Term
| Book Question: In what populations is TB most common? |
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Definition
| disadvantaged populations, such as the malnourished, homeless, and those living in overcrowded and substandard housing. |
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Term
| Book Question: What is the most common pulmonary sx in TB? |
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Definition
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Term
| Book Question: In TB meningitis, do most pts present w/ or w/o evidence of active TB elsewhere or hx of prior TB? |
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Definition
| evidence of active tb elsewhere or hx of prior tb is presnet in upt to 75% of pts. |
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Term
| Book Question: In TB meningitis, are acid-fast stains of CSF most often positive or negative? |
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Definition
| acid-fast stains of csf are usually negative |
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Term
| Book Question: In TB meningitis, is the TB skin test most often positive or negative? |
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Definition
| usually (but not always) positive |
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Term
| Book Question: In reactivation of TB, where do xrt abnormalities most often occur? |
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Definition
| the usual location is in the apical or post segments of the upper lobes or in the superior segments of the lower lobes |
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Term
| Book Question: Which would be the most important way to avert tx failure in pts w/tb: A. hospitalize all pts for initial tx of pulmonary TB. B. observe the pts ingest their medications. C. use a single drug for which the organism is susceptile. D. tx pts with previously untx pulmonary tb for a full 12 mos, then check for persistent disease and extend tx for a full 6 mos beyond documentation of conversion of sputum cultures to negative for M. TB. |
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Definition
| answer: B. observe pts ingest their medication. "nonadherence to antiTB tx is a major cause of tx failure . . .*Directly Observed Tx (DOT)*, which requires that a health care worker physically observe the pt ingest antitb meds . . . improves adherence to tx. The importance of DOT cannot be overemphasized. The CDC recomends DOT for all pts w/drug resistant tb and for those receiving intermittent (2x or 3x/week) tx." (The book also states that "single tablets improve compliance but are more expensive than individual drugs purchased separately.") (answer A is wrong b/c book says "hospitalization for initial tx of tb is not necesary for most pts. C is wrong b/c book says to "administer multiple drugs to which the organisms are susceptible." D is wrong b/c book says "most pts w/previously untx pulmonary tb can be effectively tx w/either a 6 mo or 9 mo regimen, although the 6 mo regimen is preferred.) |
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Term
| Book Question: What is the most common cause of tx failure of TB pts? |
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Definition
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Term
| Book Question: What organism most frequently causes NTM pulmonary disease in humans in the US? |
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Definition
| Mycobacterium avium complex (MAC) |
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Term
| What refers to small potato like indurated anatomical lesions found throughout the tissues? |
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Definition
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Term
| What is the derivation of the name "mycobacterium"? |
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Definition
| fungus (myces) and small rod (bakterion) |
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Term
| Why does TB qualify as "acid fast"? |
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Definition
| high lipid content in cell walls |
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Term
| What are 3 growth characteristics of TB? |
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Definition
| slow growing, aerobic, non-spore forming |
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Term
| What is the leading infectious disease killer in the world? |
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Definition
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Term
| What percentage of people on Earth are infected w/TB? |
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Definition
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Term
| How has the prevalence of TB changed through the late 80's and 90's? |
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Definition
| after an upsurge in the late '80's, US TB case rate declining since 1992 due to better public health infrastructure |
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Term
| As cases of TB among US born pts declines, what is becoming increasingly important? |
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Definition
| TB among the foreign born |
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Term
| Is TB and obligate or facultative aerobe or anaerobe? |
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Definition
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Term
| Describe the cell wall of TB. |
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Definition
| *acid-fast* organism due to the presence of mycolic acid in the bacterial cell wall |
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Term
| Is TB fast or slow growing? |
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Definition
| slow growing 15-20 hr generation time |
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Term
| For detecting TB, is auramine-rhodamine fluorescent staining or Ziehl-Nielson more sensitive? |
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Definition
| auramine-rhodamine fluorescent staining is more sensitive |
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Term
| What is the sensitivity of the AFB smear? |
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Definition
| AFB smear of expectorated sputum is 50-75% sensitive in the nml host w/pulmonary TB |
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Term
| Is sensitivity of AFB for TB higher or lower in HIV infection? |
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Definition
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Term
| Is AFB smear more or less sensitive for sputum in comparison to other bodily fluids? |
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Definition
| AFB smear is less sensitive for other body fluids: for CSF 20-37, pleural fluid 10-25%, joint fluid 20% |
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Term
| How long after exposure to TB must you wait to test for TB? |
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Definition
| wait a minimum of 4 weeks; you can check for subsequent conversion as well |
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Term
| What are 5 detection modalities for TB? |
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Definition
| 1. culture. 2. mgit. 3. bactec. 4. lowenstein-jensen. 5. middlebrook. |
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Term
| What is the rate of growth of TB on conventional media such as Lowenstein-Jensen or 7H10? |
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Definition
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Term
| Describe TB colonies on lab media. |
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Definition
| grows as rough, huff colored colonies |
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Term
| In what amt of time do radiometric techniques such as BACTEC detect growth? On what does the timing depend? What is measured? |
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Definition
| Radiometric techniques, such as BACTEC, detect growth in mean 7-10 days depending on inoculum. Ms 14CO2 production |
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Term
| What is available for rapid ID of mycobacterial spp once growth has occured-ID MTB, M. kansasli MAC, and M. gordoneae (a common contaminant)? |
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Definition
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Term
| Once you get a positive test for TB, should you get tested again? |
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Definition
| no. b/c you can have a severe rxn (pt w/scars all over arms was class example) |
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Term
| What refers to tests run on clinical secimens? How do these differ from DNA probes? |
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Definition
| Rapid Direct Tests. (as opposed to DNA probes which ID spp after culture growth) |
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Term
| Are transcription mediated (MTD) or DNA (Amplicor) amplification tests sensitive or specific in smear + sputum, or smear -specimens? |
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Definition
| 95% sensitive and specific in smear + sputum, less sensitive for smear - specimens |
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Term
| When might fale positives occur with transcription mediated (MTD) or DNA (Amplicor) amplification tests? |
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Definition
| old TB disease and congtamination |
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Term
| Which animals/insects are reservoirs of MTB? |
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Definition
| humans are the only reservoir of MTB |
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Term
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Definition
| inhalation of droplet nuclei. inhaled bacteria usually are deposited in mid to lower lung fields. activated macrophages come to the scene and ingest bacilli |
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Term
| Of the following respiratory maneuvers, which transfers the most and least particles of TB: speaking, sneezing, coughing? |
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Definition
| speaking 0-210 particles. coughing: 00-3,5000 particles. sneezing: 4,500-1,000,000 particles |
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Term
| In what cells can tubercle bacilli proliferate? |
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Definition
| tubercle bacilli able to proliferate in AM |
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Term
| When AM is killed in TB, what happens? |
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Definition
| AM is killed releasing bacili, bacilli spread locally then to hilar nodes and systemically |
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Term
| TB pathogenesis requires what for 6-12 weeks for control? |
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Definition
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Term
| How are most TB infections controlled? |
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Definition
| most infections controlled by organized immune response however viable bacilli persist in lung or other sites = latent TB infection (LTBI) |
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Term
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Definition
| most infections controlled by orgainized immune response, however viable bacilli persist in lung or other sites = latent tb infection |
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Term
| Is the lifetime risk of progression to active TB after infection in an immunocompetent person high or low? |
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Definition
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Term
| When is the highest risk of progression to active tb after infection? |
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Definition
| in the first 1-2 years after infection |
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Term
| What concurrent disease is DOUBLE TROUBLE in pts w/TB? |
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Definition
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Term
| Is the risk of progression to active TB after infection in HIV pts high or low? |
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Definition
| very high risk of progression- up to 30-40% |
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Term
| What is the risk per year of progression to active TB after infection w/latent TB? |
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Definition
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Term
| What type of TB occurs in recently infected persons who fail to contain infection? |
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Definition
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Term
| What populations generally present w/primary pulmonary TB disease? |
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Definition
| primary children and HIV infected persons |
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Term
| What pt populations would present w/ TB in lower and midlung disease w/prominent regional nodes? |
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Definition
| primary pulmonary disease: children and HIV infected persons |
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Term
| Pleural effusions occur in what type of TB? |
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Definition
| primary pulmonary disease |
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Term
| What pt population presents w/upper lobe cavitary lesions in TB? |
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Definition
| adults- reactivated latent TB |
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Term
| Pt is exposed to TB and has PPD of 14 mm. What is the 1st step? |
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Definition
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Term
| Pt is exposed to TB and has PPD of 14 mm. CXR are nml. What is your next step? |
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Definition
| Tx INH and B6 for 9 mos (avoid EtOH-) |
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Term
| Pt is exposed to TB and has PPD of 14 mm. CXR show evidence of lung infiltrates, and H&P reveals cough w/no night sweats. What is your next step? |
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Definition
| admit to hospital. keep in respiratory isolation and take 3 sputum samples, 1 every 8 hrs. |
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Term
| Pt is exposed to TB and has PPD of 14 mm. CXR show evidence of lung infiltrates, and H&P reveals cough w/no night sweats. You admit pt to take sputum samples, and 1 comes out (+): 2+AFB/HPF. What is your next step? |
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Definition
| keep in isolation for 2 weeks (maybe until (-) sputum) and tx w/INH, Rifamipin, PZA, athombutol, plus pyridoxine/B6. |
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Term
| Who is most likely to develop active TB? |
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Definition
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Term
| How might you check for induration when reading PPD? |
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Definition
| mark w/ball pt pen to pt of induration |
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Term
| Where does reactivation pulmonary TB usually occur? |
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Definition
| usually in apical +/or posterior segment of upper lobes or upper segment of lower lobes |
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Term
| Pt presents w/cough, chest pain, fever, sweats, hemoptysis (more w/cavitation), and anorexia. Cxr shows fibronodular infiltrates, thick walled, irregular cavities, and volume loss. What leads your d/dx? |
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Definition
| reactivation pulmonary tb |
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Term
| How is extrapulmonary TB usually caused? |
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Definition
| bacilli disseminated remotely before immune control in early infection |
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Term
| How does location of extrapulmonary TB vary? |
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Definition
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Term
| What is the most common extrapulmonary location for tb? |
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Definition
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Term
| The following are sites for what: lymph node, pleural (hemoptysis), bone/jt, disseminated, genitourinary, abdominal, and meningeal? |
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Definition
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Term
| Which lymph nodes are usually affected by extrapulmonary tb? |
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Definition
| posterior cervical or supraclavicular |
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Term
| How does pleural extrapulmonary TB usually present? What do you usually need to order? |
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Definition
| unilateral modest effusion, occasionally massive- usually need bx. |
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Term
| Where are some common sites for bone presentations of extrapulmonary tb syndromes? |
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Definition
| jt, spine-40%, hip-13%, knee-10% |
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Term
| What usually presents w/lower thoracic or lumbar w/anterior destruction w/paraspinous abscess +/- calcification |
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Definition
| pott's disease- extrapulmonary TB |
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Term
| What extrapulmonary tb syndrome presents w/multiple organ systems, diffuse reticulonodular (miliary) cxr pattern, high mortality? |
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Definition
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Term
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Definition
| diffuse reticulonodular cxr pattern, seen w/extrapulmonary tb syndromes |
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Term
| What common presentation of extrapulmonary TB sx has a chronic presentation w/mental status deterioration, sometimets cranial nn palsies, lymphocytic CSF w/*high protein* and low glucose? |
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Definition
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Term
| What disease causes some of the highest CSF protein levels? |
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Definition
| meningitis- extrapulmonary tb |
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Term
| What CN is most often affected by basilar meningitis? What would this cause? |
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Definition
| CN VI- lose lateral rectus |
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Term
| Are TB skin tests more or less likely to be positive in pts w/concurrent HIV infection? |
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Definition
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Term
| Do pts w/bo TB and HIV have more pulmonary or extrapulmonary TB disease? |
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Definition
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Term
| How does pulmonary TB differ in pts w/concurrent HIV? |
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Definition
| more adenopathy, effusions (plerual and pericardial), more lower zone disease, fever, cavities |
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Term
| In pts w/HIV, are sputum AFB smears more or less liklely to be positive in pulmonary TB when compared to pts w/o HIV? |
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Definition
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Term
| How do variations in TB presentation in pts w/HIV relate to CD4 counts? |
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Definition
| all unusual characteristics increase in frequency w/falling cd4 counts |
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Term
| How should TB tx be guided? |
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Definition
| by susceptibility testing |
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Term
| Should TB pts be tx w/single or multiple drugs to which organisms are susceptible? |
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Definition
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Term
| When should a single drug be added to a failing TB regimen? |
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Definition
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Term
| How should adherence to TB tx be ensured? |
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Definition
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Term
| What testing should a TB dx prompt? |
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Definition
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Term
| In which of the following mx is intrinsic resistance highest and lowest: inh, rifampin, dual 1? |
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Definition
| inh 1 in 10^6. rifampin 1 in 10^8. dual 1 in 10^14. |
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Term
| What are the 3 different strengths of TB drugs? |
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Definition
| a. rapidly multiplying (extracellular in caseum). B. slowly multiplyting (acidic, such as macrophages). C. sporadically multiplying (in host tissue) |
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Term
| The following drugs would be useful for what class of TB: INH>>SM>>RIF>EMB? |
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Definition
| rapidly multiplying (extracellular in caseum) |
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Term
| The following drugs would be useful for what class of TB: PZA>>RIF>INH? |
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Definition
| slowly multiplying (acidic, such as macrophages) |
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Term
| The following drugs would be useful for what class of TB: RIF>>INH? |
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Definition
| sporadically multiplying (in host tissue) |
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Term
| What are the 2 most common side effects of isoniazid? |
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Definition
| hepatic toxicity adn peripheral neuropathy |
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Term
| What is the most important drug interaction characteristic of rifamycin? |
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Definition
| cytochrome p450 induction therefore induces metabolism of many drugs --PI's! |
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