Transcript Tuberculosis

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 mediastinal adenopathy
• 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 nontuberculous
mycobacterial 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
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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