Congenital syphilis: Overview
Syphilis is a sexually transmitted disease caused by the spirochete Treponema pallidum. These bacteria can be transmitted from a mother to a child before or during the labor and in this case congenital syphilis may develop – the overall risk of infection transmission is 60-80%. Mothers with late syphilis are less likely to infect their unborn child, although the risk still exists and makes about 20%. This condition often has a severe course, may lead to disability or may be life-threatening. Approximately 50% of the fetuses who get infected while being in the womb die before the birth or soon after they are born, whereas only 20% of mothers with untreated primary or secondary syphilis may give birth to a healthy child. Considering the danger of syphilis to an unborn baby early diagnosis and recognition of the maternal infection is crucial.
Bacteria transmission to a child
Syphilis can be acquired by a woman via sexual contact and then a pregnant woman can pass the infection through the placenta to her child at any time during pregnancy starting from the 6th week. The child may also acquire the infection during the delivery when a baby contacts with
lesions of the mother’s birth canal. Those women who experience primary or secondary syphilis during pregnancy are more likely to transmit infection to the child than those who have latent disease.
If a pregnant woman receives appropriate treatment the transplacental transmission (transmission of the bacteria through the placenta) of Treponema pallidum can be prevented and, furthermore, if a fetus still has contracted an infection, adequate treatment before the third trimester will also be able to treat the fetus’ infection. Untreated infection in up to 40% of cases results in fetus death (both abortion and stillbirth), premature birth, low weight at birth, early death of a newborn baby or congenital syphilis. Neonatal death is caused by the liver failure, pneumonia or low thyroid function.
Therefore, pregnant women who are at increased risk of syphilis or live in areas with high syphilis prevalence should be additionally tested at 28 weeks’ gestation for syphilis. It should be noted that syphilis can accelerate the course of other infectious diseases in pregnant woman, namely – HIV. On the other hand it is not recommended to screen newborn babies for syphilis as usually infected
Early and late congenital syphilis
Infected neonate may develop early or late congenital syphilis – the disease is referred to as early if a child presents the symptoms before the age of 2, late congenital syphilis is diagnosed if a child develops characteristic symptoms after age 2 years.
Early congenital syphilis
Early congenital syphilis presents with the following signs and symptoms:
- Inflammation of the bones and cartilages (osteochondritis) or the periosteum (periostitis) with subsequent pseudoparalysis of the limbs;
- Chorioretinitis (inflammation of the eye’s vascular coat and the retina) and iritis (inflammation of the iris);
- A flu-like disease with hemorrhagic rhinitis;
- Bullous lesions or macular rash on the palms and soles, popular lesions around the mouth and nose and in the diaper area;
- Rash on the palms and/or the soles;
- Enlarged liver and spleen;
- Pneumonitis (inflammation of the lung);
- Generalized enlargement of the lymph nodes;
- Central nervous system impairment;
- Nephritic syndrome;
- Growth retardation in the fetus, failure to thrive of the newborn baby;
- Nasal discharge with blood;
Late congenital syphilis
Late congenital syphilis manifests with:
- Gummae involving the nose, septum and palate;
- Knees swelling (Clutton’s sign);
- Protruding mandible;
- Saddle nose;
- Hutchinson teeth, mulberry molars;
- Saber shins;
- Hydrocephalus (enlarged cranium);
- Interstitial keratitis (inflammation of the cornea);
- Optic nerve atrophy, resulting in blindness;
Management and diagnosis
All pregnant women should be screened for sexually transmitted diseases including syphilis. If the rapid tests are suggestive of syphilis Treponema-specific tests to confirm the diagnosis are recommended.
After the delivery the placenta should be examined in dark field to detect Treponema pallidum. Specific blood tests such as fluorescent treponemal antibody absorbed test (FTA-ABS), Venereal Disease Research Laboratory (VDRL) and rapid plasma reagin (RPR) test may be necessary to confirm or exclude syphilis. Cerebro-spinal fluid testing, ophthalmologic evaluation and X-ray may also be necessary.
Neonates with no symptoms born to infected mothers should receive a single dose of an antibiotic. Infants who present with the signs of congenital syphilis require a course of antibiotics.
The tests should be repeated every 2-3 month and if necessary the treatment should be continued.
Congenital syphilis prevention
The best way to prevent the disease is to detect the diseases and provide the adequate treatment for the mother-to-be as early as possible – respectively, pregnant woman should be tested for venereal diseases during the 1st trimester and if needed retested later and before the delivery. Erythromycin and tetracycline are contraindicated for pregnant women.