1. How is syphilis diagnosed?
The diagnosis of syphilis is generally made on the basis of a combination of the following aspects.
(1) Medical history: whether there is a history of non-marital sexual contact, what is the status of previous blood transfusion, childbirth and treatment.
(2) Physical examination: whether there are various clinical manifestations and signs consistent with syphilis.
(3) Laboratory tests: blood is drawn for syphilis serology to check for evidence of syphilis infection (syphilis antibodies) in the blood, or secretions from skin damage are taken for dark field microscopy to see if syphilis spirochetes are present. Generally need to do the initial screening and confirmation of both laboratory tests to diagnose.
2. Can a positive test for syphilis in newborns diagnose “fetal syphilis”?
Since newborns can carry various antibodies obtained from their mothers, including syphilis antibodies, even a positive serum antibody test for syphilis in newborns cannot be diagnosed? fetal syphilis”. However, maternal antibodies carried by the newborn can be metabolized by catabolism in the first 6 to 12 months of life so that they are undetectable. Therefore, it is possible to determine whether the infant is infected with syphilis through continuous follow-up for 6 months. For pregnant women who have been formally treated for syphilis, if the newborn is RPR positive but does not reach the mother’s titer, the baby can be observed once every month, and if the RPR titer decreases or becomes negative around 6 months, then “fetal syphilis” can be ruled out. For pregnant women with untreated syphilis, their newborns should be treated as necessary for fetal syphilis.
There is also information that for infants born to pregnant women with syphilis (whether treated or not), if the RPR titer at birth is greater than or equal to four times the mother’s titer, the diagnosis of “fetal syphilis” can generally be made.
3. What are the characteristics of syphilis co-infection with HIV?
HIV infection can also increase the incidence of early neurosyphilis and affect the effectiveness of anti-syphilis treatment. It can be seen that whether the syphilis patient is infected with HIV, or HIV-infected people occur syphilis, will aggravate the disease and increase the difficulty of treatment, therefore, syphilis patients or HIV-infected people should take effective protective measures to avoid co-infection.
4.Why should long-acting penicillin be used to treat syphilis?
Penicillin is still the best drug to treat syphilis, and no syphilis spirochetes resistant to penicillin have been found at home and abroad.
The main mechanism of penicillin treatment for syphilis is to stop the regeneration and repair of syphilis spirochete cell wall, i.e. block its reproduction. The reproduction cycle of syphilis spirochete is about 30-33 hours, therefore, the effective concentration of penicillin (0.03 unit/ml) must be maintained for 7-10 days to completely kill the syphilis spirochete in the body. Since aqueous penicillin is rapidly absorbed and excreted, the usual number of injections cannot achieve the effective serum concentration to maintain the above, so it is better to use long-acting penicillin, such as procaine penicillin and benzathine penicillin, for the treatment of syphilis. Just in the treatment of neurosyphilis with aqueous penicillin (because long-acting penicillin is more difficult to pass the blood-brain barrier), the dose is 3-4 million units each time, intravenous drip, every 4 hours, and after 10-14 days of continuous treatment, continue a course of treatment with Byssin penicillin.
5.What is syphilis treatment reaction (Jihai reaction)?
Syphilis treatment reaction, that is, “Jihai reaction”, refers to a series of adverse reactions that occur when the patient is first treated with syphilis. It usually occurs within 4 hours of the initial use of syphilis medication, peaks at 8 hours, and disappears in about 24 hours. The main symptoms are general malaise, a 1.5°C rise in body temperature, flu-like symptoms, aggravation of the original syphilis damage, transient deterioration, and generalized rash swelling and tenderness. Stillbirths and miscarriages can occur as a result of the Gihai reaction to syphilis in pregnancy.
The incidence of GI reaction is about 50% in stage I syphilis and about 75% in stage II syphilis, and the reasons for its occurrence have not been fully understood. In order to prevent the occurrence of Jihai reaction can be clearly explained to the patient in advance, so that they are prepared, when needed to give the patient oral prednisone, for 3 days, can reduce or eliminate this adverse reaction.
6.Why do some syphilis patients always have positive syphilis serology test after treatment?
There are two types of serological tests for syphilis, both of which check the antibodies produced by the body against syphilis spirochete infection. One is the “non-syphilis spirochete specific test”, or “RPR”, which slowly decreases after treatment for early syphilis patients and becomes negative after about six months. Another type of test is the “syphilis spirospecific test”, or “TPHA” or “TPPA”, which is specific and can be used to confirm the diagnosis of syphilis. But once you have syphilis, whether or not you are cured, there will be this antibody in the body, there will be “TPHA” or “TPPA”, positive, and can be positive for life, but does not mean that there is no cure.
7.Why do syphilis patients who are cured have antibodies for the rest of their lives and still get reinfected?
After the syphilis patient is cured, there will be antibodies for life, and some people think they will not be infected with syphilis again in the future, but in fact, they will still be infected again, there was a man who had sex with men who had syphilis and did not have sex for a long time after the cure, but recently had unprotected sex and then got infected with syphilis again. This is due to the weak antigenicity of the syphilis spirochete, can not release a sufficient amount of antigen, the antibodies produced in quality and quantity are defective, can not play a sufficient role in immunity, can not play a role in preventing infection, resulting in patients can still be reinfected after the cure.
8.When will a false-positive syphilis serological test (RPR) occur?
Technical false-positive reactions can occur due to improper preservation of specimens, poor quality of reagents or errors in laboratory operations. However, certain diseases can also cause biological false positives.
Biological false-positive reactions can be divided into acute and chronic biological false-positive reactions.
Acute biological false positives are often seen in: rubella, chickenpox, viral hepatitis, pneumonia, subacute endocarditis, active tuberculosis, malaria, filariasis, regressive fever, leptospirosis, etc.
Chronic biological false-positive reactions that can last for more than 6 months or years, or even for life. It is seen in: certain collagen diseases, systemic and discoid lupus erythematosus, rheumatoid arthritis, rheumatic heart disease, leprosy, liver cirrhosis, autoimmune hemolytic anemia, chronic nephritis, intravenous heroin, etc.
False positive reactions can also occur in a small number of pregnant women and elderly people, and false positive reactions in the general population account for 1% to 2% of RPR. Therefore, the diagnosis of syphilis cannot be based on the results of RPR alone, and confirmation tests are needed to exclude false-positive reactions.
9.What is the pre-band phenomenon (false negative reaction) of syphilis serological test?
In the non-syphilis spirochete specific test (RPR), sometimes there is a high concentration of antibodies in the serum when the weak positive or negative reaction results, but clinically like the second stage of syphilis, at this time, the serum is diluted and then tested, there is a positive result, the phenomenon is called the “pre-banding phenomenon”. The reason is that the amount of antibody in this serum is more than the antigen, so the ratio of antigen to antibody is not appropriate, which inhibits the appearance of a positive reaction. About 1% to 2% of the second stage syphilis patients have false negative syphilis serum reaction due to this phenomenon.
10.What is syphilis serum fixation?
It means that after anti-syphilis treatment, the non-syphilis spirochete specific test (RPR) does not turn negative for a certain period of time, i.e., serum resistance occurs. Early serum resistance is often associated with inadequate or irregular treatment, relapse, reinfection, or the presence of neurosyphilis. Late serum resistance is related to the type of syphilis and the timing of initiation of treatment. After standard treatment of patients with advanced serum resistance, even additional or unlimited treatment does not result in a reduction or conversion of the serum titer. For such patients, after detailed examination, especially excluding neurosyphilis, cardiovascular syphilis, treatment should be stopped and regular follow-up.
11.Is syphilis still infectious after treatment?
The infectiousness of syphilis is stronger in the early stage (within 2 years) and weaker in the late stage. If a syphilis case is cured by regular treatment, it will not be infectious if there is no recurrence or reinfection after 2 years of follow-up. If you receive irregular treatment, the RPR titer will be infectious if it always remains at a high level.
12.Why should I follow up after syphilis treatment?
In order to ensure cure, timely detection and treatment of relapsed patients, early syphilis should be followed up for 2 to 3 years after adequate treatment, with a review every 3 months in the first year and every 6 months thereafter. Late syphilis should be followed up for 3 years, every 3 months in the first year, and every six months thereafter.
13.How can syphilis be considered cured?
After standard treatment, syphilis can be cured. The criteria of cure are clinical cure and serological cure.
(1) Clinical cure.
① clinical symptoms disappear
In stage I, II and III syphilis, the damage to the skin, mucous membranes and internal organs all disappear, and the function of internal organs returns to normal. Some may have secondary or residual functional disorders, such as diminished vision; residual scarring or tissue defects (saddle nose, dental dysplasia, etc.).
(2) The syphilis serologic reaction turns negative, or remains positive.
(2) Serological cure.
Within 2 years of anti-syphilis treatment, the syphilis serologic reaction (RPR) turns from positive to negative, and the cerebrospinal fluid examination is negative.
14.Why should I be tested for syphilis during pregnancy?
Syphilis spirochetes in the blood of pregnant women can infect the fetus through the placenta, causing fetal stunting, growth retardation, or even death. Some studies show that if a pregnant woman has early syphilis and is not treated, the risk of stillbirth is 25%, neonatal mortality is 14%, and the incidence of fetal syphilis is 41%. However, with timely detection and treatment, cases of fetal syphilis can be avoided. Therefore, to ensure the health of the fetus/infant, syphilis screening should be included in prenatal care. Generally, a syphilis test is required within the first 3 months of pregnancy, and if possible, another test is preferred in the last 3 months. If the syphilis test is positive, anti-syphilis treatment should be administered. Syphilis testing is required for all pregnant women who have a stillbirth after 20 weeks of gestation.