Acute Diverticulitis: Symptoms, Diagnosis, Treatments

Acute diverticulitis is an inflammation due to a microperforation of a diverticulum. The diverticulum is a sack-shaped protrusion of the wall of the colon. Diverticulitis can occur in about 10% to 25% of patients with diverticulosis. Diverticulitis can be simple or uncomplicated and complicated. Uncomplicated diverticulitis does not presents associated complications.


The risk factors that increase the chances of developing diverticulitis are the same as those related to diverticulosis.  Diet seems to play an important role.

Diets low in fiber, high in fat and red meat may increase the risk of developing diverticulosis and possible diverticulitis It is known that obesity and smoking increase the potential of both diverticulitis and diverticular bleeding.

Finally, exposure to some medications, including nonsteroidal anti-inflammatory drugs (NSAIDs), steroids and opiates are
associated with diverticulitis.

Conversely, exposure to medications with statins may decrease the incidence of symptomatic diverticulitis.

Despite a common popular belief, nuts, seeds and popcorn are not associated with an increased risk of diverticulosis, diverticulitis or diverticular bleeding.


Diverticulosis is present in approximately 60% of the people over 60 years. Diverticulitis occurs around the 10% to 25% of patients with diverticulosis.

According to the national sample of hospitalized patients, the database of patient care hospitalized from all the United States revealed that there was a 26% increase in hospitalizations for acute diverticulitis and a 38% in elective operations from 1998 to 2005.

It shows that young patients (18 to 44 years old) have more probabilities of being admitted to the hospital that patients older (from 45 to 74 years).

This trend is probably due to the rapid diagnosis and improvement in the modalities of diagnostic tests.

Western nations have an overwhelming probability of having diverticulosis on the left side, while people from Asian descent may have the disease on the right side.

Around the world, the average age of admission for acute diverticulitis for male  is 63 years old. Although initially it was observed that the disease was more prevalent in men, the most recent data show that the distribution of diverticulitis is the same in men and women.

Diverticulitis is more common in men younger than 50 years and in women from 50 to 70 years old. Diverticulitis that occurs in patients older than 70 is more likely to be a woman.


Symptom varies according to the severity of the disease.

Patients with uncomplicated diverticulitis usually present pain in abdomen in the left lower quadrant, which reflects the propensity of the disease of the left side in the western nations.

However, patients of Asian descent present predominantly abdominal pain on the right side. The pain can be constant or intermittent.

The change in bowel habits, either diarrhea (35%) or constipation (50%), may be associated with abdominal pain. The patients may also experience nausea and vomiting, possibly for an intestinal obstruction.

Fever is not uncommon in patients with abscesses and perforation. The dysuria, frequency and urgency may occur in patients when the inflamed portion of the intestine comes into direct contact with the wall of the bladder, which is called sympathetic cystitis.

In the physical examination, sensitivity to palpation in the area of inflammation is almost always present due to the irritation of the peritoneum. You can feel a mass in about 20% of the patients if there is an abscess present.

Intestinal sounds are usually hypoactive but may be normally active. Patients may present peritoneal signs (rigidity, protection, rebound sensitivity) with perforation of the intestinal wall.

On the other hand, fever is almost always present, but hypotension and shock are rare.


The diagnosis of acute diverticulitis can be made clinically based only on the history and physical examination. However the
clinical diagnosis can be inaccurate in 24 to 68% of cases.

Therefore, laboratory and radiological tests perform a important role in the accurate diagnosis of acute diverticulitis.

Laboratory tests may show leukocytosis and elevation of acute phase reactants, such as erythrocyte sedimentation rate
(ESR) and C-reactive protein (CRP).

The radiological test for acute diverticulitis is the computed tomography of the abdomen and pelvis, preferably with
oral or rectal contrast soluble in water (if nausea and vomiting are present significant) and intravenous contrast provided.

The sensitivity, specificity and negative predictive value of a computed tomography (CT) were reported as more than 97%.

Abdominal ultrasound can accurately diagnose the acute diverticulitis, with comparative sensitivity (84% to 94%) and
specificity (80% to 93%) from the CT.

However, ultrasound results (US) depend on much of the operator and its use is limited despite of the encouraging data, the lowest cost and easy availability.

MRI is another possible diagnostic modality. Because of the cost and not the direct comparison of sensitivity or specificity, doctors usually prefer CT.

Endoscopy should be avoided in case of suspected acute diverticulitis due to an increased risk of drilling.

It is recommended to perform a colonoscopy approximately between six and eight weeks after the symptoms have resolved for
rule out malignant tumors, inflammatory bowel diseases or possibly colitis if the patient has not had a colonoscopy recently.


After clinical presentation, acute diverticulitis can be treated with outpatient care.

According to the American Society of Colon and Rectum Surgeons, a patient who can not tolerate oral intake, has excessive vomiting, shows signs of peritonitis, is immunocompromised or, at an advanced age, must be hospitalized.

Ambulatory care has 94% to 97% success rate for average people.The standard of ambulatory care includes bowel rest, increase of fluid intake and therapy with oral antibiotics (single or multiple drug regimen) that covers gram-negative rods and anaerobic bacteria.

Hospital treatment for diverticulitis requires antibiotics intravenous, intravenous fluids and pain control. Again, the
antibiotics should cover the gram-negative rods and anaerobes and administered for three to five days before switching to
oral antibiotics during a course of 10 to 14 days.

Intestinal rest is preferred in patients who require admission to hospital.

About 15% of patients with acute diverticulitis develop an abscess, specifically pericolonic and intra-mesenteric.

In the physical examination, a sensitive abdomen and a sensitive mass suggest a possible formation of abscesses. Abscesses less than 2 cm to 3 cm they can be treated conservatively with intravenous antibiotics.

Large abscesses should be drained percutaneously with CT guidance.

The formation of fistulas is another complication of diverticulitis acute It is reported that less than 5% develops a fistula; however, it has found in approximately 20% of patients undergoing surgery for diverticulitis.

The most common fistula is the colovesicular fistula, which occurs in approximately 65% ​​of the cases. Fecaluria is pathognomonic for the colovesicular fistula.

A partial intestinal obstruction or a pseudo-obstruction due to colonic ileus can be treated conservatively.

Complete bowel obstruction is rare in acute diverticulitis.