Infectious Disease 2 Flashcards
- What are the 5 main organisms that cause infections of the cervix and the vagina?
- Which ones are not sexually transmitted?
- Which ones are sexually transmitted?
- Gardnerella vaginalis in bacterial vaginosis (BV): not ST
- Candida albicans in vulvovaginal candidiasis: not ST
- Trichomonas vaginalis in trichomonas infections: ST
- Neisseria gonorrhoeae in gonorrhea infections: ST
- Chlamydia trachomatis in chlamydia infections: ST
Which infection is often associated with a foul amine odor and can be passed from female to female during sex and is not typically tested or treated in med?
gardnerella vaginalis (BV)
Which infection rarely causes symptoms in men as yeast but causes vaginitis with thick, curd-like consistency and can also cause intense vaginal and vulvar pruritis?
candida albicans
Which infection(s) causes urethritis, dysuria and other urinary symptoms in men and can cause vaginitis and cervicitis in women?
- trichomonas vaginalis
- neisseria gonorrhoeae
- chlamydia trachomatis
How can you test for gardnerella vaginalis?
- female pelvic exam with wet mount test (done in office)
- DNA hybridization probe testing (Affirm VPIII) (done in office but sent to lab for evaluation)
How can you test for candida albicans?
- female pelvic exam with wet mount test (done in office)
- DNA hybridization probe testing (Affirm VPIII) (done in office but sent to lab for evaluation)
- vaginal culture (rare-done in office but sent to lab or eval)
How can you test for trichomonas vaginalis?
- female pelvic exam with wet mount test (done in office)
- DNA hybridization probe testing (Affirm VPIII) (done in office but sent to lab for evaluation)
- nucleic acid amplification tests (in office, sent to lab for eval)
- vaginal culture
How can you test for neisseria gonorrhoeae?
- nucleic acid amplification testing NAAT
- bacterial culture (rare)
How can you test for chlamydia trachomatis?
- nucleic acid amplification testing NAAT
- bacterial culture (rare)
What is the purpose of doing a wet mount?
determining causative agent in vaginitis or cervicitis:
- vulvovaginal yeast infection
- bacterial vaginalis
- trichomoniasis
(immediate result)
What test is the only one where you can you a cotton swab to perform a test as we don’t need sterility in this instance?
wet mount
How many mL of normal saline are mixed with the swabs during a wet mount?
0.5 mL
- In a wet mount, you can formulate one or two slides, one with (…) and one without (…)
- What does this (substance you add) do?
- with KOH, without KOH
- lyses cell walls of bacteria, trichomonads, WBCs, and RBCs may be present; makes it easier to see bacteria
Describe the whiff test?
- prior to performing wet mount, place KOH on slide
- evaluate for an amine or fishy odor
- if present = bacterial vaginosis
- may also be present in trichomonas infections
What can you also do to test for infections other than the wet mount for cervical infections?
- vaginal pH
- What is the normal vaginal pH?
- If it is higher than 4.5, what does this indicate?
- If it is lower than 4.5, what does this indicate?
- 3.8-4.5
- bacterial vaginosis
- vulvovaginal candidiasis
On a wet mount, if the edges of epithelial cells are covered by coccobacilli or “clue cells”, what does this indicate?
bacterial vaginosis
What is this wet mount of?
vulvovaginal candidiasis
What is this a wet mount of, and is associated with looking like a balloon with string attached?
trichomonas vaginalis
- What 3 causes of vaginitis does DNA hybridization probe testing test for?
- This test is only approved in what individuals?
- BV
- candidiasis
- trichomonas
- only approved in females
What test can detect trichomonas rapidly (10 mins) and is only approved in females?
OSOM trichomonas rapid test
When testing for gonorrhea and chlamydia, what is preferred over culture of specimens?
nucleic acid amplification tests
What are the pros of using NAAT?
- can identify low amounts of DNA
- highly sensitive and specific
- can also use urine in most cases
What are the collection sites of NAAT for gonorrhea and chlamydia in men and women?
men: urethra (use urine, don’t swab)
women: vaginal or endocervical swab (higher sensitivity than urine)
In women (…) samples for NAAT have higher sensitivity than (…)
- vaginal samples
- urine
What are the testing options in males for BV, candida, gonorrhea, trichomonas, and chlamydia?
- gonorrhea/chlamydia: NAAT testing using NAAT swab on urine or urethral sample
- trichomonas (1 of 2 ways): perform culture using urine container (send out for G/C and trich testing)
- BV/candida: not tested
What are the testing options in females for BV, candida, gonorrhea, trichomonas, and chlamyda?
- gonorrhea/chlamydia: NAAT testing using NAAT swab on urine or urethral sample
- trichomonas/BV/candida: wet mount or BD-affirm (DNA hybridization)
- What are the 2 types of HIV?
- Which is more commonly found in US and Europe?
- Which one is more common in West Africa?
- Which one is more transmissable?
- HIV-1 and HIV-2
- HIV-1
- HIV-2
- HIV-1
What test is the earliest marker and can detect HIV as early as 10-12 days after initial infection?
HIV DNA viral load
Why is viral RNA not usually recommended as initial screening?
- less sensitive than serologic
- false-positives are possible
Viral load for HIV is often used as what? What does a low viral load mean?
measurement of response to treatment; viral load undetectable=untransmissible
Which HIV test can be measured as early as 11-13 days after infection, is less expensive than viral RNA/nucleic acid testing?
HIV p24 antigen
- Describe virologic
- Describe serology
- tests that are based on presence of virus
- tests that determine presence of antibodies in infected individuals
Which test for HIV tests for IgM and IgG antibodies?
HIV serologic tests
- In patients with HIV, IgM antibodies are not always (…)
- What is the minimum time to detect IgG antibodies to HIV?
- What is the median time to detect IgG antibodies to HIV?
- Almost all HIV positive individuals will have detectable IgG antibodies within (…)
- detectable
- 2 weeks
- 4 weeks
- 6 months
What HIV test is a combination test that detects presence of p24 and antibodies (IgG and IgM) and is indicated for both routine, perinatal screening and high-risk individuals?
Fourth generation HIV tests
When does the CDC recommend to test these groups of individuals for HIV:
- adolescents and adults 15-65
- pregnant women
- pregnant women at risk for HIV
- individuals at high risk for HIV
- at least once
- once
- initially and second test in third trimester
- initial
What is the STI that causes syphilis?
Treponema pallidum
What is usually the 1st indication a person has syphilis but goes away and people may not realize they have it?
chancres
What are the 4 stages of syphilis?
- acute - development of chancre within 2-3 weeks of exposure
- secondary - generalized rash and other systemic symptoms
- latent - disease inactivity (up to 5 years)
- tertiary - CNS, cardiac, ocular involvement
What types of tests can you perform for treponema pallidum (syphilis)?
- non-treponemal
- treponemal
For syphilis testing, if initial test comes back positive what do you have to do?
confirm with second (different) test
- In practices with low-incidence of syphilis, what test is usually used first?
- In high incidence areas (areas with better technology) what test can be used first?
- non-treponemal
- treponemal
Which syphilis test detects reaction of patient’s serum IgG and IgM antibodies and treponemal surface antibodies recognize antigen and react?
non-treponemal antibody test
What are the cons of non-treponemal testing?
- lacks specificity: false positives with TB, lupus, others
- lacks early sensitivity: 20-30% of pts with chancre have not developed antibodies at that time
- if negative result, but high suspicion, retest in 2-3 weeks
What is a common name for the non-treponemal test for syphilis?
rapid plasma reagin RPR
- Which syphilis test is more specific, as they detect human antibodies against specific treponemal antigens?
- What is a common name for this test?
- treponemal antibody test
- fluorescent treponemal antibody absorption (FTA-ABS)
- If a non-trep test comes back reactive, what do we have to do?
- confirm with another test such as trep test (comes back nonreactive, so syphilis, reactive = syphilis)
When doing a trep test that comes back reactive, what do you have to do?
- non-trep test to confirm
- if reactive = syphilis
- if non-reactive, reconfirm with TP-PA
Who should you screen for syphilis?
- patient with painless chancre
- patient with high risk behavior and possible exposure
- patient who asks for screening as part of a comprehensive evaluation of STI
- routine screening
- What is the general term for infection/inflammation of the liver?
- This can be (…) or (…)
- hepatitis
- viral or non-viral
- What are the viral-causes of hepatitis?
- hepatitis A, B, C, D, E
What are the non-viral causes of hepatitis?
- autoimmune hepatitis
- drug-induced hepatitis
- alcoholic hepatitis
What are the clinical presentations of hepatitis?
- fever and malaise
- nausea and vomiting
- jaundice
With hepatitis, labs reveal elevated (…) and (…)
- liver enzymes
- bilirubin
In hepatitis, (…) are usually at least 5x their normal value
LFTs
ESR and CRP increase with infection because they are (…)
acute phase reactants
Who should you screen for hepatitis?
patients with:
- symptoms of hepatitis
- elevated LFTs
- person lives with at-risk or positive individual
- high-risk sexual behavior or STI screening
- HIV
- IV drug user
- high-risk setting (correctional facilities)
- What test can you order to diagnose hep A?
- By the time a patient with hep A has symptoms, their (…) will be positive for hep A
- IgMs will persist for (…) months
- IgG will take (…) weeks to appear and persist for decades
- Hepatitis A IgM
- IgM
- 6 months
- 2-3 weeks
What are the 3 known antigens and complementary antibodies that can be tested to diagnose hep B?
- hepatitis B surface antigen and antibody
- hepatitis B core antigen and antibody
- hepatitis B e antigen and antibody
What Hep B test can detect hep B 1-10 weeks after infection, even prior to symptoms and you will often hear the most?
hep B surface antigen and antibody
What Hep B test tests for an inner core protein/antigen that is undetectable in blood but the antibody (IgM) can be detected in blood?
hep B core antigen and antibody
What Hep B test tests for protein that is released from the virus itself that indicated high levels of DNA and high viral load or load activity and is used primarily to determine how active the virus is replicating?
hep B antigen and antibody
- Hepatitis B infections can also be monitored through the level of Hep B DNA presence, this is referred to as (…) to see how active the virus is in a person?
- What can this be used for?
- viral load
- determine adequacy of response to treatment
HCV (hep C) is first detectable withing (…) months post-exposure (earliest marker)
2 months
What are antibody testings for Hep C?
- IgM levels in hep C are variable, so IgM not measured
- lab tests detect IgG against hep C
- antibody testing cannot be used to distinguish acute/chronic/resolved infection
What can you test for for hep C?
- HCV DNA testing (viral DNA)
- Anti-HCV (IgG): repeat at week 12 if negative initially
What is the process of test elevations in an HCV infection? (which one elevates first)
- HCV RNA
- ALT (liver specific)
- Anti-HCV (IgG)
- What is Herpes Simplex virus caused by?
- Where are these common?
- HSV-1: often causes oral lesions
- HSV-2: often causes genital lesions
either virus can occur anywhere
- How is HSV spread?
- Which is the more predominant type (more people have been exposed)
- contact with lesions or infected bodily secretions and can be transmitted when asymptomatic
- HSV-1
- HSV viral cultures are best performed if there are (…) present
- Vesicles need to be (…) which can be (…)
- This is more sensitive in (…) course of eruption and sensitivity declines as lesions begin to heal
- What is the overall sensitivity
- active lesions
- unroofed/deroofed; can be painful
- early course of eruption
- 50-70%
- It will be easier to deroof vesicles that are (…)
- It will be harder of they are (…) or (…), reducing sensitivity
- fluid-filled
- ulcerating or drying out
Difference between serology and virology?
serology is our own antibodies whereas virology is viral antibodies
What is a measurement of specific antibodies to HSV 1 and 2, and measures IgM antibodies to Glycoprotein G, which is found on HSV?
HSV serology
- gG1 is elicited from (…)
- gG2 is elicited from (…)
- HSV-1
- HSV-2
HSV serology may be negative if it is less than (…) weeks from exposure
6 weeks
What are some common reasons HSV serology is performed?
- diagnose pt who did not have viral culture during active outbreak
- diagnose pt w/ atypical presentation
- as part of routine STI workup
- test partner of HSV infected individual
What is the problem with HSV serology?
- can lead to positives that cause concern for patient
- HSV-1 always thought to be associated w/ oral herpes and HSV-2 usually associated w/ genital herpes
- in reality, either virus can exist anymore
- this causes confusion if pt has had oral-herpes (cold sores) but is concerned for genital herpes
What are some offered testing for STIs?
urine/urethral swab testing for:
- NAAT testing for gonorrhea/chlamydia
- trichomonas testing
blood testing for:
- HIV
- RPR
- Hep B
- Hep C
lesion sampling:
- herpes lesion testing (preferred way)
