Syphilis is a sexually transmitted disease (STD) caused by the bacterium Treponema pallidum. It has often been called “the great imitator” because so many of the signs and symptoms are indistinguishable from those of other diseases.
In the United States, health officials reported over 36,000 cases of syphilis in 2006, including 9,756 cases of primary and secondary (P&S) syphilis. In 2006, half of all P&S syphilis cases were reported from 20 counties and 2 cities; and most P&S syphilis cases occurred in persons 20 to 39 years of age. The incidence of P&S syphilis was highest in women 20 to 24 years of age and in men 35 to 39 years of age. Reported cases of congenital syphilis in new-borns increased from 2005 to 2006, with 339 new cases reported in 2005 compared to 349 cases in 2006.
Between 2005 and 2006, the number of reported P&S syphilis cases increased 11.8 percent. P&S rates have increased in males each year between 2000 and 2006 from 2.6 to 5.7 and among females between 2004 and 2006. In 2006, 64% of the reported P&S syphilis cases were among men who have sex with men (MSM).
Syphilis is passed from person to person through direct contact with a syphilis sore. Sores occur mainly on the external genitals, vagina, anus, or in the rectum. Sores also can occur on the lips and in the mouth. Transmission of the organism occurs during vaginal, anal, or oral sex. Pregnant women with the disease can pass it to the babies they are carrying.
The patient is physically examined. For men the penis, foreskin and urethra and for women internal examination of the vagina and external examination of the vulva is important.
For both men and women, mouth, tongue, anus and rectum is examined. In primary syphilis this may show a painless sore or chancre.
Those who are infected with syphilis have presence of antibodies against the syphilis bacteria. This can be detected in blood.
A positive result indicates presence of these antibodies and means that the person either has the infection or had it earlier. The antibodies can remain in blood for years, even after a previous infection was successfully treated.
A negative result does not necessarily mean that the person does not have syphilis as the antibodies may not be detectable for up to three months after infection. The test may be repeated in three months.
Blood tests are also recommended for pregnant women in order to detect the risk to the unborn baby and treat the mother accordingly. The blood test is usually done during an antenatal appointment at weeks 11-20 of pregnancy. If the test is positive, treatment for both the mother and baby can be started.
Blood tests include the Treponemal enzyme immunoassay (EIA). This can detect the immunoglobulin M (IgM) for early infection or immunoglobulin G (IgG) (the latter becomes positive at 5 weeks) or both. Both are checked for screening. This is the most important test for primary syphilis detection.
Other tests of blood samples include:
- T. pallidum chemiluminescent assay
- T. pallidum haemagglutination assay (TPHA)
- T. pallidum particle agglutination assay (TPPA)
- Fluorescent treponemal antibody absorbed test (FTA-abs)
- T. pallidum recombinant antigen line immunoassay
All of these will be positive in secondary and early latent syphilis.
Venereal disease reference laboratory (VDRL) or rapid plasmin reagin (RPR) or a quantitative VDRL can be used as an indication of the stage of syphilis and is also used for monitoring treatment.
From the chancre, or the sore, a swab (using a sterile cotton bud) is used to take a small sample of fluid. This is then fixed onto a glass slide and stained with special dyes. Then the slide is looked under the microscope in the clinic or sent to a laboratory for examination. The technique is called Dark field microscopy.
For detection samples from the lymph nodes in early syphilis may be taken. Other tests to see the bacteria directly include Direct fluorescent antibody (DFA) test and Polymerase chain reaction (PCR).
Penicillin is the drug of choice in primary and secondary syphilis. Those who are allergic to penicillin are prescribed other drugs as pills or injections. Later stages of the disease need to be treated with three penicillin injections, which are given at weekly intervals.
A small number of people experience a reaction to the antibiotics known as the Jarisch-Herxheimer reaction. It is thought that the reaction is triggered by the toxins released when many bacteria are killed after antibiotic treatment. The Jarisch-Herxheimer reaction causes flu-like symptoms such as fever, headaches and muscle and joint pain. These symptoms normally only last 24 hours and are not serious. The symptoms can be treated with paracetamol.
For Primary, Secondary, or Early Latent syphilis less than 1 year 2.4 million units IM (intramuscular) of Benzathine Penicillin G in a single dose is given. For latent infection over 1 year and latent infection of unknown duration 2.4 million units IM of Benzathine Penicillin G in 3 doses each at 1-week intervals (7.2 million units total) is given.
Treatment during pregnancy, childhood and congenital syphilis
Treatment during pregnancy should be the penicillin regimen appropriate for the stage of syphilis. In first and second trimesters single dose benzathine penicillin is given.
In the third trimester two doses of benzathine penicillin one week apart is chosen.
For late syphilis, treatment should be like nonpregnant (avoiding tetracyclines). Alternatives include ceftriaxone 500 mg IM for 10 days.
For congenital syphilis 100,000-150,000 units/kg/day (50,000 units/kg/dose IV every 12 hours) of Aqueous Crystalline Penicillin G during the first 7 days of life and every 8 hours thereafter for a total of 10 days is given. An alternative regimen is - 50,000 units/kg/dose IM of Procaine Penicillin G in a single dose for 10 days.
Among children with primary, secondary or early latent phase (less than 1 year), 50,000 units/kg IM of Benzathine Penicillin G in a single dose (maximum 2.4 million units) is given. For children with latent period more than a year or of unknown duration 50,000 units/kg IM of Benzathine Penicillin G for 3 doses at 1-week intervals (maximum total 7.2 million units) is given.
Follow up after antibiotics course
Once the course of antibiotics is finished the patient needs to visit the clinic again for a follow up blood test. This check if the infection is gone.
Detection and treatment of the sexual partner(s)
All sexual partners of an infected person over the last 90 days are considered infected. They need to be identified, tested and treated if needed. Some people can feel angry, upset or embarrassed about discussing syphilis with their current partner or former partner.
GPs and physicians help in disclosing the exposure to risk to these sexual partners using a 'contact slip'. This slip explains to that person that they may have been exposed to syphilis and that they should go for a check-up. The slip does not have the name of the infected person on it.
Treating tertiary syphilis
Treatment of tertiary syphilis requires longer courses of antibiotics and may need intravenous treatment. Treatment can only stop the infection. It fails to repair the damage that is caused to the brain, eyes or other organs by syphilis.
For neurosyphilis or affliction of the nerves and brain 3 to 4 million units IV of Aqueous Crystalline Penicillin G every 4 hours for 10-14 days (18-24 million units/day) is given.
Patients who acquire syphilis are at significant risk of reinfection and should therefore be regularly screened for syphilis. All patients should be offered screening for other sexually transmitted infections, including HIV.
Safer sex measures include:
- Having sex with a single faithful, tested and non-infected partner. Sexual penetration or ejaculation does not need to take place for syphilis to spread.
- Condoms can be used to reduce the risk of catching syphilis, but cannot prevent it altogether. Some risk remains via exposure to the mouth (those having oral sex) or via anus (those having anal intercourse). It is important to use a condom during vaginal, oral and anal sex.
- Other forms of barriers like use of a dental dam (square of plastic) when having oral sex or when the mouth of an uninfected individual makes contact with partner's vagina or anus. This also prevents transmission of sexually transmitted infection (STI).
- Sex toys that have been used by another individual (possibly infected) should not be shared. For people who wish to use them can wash them after each use and use a fresh condom over them.
Treatment of sexual partners
Transmission needs to be prevented by routine testing and, if positive, treatment of sexual partners of infected individuals.
The infected individuals are counselled regarding prevention of spread to their sexual partners. Individuals sexually exposed to a person with primary, secondary, or early latent syphilis within 90 days preceding the diagnosis should be assumed to be infected.
All sexual partners of the infected person in the recent past need to be identified, notified and rapidly referred for medical evaluation and treatment. Long-term sex partners of patients with late syphilis should be evaluated clinically and serologically and treated appropriately. All patients with syphilis should be tested for HIV. Patient and partner education is important.
Syphilis and injection drug users
Syphilis can also spread by sharing injection drug users. Injection drug users should avoid sharing needles. They can opt for needle-exchange programmes that are offered by many pharmacies and local authorities. In these used needles can be exchanged for new disposable clean ones.
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