Term
| What does Treponema pallidum cause? |
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Definition
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Term
| What is the significance of the corkscrew motility of Treponema pallidum? |
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Definition
| it enhances motility, for penetrating skin |
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Term
| How long does it take to double the number of Treponema pallidum? |
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Definition
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Term
| How is Treponema pallidum visualized? |
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Definition
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Term
| How long is the first phase of syphilis and what is it characterized by? |
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Definition
| painless chancre: 2-10 weeks |
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Term
| What are three categories of diagnostic testing for syphilis? |
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Definition
- Darkfield exam
- non-specific screening for antibodies against non-treponemal antigens (RPR and VDRL)
- specific confirmatory tests detecting antibody directed against Treponema pallidum
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Term
| When is the Darkfield exam most productive? |
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Definition
| during the early phase of infection, when no antibody is present |
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Term
| How do you report a Darkfield result if the characteristic spirochete shape is present but the organisms are non-viable or dying? |
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Definition
| Spirochetes seen; unable to verify species |
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Term
| How is Treponema pallidum confirmed by Darkfield exam? |
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Definition
| if a characteristic spirochete and motion are seen in a genital lesion |
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Term
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Definition
| non-treponemal tests that measure IgM/IgG produced against reagin, a lipoidal material released from damaged host cells |
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Term
| What is seen if the reagin antigen reacts with the patient's antibodies? |
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Definition
| a visible flocculation/precipitate |
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Term
| What does the Rapid Plasma Reagin test not work on? |
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Definition
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Term
| What titer value is considered indicative of syphilis in the reagin tests? |
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Definition
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Term
| What is the special role of VDRL Reagin tests? |
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Definition
| used on CSF to detect antibodies in neurosyphilis |
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Term
| What are some reasons a reagin test could yield an acute (<6 mon) false positive? |
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Definition
- hepatitis
- mononucleosis
- viral pneumonia
- chicken pox
- measles
- pregnancy
- immunizations
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Term
| What are some reasons a reagin test could yield chronic (>6 mon) false positives? |
|
Definition
- Lupus
- immunoglobulin abnormality
- narcotic addiction
- aging
- malignancy
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Term
| What is the most popular specific antigen test for syphilis? |
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Definition
| FTA-ABS (fluorescent treponema antibody test) |
|
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Term
| What are the pros and cons of the FTA-ABS test for syphilis? |
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Definition
- Pros:
- specific: false positive rate is lower (<1%)
- patients remain IgG positive for life
- special IgM version is good for congenital syphilis
- cons:
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|
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Term
What are the symptoms of stage 1 syphilis? |
|
Definition
- painless indurated papule
- progresses to chancre with regional pymphadenopathy
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|
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Term
| What is the incubation period for primary stage syphilis? |
|
Definition
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Term
| What are the symptoms of stage 2 syphilis? |
|
Definition
- secondary lesions that appear 2-10 wks later, on trunk, palms, soles, face
- lymphadenopathy
- fever
- malaise
- one third of patients are spontaneously cured
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Term
| What is the best type of diagnostic test for 2nd stage syphilis? |
|
Definition
|
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Term
| What percent of untreated syphilis cases progress to stage 3? |
|
Definition
|
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Term
| Is tertiary syphilis infectious by sexual contact? |
|
Definition
| No, it produces a very low number of organisms |
|
|
Term
| What is the pathologic mechanism of tissue damage in tertiary syphilis? |
|
Definition
|
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Term
| What are gummatous lesions? |
|
Definition
| common lesions of tertiary syphilis that are due to monocytic infiltrates and tissue destruction of various organs (including cardiovascular) |
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Term
| What are symptoms of meningovascular syphilis? |
|
Definition
| CNS degeneration, mental changes, decreased memory, frank psychosis, characteristic shuffling gait (Tabes dorsalis) |
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Term
| When is the fetus susceptible to congenital syphilis? |
|
Definition
| After 4th month of gestation |
|
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Term
| What are the organs effected by congenital syphilis? |
|
Definition
| eyes, meninges, bone, skin, anemia, jaundice, thrombocytopenia, death |
|
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Term
| What steps are taken to reduce the rate of congenital syphilis? |
|
Definition
- test all women early on
- test high risk women in the third trimester
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Term
| What are the three subspecies of Treponema can that cause non-sexual (skin or fomite) infections? |
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Definition
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Term
| What is Leptospira interrogans found in? |
|
Definition
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Term
How is Leptospira interrogans transmitted to humans?
|
|
Definition
animal urine contamination of food and water
- enters through the skin |
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|
Term
| How can Leptospira interrogans be killed? |
|
Definition
| acidic solutions, drying, soap |
|
|
Term
| How long is the incubation period for Leptospira interrogans? |
|
Definition
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Term
| What is the clinical presentation of leptospirosis? |
|
Definition
- influenza-like febrile illness for 1 week
- bacteremic phase
- spirochetes in the CSF
- muscle aches, headaches, and rash for 3+ weeks
- may develop aseptic meningitis and hepatic or renal disease
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|
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Term
| What is the mortality rate for Leptospirosis? |
|
Definition
|
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Term
| What populations are at risk for Leptospirosis and how many ppl get it per year? |
|
Definition
- sewer workers
- miners
- farm workers
- veterinarians
- meat packers
- children playing in ponds and ditches
* <100 reported cases/yr in the US |
|
|
Term
| How can leptospirosis be prevented/ |
|
Definition
| immunize animals, rodent control, drain water, promote good hygeine |
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Term
| Where are Leptospira interrogans found during the febrile/bacteremic phase? |
|
Definition
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Term
| Where are Leptospira interrogans found during the second phase? |
|
Definition
| urine- must be immediated cultured otherwise the acidity will kill the organisms |
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Term
| What is the appearance of Borrelia recurrentis? |
|
Definition
| large, irregular spirochetes, stain Gram-negative |
|
|
Term
| What sort of oxygen consumption do Borrelia recurrentis have? |
|
Definition
| microaerophilic metabolism |
|
|
Term
| What are the two forms of Borrelia recurrentis? |
|
Definition
- endemic form: carried by tick bite, reservoir in rodent
- epidemic form: carried by body louse
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|
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Term
| What is the mean incubation period for Borrelia recurrentis? |
|
Definition
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Term
| What are the symptoms of Borrelia recurrentis infection and what causes it? |
|
Definition
fever, rigors, headache, muscle pain
- endotoxin
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|
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Term
| Why does Borrelia recurrentis cause recurring fever? |
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Definition
| the febrile period lasts 1 week and antibodies will be produced, but then the organism develops a new antigenic coat that causes relapse |
|
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Term
| How many relapses typically occur in Borrelia recurrentis infection? |
|
Definition
| 2-4 relapses, each less severe |
|
|
Term
| Which form of Borrelia recurrentis is more severe, the endemic or epidemic form? |
|
Definition
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|
Term
| How is Borrelia recurrentis diagnosed during the febrile period? |
|
Definition
- Giemsa or Wright stained blood smears
- culture: special procedures necessary, slow turnaround time
- immunological tests: not helpful
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|
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Term
| What is the Jarish-Herxheimer reaction? |
|
Definition
rapid death of Borrelia recurrentis organisms widely distributed in the body can cause a massive release of tumor necrosis factor and interleukins that is sometimes fatal
- also seen in syphilis |
|
|
Term
| How is Borrelia burgdorferi transmitted to humans? |
|
Definition
By an Ixodes scapularis tick bite:
ticks feed and mate on deer and deposit their eggs on the ground, which hatch and feed on the white-footed mouse |
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Term
| What are three stages of Lyme disease? |
|
Definition
- primary lesions: erythema chronicum migrans
- secondary: spirochetemia, systemic symptoms
- late stage: few organisms, in a variety of organs, cause immunologically-mediate damage
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|
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Term
| How soon after a tick bite does the initial lesion occur? |
|
Definition
|
|
Term
| What are the constitutional symptoms of the first stage of Lyme disease and how long do they last? |
|
Definition
fever, muscle, joint pain, meningeal irritation
- months |
|
|
Term
| What symptom marks the third stage of Lyme disease and how long after the initial lesion can it occur? |
|
Definition
| arthritis, weeks or years later- fluctuating intermittent course |
|
|
Term
| What is the best way to diagnose Lyme disease? |
|
Definition
| First, EIA/ELISA screen for serum antibody, then confirm positives with multiple bands on a Western blot |
|
|
Term
| Where might a PCR sample be taken from for diagnosis of Lyme disease? |
|
Definition
|
|
Term
| How can Lyme disease be prevented? |
|
Definition
| Avoid tick bites, use insecticide, remove rodent habitats |
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