What are the treatment guidelines for a patient with HIV (Human Immunodeficiency Virus) and TB (Tuberculosis) lymphadenitis?

Treatment Guidelines for HIV-TB Lymphadenitis

Core Treatment Recommendation

All HIV-infected patients with TB lymphadenitis should receive immediate directly observed therapy with a rifabutin-based four-drug regimen (isoniazid, rifabutin, pyrazinamide, and ethambutol) for 2 months followed by isoniazid and rifabutin for 4 months, with concurrent antiretroviral therapy initiated within 2 weeks if CD4 <50 cells/μL or within 8-12 weeks if CD4 ≥50 cells/μL. 1, 2

Initial TB Treatment Regimen

Intensive Phase (First 2 Months)

• Administer isoniazid, rifabutin, pyrazinamide, and ethambutol daily under direct observation 1, 2
• Rifabutin is preferred over rifampin due to fewer drug interactions with protease inhibitors and NNRTIs 3
• Add pyridoxine (vitamin B6) 25-50 mg daily to all HIV-infected patients receiving isoniazid to prevent peripheral neuropathy 1, 2, 4

Continuation Phase (Next 4 Months)

• Continue isoniazid and rifabutin daily or twice weekly 1
• Extend treatment to 9 months if CD4 count <100 cells/mm³, positive cultures at 2 months, or delayed clinical response 1, 2, 4

Antiretroviral Therapy Timing

For Patients Not Yet on ART

• If CD4 <50 cells/μL: Start ART within 2 weeks of TB treatment initiation 2, 5
• If CD4 ≥50 cells/μL: Start ART within 8-12 weeks of TB treatment initiation 2, 5
• Earlier ART (≤4 weeks) reduces mortality by 6% in patients with CD4 ≤50 cells/mm³ but shows no mortality benefit in those with higher CD4 counts 5

For Patients Already on ART

• Continue current antiretroviral therapy without interruption 3, 1
• Never stop protease inhibitor or NNRTI therapy to accommodate rifampin use, as this increases mortality risk 3, 4
• Review and modify the ART regimen to ensure compatibility with rifabutin 1

Drug Interaction Management

Rifabutin Dose Adjustments

• Reduce rifabutin from 300 mg to 150 mg daily when used with indinavir, nelfinavir, or amprenavir 2
• Increase rifabutin from 300 mg to 450 mg daily when used with efavirenz 2
• Rifampin is contraindicated with protease inhibitors or NNRTIs due to critical drug interactions that cause treatment failure 3, 4

Alternative Regimen if Rifabutin Unavailable

• Use a streptomycin-based alternative regimen that does not contain rifamycin 3

Immune Reconstitution Inflammatory Syndrome (IRIS) Management

Recognition and Risk Factors

• IRIS occurs more frequently when ART is started within 4 weeks of TB treatment (incidence 8.86 vs 5.02 per 100 person-months) 6
• Paradoxical worsening of lymphadenitis may occur during treatment when immune function is restored 3, 7
• IRIS does not increase mortality and should not prompt cessation of therapy 8, 9

Treatment Approach

• Treat mild IRIS with nonsteroidal anti-inflammatory drugs 1
• For severe IRIS: Consider prednisone 1-2 mg/kg/day for 1-2 weeks, then taper 1
• Continue both TB treatment and ART unless space-occupying lesions develop 9
• Lymphadenitis may recur years after treatment completion as an inflammatory rather than microbiological recurrence 7

Directly Observed Therapy (DOT)

Implement directly observed therapy for all HIV-TB coinfected patients to ensure adherence and prevent drug resistance 3, 1, 2, 4

Monitoring Requirements

Baseline Assessments

• Drug susceptibility testing on TB isolates 1
• Liver function tests, serum creatinine, platelet count 1
• CD4 count and HIV viral load 1

Follow-up Monitoring

• Sputum microscopy and culture at 2 months to assess treatment response 1, 2
• CD4 count and HIV viral load every 3 months 3, 1, 2
• Regular liver function monitoring due to overlapping hepatotoxicity from multiple medications 1, 2

Critical Pitfalls to Avoid

• Never use rifampin with protease inhibitors or NNRTIs without switching to rifabutin—this causes treatment failure of either HIV or TB 3, 4
• Never interrupt antiretroviral therapy to accommodate rifampin use—this increases mortality 3
• Never delay TB treatment to accommodate other medications—TB treatment is the immediate priority for mortality reduction 4
• Never add a single drug to a failing regimen—this rapidly generates resistance 4
• Allow a 2-week washout period between the last dose of rifampin and the first dose of protease inhibitors or NNRTIs if switching regimens 3