Diverticulitis refers to the infection and inflammation of the small bulges or diverticula that can form in the intestinal lining as a person ages.

These diverticula are thought to form as a result of hard stools passing though the intestine and if a piece of stool becomes trapped in one of the bulges, bacteria can start to multiply and trigger an infection or diverticulitis.

Around one in five people who develop diverticulitis go on to develop complications of the condition. Those under the age of 50 years are most at risk of developing complications. Some examples of these include:

The formation of an abscess in the colon, which is formed when pus collects inside the bulges is the most common complication. The treatment approach is usually percutaneous abscess drainage.

Peritonitis is a condition caused on the rare occasion that an infected diverticula bursts and spills its contents into the abdominal cavity. This can cause infection to spread into the peritoneal lining of the colon, which is a medical emergency requiring urgent treatment with antibiotics.

Another common complication of diverticulitis is a fistula or abnormal passage that forms between two parts of the body. When infected tissues make contact and stick together a fistula can form, creating a passage way for the spread of bacteria from the intestine to nearby structures such as the bladder or vagina.

Severe infection and inflammation can cause scarring a of the intestinal tissue and create a blockage. A partial blockage can affect the digestion of food and cause abdominal pain, while a total blockage is a medical emergency because the intestinal tissue can decay and eventually burst, causing peritonitis.