Ocular syphilis in patients with nonreactive RPR and positive treponemal serologies: a retrospective observational cohort study.

BACKGROUND: Screening for syphilis increasingly relies on positive treponemal rather than nontreponemal tests (rapid plasma reagin [RPR]). We compared ocular syphilis in patients with nonreactive versus positive RPR. METHODS: We conducted a retrospective observational cohort study of ocular syphilis treated at two New England hospitals 1996-2021 based on ophthalmologist-diagnosed eye findings and positive treponemal serology, regardless of RPR. We excluded patients with alternative diagnoses. We categorized RPR into nonreactive RPR, low-titer RPR (<1:8), and high-titer RPR (≥1:8) and compared early and long-term response to therapy. RESULTS: Our sample included 115 patients with ocular syphilis (median follow-up 2.5 years): 25 (22%) nonreactive RPR, 21 (18%) low-titer RPR, 69 (60%) high-titer RPR. Compared with nonreactive and low-titer RPR, people with high-titer RPR were younger (mean 47 years, p<0.001), more likely male (93%, p<0.001) and more likely to be living with HIV (49%, p<0.001). People with nonreactive and low-titer RPR were less likely than high-titer RPR to have posterior/panuveitis (32% and 29% versus 75%, p<0.001) or abnormal CSF (26% and 35% versus 75%, p<0.001), and more likely to present with chronic eye findings (20% and 29% versus 1%, p<0.001). In long-term follow up, eye findings improved and did not recur in most patients (62% nonreactive, 68% low-titer, 96% high-titer RPR); improved but recurred in 29%, 11%, and 4%, respectively; and were stable in 10%, 21%, and 0%, respectively. CONCLUSION: Patients with ocular syphilis and nonreactive RPR are similar to patients with low-titer RPR, and antibiotic therapy is beneficial in most.

Evaluation of an automated rapid plasma reagin test of serum and cerebrospinal fluid for monitoring neurosyphilis treatment: A case report.

This case report explores the utility of monitoring automated rapid plasma reagin (RPR) test results in both serum and cerebrospinal fluid (CSF) samples from a patient undergoing treatment for neurosyphilis. Syphilis treatment is based on the rapid plasma reagin (RPR) and syphilis treponema antibody levels, and in the case of RPR-positive syphilis, a 1/4 reduction in the RPR value by the manual card test is considered curative. However, it should be noted that when RPR is followed by the manual card test, there may seem to be no reduction when the automated method shows a steady reduction. In the present case, initially under surveillance for an unrelated condition, was found to have symptoms; imaging and serological findings suggestive of syphilis infection including syphilitic aortitis and neurosyphilis. After two weeks of high-dose intravenous Penicillin G, the patient was treated with oral amoxicillin as an indicator of RPR titers in both the serum and cerebrospinal fluid (CSF) by automated latex agglutination. RPR in serum automated latex agglutination decreased to 1/4 at 14 weeks and treatment was terminated, with a subsequent downward trend. The RPR using the manual card test was 1/2 at 14 weeks. If only the manual card method was used, the patient might require a longer treatment. In conclusion, the automated latex agglutination method for monitoring the treatment response may be useful, especially in patients with high RPR titers.

Changes in the Syphilis Rapid Plasma Reagin Titer Between Diagnosis and Treatment.

BACKGROUND: We compared the rapid plasma reagin (RPR) titer on the day of initial presentation with that on the day of syphilis treatment to inform clinical practice as to whether a repeated RPR test should be recommended. METHODS: We undertook a retrospective study between 1 March 2011 and 31 December 2020 at the Melbourne Sexual Health Centre in Australia among individuals who underwent syphilis serology on the day of initial presentation and the day of treatment, if the latter were within 14 days after initial presentation. We calculated the percentage of individuals with a ≥4-fold change in RPR titer, stratified by the time between initial presentation and treatment and by syphilis stage. RESULTS: Among the 766 included syphilis cases, the median duration between initial presentation and treatment was 6 days (interquartile range, 5-7 days). Of these cases, 14.8% (n = 113) had a ≥4-fold increase or decrease during this interval. The number of cases with a ≥4-fold increase or decrease in RPR titer increased with increasing time between initial presentation and treatment, from 5.7% (n = 6) 1-3 days after initial presentation to 26.2% (n = 27) at 10-14 days (Ptrend < .001). There was no significant difference in the number of cases with a ≥4-fold increase or decrease in RPR titer between syphilis stages (P = .66). CONCLUSIONS: Our data support the recommendation of repeating the RPR titer if the day of initial presentation and the day of treatment are different, even when treatment is within a few days after initial presentation.

Higher serologic responses of early syphilis to single-dose benzathine penicillin G plus doxycycline versus single-dose benzathine penicillin G alone among people with HIV.

BACKGROUND: Single-dose benzathine penicillin G (BPG) is the preferred therapy for early syphilis, but poorer serologic responses have been observed among people with HIV (PWH). No enhanced regimen has previously been shown to improve serologic outcomes of early syphilis. METHODS: We conducted a retrospective study to compare the treatment responses to single-dose BPG combined with 7-day doxycycline versus BPG alone in PWH who presented with early syphilis. Rapid plasma reagin (RPR) titers were determined every 3-6 months for all included PWH. Serologic response was defined as at least a fourfold decline in RPR titers at month 12. RESULTS: During January 2018 to March 2022, 223 PWH with 307 episodes of early syphilis received single-dose BPG plus doxycycline and 347 PWH with 391 episodes received BPG alone. The median age was 36 years and baseline CD4 count was 600 cells/mm3. In the intention-to-treat with last-observation-carried-forward analysis, PWH receiving BPG plus doxycycline had a significantly higher serologic response rate at 12 months of treatment than those receiving BPG alone (79.5% vs 70.3%, respectively; P= .006). The factors associated with 12-month serologic response were RPR titer (per 1-log2 increase, adjusted odds ratio [AOR], 1.25; 95% CI, 1.15-1.35) and receipt of BPG plus doxycycline (AOR, 1.71; 95% CI, 1.20-2.46). In the subgroup analyses, BPG plus doxycycline was consistently associated with a better serologic response than BPG alone at month 12. CONCLUSIONS: Among PWH with early syphilis, single-dose BPG plus doxycycline achieved higher serologic responses than BPG alone during a 12-month follow-up period.

Evaluation of chemiluminescence immunoassay as a screening test for syphilis on blood donor samples.

BACKGROUND AND OBJECTIVE: Global re-emergence of syphilis among blood donors necessitates novel diagnostic and prevention approaches that encourage timely intervention. Thus, the present study was planned to evaluate the efficiency of Chemiluminescence immunoassay (CLIA) as a screening test for syphilis. MATERIAL AND METHODS: This prospective cross-sectional observational study was conducted from October 2021 to September 2022. A total of 344 donors were enrolled by purposive sampling method, including additional 16 donors who were reactive by the Rapid plasma reagin test (RPR) during the study period. Data from three screening tests - RPR test, Treponema pallidum haemagglutination assay (TPHA) and CLIA for 360 blood donors were analysed. TPHA was considered the gold standard test. RESULTS: Of the total 360 samples tested, 21 (5.8 %) were reactive by the RPR test. Of these 21 RPR reactive samples, 19 (90.5 %) were reactive by both TPHA and CLIA, while 2 (9.5 %) RPR reactive samples were non-reactive by both TPHA and CLIA. Of the remaining 339 RPR non-reactive samples, 1 (0.3 %) sample was reactive by both TPHA and CLIA, and 1 (0.3 %) was reactive by CLIA alone. CLIA was found to have sensitivity and specificity of 100 % and 99.7 % and positive predictive value (PPV) and negative predictive values (NPV) of 95.2 % and 100 % respectively, while it was 95 %, 99.4 %, 90 %, and 99.7 %, respectively, with the RPR test. CONCLUSION: CLIA was found to have a higher sensitivity, specificity, PPV and NPV than the RPR test. Thus, CLIA can be an acceptable alternative for syphilis screening in blood donors.

Ocular syphilis on the rise: a 10-year analysis from 2010 to 2020.

PURPOSE: The purpose of the study was to evaluate the incidence of ocular syphilis as well as diagnostic parameters, comorbidities, and visual outcomes over a 10-year time period in West Virginia. METHODS: A retrospective chart review included 25 eyes of 17 patients with ocular syphilis between 2010 and 2020. RESULTS: The incidence of systemic syphilis at a large tertiary referral center has increased from 27 cases in 2010 to 105 cases in 2020. Seventeen patients were identified with ocular syphilis. Bilaterality was present in 47.1% of cases. In this study, 70.6% of patients were male and 29.4% were female. The median age of presentation was 40.2 years (range 21-63). Panuveitis was the most common (60.0%) followed by isolated anterior uveitis (16.0%), chorioretinitis (12.0%), inner retinitis (4.0%), and papillitis (8.0%). Forty percent of patients had visual acuity worse than 20/400 on presentation. Post-treatment visual acuity improved in all patients. Rapid plasma reagin (RPR) and Treponema pallidum particle agglutination (TP-PA) tests were positive in 84.6% and 100% of cases, respectively. CSF venereal disease research laboratory (VDRL) was positive in 36.4%, CSF pleocytosis was present in 72.7%, and elevated CSF protein was observed in 81.8%. Human immunodeficiency virus (HIV) co-infection was present in 31.3%. A majority of patients experienced maculopapular rash and/or history of genital chancre. The anatomic classification of presenting uveitis (anterior, intermediate, posterior, and panuveitis) did not correlate with clinical variables including age, gender, HIV status, serologic test, presence of rash, or year of diagnosis (p > 0.05). CONCLUSION: Ocular syphilis is becoming increasingly prevalent and can present with a variety of ocular findings; therefore, it should be considered in the differential diagnosis for patients with ocular inflammation. Visual prognosis is excellent with timely diagnosis and treatment.

Intra-couple discordance in preconception syphilis screening for both spouses: a national and population-based survey in China, 2013-2018.

OBJECTIVE: The antenatal screening strategy remains inadequate for eliminating congenital syphilis. To further eliminate maternal fetal transmission, preconception syphilis screening is considered an option. In this study, we investigated syphilis seropositivity and intra-couple discordance among married couples planning a pregnancy in China to provide essential baseline evidence for preconception syphilis screening. DESIGN: Population-based survey. SETTING: National preconception registered data. POPULATION: Married Chinese couples planning conception within 6 months between 2013 and 2018. METHODS: Syphilis was screened using rapid plasma reagin (RPR); infection self-reporting and sociodemographic characteristics were collected through questionnaires and medical records, respectively. r 3.2.2 and arcgis 10.2 were used for statistical analyses and geographic mapping. MAIN OUTCOME MEASURES: RPR seropositivity. RESULTS: Among 31 955 041 couples, 29 737 172 (93.06%) had complete RPR results for both spouses; of those, 0.62% (186 100) were seropositive, with dramatic intra-couple discordance, with 0.33% positivity in wives, 0.24% positivity in husbands and 0.05% positivity in both spouses. Across time, both seropositivity and intra-couple discordance remained stable. Seropositivity in different regions varied significantly, with provincial rates ranging geographically from Tibet (0.8%) to Hebei (0.2%) (P < 0.05). Economic level was an independent factor for this regional variation, with seropositivity increasing as gross domestic product income decreased (P < 0.05). CONCLUSIONS: Intra-couple discordance in seropositivity for syphilis is notable among couples, with a considerable rate of pre-existing syphilis before pregnancy. Thus, screening both spouses during integrated preconception health care is recommended for further eliminating maternal-fetal transmission. TWEETABLE ABSTRACT: Intra-couple discordance in seropositivity for syphilis is notable among couples, with a considerable rate of pre-existing syphilis before pregnancy. Screening both spouses during integrated preconception health care is recommended to further eliminate maternal-fetal transmission.

Concurrent coronavirus disease 2019 and primary syphilis in a young man: A rare case report.

INTRODUCTION: The global rise of syphilis infections and the ongoing coronavirus disease 2019 (COVID-19) pandemic are causes for concern. We herein report a rare case of concurrent primary syphilis and COVID-19. CASE REPORT: A 29-year-old man was admitted with a diagnosis of COVID-19. Although COVID-19 pneumonia appeared during ciclesonide and favipiravir treatment, his symptoms improved without developing severe hypoxemia. A small, red ulcer on the left-side of his glans penis was noted and left inguinal lymph node swellings were detected on computed tomography (CT). He reported that his last engagement in sexual intercourse had been 3 months previously, and that his partner had subsequently been diagnosed with syphilis. Although both serum Treponema pallidum (TP) antibody and rapid plasma reagin (RPR) quantitative tests were negative on the day of admission, we clinically diagnosed a suspected case of primary syphilis and started treatment with amoxicillin (1500 mg/day). We subsequently learned that the TP antibody and RPR quantitative tests had been positive 4 days before starting syphilis treatment. Amoxicillin treatment was continued for 61 days, and the ulcer gradually improved. One year later, the RPR quantitative test was negative, and CT revealed a reduction in size of the inguinal lymph nodes and no residual signs of COVID-19 pneumonia. CONCLUSION: The prevalence of syphilis has been increasing even during the COVID-19 pandemic, and the incidence of concurrent syphilis and COVID-19 might be higher than is recognized. Asking patients with COVID-19 about high-risk sexual behavior and genital lesions could help with early diagnosis of syphilis.

Retrospective comparison between non-treponemal and treponemal tests for screening of blood donors for syphilis and their correlation with donor history in a tertiary care teaching hospital.

BACKGROUND AND OBJECTIVES: Treponemal tests provide advantage of better detection during early, late and latent stages of syphilis with equal or higher sensitivity & specificity in comparison to non-treponemal tests. The objective of the present study was to analyse the level of concordance between treponemal and non-treponemal tests for donor screening and to correlate them with donor history. MATERIALS AND METHODS: Retrospective analysis of syphilis screening by treponemal (Chemiluminescence & TPHA) and non-treponemal tests (RPR) was done and donor history for high-risk behaviour and factors associated with false positivity were collected from post-donation counselling and collected data was coded and analysed. RESULTS: Amongst the 12,000 donors screened, reactivity rate by RPR, TPHA and Chemiluminescence was 0.45%, 0.8% and 1.17% respectively. There was discordance of 62% and 32% for reactive results by RPR and TPHA respectively when compared with Chemiluminescence. History of high-risk behaviour was present in ∼ 50% and 15% of donors with discordant results by RPR and TPHA respectively. Of 34 donors who were reactive only by Chemiluminescence and were followed up, 15% had history of high-risk behaviour and 56% had factors associated with false reactivity. CONCLUSION: Treponemal tests showed high syphilis reactivity amongst blood donors as compared to non-treponemal tests most likely due to their ability to detect early, late and latent syphilis cases. This may confer added transfusion safety in centres dependent on replacement donors without NAT testing by identifying donors with high-risk history with negligible increase in discard rate due to false reactivity.

Evaluation of the BioPlex 2200 syphilis total screen (IgG/IgM) with reflex to an automated rapid plasma reagin test.

BACKGROUND: We evaluated the recently FDA cleared BioPlex 2200 Syphilis Total Screen and automated rapid plasma reagin (RPR) assay for the detection of total (IgG/IgM) treponemal and non-treponemal antibodies in the reverse syphilis algorithm. METHODS: Prospectively submitted samples (n = 885) were assayed by both the IgG/IgM BioPlex Syphilis Screen and the original IgG BioPlex Syphilis Screen. The IgG screen reactive samples were reflexed to traditional RPR, and IgG/IgM screen reactive samples were reflexed to the automated RPR. Nonreactive RPR samples were tested by the Treponemal Pallidum Particle Agglutination test (TP-PA). Additional samples were collected (n = 404 total samples) to directly compare the automated and traditional RPR assays with each other. RESULTS: The sensitivity and specificity of the IgG/IgM screen with automated RPR was 95.6% (95% confidence interval [CI] 87.0-99.1) and 99.6% (CI 99.2-99.8) while the sensitivity and specificity of the BioPlex IgG screen with traditional RPR was 97.8% (CI 89.1-99.9) and 99.3% (CI 98.8-99.4). The sensitivity and specificity of the BioPlex RPR compared with traditional RPR was 95.8% (CI 93.9-97.0) and 94.1% (CI 89.4-91.1) and 95.3% (CI 92.6-97.1). The mean of the titer differences between the BioPlex RPR and the traditional RPR was 1.0 ± 0.9 SD titers. CONCLUSION: The addition of the detection of treponemal IgM antibodies to the IgG/IgM screen did not significantly affect the sensitivity and specificity compared to the original IgG screen. However, the addition of the comparable BioPlex RPR assay to the instrumentation significantly reduces the overall labor of syphilis screening and confirmation.

Usefulness of Automated Latex Turbidimetric Rapid Plasma Reagin Test for Diagnosis and Evaluation of Treatment Response in Syphilis in Comparison with Manual Card Test: a Prospective Cohort Study.

The usefulness of an automated latex turbidimetric rapid plasma reagin (RPR) assay, compared to the conventional manual card test (serial 2-fold dilution method), for the diagnosis of syphilis and evaluation of treatment response remains unknown. We conducted (i) a cross-sectional study and (ii) a prospective cohort study to elucidate the correlation between automated and manual tests and whether a 4-fold decrement is a feasible criterion for successful treatment with the automated test, respectively, in HIV-infected patients, from October 2015 to November 2017. Study i included 518 patients. The results showed strong correlation between the two tests (r = 0.931; P < 0.001). With a manual test titer of ≥1:8 plus a positive Treponema pallidum particle agglutination (TPPA) test as the reference standard for diagnosis, the optimal cutoff value for the automated test was 6.0 RPR units (area under the curve [AUC], 0.998), with positive predictive value (PPV) of 92.5% and negative predictive value (NPV) of 99.4%. Study ii enrolled 66 men with syphilis. Their RPR values were followed up until after 12 months of treatment. At 12 months, 77.3% and 78.8% of the patients achieved a 4-fold decrement in RPR titer by the automated and manual test, respectively. The optimal decrement rate in RPR titer by the automated test for a 4-fold decrement by manual card test was 76.54% (AUC, 0.96) (PPV, 96.1%; NPV, 80.0%). The automated RPR test is a good alternative to the manual test for the diagnosis of syphilis and evaluation of treatment response and is more rapid and can handle more specimens than the manual test without interpersonal variation in interpretation.

Management of neurosyphilis: time for a new approach?

Given the long term sequelae of untreated neurosyphilis and insensitive tests to detect treponemes in the cerebrospinal fluid, questions regarding the utility of a lumbar puncture and cerebrospinal fluid analysis either to confirm or exclude neurosyphilis are raised.

Novel predictors of neurosyphilis among HIV-negative syphilis patients with neurological symptoms: an observational study.

BACKGROUND: Known predictors of neurosyphilis were mainly drawn from human immunodeficiency virus (HIV)-infected syphilis patients, which may not be applicable to HIV-negative populations as they have different characteristics, particularly those with neurological symptoms. This study aimed to identify novel predictors of HIV-negative symptomatic neurosyphilis (S-NS). METHODS: From June 2005 to June 2015, 370 HIV-negative syphilis patients with neurological symptoms were recruited, consisting of 191 S-NS patients (including 123 confirmed neurosyphilis and 68 probable neurosyphilis patients) and 179 syphilis/non-neurosyphilis (N-NS) patients. Clinical and laboratory characteristics of S-NS were compared with N-NS to identify factors predictive of S-NS. Serum rapid plasma reagin (RPR), Treponema pallidum particle agglutination (TPPA), and their parallel testing format for screening S-NS were evaluated. RESULTS: The likelihood of S-NS was positively associated with the serum RPR and TPPA titers. The serum TPPA titers performed better than the serum RPR titers in screening S-NS. The optimal cut-off points to recognize S-NS were serum RPR titer ≥1:4 and serum TPPA titer ≥1:2560 respectively. A parallel testing format of a serum RPR titer ≥1:2 and serum TPPA titer ≥1:1280 screened out 95.8% of S-NS and all confirmed cases of neurosyphilis. S-NS was independently associated with male sex, serum RPR titer ≥1:4, serum TPPA titer ≥1:2560, and elevated serum creatine kinase. Concurrence of these factors increased the likelihood of S-NS. CONCLUSIONS: Quantitation of serum TPPA is worthwhile and performs better than serum RPR in screening S-NS. Serum RPR, serum TPPA, male sex, and serum creatine kinase can predict S-NS. Moreover, patients with both a serum RPR titer <1:2 and a serum TPPA titer <1:1280 have a low probability of S-NS, suggesting that it is reasonable to reduce lumbar punctures in such individuals.

Improving the screening of blood donors with syphilis rapid diagnostic test (RDT) and rapid plasma reagin (RPR) in low- and middle-income countries (LMIC).

BACKGROUND: Syphilis testing conventionally relies on a combination of non-treponemal and treponemal tests. The primary objective of this study was to describe the positive predictive value (PPV) of a screening algorithm in a combination of a treponemal rapid diagnostic test (RDT) and rapid plasma reagin (RPR) test at Komfo Anokye Teaching Hospital (KATH), Ghana. MATERIALS AND METHODS: From February 2014 to January 2015, 5 mL of venous blood samples were taken from 16 016 blood donors and tested with a treponemal RDT; 5 mL of venous blood was taken from 526 consenting initial syphilis sero-reactive blood donors. These RDT reactive samples were confirmed with an algorithm, applying the Vitros® /Abbott-Architect® algorithm as gold standard. RESULTS: A total of 478 of 526 RDT reactive donors were confirmed positive for syphilis, making a PPV of 90·9%. Of the 172 (32·7%) donors who were also RPR positive, 167 were confirmed, resulting in a PPV of 97·1%. The PPV of the combined RDT and RPR (suspected active syphilis) testing algorithm was highest among donors at an enhanced risk of syphilis, family/replacement donors (99·9%), and among voluntary donors above 25 years (98·6%). DISCUSSION: Screening of blood donors by combining syphilis RDT and RPR with relatively good PPV may provide a reasonable technology for LMIC that has a limited capacity for testing and can contribute to the improvement of blood safety with a minimal loss of donors.

Syphilis in pregnancy.

Syphilis in pregnancy remains an important medical condition due to its consequences. We present two cases of young pregnant women who were diagnosed syphilis during their antenatal visit. The first case was a 29-year-old Malay lady diagnosed with syphilis during the first trimester of pregnancy, while the second case was a 21-year-old Chinese lady diagnosed with syphilis during the third trimester of pregnancy. The diagnosis and management of the syphilis in pregnancy are discussed.

Incidence and risk factors for the prozone phenomenon in serologic testing for syphilis in a large cohort.

BACKGROUND: The prozone phenomenon is known to be associated with high antibody titers; other associations, such as host factors, have not been elucidated. METHODS: A retrospective analysis was conducted to evaluate the incidence of the prozone phenomenon of the syphilis rapid plasma reagin (RPR) test among 46 856 clinical samples, between June 2010 and June 2013. Logistic regression was used to analyze the risk factors of the prozone phenomenon. RESULTS: Our results showed that the incidence of the prozone phenomenon was low (0.83%) and could occur during any clinical phase, particularly during primary and secondary syphilis. Pregnancy and neurosyphilis were associated with the prozone phenomenon; sex, age, and whether the patient had been treated were not. The results also revealed that the prozone phenomenon not only occurred in patients with a high titer but also could occur in patients with a moderate/low titer. In fact, almost 31% of the patients with the prozone phenomenon had titers ≤1:16. CONCLUSIONS: The prozone phenomenon in the RPR test was associated with the phase of syphilis, pregnancy, and neurosyphilis as well as a range of RPR titers between 1:8 and 1:512. This latter finding is in contrast to previous reports that the prozone phenomenon is associated with very high RPR titers.

Evaluation of Serological Tests for the Diagnosis of Syphilis.

Background Syphilis remains a significant public health concern in India. Ensuring the accuracy of diagnostic tests is crucial for effectively managing this disease. Objectives This study aims to assess the detectability of syphilis using commercially available non-treponemal and treponemal tests due to observed discrepancies in test results, which can lead to confusion and anxiety among healthcare providers and patients. Materials and methods We analyzed 2312 serum samples using the rapid plasma reagin (RPR), Treponema pallidum hemagglutination assay (TPHA), enzyme-linked immunosorbent assay (ELISA), and modified TPHA rapid test, interpreting the results according to the manufacturers' instructions. We evaluated the diagnostic accuracy of all four tests. Concordance between the traditional and reverse algorithms was determined by calculating the percentage of agreement and the kappa (κ) coefficient. Results Of the 2312 samples tested, 34 (1.5%) were positive, and 2098 (90.7%) were negative across all four tests. Comparing the test results with clinical diagnosis, TPHA and TP-ELISA showed the highest sensitivity at 96.08%, while RPR demonstrated the highest specificity at 100%. The agreement between the traditional and reverse algorithms was moderate, with a 97.3% agreement and a κ value of 0.53. Conclusion Reliance on a single serological test for syphilis screening presents limitations. A combined approach using both RPR and TPHA tests can more accurately diagnose and confirm syphilis. This combination strategy is cost-effective and relatively simple to implement.

Three cases of neurosyphilis diagnosed in the 21st century: A case report.

In the last decades, it has been considered that syphilis and its complications, including neurological damage, are able to be kept under control with proper epidemiological management. However, socio-economic changes and the problem of antibiotic resistance have brought it back into the focus of clinicians. The present study reports on the cases of three male patients of different ages (28, 76 and 51 years) from different social backgrounds and occupations were provided (first patient, nurse; second patient, pensioner; third patient, navigator); they were confirmed to have neurosyphilis, clinically, paraclinically and by imaging. The complications that may occur in the evolution of the disease but also the beneficial effects of targeted, antisyphilitic and symptomatic therapy were outlined. The purpose of the present study was to highlight issues of major importance regarding neurosyphilis, particularly for neurologists, for whom diagnosis may be challenging. It is key for the neurologist to understand the clinical manifestations and limitations of current diagnostic tests. It is important to consider that a positive rapid plasma reagin test result without confirmation of the presence of Treponema pallidum antibodies in the cerebrospinal fluid may represent a false-positive screening test.

An inscrutable entity: A case report of late congenital syphilis.

Congenital syphilis is an outcome of maternal syphilis that occurs due to the transmission of Treponema pallidum via the placenta of untreated or inadequately treated pregnant women to their newborns. It is now a very rare cause of neurological, developmental, and musculoskeletal disability and death in infants after the advent of penicillin. Here, we report a case of late congenital syphilis presented with classic stigmata of syphilis at the age of 10 years. Reactive serological titer of rapid plasma reagin test and venereal disease research laboratory test confirmed the diagnosis.

Prozone phenomenon in secondary syphilis with HIV co-infection: Two cases.

Prozone phenomenon is defined as a false-negative response resulting from higher antibody titer which interferes with formation of antigen-antibody lattice, necessary to visualize a positive flocculation test. The prozone effect can be observed in syphilis testing with cases of very high antibody titers, such as secondary syphilis, or with human immunodeficiency virus (HIV) co-infection. We report two cases of prozone phenomenon in secondary syphilis with HIV co-infection who initially tested nonreactive for rapid plasma reagin test but tested positive with further higher dilution.