Peritonitis: Causes, Symptoms And Treatment

Peritonitis is inflammation, usually caused by infection, of the peritoneum and the peritoneal cavity. Now, what is the peritoneum?

The peritoneum is a serous membrane that surrounds the abdominal viscera and the abdominal cavity. It has two layers, the space between them forming the peritoneal cavity. When this structure is colonized by pathogenic microorganisms, a serious condition occurs that requires rapid medical intervention.

Let’s see more about the peritoneum below to understand how peritonitis can affect you.

A little more about the anatomy of the peritoneum

Viscera that are completely covered by peritoneum are called intraperitoneal , while those that are only partially covered are retroperitoneal.

The limits of the peritoneum are as follows:

• Top: diaphragm.
• Lower: pelvic floor.
• Lateral: limits of the abdominal cavity.

This membrane has two layers, the parietal peritoneum, which lines the abdominal cavity; and the viscera l, which covers the viscera. A cavity is delimited between both layers, which is the peritoneal cavity.

It is interesting to know that this cavity is closed in men and open in women, through the fallopian tubes. In addition, it contains between 50 and 100 milliliters of a serous fluid called ascitic fluid.

The folds of the peritoneum are made up of mesos, ligaments and omentals, which divide the abdominal cavity into nine spaces and direct the exit of the different fluids from the cavity, so it  can be predicted where possible infections will spread. 

Types of peritonitis

Peritonitis can be divided based on different criteria:

• According to its location:
  • Generalized.
  • Located.

• According to its evolution:
  • Sharp
  • Chronicle.

• According to its etiology:
  • Septic (produced by bacteria).
  • Aseptic (irritation of the peritoneum without the presence of bacteria).
• According to its pathogenesis:
  • Primary.
  • High schools.
  • Tertiary.

Let’s see below the types of peritonitis, according to its pathogenesis.

Primary peritonitis

Primary peritonitis is an infection of the ascites fluid with inflammation of the peritoneum in which there is no abdominal focus of infection. It is not very frequent, and it occurs more during the pediatric age.

Within this pathology, different pictures that we are going to develop can be differentiated.

1. Primary peritonitis in cirrhotic patients

Primary peritonitis in patients with cirrhosis is a condition that appears in up to 25% of patients with cirrhosis and its mortality is high. This is because liver cirrhosis alters the individual’s defenses, thus promoting bacterial proliferation.

The bacteria come from the intestinal lumen or from extra-intestinal infections, such as pneumonia or a urinary tract infection. The most common is that they are due to a single bacterial type, unlike secondary peritonitis where there is usually more than one type of microorganism.

The most frequent are  Escherichia coli  and bacteria of the genus  Streptococcus. 

It is diagnosed with an aspirate of the ascitic fluid for analysis. This fluid will have little protein and an increase in neutrophils (more than 250 per cubic millimeter), blood cells that are involved in defending against infection.

With a culture of the liquid you can know the microorganism that produces them. It is a condition that requires rapid antibiotic treatment.

Other causes of primary peritonitis are infections such as tuberculosis, some autoimmune processes, and peritoneal dialysis.

2. Primary peritonitis due to peritoneal dialysis

Peritoneal dialysis is a therapeutic procedure to clean the peritoneal cavity. It consists of introducing sterile fluid into the peritoneal cavity with a catheter.

After a few hours this liquid is eliminated, dragging the waste products that were in this cavity. In some cases the cavity can become contaminated and a picture of peritonitis appears.

It is diagnosed because the patient will be feverish and with abdominal pain shortly after the procedure. In addition, the ascitic fluid acquires a cloudy color with an increase in leukocytes, blood cells that are part of the immune system.

In this case a culture will be useful to clarify the diagnosis. And with regard to treatment, in this picture it is necessary to introduce antibiotics with the dialysate, reviewing the catheter and if necessary, withdrawing it.

Secondary peritonitis

In this case, the inflammation of the peritoneum is the consequence of an intestinal infection. It may be due to a mild infection, in which the intestinal wall is not perforated; or serious pictures with intestinal perforation.

The most common is peritonitis as a complication of appendicitis, in which the wall of the appendix ruptures and bacteria reach the peritoneum. 

Although intestinal perforation from infection is the most common cause of secondary peritonitis, there are other causes. Inflammation of the peritoneum may be due to an infiltration of tumor cells due to the spread of cancer. It can also be a consequence of a postoperative period or trauma.

The intestinal wall contains different microorganisms that make up the intestinal microbiota or flora. This flora varies in each intestinal tract, so that depending on where the perforation occurs, the bacteria will be one or the other. For this reason, these infections are usually polymicrobial.

Patients with peritonitis present with fever and localized abdominal pain. In addition, they increase the leukocytes in the analysis.

In severe cases, the pain is generalized and the patient shows signs of multi-organ involvement. An abdominal X-ray can reveal the presence of abdominal gas.

Once peritonitis is suspected, the test that provides the most information is computerized axial tomography (CT).

Although in mild cases it may not be necessary, with an abdominal CT it is possible to identify the source of infection, the cause, the presence of abscesses or free fluid, and so on.

Treatment must be urgent, both surgical to correct the perforation or the cause of the inflammation; as a doctor with antibiotics and fluid therapy to stabilize the patient.

Tertiary peritonitis

Tertiary peritonitis is a less frequent condition, associated with patients with comorbidities or immunosuppressed patients.

Treatment for primary or secondary peritonitis has failed and the infection is persistent even though the focus of infection is controlled. This peritonitis is usually generalized, sometimes associated with multiple organ involvement. In this case, the fluid must be removed from the abdomen and a specific treatment must be applied against the causative microorganism.

As we have seen, there are different types of peritonitis and each of them must be treated early to avoid complications. For this reason, the medical consultation is unavoidable.