Diverticular Disease of the Colon
Ciaran J. Walsh
Helen Witt is a 65-year-old moderately obese woman who presents to the emergency department complaining of left lower quadrant abdominal pain associated with anorexia and nausea for the past 2 days. She says she had this type of pain once last year and was told she probably had diverticular disease. At that time, her symptoms settled down very quickly, no investigations were performed, and nothing more was done about her condition.
On this occasion, her pain started gradually with intermittent gripping that became constant and more severe. She felt as though she had a fever and noted that going over the speed bumps on the way into the hospital caused her pain in the lower abdomen. Her history is significant for an appendectomy and open cholecystectomy many years ago, and recently her primary care physician prescribed ranitidine for a hiatal hernia diagnosed on upper gastrointestinal (GI) endoscopy. She is not diabetic. She denies any recent change in her bowel habit, blood from the rectum, or weight loss. She has no urinary frequency or dysuria and has no history of urinary tract infections.
On examination, she looks a little flushed. Her temperature is 37.9°C, her pulse is 92 beats per minute, and her blood pressure is 156/88 mm Hg. Her abdomen is obese but not distended. Abdominal examination reveals local left lower quadrant tenderness and guarding but no palpable mass. The rest of her abdomen is soft and not tender. Her bowel sounds are normal. Digital rectal examination is normal. Her laboratory values are normal, as is her acute abdominal radiograph series. The emergency department staff members think she has acute diverticulitis, and they want to know what investigations should be performed and whether Mrs. Witt should be admitted.
What is diverticular disease?
It is a benign disease of the colon characterized by the development of pulsion-type outpouchings. These are really false diverticula because they consist of mucosa lined only by serosa. They most often occur between the mesenteric and antimesenteric taenia coli, where the colonic blood vessels pierce the muscle. They indicate herniation of the mucosa through weak points in the colon wall. They are most common in the sigmoid and left colon but may occur anywhere in the colon.
What is the difference between diverticulosis and diverticulitis?
Diverticulosis is diverticula in the colon. Diverticulitis is an infective complication of these diverticula.
What causes diverticulosis?
Diverticulosis most likely develops as a result of a low-fiber diet. As food becomes more refined and processed, the amount of dietary fiber decreases. This is particularly prevalent in Western societies, which consume only one-tenth the amount of fiber consumed 100 years ago, before refined diets were so prevalent. In rural Africa and other societies not exposed to a Western diet, diverticular disease is almost nonexistent (1). Rural Africans reportedly consume 60 to 100 g of fiber a day, whereas Americans consume only 10 to 15 g per day.
How does a high-fiber diet prevent diverticulosis?
Fiber increases stool weight, decreases whole gut transit time, and lowers colonic intraluminal pressure. A high-fiber diet requires less contraction by the bowel to propel the stool onward. There is less segmentation, and muscle hypertrophy does not occur.
What is the prevalence of diverticular disease?
Approximately 30 million Americans have diverticulosis. Only 1% to 2% of people younger than 30 years of age are affected; one third of Americans older than 45 years are affected. The incidence rises with age; two thirds of the population older than 85 years is affected (2). Most people are asymptomatic, but 15% to 30% eventually develop diverticulitis.
What is Saint’s triad?
Saint’s triad is the constellation of cholelithiasis, hiatal hernia, and diverticulosis.
What is the most likely diagnosis for Mrs. Witt? What is the differential diagnosis?
Acute diverticulitis with local peritonitis is the most likely diagnosis for this patient. She has had an appendectomy, which means that the most likely differential diagnoses are colon carcinoma, inflammatory bowel disease, and ischemic colitis.
What are the most common complications of diverticular disease?
Perforation (micro or macro) causing pericolic infection with formation of a phlegmon, pericolic abscess, fistula formation, and frank peritonitis are the most common complications of diverticular disease. Acute inflammation can also lead to ulceration or erosion into a colonic wall blood vessel (remember where on the bowel diverticula most commonly occur) and cause bleeding. Chronic inflammation may lead to stricture formation and colon obstruction. Small-bowel obstruction is a common but not frequently mentioned complication of acute diverticulitis. Up to 20% of patients with acute diverticulitis may have small-bowel obstruction as a result of a loop of small bowel getting snared in the inflammatory nest. This is to be distinguished from an ileus, which may develop as a result of acute diverticulitis.
What is the Hinchey classification of acute diverticulitis?
These classifications permit a realistic comparison of treatment outcomes and formulation of management guidelines for each stage of the disease. The basic pathophysiology of acute diverticulitis is perforation. Whereas microperforations seal and may lead to an abscess or phlegmon, a large perforation may cause fecal peritonitis.
What fistulas are associated with diverticulitis?
A fistula may develop between the inflamed colon and any surrounding structure. Colovesical fistulas are the most common, accounting for nearly 60% of fistulas associated with diverticular disease (4). Approximately 2% of patients with acute diverticulitis develop a colovesical fistula. They are more common in men than in women, probably because in women the uterus lies between the colon and the bladder. Colocutaneous fistulas are the next most common type associated with diverticulitis. A women who has had a hysterectomy may develop a colovaginal fistula.
What are the symptoms and signs of a colovesical fistula?
Dysuria (90%), pneumaturia (70%), and fecaluria (70%) are the most common symptoms. Chronic urinary tract infections may occur. There are no physical signs related to the fistula per se, although one third of patients have evidence of a systemic infection.
How is a diagnosis of colovesical fistula confirmed?
Barium enema, cystoscopy, or both may demonstrate the communication between the colon and bladder. Radiography of the urine after a barium enema is described. Often the fistula cannot be demonstrated and the diagnosis is made based on history. The patient may be asked to urinate while in the bathtub to see if bubbles appear in the water.
How should Mrs. Witt’s diagnosis be confirmed? What investigation should be ordered?
The investigation of choice at this point is computed tomography (CT) of the abdomen and pelvis with intravenous (IV) and water-soluble oral contrast. This not only helps to confirm the diagnosis but also demonstrates the extent of the disease, including any abscess collections or free intraperitoneal air or fluid. In general, the diagnosis can be made clinically with sufficient confidence to permit treatment without more definitive investigation.
What are the criteria used to diagnose acute diverticulitis by CT?
Should Mrs. Witt have a barium enema or colonoscopy?
Mrs. Witt definitely should not have a barium enema or colonoscopy. Both procedures could worsen the situation. Colonoscopy could blow open a sealed perforation. Barium enema could provoke free perforation and lead to extravasation of barium into the peritoneal cavity, causing barium peritonitis.
Mrs. Witt’s CT shows significant thickening of the sigmoid colon, stranding of the pericolic fat with colonic diverticulosis, and a very small fluid collection in the pouch of Douglas.
Should the fluid be drained percutaneously? What should be done at this point?
The films should be reviewed with the radiologist. CT-guided percutaneous drainage is an excellent option for identifiable pericolic abscesses in patients with acute diverticulitis. The potential for CT-guided percutaneous drainage is one of the reasons CT is so attractive in patients with acute diverticulitis. Approximately 75% of peridiverticular abscesses can be drained in this way. The advantages are that it facilitates resolution of the sepsis without surgical drainage, and it permits a one-stage elective operation later. There is no evidence that Mrs. Witt has an abscess, thus there is no merit in percutaneous drainage in her case.
While the physician is reviewing the CT, a staff member of the emergency department calls and says the cubicle is needed. They want to send Mrs. Witt home with antibiotics.
Is sending Mrs. Witt home with an antibiotic prescription appropriate?
No. Mrs. Witt should be admitted for bowel rest, IV fluids, IV antibiotics, pain relief, and observation. In general, outpatient management is appropriate for patients who can tolerate diet, who do not have systemic symptoms, and who do not have peritoneal signs. Mrs. Witt fails to meet all of these criteria.
What percentage of people with diverticular disease need surgery? Is Mrs. Witt likely to need surgery on this admission?
Approximately 1% of patients with diverticular disease eventually require surgery. Approximately 15% to 30% of patients admitted to the hospital with acute diverticulitis need surgery. Mrs. Witt is not likely to need surgery on this admission.
Mrs. Witt’s condition settles quickly with conservative management, and she is sent home after 3 days with a prescription for a course of oral antibiotics.
How should Mrs. Witt’s follow-up be handled?
Mrs. Witt should be seen in the clinic in a few weeks to make sure that the acute episode has settled. At that time, full assessment of her colon, either by flexible sigmoidoscopy and barium enema or by colonoscopy, should be arranged.