Diverticula are small hernias that develop in the wall of the large intestine. Macroscopically, they resemble small “pouches” that protrude into the wall of the large intestine and usually develop in “weak” points of the intestinal wall, such as the entry points of the food vessels. Theoretically, diverticula can develop in any part of the large intestine, but the vast majority (95%) are located in the sigmoid colon. Diverticula are more common in Western societies and are considered the result of poor nutrition. Specifically, the low fiber content of the diet results in the creation of smaller stools and an increase in pressure during bowel movements, in order to effectively push the stool through. The increase in pressure results in the creation of diverticula. A synergistic factor is considered to be the decrease in the intestinal wall’s collagen and elastin content with age.
Diverticula are usually asymptomatic. They only make their presence felt if they become inflamed, bleed, or perforate.
Inflammation – Diverticulitis
Inflammation of the diverticula is called diverticulitis. The old theory attributed the inflammation to the trapping of feces or food debris within the diverticula, resulting in the development of microperforations and inflammation. Newer data suggest that the low fiber content of the diet leads to a change in the intestinal flora and a reduced local immune response, which predisposes to microperforations and inflammation.
Risk factors for developing diverticulitis include age, a diet that is low in fiber and high in red meat, nonsteroidal anti-inflammatory drugs, opioids, smoking, and immunosuppression.
80% of the population will develop diverticula by the age of 80, but the majority will remain asymptomatic. 10-25% of patients with diverticula will develop an episode of diverticulitis during their lifetime, and of these, only 30% will experience a second episode of diverticulitis. The classification of diverticulitis is according to Hinchey, as shown in.
Diverticulitis manifests with pain in the left ventricle, fever, and may be accompanied by diarrhea or constipation. Laboratory tests show leukocytosis and an increase in CRP, while the diagnosis is made with computed tomography, which has a high sensitivity, specificity, and accuracy, reaching 97-98%. Colonoscopy has no place in the acute inflammation phase, but should be performed 6 weeks after the inflammation has resolved.
The initial treatment of diverticulitis is conservative, with antibiotic treatment. In cases where the patient can tolerate oral feeding, does not have a very high fever, tachycardia, or marked leukocytosis and does not show local signs of peritonitis, he can receive treatment at home, avoiding hospitalization. Treatment should be administered for 5-7 days and discontinued as soon as the fever and leukocytosis subside. Failure to improve the patient within 48 hours is a harbinger of prolonged hospitalization and treatment, or even surgery. After the inflammation has subsided, adding fiber to the diet can prevent a possible relapse, while the old perception that patients should avoid foods such as seeds, nuts, or popcorn is not based on scientific data and has been abandoned.
Regarding surgical treatment, the guidelines of the American Society of Colorectal Surgery recommend that elective sigmoidectomy, that is, the removal of the part of the intestine that has the diverticula, should be individualized. However, there are some categories of the population that would benefit significantly from a surgical intervention. These are:
a. young patients under 50 years of age, due to the low intraoperative risk but also the high probability of serious complications in the course of the disease in the coming decades.
b. Immunocompromised patients due to cancer, transplantation, or inflammatory bowel disease. In these patients, a severe episode of diverticulitis may manifest itself very mildly clinically, laboratoryally, and radiologically, due to immunosuppressive treatment, making these patients at much greater risk of perforation than other patients.
c. Patients with recurrent episodes of diverticulitis. In these patients, surgical intervention is a very reasonable option, although improvement in symptoms has been observed with the use of probiotics and mesalamine, which may indicate a possible association between diverticulitis and inflammatory bowel disease.
Surgical treatment consists of sigmoidectomy, i.e. the removal of the part of the colon containing the diverticula. This is an operation with very good results when performed electively, i.e. in the absence of inflammation, while it is absolutely indicated to be performed laparoscopically, as the patient’s postoperative course is clearly better, with less pain, better mobilization and a faster return of gastrointestinal function. In elective surgery, it is important to remove the entire sigmoid, as otherwise the probability of recurrence of diverticulitis is fourfold and reaches 12%. On the contrary, the removal of diverticula more centrally than the sigmoid without evidence of inflammation is not indicated.
In case of abscess development, the initial treatment is percutaneous drainage with the help of a CT scanner, in combination with the administration of broad-spectrum antibiotic therapy. In case the abscess is not accessible percutaneously, then an attempt is made for conservative treatment with strong antibiotics. If there is no improvement within 48-72 hours, then surgical intervention is indicated for resection of the affected part, drainage of the abscess and exostomy of a temporary colostomy.
Two other rarer complications of diverticulitis are stenosis and fistula formation. Stenosis can be acute due to inflammation, or chronic due to fibrosis from multiple episodes of inflammation. It manifests itself with a picture of intestinal obstruction (distension, flatulence, vomiting, abdominal pain) and is treated with antibiotics in case of acute inflammatory stenosis and with stent placement in case of chronic fibrotic stenosis. In case of stent failure, surgical intervention is indicated, while malignancy should always be excluded endoscopically in a stenosis. The fistula is created between the affected part of the intestine and the urinary bladder or uterus. Its diagnosis is not particularly difficult and is made with computed tomography, cystoscopy and cystography. Treatment consists of surgical excision of the fistula and the affected part of the colon, while in this case, malignancy must also be ruled out.
Diverticular bleeding
This is a rarer complication of diverticula. Its etiology is unknown, but erosion of the intestinal feeding vessel by the diverticulum is suspected. It accounts for 40% of lower gastrointestinal bleeding. Treatment is initially conservative, with hemodynamic support of the patient, blood transfusion and endoscopic interventions. If this fails, surgical intervention is indicated to resect the affected section of the colon.
Diverticulitis treatment
This is an acute condition that presents with generalized peritonitis. Treatment consists of simultaneous hemodynamic support of the patient and surgical intervention. The operation of choice is considered to be removal of the sigmoid, closure of the rectal stump and exostomy of a temporary colostomy, with restoration of the continuity of the large intestine being performed at a later time. This option is ideal in cases of extremely burdened patients with severe sepsis. Removal of the entire sigmoid is of great importance, as the presence of part of it can quadruple the likelihood of recurrence of diverticulitis (12%). On the contrary, removal of diverticula more central to the sigmoid that do not show signs of inflammation is not indicated. Also, very good results have been recorded with resection of the diseased part of the colon, immediate restoration of the continuity of the digestive system and prophylactic ileostomy exostomy. This is an excellent option that is applied to hemodynamically stable patients, without signs of septic shock.
Finally, the perforation of diverticula can be covert, when the body manages to seal the leak and prevent the development of acute generalized peritonitis. In these cases, broad-spectrum antibiotic treatment plays an important role, while surgical intervention can be performed at a later time, when the inflammation has subsided. In cases of elderly patients with compromised health and many concomitant diseases, surgical treatment can be bypassed.
