How can I be sure that the patient has diverticular disease?

Signs and symptoms usually found

The most common symptom of acute diverticulitis is left lower quadrant pain. Other common symptoms include low-grade fever, nausea, vomiting, constipation, and diarrhea.

Usual constellation of clinical features

The clinical presentation of acute diverticulitis is dependent on the severity of underlying inflammation and the presence or absence of complications. In uncomplicated disease, clinical features can range anywhere from mild abdominal cramping or bloating to significant abdominal pain or changes in bowel habits. If complicated, patients often have significant left lower quadrant pain, fevers, leukocytosis, and a palpable mass.

A tabular or chart listing of features and signs and symptoms

Are there pathognomonic or characteristic features?

Left lower quadrant pain that precedes presentation to the hospital by several days is one the most characteristic features of acute diverticulitis. In addition, several patients may report a prior history of similar episodes. The majority of patients also tend to have a low-grade fever, mild leukocytosis, and elevated CRP; however, the absence of these symptoms does not eliminate the diagnosis.

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Some less common clinical presentations

Some of less common symptoms include dysuria, abdominal cramping or bloating, nausea, vomiting, abdominal distention, constipation, diarrhea, flatulence, or right lower quadrant pain. When nausea, vomiting, and abdominal distention are present, this is suggestive of mechanical obstruction or paralytic ileus.

Other diseases and conditions might mimic the signs, symptoms, or clinical features of diverticular disease

Several other diseases and conditions may mimic diverticular disease.For example, many patients with mild uncomplicated diverticular disease report symptoms of abdominal bloating or cramping that are difficult to differentiate from irritable bowel syndrome (IBS). These two disease entities may be distinguished by the fact that symptoms due to diverticulosis are not typically relieved with a bowel movement. Lactose intolerance and small intestinal bacterial overgrowth can also be commonly mistaken for uncomplicated diverticulosis.

Patients who present with acute diverticulitis may have significant abdominal pain and fever, which may be confused with inflammatory bowel disease or peptic ulcer disease. In addition, radiographic findings of acute diverticulitis showing focal bowel wall thickening may mimic and be indistinguishable from colorectal carcinoma. Differentiating features on imaging include engorgement of the mesenteric vessels or associated fluid at the base of the mesentery. In addition, it has been suggested that diverticular inflammation and inflammatory bowel disease may have some clinical overlap.

How can I confirm the diagnosis?

What tests should be ordered first?

A diagnosis of acute diverticulitis can often be made by the history, demographics, and physical exam alone. An abdominal/pelvic computed tomography (CT) is often obtained to confirm a diagnosis of acute diverticulitis when suspected and should be the initial diagnostic test of choice. CT is also the safest and most cost-effective diagnostic modality. In addition, in patients with suspected diverticulitis, a CT with IV contrast has a 97% sensitivity and a 100% specificity rate. The positive predictive value is 100% and the negative predictive value is 98%. Most commonly, diverticulitis on CT is illustrated by a short segment or circumferential bowel thickening with adjacent infiltration of the pericolonic fat.

CT findings of acute diverticulitis include:

1. Increased soft tissue density within pericolic fat, 98%

2. Colonic diverticula, 84%

3. Bowel wall thickening, 70%

4. Soft tissue masses (representing abscesses, phlegmons, and pericolic fluid collections), 35%

In approximately 30% of patients, the inflamed diverticulum can be identified.

What additional tests may be considered to help in diagnosis?

In cases where CT is unavailable, a water soluble contrast enema may be used as an alternative diagnostic test.

High-resolution compression ultrasonography may also be used; however, this imaging modality is rarely used in the United States any longer as sensitivities and specificities are significantly lower than computed tomography. A chest X-ray may also be obtained to rule out free air, which may be a complication of a perforated diverticulum.

Following an episode of acute diverticulitis, a colonoscopy should be electively performed to evaluate the entire colon.

Listing of laboratory tests, radiographic studies, and endoscopic evaluations with descriptions of expected findings, consistent findings, and inconclusive results
Laboratory testing

1. Mild leukocytosis

2. Elevated BUN/Cr

Radiographic findings

1. Increased soft tissue density within pericolic fat, 98%

2. Colonic diverticula, 84%

3. Bowel wall thickening, 70%

4. Soft tissue masses (representing abscesses, phlegmons, and pericolic fluid collections), 35%

CT can also be used to identify complications of diverticulitis including peritonitis, fistula, obstruction, and fluid collections.

Endoscopic findings

In uncomplicated diverticular disease, asymptomatic individuals may often have significant diverticulosis identified during screening colonoscopy. In Western societies, most diverticula tend to be left sided. Mild diverticular inflammation may also be revealed during colonoscopy that is remarkable for erythema, edema, or granulation tissue found at a diverticular opening. There may also simply be friable mucosa observed in the area of diverticula. Pathology reveals a focal chronic colitis without granulomas in the area of interdiverticular colonic mucosa. Although these findings can be mistaken for ulcerative colitis or Crohn’s disease, the absence of aphthous ulcers and focal chronic colitis without granulomas make these two disease entitiesdistinguishable.

In general, in cases where acute diverticulitis is suspected, colonoscopy should not be performed because these patients are at high risk for perforation; however, this concern has recently been challenged.

What other diseases, conditions, or complications should I look for in patients with diverticular disease?

The development of diverticula occurs at weak points in the intestinal wall and is thought to be the result of increased intraluminal colonic pressures. The sigmoid colon has the narrowest diameter of the large intestine and is, therefore, considered to be most susceptible to raised intraluminal pressures. High intraluminal pressures tend to occur when the sigmoid colon undergoes smooth muscle contraction. In the setting of low-volume/nonbulky stools, this process becomes more significant, subsequently generating markedly elevated pressures that are transmitted to the colonic wall. Low-volume stools are thought to be generated as a result of poor dietary fiber intake and considered to be one of the biggest risk factors for this disease. The observation that Asian Americans who adopt a Western diet have increased rates of diverticulosis as compared to those Asian populations residing in Asia, lends further support to poor dietary fiber in the formation of colonic diverticula.

An association between obesity, physical inactivity, constipation, smoking, and the use of nonsteroidal anti-inflammatory medications has also been associated with an increased risk for diverticular disease. Therefore, these risk factors should be evaluated in any patient who presents with diverticular disease.

Last, the presence of IBS has also been associated with increased odds for the development of diverticulosis but not diverticulitis. This relationship has been most prominent in those with diarrhea-predominant IBS.

Traditionally, acute colonic diverticulitis has been thought to occur when a diverticula becomes obstructed from a fecalith or feces, resulting in bacterial stasis, overgrowth, and toxin and gas production. More recent theories have emphasized chronic inflammation, alterations to commensal gut microbiota, and abnormal colonic motility likely have inter-related roles in the pathophysiologic causes of diverticular disease. In addition, it has been felt that up to 30% of patients with diverticulosis develop acute diverticulitis, but more recent population-based cohort studies indicate that the incidence of diverticulitis in patients with diverticulosis may be < 5%.

Major risk factors for patients with this disease

A low fiber diet and the development of diverticula are the major risk factors for the development of diverticulitis. The most widely accepted theory for the pathogenesis of diverticulitis is diverticular obstruction due to a fecalith or increased diverticular pressure. Increased intradiverticular pressure may also be associated with perforation.

Commonly encountered complications of diverticular disease

Although acute diverticulitis can be uncomplicated, up to 25% of patients present with complicated diverticulitis the first time they are diagnosed. Complications can be both immediate or long-term and include the presence of abscess formation, perforation, obstruction, hemorrhage, peritonitis, and fistula formation. The most common type of fistula is the colovesical fistula, with a rate reported to be as high as 26%.

Complications of diverticular disease

Abscess. Occurs in ~16% of patients without peritonitis.

Obstruction. Very rare and usually not complete.

Perforation. Also very rare, with mortality rates of up to 20-30%.


What is the right therapy for the patient with diverticular disease?

What treatment options are effective?

The mainstay of therapy in those with a first attack of acute uncomplicated diverticulitis includes conservative management with bowel rest, antibiotics, and pain control. Antibiotic regimens thought to be effective include those that cover gram negative organisms and anaerobes, and should be continued for at least 7 to 10 days. Typical antibiotic regimens include a quinolone, such as Ciprofloxacin, along with metronidazole or amoxicillin-clavulanate.

For those patients with uncomplicated disease necessitating hospitalization or those with complications such as peritonitis, broad spectrum intravenous antibiotics are recommended. Typical treatment regimens include:

Imipenem/cilastatin (500 mg IV every 6 hours)

Piperacillin-tazobactam (3.375 g IV every 6 hours)

Ceftriaxone (1g IV every 24 hours) plus metronidazole (500mg IV every 8 hours)

A Fluoroquiolone plus metronidazole

With resolution of an acute attack, certain preventative measures have been recommended in patients with diverticular disease in order to prevent recurrent disease. Patients with diverticular disease are encouraged to begin a long-term, high-fiber diet. In addition, many physicians have historically instructed patients to avoid seeds and nuts because these indigestable fragments could potentially lodge in a diverticulum; however, there is little evidence to support this practice.

There is increasing evidence that the use of 5-ASA agents (mesalamine), antibiotics (rifaximin), and probiotics may have a role in preventing recurrent episodes of diverticulitis and managing symptoms of chronic diverticular disease.

A decision for hospitalization is based on the severity of presentation and on whether the disease is complicated or uncomplicated. It is widely accepted that all patients with complicated disease be hospitalized with IV antibiotics. In addition, those patients with complicated disease often will require invasive treatment strategies, including percutaneous drainage and/or surgery.

What is the most effective initial therapy?

The most effective initial therapy includes oral antibiotics and bowel rest. Common regimens include monotherapy with a beta-lactam/beta-lactamase inhibitor or a third-generation cephalosporin plus metronidazole.

For those patients who fail to respond to oral medications or have beta-lactam intolerance, therapy with a fluoroquinolone along with metronidazole can also be used. In cases that fail to respond to all of these regimens, intravenous therapy with a carbapenem may also be used.

Listing of usual initial therapeutic options, including guidelines for use, along with expected result of therapy.

What therapy is best if initial therapy fails, including definitions of failure?

In addition to oral antibiotics, outpatients should also be told to initially only consume clear liquids for 1 to 2 days. If no clinical improvement is evident after this time, patients should be admitted to the hospital for intravenous fluids and antibiotics along with bowel rest.

Failure to respond is evident in those patients with ongoing abdominal pain and fever, along with persistent nausea, vomiting, and/or diarrhea. Failure to respond to intravenous antibiotics and bowel rest may be indicative of complicated diverticulitis and further imaging is warranted at this time. If complicated disease is present, these patients may require percutaneous drainage or surgery along with broad spectrum intravenous antibiotic therapy.

A listing of a subset of second-line therapies, including guidelines for choosing and using these salvage therapies

For those who fail to respond to beta-lactam therapy or who have beta-lactam intolerance, therapy with a fluoroquinolone along with metronidazole can also be used. In cases that fail to respond to all of these antibiotic regimens, intravenous therapy with a carbapenem can also be used.

In those who have recurrent uncomplicated diverticulitis, many subsequent attacks have a higher likelihood to fail medical management. In these patients, elective surgery early on should be considered. Some experts recommend an elective sigmoid resection after only two episodes of diverticulitis.

Listing of these, including any guidelines for monitoring side effects.


How should I monitor the patient with diverticular disease?

In general, approximately 25% of patients with a first episode of uncomplicated diverticulitis will suffer from a recurrent attack. Those who are managed as outpatients should be counseled to call their physician if they have persistent fever, abdominal pain, nausea/vomiting, or inability to tolerate liquids. All of these may be signs of failure of conservative management or progression to complicated disease. In general, any patient who does not experience significant improvement in their symptoms in 2 to 3 days, should undergo further evaluation, including imaging (e.g., repeat CT) or routine labs (e.g., CBC) to evaluate for complications of the disease.

Monitoring recommendations and further therapies

In those who do respond to medical treatment, all of these patients should undergo colonoscopy in 6 to 8 weeks from the time of diagnosis. Colonoscopy is important not only for evaluating the extent of diverticulosis but also necessary to rule out colonic neoplasm. In those patients who decline full colonoscopy, a flexible sigmoidoscopy along with barium enema may also be used as an alternative for monitoring. In those patients with recurrent disease, surgery should be considered.

Surgery should not be delayed in any patient who appears to be failing medical therapy or if their symptoms (i.e., abdominal pain) worsen. The preferred surgical procedure is resection of the affected colonic segment and primary anastomosis with or without proximal fecal diversion.

Until recently, most experts recommended an elective sigmoid resection after two or more episodes of diverticulitis, based on a landmark study demonstrating that subsequent attacks of diverticulitis were more likely to fail medical therapy and require emergent surgery. This recommendation was in an effort to prevent the development of serious complications.

However, several newer studies have reported no increased risk of complicated diverticulitis or higher mortality with conservative management of recurrent attacks.

What's the evidence?

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