Diverticulitis vs. Peritonitis

What's the Difference?

Diverticulitis and peritonitis are both conditions that affect the abdomen, but they have different causes and symptoms. Diverticulitis occurs when small pouches in the colon become inflamed or infected, leading to symptoms such as abdominal pain, fever, and changes in bowel habits. Peritonitis, on the other hand, is a serious infection of the peritoneum, the lining of the abdominal cavity, usually caused by a ruptured organ or perforated bowel. Symptoms of peritonitis include severe abdominal pain, fever, nausea, and vomiting. Both conditions require prompt medical attention and treatment to prevent complications.


CauseInflammation or infection of diverticula in the colonInflammation of the peritoneum, often due to infection
SymptomsAbdominal pain, bloating, fever, nausea, changes in bowel habitsSevere abdominal pain, fever, nausea, vomiting, bloating
TreatmentAntibiotics, pain medication, dietary changes, possible surgeryAntibiotics, surgery to remove infected tissue, supportive care
ComplicationsAbscess formation, perforation of the colon, sepsisSepsis, organ failure, death

Further Detail


Diverticulitis and peritonitis are two medical conditions that affect the digestive system. While they both involve inflammation in the abdominal area, they have distinct differences in terms of causes, symptoms, and treatment. Understanding these differences is crucial for proper diagnosis and management of these conditions.


Diverticulitis is a condition that occurs when small pouches, called diverticula, form in the walls of the colon and become inflamed or infected. These pouches are usually harmless, but when they become infected, they can cause symptoms such as abdominal pain, fever, and changes in bowel habits. The exact cause of diverticulitis is not fully understood, but it is believed to be related to a low-fiber diet and aging.

Diagnosis of diverticulitis is typically done through a combination of physical examination, imaging tests such as CT scans, and blood tests to check for signs of infection. Treatment usually involves antibiotics to clear the infection, along with dietary changes to prevent future flare-ups. In severe cases, surgery may be necessary to remove the affected portion of the colon.


Peritonitis, on the other hand, is a more serious condition that occurs when the peritoneum, the membrane lining the abdominal cavity, becomes inflamed. This inflammation is usually caused by an infection, such as a ruptured appendix, perforated ulcer, or abdominal trauma. Peritonitis can also occur as a complication of surgery or other medical procedures.

Symptoms of peritonitis include severe abdominal pain, fever, nausea, and vomiting. Left untreated, peritonitis can lead to serious complications such as sepsis and organ failure. Diagnosis is typically done through physical examination, imaging tests, and analysis of fluid samples taken from the abdomen. Treatment involves antibiotics to clear the infection, along with surgery to repair any underlying causes of the inflammation.


While both diverticulitis and peritonitis involve abdominal pain and inflammation, there are some key differences in their symptoms. Diverticulitis often presents with localized pain in the lower left side of the abdomen, along with fever, nausea, and changes in bowel habits. In contrast, peritonitis causes more generalized abdominal pain that is often severe and constant, along with tenderness, rigidity, and bloating.

Other symptoms of peritonitis may include a rapid heart rate, shallow breathing, and a high fever. These symptoms indicate a more serious condition that requires immediate medical attention. In contrast, diverticulitis symptoms may come and go, depending on the severity of the infection and the individual's response to treatment.


Treatment for diverticulitis and peritonitis varies depending on the underlying cause and severity of the condition. In mild cases of diverticulitis, treatment may involve rest, a clear liquid diet, and antibiotics to clear the infection. In more severe cases, hospitalization and intravenous antibiotics may be necessary.

Peritonitis, on the other hand, is a medical emergency that requires immediate surgery to remove the source of infection and prevent further complications. Antibiotics are also given to clear the infection, but surgery is the primary treatment for peritonitis. Recovery from peritonitis can be lengthy and may require intensive care in a hospital setting.


In conclusion, diverticulitis and peritonitis are two distinct medical conditions that involve inflammation in the abdominal area. While diverticulitis is usually less severe and can be managed with antibiotics and dietary changes, peritonitis is a serious condition that requires immediate medical attention and often surgery. Understanding the differences in symptoms, causes, and treatment options for these conditions is essential for proper diagnosis and management.

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