Congenital syphilis overview

# Overview
Congenital Syphilis is caused by Treponema pallidum, its transmitted to the fetus in utero from an infected mother via the placenta. The severity of the disease is dependent on the stage of maternal infection and the duration of exposure to the fetus. Transmission is typically in the second trimester and the highest rates of transmission are seen in women with primary syphilis. The rates of transmission decrease with the increasing duration of the maternal infection, as the concentration of spirochetes in the blood stream decreases. Syphilis infection to the fetus in utero can result in stillborn, miscarriage and a live birth with severe manifestations of hydrops. Prenatal screening for syphilis during the first trimester is recommended to all pregnant women and adequate treatment with penicillin prevents the transmission to the fetus.

# Historical Perspective
Congenital syphilis was first described in an English 17th century in a pediatric textbook. Transplacental transmission from an asymptomatic infected mother was first described in 1906. Sir Jonathan Hutchinson described the triad of notched incisors, interstitial keratitis, and eighth cranial nerve deafness as a criterion for diagnosis of congenital syphilis.

# Classification
Congenital syphilis can be classified into early (presenting 0-2 years) and late (greater 2 years) based upon on time of presentation. There is also a diagnostic classification of syphilis used for surveillance purpose.

# Pathophysiology
Pathophysiology of congenital syphilis is still unclear.The risk of transmission to the fetus is dependent on the stage of the maternal disease (dependent on the spirochete concentration in the blood stream) and the duration of exposure to the fetus in utero. The risk of vertical transmission of syphilis from an infected untreated mother decreases as maternal disease duration progresses: transmission risk of 70100% for primary syphilis and 40% for early latent syphilis to 10% for late latent disease. The variation in the percentages with the duration of infection is due to the concentration of spirochetes in the blood stream, which decrease with the duration of maternal syphilis infection.

# Causes
Congenital syphilis is caused by the bacterium Treponema pallidum, which is passed from mother to child during fetal development or at birth.

# Screening
Routine screening for syphilis during the antenatal period is recommended.

# Diagnosis

## History symptoms
Infants present with symptoms such as failure to gain weight or failure to thrive, fever, irritability, small blisters on the palms and soles, and with watery discharge from the nose.

## Physical Examination
Physical examination findings suggestive of congenital syphilis include low birth weight, signs of prematurity, skin edema, pleural effusion, vesicular skin rash, corneal clouding, jaundice and deafness.

## Laboratory Findings
Prental diagnosis is by detection of IgM antibodies aganist T.pallidum in the blood collected by chordocentesis, antenatal ultrasound is commonly done and the findings suggestive of congenital syphilis include: hydrops fetalis characterised by scalp oedema, placental thickening, serous cavity effusion, and polyhydramnios. Other additional findings inlcude hepatosplenomegaly, placentomegaly, non-continuous gastrointestinal obstruction and dilatation of the small bowel. Postnatal diagnosis is by examination of the placenta or umbilical cord using a silver  stain demonstrates spirochetes or a T. pallidum PCR test can be done.

# Treatment

## Medical Therapy
Medical therapy for neonate presenting with symptoms of congenital syphilis is aqueous penicillin G. However evaluation and management is dependent on the clinical senario of presentation.

# Prevention

## Primary Prevention
Primary preventive measures include routine screening in pregnant females, individuals with high risk behaviours, and those residing in highly prevalent areas, abstinence from intimate physical contact with an infected person, consistent use of latex condoms, limiting no of sexual partners, avoid sharing sex toys and practice of safe sex.

## Secondary Prevention
Regular follow up of infants with congenital syphilis to examine for the re-appearance of signs and symptoms of syphilis after recommended treatment has shown to improve outcomes.