Tuberculous peritonitis is a bacterial infection that affects the peritoneum. It commonly causes abdominal pain and fever, but symptoms may also include weight loss, tiredness, and a loss of appetite.

Doctors might refer to the condition as peritoneal or abdominal tuberculosis. It occurs due to infection of the peritoneum with Mycobacterium tuberculosis (M. tuberculosis). The peritoneum is a membrane in the abdomen and pelvis.

Keep reading to learn more about tuberculous peritonitis, including its symptoms, causes, diagnosis, and treatment options. This article will also explore potential complications and the outlook for a person with this condition.

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Tuberculous peritonitis is an infection of the peritoneum with M. tuberculosis. The peritoneum is a membrane that lines the abdomen and pelvis, covering many organs.

While M. tuberculosis most commonly affects the lungs — causing pulmonary tuberculosis — it sometimes affects other body parts.

Who is at risk?

According to research, tuberculous peritonitis is rare in the United States. It tends to affect people with certain risk factors, such as:

  • the elderly
  • individuals with AIDS
  • those living in poverty in cities
  • immigrants from countries where the condition is more common

A 2019 review reports that the peritoneum is the sixth most common site of tuberculosis outside of the lungs, accounting for 0.1–0.7% of all cases.

Learn more about tuberculosis.

Research notes that the two most common symptoms of tuberculous peritonitis are abdominal pain and fever.

Other symptoms occur more frequently in tuberculosis peritonitis than in other forms of abdominal tuberculosis. These may include:

A minority of individuals also have symptoms of pulmonary tuberculosis, such as a cough and coughing up blood.

The most common cause of tuberculous peritonitis is the reactivation of a latent — or inactive — tuberculosis infection in the peritoneum that has spread through the blood from a previous pulmonary infection.

Very rare cases may stem from drinking unpasteurized milk that contains Mycobacterium bovis.

According to evidence, one risk factor for developing the condition is having HIV or AIDS. Around 50% of people with these conditions develop manifestations of tuberculosis outside of the lungs, compared with 10–15% of those who do not have HIV or AIDS.

Tuberculous peritonitis also has links with the following conditions:

Research notes that diagnosing tuberculous peritonitis can be challenging if a doctor does not suspect the condition.

A doctor may order the following:

  • An ultrasound: This may show ascites, a buildup of fluid in the area.
  • A CT scan: This may reveal swelling of the lymph nodes and bowel thickening.
  • Other tests: Tests that measure substances in ascites fluid may also help.

However, the gold standard for diagnosis is laparoscopy and peritoneal biopsy.

Laparoscopy is a type of surgery that permits a doctor to look inside the internal structures of the body. A biopsy is the removal of tissue to examine under a microscope.

Research from 2019 suggests that treating tuberculous peritonitis involves using the same antibiotics that treat pulmonary tuberculosis.

The five most common first-line options include:

  • isoniazid (Nydrazid)
  • pyrazinamide
  • rifampin (Rifadin, Rimactane)
  • streptomycin
  • ethambutol (Myambutol)

Doctors treat the condition with a four-medication regimen over 2 months, then prescribe isoniazid and rifampin for 4 or more months.

People typically show responses within the first 3 months.

Doctors usually only use surgery if there are signs of complications.

Potential complications of tuberculous peritonitis include:

  • a bowel perforation, which is a hole in the innermost lining of the colon
  • a fistula, an atypical connection between two structures
  • hemorrhage or bleeding
  • intestinal obstruction from adhesions or blockages that form from fibrous bands of tissue and can prevent food from passing through the small or large intestine

Aside from complications that stem from the condition, complications may also occur due to treatment.

Specifically, it may cause toxicity in the liver, which can result in potentially serious effects in people who already have liver disease.

Some complications of tuberculous peritonitis can be life threatening.

A person’s outlook will depend on several factors.

A 2002 study found that the below factors were associated with higher death rates:

  • older age
  • a delay in starting treatment
  • underlying co-occurring conditions that are severe, such as:

The authors note that standard treatment for tuberculosis is highly effective, but diagnosing tuberculous peritonitis may involve delays. Delays in diagnosis and treatment can affect the likelihood of recovery.

A 2017 review cites older research that states that 80% of individuals experienced a worsening of their condition while waiting for a full evaluation and diagnosis. The overall death rate among those waiting was 35%.

Tuberculous peritonitis happens when M. tuberculosis affects the peritoneum. The most common cause is the reactivation of a latent tuberculosis infection in the peritoneum.

Symptoms include fever, abdominal pain, tiredness, weight loss, and loss of appetite. Although diagnosis can be challenging, a laparoscopy and peritoneal biopsy can provide confirmation. Treatment involves taking a long course of antibiotics.

Doctors may use surgery to address complications, such as an intestinal obstruction. Because a delay in treatment may lead to an unfavorable outcome, it is important for people to contact a doctor as soon as possible if they have symptoms of the condition.