Shared Flashcard Set

Details

4.26 Micro Lab II
By Dr. Barbeau
72
Pathology
Professional
04/27/2012

Additional Pathology Flashcards

 


 

Cards

Term
What is Kernig's sign?
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
Term
What idoes SMAC stand for?
Definition
sequential multi-analyzer for Chemistries/computer
Term
What is a normal CSF glucose?
Definition
60% of plasma
Term
Why do you order CMPs on CSF for a patient if you suspect meningitis?
Definition
you want a glucose level
Term
What is teh WBC in a CSF with septic versus aseptic meningitis?
Definition
bacterial= 100-1,000 cells/mL
viral= 50-200 cells/mL
Term
How do you test CSF for cryptococcal meningitis?
Definition
india ink or latex agglutination
Term
What is a cheap test to screen for malaria?
Definition
blood smear (thick smear for sensitivity and thin smear for better morphology)
Term
Describe the blood smear appearance of plasmodium falciparum.
Definition
banana shaped gametocytes, multiple ring forms, some applique
Term
95% of all malaria deaths in US travelers is caused by...
Definition
plasmodium falciparum
Term
Name the rapid malaria diagnostic test.
Definition
Binax NOW
Term
Which species can Binax NOW identify?
Definition
P. falciparum and P. vivax
Term
If a smear can't diagnose malaria, you can go on to...
Definition
PCR
Term
A tetrad within a RBC is pathognomonic for...
Definition
babesia
Term
What are the two significant species of babesia?
Definition
B. microtii and B. divergens
Term
How do people get babesiosis?
Definition
invertebrate vector: Ixodes tick that lives in the northeast and upper midwest; OR from blood transfusion-transmitted infections
Term
What is the vertebrate reservoir of babesiosis?
Definition
small mammals (white-footed mouse, rabbits), cattle, horses, dogs, etc.
Term
What is the incubation period for babesiosis?
Definition
if transmitted by tick bite= 1 wk- 3 mths
if by blood transfusion= 17 days to 8 weeks
Term
Can mycobacterium respiratory infections be transmitted person to person?
Definition
mycobacterium tuberculosis is transmissible person-to-person but there are many other non-tuberculous mycobacteria (NTM)
Term
What does MOTT stand for?
Definition
mycobacteria other than tuberculosis (MOTT)
Term
How do patients get MOTT or NTM?
Definition
environmental exposure, not person-to-person
Term
How does MTB get down into the alveoli?
Definition
droplet nuclei
Term
What happens between the time someone get MTB and when they become PPD positive?
Definition
1-3 weeks= mycobacteria multiply unrestricted in macrophages, which remain unactivated; lymphocytes infiltrate, express cytokines and IFN Macrophages activate and PPD becomes positive
Term
What type of immunity is needed against MTB?
Definition
intact cell mediated immunity/CD4 response
Term
T/F Most MTB infections are symptomatic.
Definition
false
Term
T/F MTB infections that cause symptoms rarely progress.
Definition
true
Term
What happens to the primary lesion or tubercle in the vast majority of TB?
Definition
primary lesion becomes fibrotic and calcifies
Term
What is a Ghon focus?
Definition
a focus of granulomatous inflammation that calcifies and can be detected by CXR
Term
What is a Ghon complex?
Definition
when there is a peripheral gohn focus plus hilar lymph nodes and they are both calcified on CXR
Term
Are there organisms in a calcified Gohn focus?
Definition
yes; there are often small numbers of MTB
Term
Where does reactivation tuberculosis most often occur?
Definition
usually apical upper lobes or superior segments of lower lobes
Term
How does TB spread throughout the body?
Definition
via lymphatics and blood
Term
Cavitary lesions left by tuberculosis can be colonized by what other microorganism?
Definition
fungus ball (mycetoma or aspergilloma)
Term
What is tuberculous lymphadenitis called?
Definition
scrofula
Term
An individual who has been infected with TB but does not have active disease is said to have a ____.
Definition
latent TB infection
Term
Are people with latent TB infection infectious to others?
Definition
no
Term
What should be done for patients with a latent TB infection?
Definition
should be treated
Term
Name some different methods for testing for latent TB infection.
Definition
tuberculin skin testing, quantiFERON gold, elispot
Term
How long do you have before a TB skin test should be red?
Definition
48 to 72 hours later
Term
What is measured as a reaction to PPD?
Definition
palpable induration, NOT erythema
Term
What is a positive TB skin test?
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
Term
Which patients is tuberculin skin testing unreliable?
Definition
HIV+ patients
Term
How is the quantiFERON Gold test performed?
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
Term
What are the advantages of using the QuantiFERON Gold?
Definition
detects latent infection, detects MTb infection in individuals who have recieved the BCG vaccine, no need to have PPD read
Term
What is the difference in the test tube of patients who are sensitized to TB versus those who are not?
Definition
if prior exposure, an antigen specific T-Cell will recognize the antigen presented by the APC and bind
Term
When working up a patient for active TB, which tests come back on the same day?
Definition
AFB smear and MTD nucleic acid amplification test (may not be sensitive enought on the first day)
Term
How is an AFB smear for active TB infection performed?
Definition
concentrated sputum, read using flourescence microscopy
Term
If you suspect a person has active TB, you must admit them to a...
Definition
negative pressure room and isolation
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?
Definition
3 sputum spears (on seperate days) must be AFB-negative
Term
What allows mycobacteria to be "acid fast"?
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
Term
Describe the different stains for AFBs.
Definition
Ziehl-Neelson= traditional, "hot" stain
Kinyoun= "cold"
Auramine-Rhodamine= flourochrome stain that is read with immunoflourescent scope and is very sensitive
Term
What is the most sensitive mycobacterial stain?
Definition
auramine-rhodamine
Term
What are some media on which mycobacteria can be cultured?
Definition
Lowen-stein Jensen (LJ) slants; or MIddlebrook 7H11 Agar
Term
What is Lowenstein-Jensen slant made out of?
Definition
coagulated whole eggs to solidify media; malachite green bacterial inhibitor
Term
What are the advantages to using Lowenstein-Jensen slants?
Definition
tubes are good for shipping (like to send off for drug susceptibility testing)
Term
What is middlebrook 7H11 agar made out of?
Definition
solid, agar-based medium (clear)
Term
What are the advanatages to using Middle brook 7H11 agar?
Definition
growth is faster than with egg-based media; easier to observe colony morphology with a microscope
Term
What is the gross description of MTb colonies?
Definition
"rough and buff"
Term
A smear of MTb grown in culture shows...
Definition
"cording"
Term
What is the gold standard for MTb culture?
Definition
broth-based (liquid) culture
Term
What are the advantages to using liquid culture to culture MTb?
Definition
can culture sputum, blood, BM; used in automated systems
Term
What is the sensitivity and specificity of Gen-Probe MTD on smear positive respiratory specimens?
Definition
senesitivity > 99%
specificity nearly 100%
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
Term
What is the sensitivity and specificity of Gen-Probe MTD on smear-negative respiratory specimens?
Definition
sensitivity= 70-85%; specificity >99%
Term
What is probe amplification?
Definition
if the probe binds to the target, the probe is amplified
Term
Gen-Probe's AccuProbe identify what mycobacteria?
Definition
M. tuberculosis, MAC, M. kansasii, M. gordonae
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
Term
What does HPLC stand for?
Definition
high-performance liquid chromatography
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
Term
Is biochemical testing used for identifying mycobacteria?
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
Term
Working with sputum for acid fast bacilli has a BSL of ____, while working with culture for acid fast bacilli has a BSL of ___.
Definition
2; 3
Term
How long does it take for drug susceptiblity testing for MTb to come back?
Definition
2-4 weeks
Term
Name some standard drugs for treating MTb.
Definition
isoniazid, rifampin, pyrazinamide, ethambutol, and streptomycin
Supporting users have an ad free experience!