KEY POINTS
- 1.
Congenital syphilis is a global public health problem, particularly in the Americas where its incidence appears to be rising.
- 2.
At birth 90% of infants are asymptomatic, the remaining 10% present a wide variety of symptoms from mild to lethal.
- 3.
To confirm the presence of spirochete may be challenging, diagnosis will usually be based on maternal syphilis history, treponemal and non treponemal test performed (maternal and newborn’s) and the presence of symptoms.
- 4.
Patients will be treated with aqueous/procaine penicillin if congenital syphilis is proven or probable. Possible disease may be treated with a single dose of benzathine penicillin. This might also be the case if infection is less likely.
- 5.
Follow up is paramount to ensure infants do not develop long term complications. Follow up will consist of periodical physical examination and non treponemal serologic test.
- 6.
Prevention is key in diminishing the burden of congenital syphilis. Screening during pregnancy is recommended. Epidemiological surveillance through notifications systems remains a cornerstone to tackle this problematic.
Introduction
Congenital syphilis is the infection of a fetus and newborn infant caused by Treponema pallidum , a bacterium from the family Spirochaetaceae. The infection was described for the first time in Europe during the 15th century by Gaspar Torella. In the Americas, the infection might have been brought by Europeans during colonization. T. pallidum was first identified in 1905 by Fritz Schaudinn, a zoologist, and Erich Hoffmann, a dermatologist. Penicillin was tested and proven to be an effective bactericidal agent against T. pallidum by John Mahoney, Richard Arnold, and A.D. Harris in 1943, and these findings provided an effective treatment for this infection.
Syphilis is seen all over the world, particularly in urban areas. The reservoir of Treponema is exclusively human, and it is transmitted by body fluids or lesions that contain high concentrations of spirochetes, leading to a systemic and chronic infection. Despite all the medical advances and the availability of an effective, affordable, and universally available treatment, congenital syphilis continues to cause considerable morbidity and mortality worldwide and is seen to evolve into various stages in patients with age ( Fig. 34.1A ). The consequences are particularly dire in infected pregnant women and newborn infants. Congenital syphilis remains a globally relevant public health problem.
Epidemiology
A large number of new cases of syphilis continue to be diagnosed each year. In 2016, 5.6 million new cases were diagnosed. The burden of congenital syphilis was estimated to be 473 per 100.000 births. The incidence of syphilis showed some improvement during the period from 2007 to 2016, but it has plateaued since then. The number of new patients may be diminishing worldwide, but the incidence seems to be rising in the Americas. In the United States, the Centers for Disease Control and Prevention (CDC) has reported an increased number of new cases since the year 2000. The frequency of new cases has increased from 11.2 to 39.7 per 100,000 inhabitants, particularly in the western parts of the United States. , Syphilis is seen less frequently in women than in men, but the rate of new infections has increased by 178.6% during the period from 2015 to 2019. The prevalence is higher among women aged 20 to 39 and in African American, Latino, and Native American individuals living in the United States, Alaska, or the Pacific Islands. , The frequency of congenital syphilis has also increased during this period (see Fig. 34.1B ).
In 2017, most parts of Latin America and the Caribbean region had reported advances in prevention of congenital syphilis; 15 out of the 17 countries in these regions reported virtual elimination of vertically transmitted syphilis (incidence <0.5 new cases per 1000 newborn infants per year). However, most of these advances have since been lost with a resurgence in the past few years. The largest rise in case load has been noted in Brazil. Studies suggest that inadequate treatment of infected mothers is an important factor. Lack of proper prenatal care, difficulties in timely diagnosis of the infection, and clinical evidence of maternal infection despite proper treatment were also found to be fundamental to determining obstetric results.
Pathogenesis
T. pallidum is a helical-shaped bacterium in the family Spirochaetaceae, subspecies pallidum ( Fig. 34.2 ). These bacteria are host-dependent and can survive only in the human body, not freely in the environment. The unique adaptations in the outer membrane help circumvent clearance by the patient’s immune system and facilitate prolonged subclinical/low-grade infections. ,
After infection in the mother, the transmission to the fetus occurs most frequently during the incubation phase and in the primary stage of infection, when bacteremia is more frequent. Most infants get infected across the placenta in utero. T. pallidum has been detected in placental tissue as early as 9 to 10 weeks of gestation, although the risk of infection increases with advancing gestation. , Some infants get infected during labor after exposure to the mother’s body fluids or to lesions in the birth canal that contain high concentrations of these spirochetes, which can penetrate the fetal mucous membranes or skin. , ,
After a highly variable incubation period of 9 to 90 days, the primary stage of congenital syphilis begins. During this stage, the characteristic lesion, known as a chancre or a hallmark ulcer, appears. The chancre is a painless, indurated ulcer that develops at the site of inoculation in the genital region, anus, or oral cavity and is usually associated with locally enlarged lymph nodes. The chancre then usually disappears spontaneously in a few days. Once inside the host, the microorganisms proliferate locally and are then disseminated extensively via the lymphatic and blood vessels.
The secondary stage begins 4 to 10 weeks later, when the spirochete can be detected in high concentrations in blood and infected tissues. The hematogenous dissemination and infiltration of various tissues can explain the variable clinical presentation, such as with fever; maculopapular nonpruritic lesions (syphilitic roseola) on the skin, including the palms and soles; papular lesions known as condyloma lata ; alopecia; and hepatosplenomegaly. Generalized infections may also present with anorexia, irritability or lethargy, myalgia, arthritis, and/or generalized lymphadenopathies. This stage usually resolves spontaneously in 1 to 6 months and is followed by a latent period, which is usually asymptomatic. However, recurrent symptomatic episodes of bacteremia may continue to occur. There may be an early latent stage in the first 12 months after the primary infection and a late latent stage that occurs after 12 months.
About 30% to 50% of untreated patients develop a tertiary stage that might be seen in a period extending up to 30 years after the primary infection. This stage may involve multiple organs and show diverse presentations including cardiac valvulitis, aortitis with aortic aneurysms, meningitis, cerebrovascular accidents, neurosyphilis, or cutaneous granulations that have been described as gummas due to a gum-like or rubbery consistency.
Clinical Features
Fetal Treponema infections are frequently associated with adverse outcomes. Up to 21% of pregnancies end in miscarriages, 9% in stillbirths, and 6% in preterm deliveries. Intrauterine growth restriction and nonimmune hydrops fetalis ( Fig. 34.3 ) are seen frequently. Multiple prenatal findings may be observed in 31% of affected fetuses, particularly hepatomegaly (seen in 80% of affected pregnancies). Increased blood flow in the middle cerebral artery is seen in one-third of all infected fetuses. The placenta is enlarged with inflammation and edema in 27%. In some fetuses, cardiomegaly, pericardial effusion, splenomegaly, and bone alterations are also seen. Unfortunately, prenatal ultrasonography is not a sensitive method to detect these changes. ,
The infected placenta may appear edematous and pale. Microscopically, a typical triad of enlarged, hypercellular villi, proliferative vascular changes, and acute or chronic villitis is seen. The decidua may show leukocytosis and erythroblastosis, particularly in stillbirths. , The umbilical cord is normal in most cases, but some may show necrotizing funisitis with nonspecific inflammatory changes.
At birth, more than 90% of infants are asymptomatic. About 10% present with a wide variety and severity of symptoms ranging from mild nonspecific constitutional signs to lethal hydrops ( Box 34.1 and Fig. 34.4 ). , , Mucocutaneous lesions on the palms and soles (syphilitic pemphigus), genitourinary areas, and hepato- and/or splenomegaly are frequently seen. , , The hepatosplenomegaly is likely caused by both inflammation and extramedullary hematopoiesis. In a study conducted by Lago et al. in 2013, hepatomegaly and splenomegaly were seen in 71% and 60%, respectively, of infected infants.
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