Evaluating acute diverticulitis

In this video, surgeon Olutayo A. Sogunro will take you through a step-by-step process in how to evaluate diverticulitis, complications you need to be aware of, and what to do when your intervention isn't working.

Olutayo A. Sogunro, DO FACS FACOS
Olutayo A. Sogunro, DO FACS FACOS
6th Oct 2021 • 5m read

Acute diverticulitis, if not managed correctly, can easily lead to surgery. In this video, surgeon Olutayo A. Sogunro will take you through a step-by-step process in how to evaluate diverticulitis, complications you need to be aware of, and what to do when your intervention isn't working.

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Video transcript

In this Medmastery lesson, we will discuss acute diverticulitis. So what is diverticulitis? Diverticulitis is defined as inflammation of a diverticulum, which is a sac like protrusion of the colonic wall. The presence of diverticula is referred to as diverticulosis and the inflammatory disease developed by some of these patients is called diverticulitis.

The term acute diverticulitis generally applies to disease of the large intestines. In terms of diverticulosis, western and industrialized nations have prevalence rates the range from 5 to 45%. The prevalence of diverticulosis is age dependent, increasing from less than 20% at age 40 to 60% by age 60. Diverticulitis is present in up to 15% of diverticulosis patients. Men and women are generally equally affected.

The sigmoid colon is the most common location for diverticulitis. The underlying cause of diverticulitis is micro or macro scopic perforation of a diverticulum. The primary process is thought to be erosion of the diverticular wall by increased intraluminal pressure or inspissated food particles, inflammation and focal necrosis ensue, resulting in perforation.

High dietary intake of red meat, low dietary fiber, lack of vigorous exercise, high BMI greater than 25 and smoking were all independently associated with an increased risk of diverticulitis. Approximately 25% of patients with acute diverticulitis have associated acute or chronic complications.

These include abscess formation, in about 17% of patients, colonic obstruction, fistula to nearby structures such as the small bowel, and perforation which occurs in 1 to 2% of patients. Let's look at the common signs and symptoms of diverticulitis. Abdominal pain is the most common complaints associated with diverticulitis and is usually in the left lower quadrant.

Nausea and vomiting occurs in 20 to 62% of patients. A tender mass is probable in approximately 20% of patients due to pericolonic inflammation or a peridiverticular abscess. Patients may also present with fever. Acute diverticulitis may be associated with a change in bowel habits, with constipation reported in approximately 50% of patients and diarrhea in 25 to 35% of patients.

Patients may also present with urinary urgency, frequency, or dysuria due to irritation of the bladder from an inflamed sigmoid colon, this is seen in 10 to 15% of patients. Now let's discuss the workup. On observation the patient can range from appearing normal and asymptomatic disease to ill appearing, especially in disease complicated by obstruction, bleeding or perforation.

Dehydration will be present in an obstructive patient who has had profound nausea and vomiting. These patients may have dry mucous membranes, reduce skin turgor and sunken eyes and overall apprear ill. On inspection distension may be noted in an obstructed patient. On palpation, that patient may have left lower quadrant pain and a tender mass may be present.

Patients may also have right lower quadrant or suprapubic pain due to the presence of a redundant inflamed sigmoid colon or right sided cecal diverticulitis. Patients may have localized peritoneal signs with localized guarding, rigidity and rebound tenderness. A digital rectal exam should be performed and may reveal mass or tenderness to palpation in the presence of a distal sigmoid abscess. So what might you expect to see in the lab results?

A complete blood count with differential can be obtained, it may show a leukocytosis with the left shift, which may indicate the presence of bowel complications. However, the white count may be normal in up to 45% of patients. Patients may also have an elevated c reactive protein on lab work. A urinalysis can be obtained and may reveal sterile pyuria, white blood cells in the urine due to inflammation from the sigmoid colon. Now let's discuss diagnostic imaging.

Computed tomography CT scan is an excellent imaging modality for patients with acute diverticulitis, it is commonly performed for the evaluation of an adult with abdominal pain presenting to an emergency department. If tolerated an IV and oral contrast at CT scan can provide valuable information and help with the evaluation of complications.

Computed tomography findings suggestive of acute diverticulitis include the presence of a localized bowel wall thickening greater than four millimeters, and an increase in soft tissue density within the pericolonic fat secondary to inflammation or fat stranding and the presence of colonic diverticular with inflammatory changes, like that seen in this axial CT slice.

MRI can also be used and has the advantage of less radiation. However, it is not first line and not as readily available as CT. Ultrasound can also be performed. It has the advantage that it is widely available, inexpensive and avoids radiation exposure. However, abdominal ultrasound is operator dependent and cannot exclude other causes of abdominal pain.

Ultrasound features suggestive of acute diverticulitis include diverticula, which are characterized as bright bowel out pouchchings, a hypoechoic peridiverticular inflammatory reaction and bowel wall thickening greater than four millimeters. Organized collections suggestive of abscess formation with or without gas bubbles may also be seen in some cases. Let's discuss the treatment options.

Patients with acute diverticulitis should receive inpatient treatment if their CT scan shows complicated diverticulitis, defined by the presence of frank perforation, abscess, obstruction, or fistulization. If they have uncomplicated disease, but the patient has one or more of the following characteristics, sepsis, micro perforation or phlegmon, high fever greater than 102.5 degrees Fahrenheit and 39 degrees Celsius, significant leukocytosis, severe abdominal pain or diffused for tinnitus, age greater than 70 or if outpatient treatment failed. So how should I manage these patients?

The management of uncomplicated diverticulitis is initially medical. It involves administration of intravenous antibiotics converted to oral antibiotics, once an oral diet is tolerated. The antibiotics should cover against gram negative rods and anaerobic organisms. Management should also include bowel rest was nothing given per mouth. Intravenous fluid resuscitation as these patients can be greatly dehydrated, serial abdominal exams and minimally invasive treatment of complications of the disease, for example, diverticular abscess can be drained percutaneously by interventional radiology.

Surgery is usually indicated for patients with significant obstruction, bleeding or infection from complicated disease. A surgical consult should be obtained if the patient is suspected to have complicated disease or if the patient has had multiple episodes of diverticulitis. After non operative management of acute diverticulitis patients have a 16 to 42% chance of developing recurrent diverticulitis.

Elective surgical resection of the segment of bowel with that diverticulitis should be considered and all options discussed with the surgeon. Colonoscopy is not routinely used in establishing the diagnosis of acute diverticulitis and should be avoided during the acute disease process due to a risk of perforation during the procedure. After the complete resolution of symptoms associated with acute diverticulitis, typically in six to eight weeks, a colonoscopy is performed to exclude an underlying malignancy, especially in older patient with whom the risk is greater.