Sexually Transmitted Transmitted

DiseasesDiseasesCommon Diseases

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DR NAGLAA MAKRAM CONSULTANT CLINICAL PATHOLOGY

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STI Pathogens

*Not classified as an STI

Pathogen = Bacteria

•Chlamydia•Gonorrhea•Bacterial Vaginosis*•Syphilis

Pathogen= Virus

•Herpes•Hepatitis B•Genital Warts (HPV)•HIV/AIDS

Pathogen= Parasite

• Pubic Lice• Scabies• Trichomoniasis

Common Symptoms

Pain during urination Bump/sores Bleeding between periods Unusual discharge Pain during intercourse Rash

Many people can have no symptoms(asymptomatic) and still pass on a STI.

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STD’s of Concern “Sores” (ulcers)

• Syphilis

• Genital herpes (HSV-2, HSV-1)

• Others uncommon

•Lymphogranuloma venereum

•Chancroid

•Granuloma inguinale

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“Drips” (discharges)• Gonorrhea

• Chlamydia

• Nongonococcal urethritis / mucopurulent cervicitis

• Trichomonas vaginitis / urethritis

• Candidiasis (vulvovaginal, less problems in men) Other major concerns

• Genital HPV (especially type 16, 18) and Cervical Cancer

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Genital Ulcer Diseases – Does It Hurt?Painful

• Chancroid

• Genital herpes simplexPainlessPainless

• Syphilis

• Lymphogranuloma venereum

• Granuloma inguinale

Sores

Bacterial Infections

Infections caused by bacteria,this agent represents about half of the STIs identified.

Bacterial infections are curable. Medication does not protect against future exposure.

SyphilisTransmission • Skin to skin contact• Contact with mucous

membrane• Mother-to-child through

placenta

First Stage Syphilis

Chancres (shangker) (painless open sore) appear on the body.They disappear in about 14 days.

Second Stage Syphilis

Flu-like symptoms and rash. Rash is brownish redand can appear on any part of the body.

If gone untreated…

Third Stage Syphilis

• Transmission to sex partners and newborns• Nerve and brain damage• Blindness• Physical damage• Death

Degenerative lesions calledgummas appear as a result of hypersensitivity

Congenital Syphilis

Occurs following vertical transmission of T. pallidum from the infected mother to the fetus in utero, but neonates may also be infected during passage through the infected birth canal at delivery.

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Treponema pallidum

Syphilis

I- Detection of T. pallidum in lesions:I- Detection of T. pallidum in lesions: Serous exudate from lesions of 1ry and 2ry stages is Serous exudate from lesions of 1ry and 2ry stages is examined by:examined by:

1- wet film for dark ground microscopy to detect the 1- wet film for dark ground microscopy to detect the darting movement of the spiral T. pallidum.darting movement of the spiral T. pallidum.

2- IFT using fluorescein-labelled antitreponemal 2- IFT using fluorescein-labelled antitreponemal

antibodies.antibodies.

3- staining with silver impregnation technique 3- staining with silver impregnation technique

(Fontana stain).(Fontana stain).

Dark-ground microscopy showing long slender spiral bacteria Treponema pallidum

the quickest

characteristic motility associated with T. pallidum: a forward and backward motion with rotation about the longitudinal axis (picture 1) [13]. Soft side-to-side bending and twisting may also be seen.characteristic motility associated with T. pallidum: a forward and backward motion with rotation about the longitudinal axis (picture 1) [13]. Soft side-to-side bending and twisting may also be seen.characteristic motility associated with T. pallidum: a forward and backward motion with rotation about the longitudinal axis (picture 1) [13]. Soft side-to-side bending and twisting may also be seen.

•Failure to identify the organisms in a specimen does not exclude the diagnosis of primary syphilis.

• Optimal performance of darkfield microscopy starts with adequate collection of the specimen ,antibiotics may result in a false-negative finding.

• Dark field microscopy is generally limited to clinics that specialize in the diagnosis and treatment of sexually transmitted diseases (STDs).

Specimen Of Choice

Collect clear, serous fluid free of erythrocytes, tissue debris and other organisms. Gentle abrasion of lesions may be necessary to express clear, serous fluid. Lesions should be cleansed with saline or water before collecting the specimen. This is especially important when collecting specimens from areas such as under the prepuce, where nonpathogenic treponemes may be present.

Direct fluorescent antibody testing

•This technique has the advantage of permitting the identification of the organism when smears cannot be examined immediately. •It also avoids the problem of misidentifying other miscellaneous spirochetes since it is specific for T. pallidum antigens.•sensitivity (approaching 100 percent for the DFA), but a negative test does not totally exclude the diagnosis of syphilis

IF staining showing the spiral Treponema pallidum

Treponema pallidum smear Stained Treponema pallidum smear Stained by silver impregnation Technique by silver impregnation Technique (Fontana Stain) showing the spiral (Fontana Stain) showing the spiral

morphologymorphology

II- Serological diagnosis:II- Serological diagnosis:A- non-treponemal antigen tests:A- non-treponemal antigen tests:

- detect the reagin antibody that react with a non-detect the reagin antibody that react with a non-specific antigenspecific antigen

- Reagin is a mixture of IgG and IgM that appear 2-3 Reagin is a mixture of IgG and IgM that appear 2-3 weeks in the patient serum and 4-8 weeks in the weeks in the patient serum and 4-8 weeks in the CSF after exposure to infection.CSF after exposure to infection.

•called "nontreponemal" because they detect antibodies that are not specifically directed against the Treponema pallidum bacteria. •. The tests are highly sensitive but, BUT non-specific .• false-positive in : IV drug use, pregnancy, Lyme disease, certain types of pneumonia, malaria, tuberculosis, or certain autoimmune disorders including lupus.

• A positive screening result must be confirmed with a more specific (treponemal) test.

Some false positive nontreponemal test results are transitory typically last for six months or less.

These false positive test results tend to be of low titer but

this is not always true, especially in HIV-infected patients; thus, the level of the titer alone does not reliably help the clinician differentiate between a true or false positive result.

non-treponemal antigen tests are characterized by:non-treponemal antigen tests are characterized by:

- Non-specific and can lead to false positive results.- Non-specific and can lead to false positive results.

- Become negative 6-18 months after effective - Become negative 6-18 months after effective treatment, so can be used to follow up the effect of treatment, so can be used to follow up the effect of treatment.treatment.

- They are mainly used for screening and They are mainly used for screening and epidemiological studies because they are cheep, epidemiological studies because they are cheep, rapid and simple.rapid and simple.

- VDRL (Venereal Disease Research Laboratory)--in addition to blood, performed on CSF to help diagnose neurosyphilis.

-

RPR and VDRL are agglutination assays

Non-Treponemal Assays

Cardiolipin

Charcoal

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Serumor

CSF

ReaginCardiolipin

Charcoal

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VDRL

Each preparation of antigen suspension should first be examined by testing with known positive or negative serum controls.

The antigen particles appear as short rod forms at magnification of about 100x. Aggregation of these particles into large or small clumps is interpreted as degrees of positivity

Reactive on left, non-reactive on right

Dr.T.V.Rao MD 26

The rapid plasma reagin (RPR) test

- RPR appears to be more sensitive than the VDRL.

A negative blood test

Means that it is likely that no infection is present. However, a negative screening test means only that there is no evidence of disease at the time of the test. Antibodies may not be detected for up to several weeks after exposure to the bacteria. If a person knows he or she has been exposed, or if suspicion of infection remains high, then repeat testing at a later date may be required.

Serologic testing is an indirect method of diagnosis since it relies upon a humoral immune response to infection.

As such, it has some inherent limitations, particularly in the HIV-infected patient with advanced immunosuppression. Reflect abnormally active B-cell function during early HIV infection and B-cell failure during late-stage HIV infection.

Possibility for prozone effect

•High levels of antibody may inhibit the agglutination reaction

•To identify prozone, labs must serially dilute samples

Undilute 1:2 1:4 1:8 1:16

Limitations

142 PERCENT 30

Patients with a history of treated syphilis —

Titers decline following successful therapy and serologic testing usually revert to nonreactive over timehowever, some patients may remain "serofast"; these reactive tests, but at low titer (eg, 1:2), despite successful treatment. Re infection is diagnosed if a fourfold or greater increase in titer. When possible, all titers should be compared using the same test methodology.

Traditional AlgorithmNon-treponemal test (e.g., RPR)

Treponemal test (e.g., FTA) Negative for syphilis

Non-reactive

Non-reactive

Syphilis Negative for syphilis

Reactive

Reactive

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B- Treponemal antigen testsB- Treponemal antigen tests

- Highly specific and sensitive tests as they use - Highly specific and sensitive tests as they use

T. pallidum as the antigen.T. pallidum as the antigen.

- But they are complex and expensive, so used - But they are complex and expensive, so used mainly for confirmation of diagnosis.mainly for confirmation of diagnosis.

-They remain positive for life, so cannot be used to -They remain positive for life, so cannot be used to

judge the efficacy of treatment.judge the efficacy of treatment.

SO SO

How u How u differentiate between an active re infection and old infection .

1- Fluorescent treponema antibody test (FTA). 1- Fluorescent treponema antibody test (FTA).

The presence of IgM FTA in the blood of a new-borne The presence of IgM FTA in the blood of a new-borne is good evidence of in-utero infection.is good evidence of in-utero infection.

2-Treponema pallidum hemagglutination (TPHA).2-Treponema pallidum hemagglutination (TPHA).

3- T. pallidum Particle Agglutination (TPPA).3- T. pallidum Particle Agglutination (TPPA).

performed instead of FTA-ABS because it is more specific and there are fewer false positives.

4- 4- MHA-TP (Microhemagglutination assay)

5- 5- Immunoassays (AIA)--in more recent years

Immunoassays (AIA)--in more recent years

1- Fluorescent treponema 1- Fluorescent treponema antibody test (FTA).antibody test (FTA).

2- TPHA2- TPHA

Reverse AlgorithmTreponemal test (eg, EIA)

Non-Treponemal test (eg, RPR) Negative for syphilis

Non-reactive

Non-reactive

Syphilis Second Treponemal Test (e.g., TP-PA)

Reactive

Reactive

Non-reactiveReactive

Evaluation Required* Negative for syphilis

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Other Diagnostic Other Diagnostic TestsTests

Biopsy rarely needed. It shows endarteritis obliterans with inflammatory reaction containing a plenty of plasma cells. Granuloma may found in tertiary syphilis.

Dr.T.V.Rao MD 37

Polymerase chain reaction testing — 

Detection of various DNA target sequences . able to detect as low as one to 10 organisms per specimen

The sensitivity of PCR testing in swab specimens of mucosal sites 70 to 95 percent with a specificity from 92 to 98 percent .

 Unfortunately, sensitivity tends to be much lower in blood specimens (approximately 24 to 32 percent).

Western blot

This test can detect either IgG or IgM antibodies and is considered a very useful adjunct confirmatory test .

This technique is used in some laboratories to resolve questionable results obtained with other treponemal tests 

Rapid serologic testing — 

Immunochromatography-based point-of-care tests good sensitivity 74 to 90 percent and specificity 94 to 99 percent.The advantages :use of blood from a finger stick and the availability of rapid results (15 to 20 minutes), which can be interpreted by non-laboratory personnel. such assays do not distinguish between active and treated syphilis since treponemal antibody tests are non-quantitative and are not used to assess response to treatment 

Early treatment — 

A patient with a history of early treatment intervention may have no laboratory evidence of prior syphilis because of full seroreversion in both nontreponemal and treponemal serologies. However, this is uncommonly seen.

Every Pregnant women Needs Screening

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The standard serological tests are less useful in newborns because of IgG transfer across the placenta. 

IgM test which depends on the infant’s response has more specificity in diagnosing connatal syphilis. 

Maternal IgM immunoblot results identify mothers at risk of delivering babies with connatal syphilis better than the height of maternal RPR titer.

DIAGNOSTIC TESTING FOR NEUROSYPHILIS — 

Examination of CSF is the only way to diagnose asymptomatic neurosyphilis . A positive CSF VDRL is highly specific for neurosyphilis, but sensitivity is poor; only 50 percent. Elevations of white blood cells and protein are non-specific, especially in HIV-infected patients. Thus, the laboratory diagnosis of neurosyphilis usually depends on various combinations of reactive serologic test results, CSF cell count and protein, and a reactive CSF-VDRL with or without clinical manifestations .

If the CSF-VDRL is nonreactive, and neurosyphilis is suspected, a CSF FTA-ABS (Fluorescent treponemal antibody absorption (FTA-ABS)) can be ordered .

Although it is less specific than a CSF-VDRL, the CSF FTA-ABS test is highly sensitive; neurosyphilis is highly unlikely with a negative CSF FTA-ABS test . HIV-infected patients, the presence of a serum RPR ≥1:32 or a CD4 count <350 cells/mm3 were both associated with an increased risk of neurosyphilis