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12 Cards in this Set
- Front
- Back
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Why did case rates of Tb increase in the US in the 1990s?
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Appearance of HIV-->increased risk of progression to disease
Migration to US from SE Asia (higher prevalence of Tb there) Crumbling health infrastructure in marginalized populations |
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How is Tb spread?
Which form of Tb is spread? |
Person to person
Must have PULMONARY Tb Organism is spread via aerosolized droplet nuclei that remain in air for up to 6 hours after coughing/breathing/sneezing Transmission DOES NOT occur by fomites |
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What events occur once someone has inhaled pulmonary Tb droplet nuclei--end with Tb's dormant state.
Where does Tb lie dormant? |
-Organism is inspired into LOWER LOBES
-Alveolar macs and WBCs phagocytize -Carried to lymphatics, systemic circuln -Cell-mediated immunity act'd, organism becomes dormant (most commonly in apices of lung, long bone or kidneys--areas of high O2 tension) |
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In immunocompetent patient, what is risk of developing Tb while Tb is in latent form?
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10% risk that fluctuates over lifetime; 5% will progress after 2 years, 5% will progress within 2 years
Diabetes increases risk by 3 fold, while HIV increases risk by 100 fold |
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Where can Tb infection occur?
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Anywhere (systemic circulation), but occurs most commonly in lungs.
80% occurs in lungs, 20% elsewhere, e.g., eyes. |
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Exposure to Tb can lead to ________, which leads to _________, and can result in ___________.
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Exposure-->Infection-->Disease-->Contagion
Only pulmonary cases are contagious! |
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Which epidemiologic groups are at risk for developing Tb (in the US)?
Presentation of Tb? |
At risk groups: foreign born, HIV, DM, chronic renal failure, steroid use
Presentation: non-specific; chronic febrile illness unresponsive to abx |
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Clinical manifestations of Tb in pulmonary system.
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Chronic cough, fever, weight loss
May not have syx if early in dz |
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Diagnosis of Tb
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Gold standard-->culture (slow; takes up to 6 weeks)
Mostly depends on physician's suspicion |
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Treatment of Tb (latent vs cavitary Tb disease)
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INH, Rifampin at least 6 months
If Latent and 10-100 organisms present, use 1 drug. If Cavitary and 100 billion organisms present, use 2 drugs. Do not uncouple or will risk mutation and drug resistance! |
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What is the main challenge to Tb control?
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Adherence to tx
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Utility of BCG Vaccine
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Not the same globally due to genetic shift.
Modulates Tb disease at childhood; if get Tb under 2 years of age, don't have developed immune response, and can result in TB meningitis. BCG vaccines prevents the meningitis. Doesn't prevent TB infection, or TB in adults. Effect wanes with time. |
