fatality and Tb from _____
HIV
organism causing TB
Mycobacterium tuberculosis
acid-fast aerobic rod
transmission
inhalation of aerosolized infectious droplets
initial pathophys
- bacilli grow in lungs
- vigorous immune response
- droplet nuclei deposited in lung airspaces
- alveolar macrophages engulf bacilli
types of TB
- Primary TB
- Progressive primary tuberculosis
- Latent TB
- Reactive TB
primary TB
growth occurs, kills macrophages and releases bacilli
local infection and destruction
Unable to be walled off, active form of Dz
progressive primary tuberculosis
hematogenous and lymphatic spread of infection
targets: lymph nodes, vertebrae, adrenal gland, meninges, GI tract
OXYGEN rich areas
latent TB
lung collects and encaseates within granulomas
lies dormant in lungs (can’t get rid of it!)
NOT infectious, NO active infection
reactive TB
disruption of cellular immune function that cause break down of granuloma and development of TB years to months following exposure
when is risk of development of reactive TB
<2 yrs following exposure
young and old increased risk
impaired immune action
populations in US at risk for TB
immigrants
low SES
homeless
crowded conditions
lesions of TB
granuloma with central caseation necrosis
has low levels of O2, low pH, high levels of fatty acids to inhibit growth
symptoms of active TB
insidious
cough, weight loss, fatigue, fever, night sweats, hemoptysis
extrapulmonary TB
involvement of sites with high O2 tension
mediastinal, retroperitoneal, cervical/scrofula lymph nodes, vertebrae, adrenal glands, meninges and GI tract
TB exposure
purified TB injected into skin and strong cell mediated immune response will occur if exposed again
delayed type hypersensitivity response then read again in 47-72 hrs
PPD results high risk
5 mm or greater
close contacts, immunosuppressed, clinical or radiographic evidence of TB
PPD results low-intermediate risk
10 mm +
persons born in high TB incidence, occupational exposure
PPD results unlikely risk
15 mm +
qunatiferon test
T cells from those infected with TB release measurable amounts of interferon gamma when mixed with Ags of TB
screen for latent AND active TB
evaluation for Active TB infection
PA and lateral CXR
if abnormal - contrast CT of chest
if TB is suggestive after imaging…
sputum smear, sputum culture, nucleic acid testing of sputum
sputum smear for TB
suggestive but not diagnostic
may take long time for results
nucleic acid testing
rapidly diagnostic and can guid treatment
lymph node biopsy
preformed if lymphadenopathy present
determine second disorder present or due to TB
typical TB CXR
apical cavitary disease, nodules, infiltrates
miliary TB
hematologic or lymphatic spread
widespread small nodular densities
tx of active TB
hospitalization
negative pressure ventilation and air exhausted to outside/filtered
report of confirmed AND suspected cases to CDC
4 drug regimen
labs done for active TB tx
baseline CBC renal function LFTs pregnancy HIV status
4 drug regimen
isoniazid
rifampin
pyrazinamide
ethambutol/streptomycin
isoniazid toxicity
peripheral neuropathy
increased transaminases
weakness
Rifampin toxicity
increased transaminases
pancreatitis
fever, rash, N/V/D
pyrazinamide toxicity
increased transaminases, NV
ethambutol toxicity
optic neuritis (decreased visual acuity)
color blindness
how often are sputum spheres collected?
weekly during tx
isolation until 3 consecutive negative smears
tx concomitant HIV
longer duration of rx
some drug interactions with HAART
tx of extrapulmonary TB
longer duration of rx
consider surgical debridement of bone and corticosteroid
tx of TB in pregnancy
teratogen risk of meds
breast feeing OK
MDR TB
associated with high mortality and short survival
prolonged (2-3 yrs) survival
how do you tx latent TB?
3-9 mo tx of anti TB meds
have to rule out active disease and concomitant HIV
