What is peritonitis?

Do you know what peritonitis is? Do you know anyone who has been affected by peritonitis? If not, peritonitis is a serious condition which is characterised by the inflammation of the peritoneum.¹ The peritoneum is a thin tissue that lines the inner wall of the abdomen and covers the abdominal organs.² Based on its indicative type, peritonitis can be caused by a variety of factors including liver disease, burst stomach ulcers, digestive problems and even surgery. The general symptoms of peritonitis include abdominal or stomach pain, a high temperature, a rapid heartbeat and a lack of appetite.³ In this article, you will learn more about the different types of peritonitis and its causes and symptoms.

What are the four different types of peritonitis?

Peritonitis can be classified into four different types based on its underlying cause or clinical presentation. The four types are primary:⁴

• Peritonitis
• Secondary peritonitis
• Tertiary peritonitis
• Sterile peritonitis

What are the causes and symptoms of primary peritonitis?

The first type of peritonitis is primary peritonitis, also known as spontaneous bacterial peritonitis.⁴ Primary peritonitis occurs without an obvious source of infection or perforation in the abdomen itself but by bacteria from the bloodstream or lymphatic system.⁵ These bacteria can include Escherichia coli, Klebsiella species, Enterococcus faecalis and others.⁶ All these bacteria can infect the peritoneum, causing primary peritonitis.

The causes of primary peritonitis primarily consist of liver disease, also known as liver cirrhosis and kidney failure, also known as nephrotic syndrome⁷. Liver cirrhosis can lead to portal hypertension, which develops into ascites. Portal hypertension is increased pressure within the portal venous system, which is a major system of veins that carries blood from the intestines, spleen pancreas and other organs within the abdomen to the liver.⁸ It can develop into ascites, which is an accumulation of fluid in the abdominal cavity. This fluid provides a medium for bacterial growth and increases the risk of bacterial translocation into the peritoneal cavity, which is the area within the abdomen that contains the intestines, liver and stomach.⁹  Additionally, nephrotic syndrome is a syndrome that leaks large amounts of protein in the urine, leading to low serum albumin levels and ascites¹⁰ - this also increases the risk of peritoneal infections, contributing to peritonitis.

The symptoms of primary peritonitis can depend on the severity of the infection and the underlying cause. The most common symptoms of primary peritonitis include abdominal pain, abdominal tenderness, fever, nausea and vomiting.¹¹

What are the causes and symptoms of secondary peritonitis?

The second type of peritonitis is secondary peritonitis. Secondary peritonitis is the most common type of peritonitis and can occur due to a rupture inside the organs of the abdomen, such as the intestines or stomach.¹² This can be caused by conditions such as appendicitis, diverticulitis or traumatic injury to the abdomen.⁴ Appendicitis is the inflammation of the appendix, diverticulitis is a condition that affects the large intestine, and traumatic injury to the abdomen can be caused by blunt force. The bacteria and digestive juices leak from these conditions into the peritoneum, causing infection and inflammation.

The symptoms of secondary peritonitis consist of severe abdominal pain, abdominal tenderness, fever, nausea and decreased bowel sounds.⁴

What are the causes and symptoms of tertiary peritonitis?

The third type of peritonitis is tertiary peritonitis. Tertiary peritonitis is the recurrent inflammation of the peritoneum that persists for 48 hours after surgery after a well-succeeded control of secondary peritonitis.¹³ It is usually the most delayed and severe consequence of an intra-abdominal infection such that patients who are diagnosed with tertiary peritonitis are immediately admitted into the hospital due to their critical state.¹³ In addition, tertiary peritonitis is often associated with severe underlying diseases, immunosuppression or complications from previous surgeries.

The symptoms of tertiary peritonitis consist of persistent abdominal pain, distended abdomen, abdominal tenderness and fever.⁴

What are the causes and symptoms of sterile peritonitis?

The fourth type of peritonitis is sterile peritonitis. Sterile peritonitis is the inflammation of the peritoneum, which shows no signs or symptoms of bacterial infection.¹⁴ In other words, there are other causes which cause sterile peritonitis. These other causes consist of chemical irritation, foreign material and autoimmune disorders.¹⁵ Chemical irritation consists of the presence of irritating substances, such as bile and stomach acid, within the abdominal cavity. These irritating substances can leak into the peritoneum due to perforations in nearby organs, such as the stomach. Foreign material consists of the implantation of foreign material within the peritoneal cavity. The peritoneal cavity may also contain remnants of e surgical mesh and gauze, which can trigger inflammatory responses. Additionally, autoimmune disorders, such as rheumatoid arthritis, can also contribute to the inflammation of the peritoneum.

The symptoms of sterile peritonitis include abdominal pain, abdominal distension, fever, nausea and changes in bowel habits.

Summary

To summarise, peritonitis is a serious disease which can affect a wide range of people. It exists in four different types: primary, secondary, tertiary and sterile, with tertiary being the most severe. Each type has its own causes but the range of symptoms across all types remains more or less similar.