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Improving diagnosis of TB among HIV infected persons. Alwyn Mwinga HIV Implementers Meeting 18 June 2007. Background – what do we know?. Focus of TB control programs is Smear positive cases Source of infection Program performance evaluated by outcomes of smear positive cases
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Improving diagnosis of TB among HIV infected persons Alwyn Mwinga HIV Implementers Meeting 18 June 2007
Background – what do we know? • Focus of TB control programs is Smear positive cases • Source of infection • Program performance evaluated by outcomes of smear positive cases • TB programs in high TB/HIV settings have increasing burden of smear negative disease • Smear positive – 65% of total TB cases, 50% of all cases • Zambia 2005 – Sm + - 33% of PTB, 28% of all cases
Current algorithim Smear negative Antibiotic, CXR Review in 2-4 weeks If no improvement, repeat sputum, x-ray If smear negative, and pt and/or CXR worse, seek other diagnosis, if no other diagnosis treat as TB If pt stable, no change in x-ray, repeat sputum in 4 weeks
The prevailing practice Empiric antibiotics trial = up to 4 weeks AFB smears = up to 9 CXR = very late after a number of visits Time before diagnosis = 13 – 44 days Number of consultations = 5 – 7 times Not included : HIV status, severity, culture In the meantime patients die
Delays in diagnosis Increased mortality in smear negative disease Public confidence in program Transmission potential? – 17% transmission in NY(1999 – Behr, Lancet) Change in focus to smear negative disease
Laboratory 10,000 bacilli/ ml required for positive result Sample quality Concentration methods Improved technical capacity for lab techs Training QA/QC Work load Introduction of more sensitive techniques Fluorescent microscopy Increased diagnosis of smear positive disease Training, facilities, waste disposal LED Expanded access to culture Liquid culture Improving diagnosis of smear negative disease
Clinical evaluation Include questions to identify HIV risk factors HIV testing Introduce PICT for TB suspects Earlier identification of HIV status and consideration for other OIs Radiological investigation Supporting evidence for TB Introduce earlier in diagnostic algorithm Improving diagnosis of smear negative disease
Improving diagnosis of resistant cases Introduction of culture for all cases failing treatment Failure at 5 months, 8 months Any smear positive results after an initial smear negative result Routine culture at diagnosis for all re-treatment cases