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17 Cards in this Set
- Front
- Back
What are the two species of mycobacterium?
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Mycobacterium tuberculosis and Mycobacterium leprae
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What are the two acid-fast staining bugs?
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Mycobacteria and Nocardia
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Mycobacteria - aerobes or anaerobes?
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Obligate aerobes
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Growth and pathogenesis of Mycobacterium tuberculosis?
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Facultative intracellular growth - allows the bacteria to cruise through the lymphatics and blood. Eventual macrophage attack results in local destruction of tissue and caseous necrosis.
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PPD? what does it detect?
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Purified Protein Derivative. Detects whether a person has been exposed to/infected with tuberculosis, NOT necessarily active tuberculosis.
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Describe primary tuberculosis? Transmission
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Usually a subclinical lung infection. Transmitted via aerosolized droplet nuclei, which land in the middle and lower lung zones. Cell-mediated immunity walls off and suppresses the bacteria, which lie dormant.
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Describe secondary tuberculosis? aka?
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Aka reactivation TB. Infection can occur in any organ system seeded during the primary infection.
1. Pulmonary - most coomon 2. Pleural, pericardial infection 3. Lymph node infection 4. Kidney 5. Skeletal 6. Chronic arthritis of a joint 7. Subacute meningitis 8. Miliary tuberculosis |
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What is a Ghon focus?
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A calcified tubercle in the middle or lower lung zone.
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What is a Ghon complex?
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A Ghon focus accompanied by perihilar lymph node calcified granulomas.
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What is the general presentation of TB?
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Chronic - weight loss, low-grade fever, symptoms related to the organ system infected. Often confused with cancer; one of the great imitators.
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How can TB be diagnosed?
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PPD skin test, chest Xray, and sputum acid-fast stain and culture.
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What is the lifetime reactivation risk in patients exposed to TB? What is the ANNUAL reactivation risk in HIV patients?
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10% for both.
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What is Mycobacterium avium-intracellulare?
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Usually only affects birds and other animals - but infects up to 50% of AIDS patients.
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Leprosy involves which parts of the body?
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The cooler areas - skin (except the armpit, grouin and perineum), the superficial nerves, eyes, nose, and testes.
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What is the severest form of leprosy? Manifestations?
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Lepromatous leprosy (LL) - no cell-mediated immune response can be mounted. Leonine facies (lion face), saddlenose deformity, internal testicular damage, loss of sensation in glove and stocking distribution.
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What is tuberculoid leprosy?
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Patients can mount a cell-mediated defense - milder and often self-limiting disease.
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How is leprosy tested for?
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Lepromin skin test - measures the ability of the host to mount a delayed hypersensitivity reaction against antigens of Mycobacterium leprae.
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