Congenital syphilis results from the transmission of the spirochete Treponema pallidum (T. pallidum) from infected mother to fetus through the placenta. It can occur as early as 9 weeks gestation through to the end of pregnancy and results in spread of T. pallidum mostly to the bones, brain, liver, and lungs . Although congenital syphilis is still considered uncommon, the rate increase of 38% from 2012 to 2014 makes this an ongoing public health concern .
The typical clinical presentation for a live infant is dependent on when the infection was acquired . Common clinical findings include rash, fever, hepatosplenomegaly, leukocytosis, anemia, and thrombocytopenia [1, 2]. Skeletal changes on radiographic evaluation are evident in up to 80% of patients diagnosed early . Given the morbidity of syphilis if undetected and untreated, along with the lack of examination findings specific to the disease, the Center for Disease Control (CDC) recommends long-bone radiographs in the diagnostic evaluation of congenital syphilis [3, 4].
The most common radiographic findings include bilateral and symmetrical bands of lucency involving the metaphysis of long bones with periosteal reaction thought to be secondary to alterations in bone growth [3, 5]. Additional findings include separation of the epiphysis, pathologic fractures, or alterations in normal joint anatomy . Although bony findings do not always correlate with the physical exam, disruptions in bone architecture can cause pain and decreased range of motion resulting in “Parrot pseudoparalysis”, a term used to describe reduced extremity motion resulting from periostitis . The clinical history, laboratory, and radiographic findings for this patient were consistent with a diagnosis of congenital syphilis.