Syphilis and spirochetes Flashcards
In the former question, if the patient’s physician still suspects syphilis, what testing could best confirm
or rule out the diagnosis?
FTA-Abs on serum and a darkfield exam on the genital lesion
Which quality control data set represents acceptable results for the RPR test? (It may help to refer to
your upcoming Syphilis RPR lab)
Temp: 24 degrees C Rotation speed: 100 rpm/min Needle drops: 30 in 0.5 cc
Which of the following is true of reagin?
It is an antibody-like substance directed against cardiolipin
What is the principle of the methodology of the RPR tests?
Flocculation: Antigen is a carbon particle-cardiolipin which tests for non-specific reagin (antibody-like)
substance
In the fluorescent treponemal antibody absorption test (FTA-ABS), what is the purpose of absorption
with Reiter treponemes?
The Reiter strain is used as a sorbent to remove antibodies to nonpathological strains of treponeme
A syphilis test that does not detect specific treponemal antibodies is:
RPR
A baby is born to a mother who is in the latent stage of syphilis. The baby exhibits no symptoms of the
disease at birth, but a cord blood RPR and a total FTA-ABS is positive, IgM FTA-Abs is negative. How
should these results be handled?
Repeat tests over several month and look for a rise in titer of the RPR and FTA-Abs to determine if the
positivity is due to transplacental passage of mother’s antibodies or production of antibodies by the baby
Which of the following is true of treponemal tests for syphilis?
They should be used as confirmatory tests rather than for screening
An RPR test done on a 19-year old female as part of a prenatal work-up seemed negative but exhibited a rough appearance.
What, if anything, is (are) the BEST next step(s) you should take? (Select all that apply)
If in question, send off for confirmatory testing
Check to make sure prozone is not occurring
A “rough” (less than minimally reactive but still not negative) reaction may be an indication of
prozone and a very high titer; it may also be an indicator of a false positive. Most labs dilute
the sample first. If the results do not show evidence of prozone, then the sample should be
evaluated by an alternative method
From which sample can a + darkfield exam be performed on a newborn to assist with the diagnosis of congenital syphilis
genital lesion
skin rash
nasopharynx in newborn babies with syphilis
Which serum antibody response usually characterizes the primary (early) stage of syphilis?
Detected 1-4 weeks after the appearance of the primary chancre
An RPR card test performed on a spinal fluid sample was non-reactive. The physician was skeptical
and asked for a repeat test on the spinal fluid. The RPR result was reactive at a 1:1 dilution. The
result:
Is unreportable; the RPR card test should not be performed on spinal fluid
What is the most likely interpretation of the following syphilis serology restults?
RPR : Reactive
VDRL: Reactive
FTA-Abs: Neg
EIA Test: Neg
Darkfield Exam: Neg
Biological false positive
Cholesterol is added to the antigen used in flocculation tests for syphilis to
increase sensitivity of the antigen
A 21 year old female suffering from systemic lupus erythermatosus (SLE) and an ear infection is
tested for syphilis using the RPR card test. The result is reactive. The patient denies any sexual
activity. A repeat test 8 month later is still reactive although the ear infection has resolved. The most
likely explanation for these results and a test that can confirm the presence of syphilis are:
chronic biological false positive due to SLE FTA-Abs
The RPR test is often considered to be an improvement over the VDRL because of the following:
charcoal has been added to help visualization of the reaction
choline chloride has been added to destroy complement thus eliminating the need to heat inactivate
A VDRL serum sample is heat inactivated then placed in a refrigerator for overnight storage. Before
being tested, the serum must be:
reheated to 56 degrees C for 10 minutes
Flocculation tests for syphilis detect the presence of:
reagin
Cause of syphilis
Treponema pallidum
T. pallidum can survive in what hosts?
humans and footpads of armadillos
spread of syphilis is
direct contact
Can T. pallidum breach skin?
yes
Treponomes are destroyed by
heat, cold, drying
what percentage of individuals exposed to a primary lesion contact syphilis?
30-50%
primary syphilis symptoms
chancer lesion
25% of cases develop into 2nd syphilis
primary syphilis incubation period
21 days
when do ab first appear in syphilis
several weeks after chancre appears (chancre appears 21 days after exposure)
secondary syphilis symptoms
systemic dissemination:
lymphadenopathy
fever
pharyngitis
rash skin/mucous membranes
lesions
visual disturbances
hearing loss
facial weakness
what percentage of 2nd syphilis patients exhibit neurologic signs?
40%
when do 2nd syphilis symptoms appear?
1-2 mons after primary chancre disappears
2nd syphilis lesions persist for
8 wks
Can you have T. pallidum in the rash?
yes
latent syphilis symptoms
lack of clinical symptoms
lasts a month to lifetime
bacteria infect BM, lymph glands, organs, CNS
is latent syphilis still contagious?
in pregnant women yes
tertiary syphilis symptoms
lesions in bone, skin, organs
gummas
lack of coordination
cardiovascular complications
paralysis
blindness
demintia
impotency
vomiting
gummas
tertiary syphilis
painful immune tumors on skin
contain: lymphs, epis, fibroblastic cells
Darkfield exam for syphilis
used for primary syphilis
can be used on skin lesions in secondary
process quickly- look for rapid motility
VDRL
veneral disease research laboratories
slide flocculation
antigen in VRDL
Cardiolipin
w/ lecithin & cholesterol
VRDL antibody
reagin (Ab formed against lipid material from damaged cells)
neurosyphilis can be diagnosed from what test?
VDRL
When is the earliest you can test for syphlis from serum on VDRL?
1-4 wks after apperance of the primary chancre
false negatives for VDRL
PROZONE
Biological false postives for non-treponemal tests
lupus
rhematic fever
vaccine, viral, pneumococcal pneumonia
IM
Leprosy
hepatitis
malaria
rheumatoid arthritis
pregnancy
aging
test titers
the greatest dilution at which an antibody and its corresponding antigen still react
purpose of titers
track concentration of antibody in specimen over time
acute titer
concentration of antibody present during acute phase of disease
convalescent titer
concentration of antibody present 2 wks after onset of infection
clinically significant titer
4x or 2 tube increase between acute and convalescent titer
FTS-ABS
Fluorsecent treponemal antibody absorption test
indirect fluorescent antibody test
sorbent of FTS-ABS
Reiter strain of Treponeme used to remove antibodies to nonpathological strains of treponeme
what is the purpose of the Nicols strain on the test slide of the FTS-ABS?
if patient has antibody to T. pallidum it will bind to the Nicols strain. Labeled conjugate is added and will bind to the antibody
what are the limitations for FTS-ABS
minimally reactive result must be repeated 1-2wks later
experienced personnel needed to read results
false positives
time consuming
false positives for FTS-ABS
SLE
autoimmune disorders
congenital syphilis
caused by maternal infection and trans placental transmission
what percentage of babies will develop symptoms from congenital syphilis
60-90%
symptoms of congenital syphilis
lesions on mouth, anus, genitalia
watery discharge
skin eruptions
saddle nose
hutchinson’s teeth
bone deformations
baby test results from congenital syphilis
maternal VDRL titers
FTA-ABS IgG from mom
relapsing fever is from what organism
Borrelia recurrentis (epidemic- louse born)
Borrelia spp. (endemic- tick born)
lyme disease is from what organism
Borrelia burgdorferi
relapsing fever is associated with what
poverty
crowding
warfare
louse borne borreliosis
epidemic relapsing fever
how is epidemic relapsing fever transmitted?
person-person by lice
how is endemic relapsing fever transmitted
sporodic through ticks
incubation time for relapsing fever
2-14 days
endemic relapsing fever in US from what 3 Borrelia?
Borrelia hermsii (most common)
Borrelia parkerii
Borrelia turcatae
Borrelia hermsii
tick: Ornithodoros hermsi
higher altitudes
squirrels and chipmunks
Borrelia parkerii
tick Ornithodoros parkeri
lower altitudes/ caves
squirrels, prairie dogs, owls
Borrelia turicatae
tick Ornithodoros turicata
caves of SW
squirrels, prairie dogs, owls, cave dwellers
relapsing fever clincial progression
fever lasting several days
interval w/o fever
another episode of fever
also: body aches, muscle pain, headache, joint pain, eye pain, neck pain, confusion, dizziness
First lab department to see Borrelia
hematology
lyme is transmitted by
arthropod Ixodes scapularis
humans place in lyme disease
accidental host
lyme disease early stage
lesion after 3-30 days
bulls eye rash
flu like symp
late stage lyme disease
type 3 hypersensitivity to:
persisting lyme Ag, Ag-Ab cmplxs,
inflamm & tissue damage by neut. macro.
late stage lyme disease symptoms
foci rash
lymes carditis
tendon, muscle, joint, bone pain
facial/ bells palsy
inflamm of brain/spinal cord
problems w/ short term memory
treatment of lyme disease
doxycycline
followed by amoxicillin
CDC diagnosis of Lyme disease must have
either:
erythema migrans or
@ least one late manifestation (musculoskeletal, NS, Caridovascular) and lab confirmation
Lab: at least one-
isolation of spirichetes or
IgM/ IgG Ab or
sig increase titer
Ab for lyme disease last
for months or years
true false
seroreactivity alone cannot be used as marker of active disease of lyme disease
true
test for lyme disease
enzyme immunoassay
IFA
western blot
