Diverticulitis is a frequent, acute disease, especially but not exclusively in older adults.
The colon wall is multi-layered. During life, especially when the pressure in the colon is increased, such as with straining, the inner layer tends to protrude through weaker spots of the outer layer. This forms small pouches, which are diverticula. When one, or sometimes more of these diverticula becomes inflamed or infected, diverticulitis ensues.
Diverticula tend to be more frequent in the sigmoid colon, which is the last part, before the rectum. It is on the left side of the abdomen, thus diverticulitis presents most commonly as left sided pain. However, all parts of the colon can form diverticula. In patients with Asian ancestry, right sided diverticulosis is more common. This can be mistaken for appendicitis.
Diverticulitis is almost always an acute disease. It presents with sometimes severe abdominal pain, tenderness. Frequently it is accompanied by fever, chills, bloating, a feeling of fullness, nausea, vomiting, general malaise. In the majority of cases it progresses rapidly but there are patients, in whom the onset is more insidious, the symptoms wax and wane over several days or even weeks.
Diverticulitis may cause diarrhea but constipation is more common. Although we don’t quite understand the factors leading to the development of diverticulitis, constipation is probably one of them.
It is also not clear, if uncomplicated diverticulitis is just an inflammation of the diverticulum or also an infection. However, when the disease progresses, not infrequently there is a micro-perforation of the involved diverticulum, leading to a localized, small abscess formation in the colon wall. This can progress to larger, bone fide abdominal abscesses, which may rupture, leading to infectious peritonitis. This is a potentially very serious condition, the infection of the peritoneum, the lining of the abdominal wall and the covering layer of most intraabdominal organs.
The usual treatment of diverticulitis is going on a liquid diet and antibiotics, for 7-10 days. Recently it has been shown, that uncomplicated diverticulitis probably does not require antibiotics. Once the pain resolves, diet can be gradually advanced. It is important, that patients drink plenty of liquids.
Diverticulitis tends to recur and we don’t have a good handle on when and why this happens. It is thought that regulating bowel movements, avoiding constipation, may help prevent recurrent attacks.
When it recurs, especially several times, surgery can be considered. The operation will remove the sigmoid colon. If the diverticula are present only in the sigmoid, this will indeed prevent recurrence. There is no clear agreement, after how many episodes would surgery be indicated, but generally after three or four, the benefits of surgery outweigh its risks, which are minimal, given that it is done laparoscopically most of the time.
If an abscess is present, surgery is more likely needed. In the acute situation, when surgical risks are higher, the abscess can be drained under X-ray guidance.
