Term
| How does M. Tuberculosis spread? |
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Definition
M. Tuberculosis
-spread through airborne droplets
-can stay airborne for 1 hr.
Transmission More Likely
1) Caviatary or laryngeal disease: Billions of bacilli
2) Sputum AFB Smear +++
3) Coughing ( & sneezing & talking)
4) Household Contact |
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Term
| What features of M. Tuberculosis make it an effective pathogen? |
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Definition
Pathogenesis of Tb:
-bacterial particles are ingested & taken up by alveolar macrophages
-mycobacterial are not killed
-prevent acidification & fusion w/ lysosome,s and their thick cell wall makes them relatively resistant to reactive oxygen and nitrogen intermediates
-remains latent for many years-creating a stable reservior difficult to eradicate |
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Term
| How is tuberculosis disease diagnosed? |
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Definition
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Term
| Where does Ractivation of TB occur? |
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Definition
REactivation Diease
-upper lobes, apical/posterior segments w/ cavity formation |
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Term
| What is the Major Utility of the PPD test? |
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Definition
PPD
-major utility is for surveilance of healthy persons |
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Term
| Who may show a false negative PPD? |
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Definition
False Negative PPD
1) Acutely ill
2) Malnourished patients
3) pts taking steroids
4) HIV
5) Certain TB syndromes (pleural TB, miliary TB) |
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Term
| How may have False Postive PPD's |
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Definition
False Positive PPD's
1) Recent BCG vaccinees
2) in ares w/ high environmental non-tuberculos mycobacterial prevalence |
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Term
| What are the two things a Dr. should do if a PPD is pos> |
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Definition
Positive PPD
-First: rule out active disease
-Second: rule out prior TB Therapy |
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Term
| What is the usual presentation of a pt w/ TB diease? |
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Definition
TB Disease
-pt comes in w/ weight loss, fever, NIGHT SWEATS, cough w/ BLOOD |
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Term
| How does Drug Resistance in M. Tuberculosis arise? |
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Definition
M. Tuberculosis Resistance
-there are naturally occurring chromosomal mutations
-we are selecting for mutations by:
1)singel drug therapy of multi-bacillary diease
2)Sporadic Therapy
3)Inadequate doses of drugs |
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Term
| What is the difference btwn MDR-TB & XDR-TB? |
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Definition
MRR-TB
-resistant to isoniazid & Rifampicin
XDR-TB
-resistant to isoniazid, rifampicin
-plus fluoroquinoloine
-plue at lease 1 of 3 injectable second-line drugs |
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Term
| Typical presentation of pt w/ M. Avium-Intracellulare |
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Definition
M. Avium-Intracellulare
-TB-like lung diease
-older male pts w/ prior TB or bronchiectasis or other lung diease (COPD)
-thin middle-aged women w/ no underlying diease except often scoliosis
-Typical CT appearce of TREE-IN-BUD densities |
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Term
| Presentation of pt w/ Nocardiosis |
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Definition
Nocardiosis
-Largely in Immunocompromised (T-cell deficient) persons, with soil exposure
Cavitating Nodules in lung (50%) and Central Nervous System (30%) - PMN reaction (not granulomas)
Treat with Sulfa drugs for at least 6 months. |
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Term
| Presentation of pt w/ Actinomyces |
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Definition
Actinomyces
-ImmunoCOMPETENT patients with subtle breaks in mucosal surfaces, allowing entry of endogenous Actinomyces species
Form large tumors in neck, chest, abdomen & pelvis, with necrosis and sinus tract formation
Fibrosis/granulation tissue surrounding central necrosis ; form “sulfur granules” with clumps of gram-positive filamentous rods
Treat with Penicillin for 6-12 months |
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