Term
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Definition
sign of meningeal inflammation= when the patient experiences pain if you are holding their thigh at a 90 degree angle to their body and then try to straighten their leg |
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Term
What idoes SMAC stand for? |
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Definition
sequential multi-analyzer for Chemistries/computer |
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Term
What is a normal CSF glucose? |
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Definition
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Term
Why do you order CMPs on CSF for a patient if you suspect meningitis? |
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Definition
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Term
What is teh WBC in a CSF with septic versus aseptic meningitis? |
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Definition
bacterial= 100-1,000 cells/mL viral= 50-200 cells/mL |
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Term
How do you test CSF for cryptococcal meningitis? |
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Definition
india ink or latex agglutination |
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Term
What is a cheap test to screen for malaria? |
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Definition
blood smear (thick smear for sensitivity and thin smear for better morphology) |
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Term
Describe the blood smear appearance of plasmodium falciparum. |
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Definition
banana shaped gametocytes, multiple ring forms, some applique |
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Term
95% of all malaria deaths in US travelers is caused by... |
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Definition
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Term
Name the rapid malaria diagnostic test. |
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Definition
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Term
Which species can Binax NOW identify? |
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Definition
P. falciparum and P. vivax |
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Term
If a smear can't diagnose malaria, you can go on to... |
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Definition
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Term
A tetrad within a RBC is pathognomonic for... |
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Definition
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Term
What are the two significant species of babesia? |
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Definition
B. microtii and B. divergens |
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Term
How do people get babesiosis? |
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Definition
invertebrate vector: Ixodes tick that lives in the northeast and upper midwest; OR from blood transfusion-transmitted infections |
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Term
What is the vertebrate reservoir of babesiosis? |
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Definition
small mammals (white-footed mouse, rabbits), cattle, horses, dogs, etc. |
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Term
What is the incubation period for babesiosis? |
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Definition
if transmitted by tick bite= 1 wk- 3 mths if by blood transfusion= 17 days to 8 weeks |
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Term
Can mycobacterium respiratory infections be transmitted person to person? |
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Definition
mycobacterium tuberculosis is transmissible person-to-person but there are many other non-tuberculous mycobacteria (NTM) |
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Term
What does MOTT stand for? |
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Definition
mycobacteria other than tuberculosis (MOTT) |
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Term
How do patients get MOTT or NTM? |
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Definition
environmental exposure, not person-to-person |
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Term
How does MTB get down into the alveoli? |
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Definition
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Term
What happens between the time someone get MTB and when they become PPD positive? |
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Definition
1-3 weeks= mycobacteria multiply unrestricted in macrophages, which remain unactivated; lymphocytes infiltrate, express cytokines and IFN Macrophages activate and PPD becomes positive |
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Term
What type of immunity is needed against MTB? |
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Definition
intact cell mediated immunity/CD4 response |
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Term
T/F Most MTB infections are symptomatic. |
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Definition
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Term
T/F MTB infections that cause symptoms rarely progress. |
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Definition
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Term
What happens to the primary lesion or tubercle in the vast majority of TB? |
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Definition
primary lesion becomes fibrotic and calcifies |
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Term
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Definition
a focus of granulomatous inflammation that calcifies and can be detected by CXR |
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Term
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Definition
when there is a peripheral gohn focus plus hilar lymph nodes and they are both calcified on CXR |
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Term
Are there organisms in a calcified Gohn focus? |
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Definition
yes; there are often small numbers of MTB |
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Term
Where does reactivation tuberculosis most often occur? |
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Definition
usually apical upper lobes or superior segments of lower lobes |
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Term
How does TB spread throughout the body? |
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Definition
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Term
Cavitary lesions left by tuberculosis can be colonized by what other microorganism? |
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Definition
fungus ball (mycetoma or aspergilloma) |
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Term
What is tuberculous lymphadenitis called? |
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Definition
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Term
An individual who has been infected with TB but does not have active disease is said to have a ____. |
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Definition
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Term
Are people with latent TB infection infectious to others? |
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Definition
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Term
What should be done for patients with a latent TB infection? |
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Definition
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Term
Name some different methods for testing for latent TB infection. |
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Definition
tuberculin skin testing, quantiFERON gold, elispot |
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Term
How long do you have before a TB skin test should be red? |
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Definition
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Term
What is measured as a reaction to PPD? |
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Definition
palpable induration, NOT erythema |
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Term
What is a positive TB skin test? |
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Definition
if no risk factors for TB= >15 mm immigrant from endemic country, IVDA, prison/nursing home/hospital/laboratory, children over 5: >10mm HIV, recent TB contact, CXR, immunosuppresed >5 mm |
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Term
Which patients is tuberculin skin testing unreliable? |
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Definition
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Term
How is the quantiFERON Gold test performed? |
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Definition
patient's blood sampel is incubated for 16-24 hours with MTb-specific antigens; then the degree of cell-mediated immune reactivity (INF-gamma) is measured |
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Term
What are the advantages of using the QuantiFERON Gold? |
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Definition
detects latent infection, detects MTb infection in individuals who have recieved the BCG vaccine, no need to have PPD read |
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Term
What is the difference in the test tube of patients who are sensitized to TB versus those who are not? |
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Definition
if prior exposure, an antigen specific T-Cell will recognize the antigen presented by the APC and bind |
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Term
When working up a patient for active TB, which tests come back on the same day? |
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Definition
AFB smear and MTD nucleic acid amplification test (may not be sensitive enought on the first day) |
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Term
How is an AFB smear for active TB infection performed? |
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Definition
concentrated sputum, read using flourescence microscopy |
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Term
If you suspect a person has active TB, you must admit them to a... |
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Definition
negative pressure room and isolation |
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Term
What labs do you need to release a patient from isolation who is suspected of TB by proving that they do not in fact have TB? |
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Definition
3 sputum spears (on seperate days) must be AFB-negative |
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Term
What allows mycobacteria to be "acid fast"? |
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Definition
cell walls have a very high lipid content due to presence of mycolic acids; these bind well to fuchsin (a red dye) in presence of carbolic acid ("phenol"), hence carbol-fuchsin stains; They then resist decoloration with ethanol and 3% HCL |
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Term
Describe the different stains for AFBs. |
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Definition
Ziehl-Neelson= traditional, "hot" stain Kinyoun= "cold" Auramine-Rhodamine= flourochrome stain that is read with immunoflourescent scope and is very sensitive |
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Term
What is the most sensitive mycobacterial stain? |
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Definition
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Term
What are some media on which mycobacteria can be cultured? |
|
Definition
Lowen-stein Jensen (LJ) slants; or MIddlebrook 7H11 Agar |
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Term
What is Lowenstein-Jensen slant made out of? |
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Definition
coagulated whole eggs to solidify media; malachite green bacterial inhibitor |
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Term
What are the advantages to using Lowenstein-Jensen slants? |
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Definition
tubes are good for shipping (like to send off for drug susceptibility testing) |
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Term
What is middlebrook 7H11 agar made out of? |
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Definition
solid, agar-based medium (clear) |
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Term
What are the advanatages to using Middle brook 7H11 agar? |
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Definition
growth is faster than with egg-based media; easier to observe colony morphology with a microscope |
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Term
What is the gross description of MTb colonies? |
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Definition
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Term
A smear of MTb grown in culture shows... |
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Definition
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|
Term
What is the gold standard for MTb culture? |
|
Definition
broth-based (liquid) culture |
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Term
What are the advantages to using liquid culture to culture MTb? |
|
Definition
can culture sputum, blood, BM; used in automated systems |
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Term
What is the sensitivity and specificity of Gen-Probe MTD on smear positive respiratory specimens? |
|
Definition
senesitivity > 99% specificity nearly 100% |
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Term
A patient who has a smear positive test for MTb but has a negative MTD has... |
|
Definition
acid-fast bacilli infection but they are not mycobacterium tuberculosis; patient can come out of isolation |
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Term
What is the sensitivity and specificity of Gen-Probe MTD on smear-negative respiratory specimens? |
|
Definition
sensitivity= 70-85%; specificity >99% |
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|
Term
What is probe amplification? |
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Definition
if the probe binds to the target, the probe is amplified |
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Term
Gen-Probe's AccuProbe identify what mycobacteria? |
|
Definition
M. tuberculosis, MAC, M. kansasii, M. gordonae |
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Term
What specimens can you use Gen-Probe's AccuProbe on? |
|
Definition
positive AFB culture (either plate or liquid broth); not from a direct smear |
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|
Term
What does HPLC stand for? |
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Definition
high-performance liquid chromatography |
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|
Term
How do you identify AFB via HPLC? |
|
Definition
analysis of their mycolic acids; acid fast bacteria are saponified to remove their mycolic acids from the cell wall; mycolic acids are separated by acidification and extraction into chloroform; they are absorbed onto a reverse-phase colomn and detected with a flourescence spectrophotometer; different mycolic acid chromatographic patterns are charactersitic of the different spcies of mycobacteria |
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Term
Is biochemical testing used for identifying mycobacteria? |
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Definition
yes; historically it was the only method for identifying mycobactera and there is still some use fro biochemicals but they are relegated to reference labs when nothing else works |
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Term
Working with sputum for acid fast bacilli has a BSL of ____, while working with culture for acid fast bacilli has a BSL of ___. |
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Definition
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|
Term
How long does it take for drug susceptiblity testing for MTb to come back? |
|
Definition
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|
Term
Name some standard drugs for treating MTb. |
|
Definition
isoniazid, rifampin, pyrazinamide, ethambutol, and streptomycin |
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