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Management of TB: Medical and Public Health considerations. Clydette Powell, MD, MPH, FAAP November 2012. Learning Objectives. Briefly review the basics of TB and its medical management
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Management of TB:Medical and Public Health considerations Clydette Powell, MD, MPH, FAAP November 2012
Learning Objectives • Briefly review the basics of TB and its medical management • Describe the global TB situation and challenges: DOTS expansion, TB/HIV, M/XDR-TB, engaging all providers • Describe the need and approach for new drugs and diagnostics, with focus on Gene Xpert • Describe the priority settings for Xpert and its implications for patients, providers, and public health authorities
MDR-TB patient • Migrant worker, South Asia • Battling TB for 8 years • Dx at 20 yo – Rx x 6 mos, “cured” • 3 yrs later- cough and weight loss • Rx- higher doses, for 8 mos • 2 yrs later – Rx for 4 mos • Finally dx’d with MDR-TB • Severe side effects, unable to work
The Global Burden of TB Number of cases diagnosed, 2011 Estimated number of cases, 2011 5.8 million (67%) 8.7 million (8.3–9.0 million) All forms of TB ~600,000 (55%) HIV-associated TB 1.1 million (1.0–1.2 million) 60,000 (9%) 650,000 out of 12 million prevalent TB cases Multidrug-resistant TB Source: WHO Global Tuberculosis Control Report 2012
TB Incidence (%) by WHO Region Most cases are in Asia
What Needs to Be done to Control TB • Improve TB case detection (Prompt and early identification): to minimize TB transmission • Community education for early symptom recognition and action • Aggressive contact investigation and management • Minimize factors associated with delay in seeking medical care and establishing definitive TB diagnosis • Engage all health care providers, civil society organization and other sectors in TB control
What Needs to Be done to Control TB • Improve TB prevention through scaling up of infection control and targeted treatment of a latent TB infection • Support development and deployment of new tools for TB diagnosis, treatment and prevention
Global Plan to Stop TB 2011–2015 Launched 13 October 2010
LTBI vs. TB Disease TB Case NOT a TB Case
Evolution in TB Diagnostics 2006 - 2010 1882 1895 1907 1936 1950 1980s Short-course chemotherapy; Liquid culture developed LED/fluorescence microscopy; Line Probe Assay First anti-TB drugs discovered Robert Koch: identified TB bacilli Tuberculin skin test developed Solid culture used to identify TB HIV & MDR-TB
Diagnosis of Tuberculosis Disease • Identification of individuals with TB symptoms • Collection of specimen • Laboratory examination: • Microscopic Exam • Culture • Chest X-Ray • Molecular: • GeneXpert • Line Probe Assay
Specimen Collection • Persons suspected of having pulmonary or laryngeal TB should have at least three sputum specimens examined by acid-fast bacilli and culture • It is best to obtain a series of early-morning specimens collected on 3 consecutive days. • Specimens should be obtained in an isolated, well-ventilated area or sputum collection booth.
Specimen Collection: Gastric Aspiration • Gastric aspiration can also be used to obtain specimens of swallowed sputum. • It is the best way to obtain specimens from infants and some young children who cannot produce sputum.
Laboratory Examination: Smear Microscopy • Detection of Acid Fast Bacilli in stained smears examined microscopically may provide the first bacteriologic clue of TB. • Smear examination is a quick procedure; results should be available within 24 hours of specimen collection.
Laboratory Examination: Cultures • Positive cultures for M. tuberculosis confirm the diagnosis of TB disease • Conventional culture on solid medium (egg or agar): Labor intensive and provides results in 1-8 weeks • The BACTEC Radiometric System and other recently developed liquid medium systems allow detection of most mycobacterial growth in 4 to 14 days compared to 3 to 6 weeks for solid media
Laboratory Examination: Molecular • Line Probe Assay • GeneXpert: A fully-automated diagnostic molecular test that simultaneously detects TB and rifampicin drug resistance and provides results in less than 2 hours
Treatment of TB disease: Goals • The overall goals for the treatment of TB are to: • Cure the individual patient, minimizing death and disability from TB • Interrupt the transmission of M. tuberculosis to other persons
Treatment Regimens • TB treatment regimen consists of two phases: • Initial phase: 2 months of 4 drugs (isoniazid, rifampicin, pyrazinamide and ethambutol or streptomycin) aimed at rapidly killing actively dividing bacteria, resulting in the negativization of sputum • Continuation phase: 4 to 7 months of at least 2 drugs (isoniazid and rifampicin) aimed at killing any remaining or dormant bacilli and preventing recurrence
Treatment monitoring • Monitor for adherence • Monitor for Adverse Drugs Events • Monitor response to treatment: • Smear Microscopy at 2, 5, 6 months
HIV testing for TB patients expanding Although more needed to reach 100% targets in Global Plan Several countries show very high testing rates achievable Percentage of TB patients Africa Rwanda: 97% Kenya: 88% Tanzania: 88% Malawi: 86% Mozambique: 84% World
CPT and ART for HIV-positive TB patients also expanding Although more needed to reach 100% targets in Global Plan Several countries show higher rates of enrolment are possible Percentage of HIV+ TB patients CPT CPT 86%–97% in 2009 Kenya, Malawi, Mozambique, Rwanda, Tanzania, Uganda ART close to 50% in 2009 Rwanda, Malawi ART
18/36 HBCs* have insufficient capacity to diagnose MDR-TB ≥1 <1 Culture laboratories per 5M and DST laboratories per 10M population, 2009 *HBC= high-burden country Countries = Afghanistan, Armenia, Azerbaijan, Bangladesh, Belarus, Brazil, Bulgaria, Cambodia, China, DR Congo, Estonia, Ethiopia, Georgia, India, Indonesia, Kazakhstan, Kenya, Kyrgyzstan, Latvia, Lithuania, Mozambique, Myanmar, Nigeria, Pakistan, Philippines, Republic of Moldova, Russian Federation, South Africa, Tajikistan, Tanzania, Thailand, Uganda, Ukraine, Uzbekistan, Viet Nam, Zimbabwe
What is GeneXpert MTD/RIF? • A fully-automated diagnostic molecular test that simultaneously detects TB and rifampicin drug resistance • Can provide results in less than 2 hours • Specially designed for use at the district or sub-district level of the health system