Treatment of Peritoneal Tuberculosis
Peritoneal tuberculosis should be treated with the standard 6-month regimen used for pulmonary tuberculosis: 2 months of isoniazid, rifampicin, pyrazinamide, and ethambutol (2HRZE), followed by 4 months of isoniazid and rifampicin (4HR). 1
Standard Treatment Regimen
Initial Intensive Phase (First 2 Months)
- Administer four drugs daily: isoniazid (H), rifampicin (R), pyrazinamide (Z), and ethambutol (E) 1
- Daily dosing is strongly recommended over intermittent dosing during this phase 1
- Ethambutol may be omitted only in previously untreated patients who are HIV-negative and not contacts of drug-resistant cases, though this applies primarily to white patients in the original guideline 1
- Fixed-dose combinations of these drugs provide more convenient administration and may improve adherence 1
Continuation Phase (Next 4 Months)
- Continue isoniazid and rifampicin for 4 additional months after completing the intensive phase 1
- This can be administered daily or 2-3 times weekly under directly observed therapy (DOT) 1
- The continuation phase should only begin after confirming susceptibility to isoniazid and rifampicin 1
Evidence Supporting 6-Month Duration
The 6-month regimen is well-established for peritoneal tuberculosis based on multiple lines of evidence:
- Non-respiratory tuberculosis, including peritoneal disease, responds to the same 6-month regimen as pulmonary TB 1
- A Cochrane systematic review of 328 participants with intestinal and peritoneal TB found no difference in clinical cure rates between 6-month and 9-month regimens (RR 1.02,95% CI 0.97-1.08), with relapse being uncommon in both groups (2/140 in 6-month group vs 0/129 in 9-month group) 2
- The evidence quality for clinical cure is moderate, though confidence in relapse estimates is limited by small sample sizes 2
Drug Dosing
Adults
- Isoniazid: 5 mg/kg daily (maximum 300 mg) 3
- Rifampicin: 10 mg/kg daily 3
- Pyrazinamide: 35 mg/kg daily for patients <50 kg; 2.0 g daily for patients ≥50 kg 3
- Ethambutol: 15 mg/kg daily 3
Children
- Isoniazid: 10-15 mg/kg daily (maximum 300 mg) 3
- Rifampicin: Standard daily dose adjusted for weight 4
- Pyrazinamide: Standard daily dose adjusted for weight 4
- Ethambutol: Should be used with caution in children whose visual acuity cannot be monitored 3
Treatment Monitoring and Adherence
- Directly observed therapy (DOT) is the central element of successful TB management and should be implemented whenever possible 1, 3
- Patient-centered approaches should be individualized based on clinical and social history, using measures such as video-observed treatment, treatment supporters, and financial/social support 1
- Drug susceptibility testing should be performed on all initial isolates to guide therapy 3
- Monitor for clinical improvement; patients not responding after 3 months require reevaluation 4
Special Situations
Drug Resistance
- If isoniazid resistance is detected: Use rifampicin, ethambutol, pyrazinamide, and a later-generation fluoroquinolone for 6 months 1
- For multidrug-resistant TB (MDR-TB): Treatment must be based on drug susceptibility testing with consultation from a TB expert, using individualized regimens with at least 5 effective drugs 1, 3
HIV Co-infection
- The standard 6-month regimen is effective for HIV-positive patients with peritoneal TB 1
- However, HIV-positive patients with CD4+ counts <100 cells/mm³ may require extended treatment duration (9 months total) 3
- Daily therapy is recommended during the intensive phase for HIV-positive patients 3
Pregnancy
- Do not use streptomycin (causes congenital deafness) 3
- Pyrazinamide is not routinely recommended due to inadequate teratogenicity data 3
- Use isoniazid, rifampicin, and ethambutol as the initial regimen unless isoniazid resistance is documented to be <4% in the population 3
Adjuvant Therapy
Corticosteroids
- Not routinely indicated for peritoneal tuberculosis 1
- The 2017 WHO guidelines recommend corticosteroids for TB pericarditis, TB meningitis, renal TB (to prevent ureteric stenosis), and spinal TB with cord compression, but not for peritoneal disease 1
Surgery
- May be necessary to obtain diagnostic specimens when bacteriologic confirmation is difficult 3, 5
- Laparoscopy can provide tissue for histopathology and culture when ascitic fluid analysis is non-diagnostic 5
Common Pitfalls
- Do not extend treatment beyond 6 months without clear indication: Longer regimens increase costs, reduce adherence, and do not improve outcomes for drug-susceptible peritoneal TB 2
- Do not delay treatment while awaiting culture results: Peritoneal TB cultures can take 6 weeks to become positive; start treatment based on clinical suspicion and supportive findings 5
- Do not omit pyrazinamide from the initial phase: This would require extending total treatment duration to 9 months 1
- Monitor for hepatotoxicity: Isoniazid and pyrazinamide can cause severe hepatitis requiring drug withdrawal and potentially liver transplantation in extreme cases 6
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