A18.31 Tuberculous peritonitis

Name of the Condition

• Tuberculous peritonitis
• ICD Code: A18.31

Summary

Tuberculous peritonitis is a form of extrapulmonary tuberculosis where Mycobacterium tuberculosis infects the peritoneum, the lining of the abdominal cavity. This condition typically results from the spread of TB bacteria from a primary site, usually the lungs, via the bloodstream or lymphatic system. It can involve inflammation of the peritoneal membrane, leading to localized or systemic symptoms.

Causes

Tuberculous peritonitis is caused by the dissemination of Mycobacterium tuberculosis from an existing infection, most commonly pulmonary tuberculosis. The bacteria may travel to the abdominal region during active disease or reactivation of latent TB. Direct ingestion of infected material is rare but possible in certain cases.

Risk Factors

• Immunocompromised states, such as HIV/AIDS or chronic immunosuppressive therapy.
• History of untreated or inadequately treated tuberculosis.
• Close contact with individuals who have active TB.
• Living in or traveling to regions with high TB prevalence.
• Underlying conditions like diabetes, malnutrition, or chronic kidney disease.

Symptoms

• Abdominal pain or distension.
• Fever, chills, or night sweats.
• Nausea, vomiting, or loss of appetite.
• Unintentional weight loss.
• Ascites (fluid accumulation in the abdomen).

Diagnosis

Diagnosis involves a combination of clinical evaluation, imaging studies (e.g., ultrasound or CT scan), and laboratory tests. Peritoneal fluid analysis may show elevated white blood cells, low glucose, and high protein levels. Acid-fast bacilli (AFB) staining or culture of peritoneal fluid or tissue biopsy can confirm the presence of Mycobacterium tuberculosis. Histopathological examination of biopsy samples may reveal granulomas or caseating necrosis.

Treatment Options

Treatment typically involves a standard course of anti-tuberculosis medications, including isoniazid, rifampin, pyrazinamide, and ethambutol, administered for 6–9 months. Corticosteroids may be used in severe cases to reduce inflammation. Drainage of ascites or surgical intervention may be necessary for complications like bowel obstruction or abscess formation.

Prognosis and Follow-Up

With appropriate treatment, the prognosis is generally favorable, though recovery may take several months. Follow-up care includes monitoring for treatment response, managing side effects of medications, and ensuring completion of the full course of therapy. Regular clinical assessments and imaging may be used to evaluate resolution of symptoms and ascites.

Complications

• Bowel obstruction due to adhesions or strictures.
• Perforation of the intestinal wall.
• Severe malnutrition or cachexia.
• Chronic abdominal pain or discomfort.
• Recurrence of infection if treatment is incomplete.

Lifestyle & Prevention

• Complete the full course of prescribed anti-TB medications to prevent recurrence.
• Maintain good nutrition and hydration to support recovery.
• Practice good hygiene, especially in high-prevalence areas.
• Avoid close contact with individuals who have active TB until they are no longer infectious.
• Seek prompt medical care for persistent abdominal symptoms.

When to Seek Professional Help

Seek immediate medical attention if you experience severe abdominal pain, fever, vomiting, or signs of dehydration. Consult a healthcare provider if symptoms persist or worsen despite treatment, as these may indicate complications or treatment failure.

Tips for Medical Coders

When coding for tuberculous peritonitis (A18.31), ensure documentation supports the diagnosis, including clinical findings, imaging results, and laboratory confirmation. Verify that the code is used for peritoneal involvement specifically, as opposed to other abdominal TB manifestations. Document any associated conditions or complications to support additional coding if applicable.