Master Clinician Series - Diverticulitis

This morning I presented a case-study on "diverticulitis." At 0700, a Master Clinician Series was held where I led a discussion on one of my surgical cases: a patient who required colonic resection due to recurrent disease. In the standard 3 minutes, I presented the patient's chief complaint, history of present illness, past medical/surgical/family history, current medications, allergies, a systems review, and physical exam and laboratory findings. From there, the faculty led a discussion of the medical and surgical issues involved in this person's care. I obviously pulled out the pink tie and blue shirt for the affair (brings out my eyes), and I wrote a short little summary of diverticular disease for the class.

So. In an effort to chart my progress throughout my medical training, and to see how medicine changes in the years to come, here is my short little ditty on diverticulitis...

------

When describing diverticular disease, it is important to first clarify a few terms. A “diverticulum” is an outward protrusion of the colonic wall. “Diverticulosis” simply comprises the existence of diverticula in the colon, and “diverticulitis” is active inflammation of these diverticula. The disease itself encompasses all three pathologies. Diverticula are usually formed in areas of weakness, caused by increased intraluminal pressure. These colonic projections are common: 30% of all individuals age 60 have diverticular disease, and the incidence jumps to 65% by age 85. The disease is found equally in men and women, although a preponderance of males are diagnosed with acute diverticulitis under the age of 40. Diverticular disease is almost exclusively left-sided in “westernized nations,” with perhaps only 1.5 percent of patients presenting with right-sided disease. This summary will briefly describe the pathophysiology, clinical manifestations and complications, and treatment of diverticular disease.

Pathophysiology. Diverticula develop near the vasa recta in the colonic wall. As the wall of the colon grows thicker with age (due to multiple dietary and hereditary factors), these weaknesses in the wall undergo greater and greater stress. Anything that increases intraluminal pressure will exacerbate the diverticula. As the colon thickens over time, pressure in the sigmoid colon becomes the greatest of any segment, since it’s lumen is the smallest in diameter. Diverticular disease is associated with a high fat diet, red meat consumption, and low dietary fiber intake (RR: 2.35 and 3.32 in different cohorts). High dietary fiber intake, resulting regular, large, and bulky stools, may normalize intraluminal pressure, and decrease the risk of hard stools that precipitate constipation and straining during defecation. However, it is important to note that “there is no clear correlation between constipation and diverticular disease,” due to the difficulty of designing an appropriate study for this association.

It is also important to note that use of alcohol, tobacco products, and caffeine does not increase one’s risk for diverticular disease. The presence of diverticula is inversely related to strenuous physical exercise: patients who exercise more are less likely to develop this disease. As a corollary, obese patients typically have a propensity for developing symptoms.

Diverticulitis, which results from inflammation of the diverticula, is due to micro- or macro-perforations along the bowel. Although fecaliths were initially thought to be the primarily etiology, the mechanism of injury actually involves erosion of the diverticular wall due to high intraluminal pressure or “inspissated food particles” (such as indigestible small nuts and seeds). After inflammation begins, necrosis of the bowel wall ensues, resulting in perforation. Depending on size and the surrounding anatomy of the perforation, a patient may present with different pathologies. Mesentery and nearby fat may “wall off” a small perforation; or, if the tear is near another organ, a fistula or obstruction may result. However, if the leaking contents are not well-contained, peritonitis can be a major complication. In these cases, generalized tenderness of the entire abdomen is seen.

Clinical Manifestations and Complications. While approximately 70% of patients with diverticulosis are asymptomatic, one out of every four may develop diverticulitis, and one out of ten will experience bleeding. These are considered the two major complications of diverticulosis. While symptoms such as “cramping, bloating, flatulence, and irregular defecation” may be present, “it is unclear if these symptoms are attributable to the underlying diverticulosis or to coexistent irritable bowel syndrome.” Left lower quadrant (LLQ) pain is the most common presenting symptom of diverticulitis in Western countries. Past history of similar episodes, nausea, vomiting, constipation or diarrhea, and urinary symptoms may help to narrow the differential diagnosis toward diverticular disease. LLQ tenderness, low grade fever, and mild leukocytosis may also be present. Hematochezia may be discovered in the patient history or physical exam. This is due to progressive injury to the surrounding vasa recta, leading to diverticular bleeding. Painless, self-limited rectal bleeding is a common manifestation.

There is also some evidence that diverticulosis may be associated with an increased risk of colon cancer; however, the line between these two diseases is blurred, as the risk factors that precipitate both diverticula and colon cancer are very similar.

Diagnosis and Treatment. History and physical exam are the primary tools when diagnosing acute symptomatic diverticular disease. Abdominal radiographs can be used to evaluate for free air in the peritoneum, but a CT scan with IV and oral contrast is the gold standard for diagnosis. “The sensitivity, specificity, positive, and negative predictive values of helical CT…were 97, 100, 100, and 98 percent, respectively, in a study that included 150 patients presenting to the emergency department with clinically suspected diverticulitis.” Since diverticulitis is a disease of the soft tissue, a CT scan allows for better visualization of bowel wall thickening, inflammation, and masses. In the non-acute setting, colonoscopy is the preferred approach, allowing for both direct visualization and biopsy.

Treatment recommendations depend on whether the disease is “uncomplicated” or “complicated.” Complicated diverticulitis includes inflammation with subsequent perforation, obstruction, abscess, or fistula. Conservative therapy of antibiotics and bowel rest (clear liquid diet, etc.) is currently recommended for patients with uncomplicated disease, and ciprofloxacin plus metronidazole are the medications of choice to target enteric bacteria. “Following successful conservative therapy for a first attack of diverticulitis, 30 to 40 percent of patients will remain asymptomatic, 30 to 40 percent will have episodic abdominal cramps without frank diverticulitis, and one-third will proceed to a second attack of diverticulitis.” Treatment of complicated diverticulitis or recurrent uncomplicated disease commonly requires surgical intervention. These cases should be managed on a patient to patient basis, with regard to differences in pathology and treatment goals.

1. Young-Fadok T, Pemberton JH. Epidemiology and pathophysiology of colonic diverticular disease. In: UpToDate, Basow, DS (Ed), UpToDate, Waltham, MA, 2011.
2. Acosta JA, Grebenc ML, Doberneck RC, et al. Colonic diverticular disease in patients 40 years old or younger. Am Surg 1992;58:605.
3. Fischer MG, Farkas AM. Diverticulitis of the cecum and ascending colon. Dis Colon Rectum 1984;27:454.
4. Young-Fadok T, Pemberton JH. Clinical manifestations and diagnosis of colonic diverticular disease. In: UpToDate, Basow, DS (Ed), UpToDate, Waltham, MA, 2011.
5. Rao PM, Rhea JT, Novelline RA, et al. Helical CT with only colonic contrast material for diagnosing diverticulitis: prospective evaluation of 150 patients. AJR Am J Roentgenol 1998;170:1445.
6. Young-Fadok T, Pemberton JH. Treatment of acute diverticulitis. In: UpToDate, Basow, DS (Ed), UpToDate, Waltham, MA, 2011.