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Diverticular Disease
Introduction(Ref 8,17,18,21,32) Diverticular disease is a common disorder in people over the age of 50, where 50% of people have this disease. It can be congenital such as Meckel’s iliac diverticulum or aquired, but the main problems are resulted from aquired diverticular diease. It can also occur in the colon aswell as the small intestine. Each diverticulum is typically 5 to 10 mm in diameter, but at times they can exceed 20 mm. The most common site is the sigmoid colon, although diverticula can occur throughout the large bowel, with right-sided disease being more common in asians and in patients younger than 60 years. This is called diverticulosis. Diverticula otherwise known as pseudodiverticula are generally termed as uncomplicated diverticular disease. When faeces get trapped or obstructed within this, this can cause a bacterial infection within the pouches, leading to diverticulitis which starts off an inflammatory process, which can further lead to perforation causing further complications which shall be mentioned later on in this write-up. The presence of diverticular disease occurs alongside age, 50% of people get affected at the 5th decade, and 67% by the 8th decade. 30% of the elderly who undertake an autopsy have diverticular disease.

Figure 1(Ref 22)

Aetiology and Pathogenesis(Ref 5,7,13,17,18) Precise aetiology of this disease is unknown but it is multifactorial. It is thought that the muscular wall of the colon grows thicker with age. Thickening of the colon wall may reflect the increasing pressures required by the colon to eliminate feces. A diet low in fiber or low physical activity can lead to small, hard stools which are difficult to pass. It also appears that more cellulose, i.e. vegetables reduces the incidence of diverticular disease. Over time, vigorous contractions in the colon or motor dysfunction push the inner intestinal lining outwards (herniates) through cracks in the muscle walls. Diverticula develop in rows between the mesenteric and lateral teniae. It occurs due to high intra-colonic pressure or an abnormal distribution which causes pouches to be formed within the weak areas or sites where arteries (the vasa recta) penetrate the muscularis layer to reach the mucosa and submucosa of the colon, producing diverticula which are seen as pouches or sacs and diverticulosis forms. The condition also may be caused by abnormal colonic motility, defective muscular structure, defects in collagen consistency. The sigmoid is the most affected region, but it can occur in the ascending, descending and transverse colon. With sigmoid diverticulosis both of the muscle layers get more thicker, and this causes the shortening of the teniae which produces a deformity called myochosis, which narrows the colonic lumen, the muscular contractions then begin to obliterate the lumen which divides the bowel into isolated segments. Luminal narrowing may occur after the shortening of the sigmoid musculature as well as pericolic fibrosis.

Figure 2(Ref 16)

Diverticulitis is due to both micro and macro perforation of a diverticulum, which can be caused by the luminal wall eroding due to increased intraluminal pressure or when there is thickened faecal matter at the neck of the diverticulum. When micro perforation occurs, the infection is contained by the pericolonic fats, the adjacent organs, mesentery which causes a localised phlegmon to occur. However when macro perforation occurs, the infection is less restricted, so peritonitis and pericolonic abscesses can occur. If this erodes into adjacent structures, this may cause a fistula to form.

Clinical features and symptoms(1,2,3) Diverticular disease is usually asymptomatic in 95% of people so is usually discovered by accident. This is true of diverticulosis where the symptoms may be very general and not specific. Therefore there are very little symptoms to report on. The main symptoms occur in the rare circumstances(10%) that diverticulitis results and and produces further complications. The main general symptoms of diverticulitis are left iliac fossa pain, nausea, vomiting, fever, chills and loss of appetite. Other less general symptoms include episodic cramping abdominal pain, bloating, and the passage of excess wind are common. These are often accompanied by a change in their normal bowel-opening pattern with the occurrence of constipation, diarrhoea or both alternating.

Investigations(Ref 16,10,15) Diverticulosis Diverticulosis is often discovered by chance during tests for something else. The pouches may be noticed during a barium enema which shows the severity of diverticulosis, when a liquid is inserted into the intestine through the anus and an X-ray of the abdomen is taken. Alternatively the pouches may be discovered during an endoscopy, when a thin tube with a camera is put down the throat and into the digestive system. A barium enema can show colonic spasm, sacculation, and retained contrast within diverticula. Gastrointestinal endoscopy can be used to aid in he confirmation of diagnosis, though it is best applied in the large bowel.

Flexible sigmoidoscopy is also a useful tool, however there is a great risk to use it in checking for diverticulitis because it may convert a sealed perforation into a free leak. However it may be useful to rule out the conditions shown on the next paragraph. Diverticulosis may be misdiagnosed as Irritable Bowel Syndrome (IBS), because some of the symptoms such as colicky pain, are similar. We need to exclude other causes of the symptoms such as IBS or colon cancer by carrying out sigmoidoscopy or colonscopy which examines the colon guided by a combination of visual and xray control. Flexible forceps can be used to aquire a biopsy if need. Colonic endoscopy is best for evaluation purposes. Diverticulitis This is diagnosed by the presence of severe abdominal pain. Abdominal pain is a common and non-specific symptom of various things so occasionally diverticulitis may be misdiagnosed as appendicitis or, in women as a gynaecological problem such as fibroids. Can very commonly occur in the sigmoid colon. Figure 4

Investigations(Ref 1,2,3,8,15) Abdominal(CT) and chest radiographs exclude other causes such as free air and causes of abdominal pain, such as obstruction, rather than making a confirmation of diverticulitis. Figure 5(Ref 24)

A barium enema or colonoscopy (when a thin flexible tube is inserted into the intestine through the anus to transmit pictures of the intestine) may be used to confirm the diagnosis. Ultrasound scans or spiral computerised tomography (CT scan) with an intravenous or oral contrast may be used to show thickening in the wall of the colon, diverticular, abscesses,pericolic collections along with thickened muscular hypertrophy. There is an increase in density due to pericolic fat with the thickening of pelvic fascial planes. It can provide both diagnostic and prognostic information. The contrast enema is no longer used as much since the introduction of the abdominal CT scan. Also injections carry the risk of spreading the infection.

Blood tests show a polymorphonuclear leucocytosis which may also show immateur band forms and the ESR is raised. Other tests such as urinalysis can also be done. Direct visualisation may be required with a sigmoidoscope or colonoscope as mentioned earlier. A general examination can also be done to show a left iliac region mass along with a digital rectal examination (DRE) to feel for tenderness, blockage, or blood. When someone presents with diverticular disease, it is best to initially start with less invasive tests such as blood tests, and by doing a rectal examination. This will reduce the need to waste unnecessary money and will point the diagnosis in the right direction. Afterwards, if the diagnosis looks like it may be diverticular disease, then tests like flexible sigmoidoscopy and CT scans can be performed.

Differential Diagnosis There are many types of conditions which can be confused for diverticular disease, these include acute appendicitis, colorectal cancer, complicated ulcer disease, crohn's disease, cystitis, ectopic pregnancy, peritonitis, ulcerative colitis, renal disease, pancreatic disease, pelvic inflammatory disease and an incarcerated hernia. The main type of condition which is difficult to diagnose from is the carcinoma of the colon. This is because there are so many similar clinical features such as a change on bowel habit, large bowel obstruction which presents with vomiting, constipation and abdominal pain, blood and mucus in the rectum, tenderness and fistula formation. Even with a laparotomy it is difficult to tell.The main way to tell is to take a positive biopsy by using a flexible sigmoidoscopy or colonoscopy.

Complications(Ref 4,8,10,12,20) Abscesses/Perforations The infection causing diverticulitis often clears up after a few days of treatment(mentioned later in this write-up) with antibiotics. If the condition gets worse, an abscess may form in the colon. It is suspected when a person still has fever, leucocytosis or both even when antibiotics are being administered. It often occurs when the pericolic tissues fails to control the spread of inflammation. An abscess is an infected area with pus that may cause swelling and destroy tissue. Sometimes the infected diverticula may develop small holes, called perforations. These perforations allow pus to leak out of the colon into the abdominal area. This can lead to the formation of a paracolic or pelvic abscess or generalized peritonitis. If the abscess is small and remains in the colon, it may clear up after treatment with antibiotics. If the abscess does not clear up with antibiotics, it may need to be drained. The drainage is called CT-guided percutaneous drainage using a catheter. If the patient has sepsis, then surgery may be needed, along with the perhaps the removal of part of the colon. A large abscess can have a very large mortality, as high as 35 percent if the infection leaks out and contaminates areas outside the colon. Infection which spreads into the abdominal cavity is called peritonitis. With generalised peritonitis, the mortality rate is a lot higher. Peritonitis requires emergency surgery to clean the abdominal cavity and remove the part of the colon which is damaged. Without surgery, peritonitis can be fatal. Fistula A fistula is an abnormal connection between two organs. This can arise when inflamed or damaged tissue sticks to another organ and heals that way.

Figure 7(Ref 23)

Some peridiverticular abscesses can progress to form fistulas between the colon and surrounding structures in up to 10 percent of patients. Colovesical fistulas are the most common variety and require surgery for treatment. Fistulas involving the bladder and the diverticulum(colon) are more common in men and can cause dysuria or pneumaturia, it can also result in a severe, long-lasting infection of the urinary tract. The problem can be corrected with surgery to remove the fistula and the affected part of the colon or colon resection.; in women, the uterus is interposed between the colon and the bladder, so this cannot happen but in the likely event it occurs in the vagina, this can cause vaginal discharge. Intestinal obstruction Intestinal obstruction is not very common in diverticulitis, and occurs in less than 2 percent of patients. It occurs with a repeated occurrence of acute diverticulitis. The small bowel is affected the most, and an obstruction is usually caused by adhesions. The colon normally becomes obstructed because of luminal narrowing caused by inflammation or compression by an abscess. Multiple attacks can lead to progressive fibrosis and stricture of the colonic wall. Obstruction generally is self-limited and responds to conservative therapy. If persistent, obstruction of the colon can be treated by a variety of endoscopic and surgical techniques. Haemorrhage As mentioned in the aetiology of this write-up, it commonly occurs at the entry of the small arteries into the sub-mucosa. Gradually these arteries(vasa recta) become weak and can then burst, this mainly occurs over the dome of the divertculum. Diverticulitis normally involves the left or sigmoid colon, most diverticular bleeding occurs in the right side of the colon. Emergency angiography is the initial procedure where the superior mesenteric artery is studied first because incidence of acute bleeding is highest from the right side. Nuclear scanning techniques useful in patients with slow rate of bleeding, a patient with a negative arteriogram but positive should be good for colonoscopy. Diverticular disease is the most common cause of lower gastrointestinal bleeding. In 16 percent of patients, bleeding in the most common sign and occurs with great volume and is painless. The diagnosis and treatment of lower GI bleeds require a coordinated approach. Intra-arterial infusion of vasospastic substances or selective embolization is the most likely treatment. Vasopressin temporarily effective. Emergency surgery such elective resection is also considered in severe circumstances. Angiography, nuclear bleeding scans, colonoscopy, fluid resuscitation may be useful in patients with ongoing bleeding. Surgery can be applied for patients where medical management is unsuccessful, where an operation occurs to remove the segment of the colon containing the bleeding diverticulum. Treatment(Ref 18,31) In general, diverticular disease can be prevented or even treated with an improved diet if its not too severe. A diet with a lot of fibre, and less fat and red meat along with an increase in exercise could make all the difference. In general or minor incidents is a high fibre diet along with fibre supplements such as Citrucel or Metamucil once a day are advisable to prevent constipation and the formation of more diverticula. These products are mixed with water and provide about 2 to 3.5 grams of fibre per tablespoon, mixed with 8 ounces of water. Here a table to shown to show what type of foods have a good fibre diet: On next page…

If the disease progressed to non-severe diverticulitis then certain antibiotics are usually given. Oral antibiotics are good if the symptoms are mild. Some examples of commonly prescribed antibiotics include ciprofloxacin, metronidazole, and a cephalosporin such as cephalexin. Liquid or low fiber foods are advised during acute diverticulitis attacks. If the diverticulitis is severe where there is a high fever and pain, where drugs cannot be given orally or pain is too hard to bare the patients are hospitalized and given intravenous antibiotics along with bedrest. The types of intravenous antibiotics varies but can be cefuroxime with metronidazole, gentamycin clindamycin, beta-lactamase inhibitors such as ampicillin-sulbactam or ticarcillin-clavulanate along with a cephalosporin. Morphine cannot be given because it increases intra-luminal pressure via colonic spasms therefore Meperidine (Demerol) is the opiate of choice because it has been shown to decrease intraluminal pressure. Surgery is not need unless there are complications but is mainly used for those with persistent bowel obstruction or abscesses not responding to antibiotics. Surgery(Ref. 1,3,4,6,9,15,19,28,29,30,33) Surgery is usually performed if the disease progresses into one of the complications mentioned earlier in this write-up. For very severe diverticulitis, twenty percent of people will require surgery. The decision to perform prophylactic sigmoid resection must be based on a balance assessment of risk factors including age, severity of attacks and their recurrence. The main time surgery is considered is when complications develop. There is a 1-stage procedure which is concerned with elective sigmoid resection, and is fairly simple, usually involving a laparascope. Is also known as resection and primary anastomosis where the part which is diseased is removed and intestinal continuity is restored. It is mainly used in patients with fistula or those that have undergone preoperative percutaneous drainage of an abscess when intraoperative contamination will be minimized. A primary anastomosis should not be undertaken if a person has mal-nutrition, severe anaemia, feculent peritonitis, immuno- suppression, and uncertain viability of the bowel. In these cases a Hartmann procedure should be performed.

Figure 9(Ref 25)

There is also a more complicated 2-stage procedure, the first surgery removes the part of the colon which has the disease, and the end of the upper section of the colon is attached to an opening in the abdomen wall which known as a colostomy and closure of the rectal stump occurs. After inflammation and infection have cleared up, another surgery is then done to reconnect the ends of the colon and the rectal stump.. A colostomy is a surgical method where the upper part of the intestine is sewn to an opening made through the skin of the abdomen. Stool passes out of the body at this opening and into a disposable bag. This procedure is also known as the Hartmann’s procedure. The rectal stump is stapled or sutured, with a rectal tube to drain the left pelvis which prevents disruption of the rectal stump. Use of long, non-absorbable monofilament sutures can be used, which is to mark the top of the rectal stump which can help in identification when closing the colostomy after surgery. This procedure is a popular one to consider, and is often used when treating complications such as perforations when general peritonitis develops, and when an acute obstruction occurs.

As mentioned early, in the complications section, abscesses are treated by drainage them. However, if it isn’t too severe, it can be treated conservatively with antibiotics.

When someone has a fistula, it is best to start with a colostomy or loop ileostomy. This prevents faeces from disturbing the fistula while is being treated so preventing infection. Fistulas are generally treated by resection of the affected segment of the colon and bladder wall, a primary colonic anastomosis is undertaken and the defect in the bladder is oversewn.

If someone has perforations and peritonitis, antibiotics are given. Also, either the one or two stage procedure can be undertaken. A hemicolectomy can be done with or without a defunctioning transverse colostomy for the proximal end.

With haemorrahages, if someone loses more than four units, then causing an embolization may not be able to help. If the site of bleeding is unknown, then a total colectomy with an ileorectal anastomosis or ileostomy may be the best line of treatment. If it is known, then the best line of treatment would be segmental resection.

Laparascopic surgery is also said to be a good way to treat someone with uncomplicated diverticulitis.

Once upon a time, the 3-stage procedure was the traditional operation of use for diverticulitis and abscesses. This is where transverse colostomy and drainage occur. However this would cause a high mortality, because the colostomy would occur in the transverse colon, and stools would still remain in the left colon. When drainage occurs, this causes sepsis. It may lead to a fistula, and is only used if there is no other choice, when the condition is most severe, where inflammation can threaten the ureter and iliac vessels, but generally this is not in use anymore, and was considered one of the easiest surgical procedure for diverticular disease.

The Hartmann operation is currently the most popular, but resection with primary anastomosis is the safest procedure for all types of complicated diverticulitis, and reduces costs. There is no clinical indication for the three-stage operation due to its unsafety. References 1.	Operative Surgery-Alimentary tract and Abdominal wall, Fourth Edition – Hugh Dudley 2.	Diseases of the gut and pancreas, 2nd Edition – Misiewicz, Pounder,Venables 3.	Gastrointestinal and Liver disease, Volume 2, Feldman, Scharschwidt,Sleisenger 4.	Textbook of gastroenterology, Boucheire, Allan, Hodgson, Keighley 5.	Morson and Dawson’s Gastrointestinal pathology, 3rd Edition, Morson, Dawson, Day, Jass, Price, Williams 6.	Oxford Medical Dictionary, 6th Edition 7.	Human Anatomy and Physiology, 6th Edition, Elaine N. Marieb 8.	Oxford Handbook of Clinical Medicine, 6th Edition, Murray Longmore, Ian B. Wilkinson, Supraj Rajagopalan 9.	Diverticular Disease: Management of the Difficult Surgical Case, John P Welch, Jeffrey L Cohen, William V Sardella 10.	Gastrointestinal Physiology, 6th Edition, Leonard R Johnson 11.	Gastrointestinal Pathology an atlas and text, 2nd Edition, Cecilia M Fenogleo Preiser 12.	http://www.wrongdiagnosis.com/d/diverticular_disease/complic.htm 13.	http://www.aboutibs.org/Publications/diverticula.html 14.	http://www.healthsystem.virginia.edu/uvahealth/adult_digest/divertic.cfm 15.	http://www.aafp.org/afp/20051001/1229.html 16.	http://www.medicinenet.com/diverticulosis/article.htm 17.	http://digestive.niddk.nih.gov/ddiseases/pubs/diverticulosis/ 18.	https://www.harvardvanguard.org/info/content.asp?pageID=P00367 19.	http://www.webmd.com/hw/digestive_problems/hw252327.asp 20.	http://www.ehealthmd.com/library/diverticulardisease/DD_risks.html 21.	http://www.ehealthmd.com/library/diverticulardisease/DD_whatis.html 22.	http://www.merck.com/media/mmhe2/figures/fg128_1.gif 23.	http://www.merck.com/media/mmhe2/figures/fg128_2.gif 24.	http://www.aafp.org/afp/20051001/1229_f1.jpg 25.	http://www.gastrolab.net/m106.jpg 26.	http://www.surgical-tutor.org.uk/default-home.htm?system/abdomen/diverticular.htm~right 27.	http://www.gastrolab.net 28.	http://xray2000.co.uk Journals: 29.	Surgical Endoscopy; Kohler L, Sauerland S, Neugebauer E. 1999 Apr;13 30.	The British Journal of Surgery, Surgical management of complicated colonic diverticulitis 2003 29. March, Wedell J, Banzhaf G, Chaoui R, Fischer R, Reichmann J. 31. Diseases of colon and rectum, Primary anastomosis or Hartmann's procedure for patients with diverticular peritonitis? A systematic review. 2004 Nov Salem L, Flum DR. 32. Canadian Family Physician 2002 October, Preventing diverticular disease. Review of recent evidence on high-fibre diets, Aldoori W, Ryan-Harshman M. 33. Journal of the Royal Society Of Medicine, 2006 October, Meckel's      diverticulum: a systematic review Sagar J, Kumar V, Shah DK. 33. Journal de chirurgie 2003 Feb, Surgical treatment of acute sigmoiditis

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