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Tuberculosis. August 17, 2010. Tuberculosis. Mycobacterium tuberculosis Fastidious, aerobic, acid-fast bacillus Tremendous increase in incidence over 25 yrs On average, a dult pts infect 8 to 15 individuals prior to being diagnosed Increased risk HIV, diabetes, renal failure
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Tuberculosis August 17, 2010
Tuberculosis • Mycobacterium tuberculosis • Fastidious, aerobic, acid-fast bacillus • Tremendous increase in incidence over 25 yrs • On average, adult pts infect 8 to 15 individuals prior to being diagnosed • Increased risk • HIV, diabetes, renal failure • 9% of pts in US coinfected with HIV
Three Groups • Exposed, but status unknown • Insufficient period of time to rely on TST • Latent TB Infection • Positive TST but no signs or symptoms, nl CXR • 30% global population • 5-10% progress to disease • TB Disease • Clinical or radiographic findings • Reportable
Resistance • Drug-resistant TB (DR-TB) • Relapse after tx • Positive sputum smear after 2mos tx • Multidrug-resistant TB (MDR-TB) • Resistance to at least 2 first line abx (1% in US) • Extensively drug-resistant TB • Resistance to INH, rifampin, any fluoroquinolone, and any second line IV agent
Pathogenesis • Lymphadenitis • Ghon complex • Focus of infection with enlarged regional nodes • Contained • Spread rapidly • Reactivated later in life • Most clinical manifestations in children 1-2 yrs from initial infection
Clinical Manifestations • Lung is most common site of infxn (80%) • Tuberculous LAD (67%) • Meningitis (13%) • Most commonly infants and toddlers • Pleural, miliary, skeletal account for <6%
Pulmonary Disease • Primary Parenchymal • Most common, Infants most likely to be symptomatic • Cough, low-grade fever, wt loss • CXR: hilar or mediastinaladenopathy • Collapse-consolidation pattern • Progressive Primary Disease • Lung tissue destruction and cavitary lesion • Reactivation disease • Immunocompromised adolescents or adults
Lymphatic Disease • Most common extrapulmonary form of TB • Usually cervical nodes • Slightly older than pts with nontuberculousmycobacterial LAD • 2-4cm, may have overlying violaceous skin color • Lack classic findings of pyogenic nodes • CXR abnl in 33% • Tx: 6 mos multidrug tx, +/- excision
CNS Disease • 50% are <2y/o • May include CNS vasculitis or increased ICP • Consider in cases of childhood stroke • Tuberculomas in 5% of CNS TB • Single rim-enhancing lesion • CSF: lymphocytes, low glucose, high protein • TST in only 33% • CXR in 90% • Highest morbidity/mortality
Diagnosis • TST, epidemiologic info, clinical/radiographic findings • Children: vigorous response to few organisms • 30% with positive cx (AFB) • TST (purified protein derivative or Mantoux) • Read at 48-72hrs • Delayed hypersensitivity rxn in those exposed • Negative in 15% of cases • Interferon-gamma release assay (IGRA) • Use CXR, CT not routine
Treatment • TB Exposure • Contact with index case, but asymptomatic, neg TST and CXR • If < 4y/o or immunocompromised • INH pending results of repeat TST (2-3 mos) • LTBI • INH for 9mos • If intermittently dosed, used Directly Observed Tx
Treatment • TB Disease • 4 drug Directly Observed Therapy • INH, rifampin, pyrazinamide, ethambutol • 6 months • If CNS involvement, 9-12 mos
What about infant of TB mom? • Maternal LTBI… no workup or isolation for infant • Maternal positive TST and CXR abnl but not consistent with TB • Maternal AFB sputum smear neg • No isolation or workup for infant • Tx maternal LTBI
What about infant of TB mom? • Mom with CXR consistent with TB • Evaluate infant for TB • CXR and PE • If infant is normal • Separate from mother until she is being treated and infant starts INH • Once on INH, separation unnecessary and may breastfeed
Health Care Workers • Positive TST with normal CXR • Offer therapy for LTBI • Repeat screening should be done with CXR, not TST
Prevention • Negative pressure and N95 use in children • Cavitary or extensive pulmonary involvement • AFB positive TB • Procedures such as intubation/bronchoscopy • BCG vaccine in US • Children continually exposed to MDR-TB • Continually exposed to adults who have infectious TB who cannot be removed from setting