprise many young surgeons and shock the health providers today. But 40 years back when I started operating on these cases in England, the term cost effectiveness was unheard of. Even then some experienced surgeons would perform, in selected cases, an emergency colectomy and support it with a proximal colostomy that was closed at a later date. However much depended upon the infrastructural facilities and the surgical expertise. All surgeons do not have the same dexterity, experience and patience.

Some important developments have influenced the management in recent times.

In 1980, CT guided percutaneous drainage of abscesses was introduced for the first time.

The advantages are-

It helps to tide over the emergency created by sepsis and earns valuable time to make the patient safe for surgery

There is no need for anaesthesia which is a great advantage in sick patient.

Evacuation of pus leads to rapid control of sepsis.

It helps to avoid a staged procedure.

In this era of cost effectiveness, aggressive management with only one operation is being encouraged. Antibiotics and intensive care units have proved an asset in salvaging some lives. One stage approach is a better and convenient choice provided the indications are right and efficient expertise and infrastructure is available. What is safe in expert hands may not be so for the less experienced. A one stage procedure, though desirable, is not always feasible.

Percutaneous drainage has limitations and hazards; also facilities may not be always available. Some individuals at admission are so sick that conventional surgical drainage and staged operations are the only safe solutions.

CONCLUSIONS

The incidence of diverticular disease is on the rise, as life expectancy is increasing.

Diverticulosis need no treatment.

Patients with mild symptoms should be managed with high fibre diet.

In management, care should be exercised in attributing symptoms to diverticulosis.

Always exclude cancer colon.

Exclude angiodysplasia in cases of severe bleeding.

Avoid emergency operations as and when possible.

Choose a plan that will suit the patient and the institution.

One stage operation is to be preferred to staged operations.

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