A 2-month-old girl is brought to the office due to restricted movements of her upper and lower extremities with swelling of the wrist and knee joints for a week. She was born at 38 weeks gestation via an uncomplicated vaginal delivery and had an unremarkable neonatal course with no history of birth trauma or excessive bleeding. The mother had inconsistent prenatal care. The patient is exclusively breastfed. Examination shows swelling with no warmth or erythema of the bilateral wrist and knee joints. Spontaneous limb movements are decreased; the patient cries on passive movement of the joints. Mild pallor, generalized lymphadenopathy, and hepatosplenomegaly are present. X-rays of the wrist and knee joints reveal metaphyseal erosions with periosteal reaction. Which of the following is the most likely cause of this patient's illness?

Question

A 2-month-old girl is brought to the office due to restricted movements of her upper and lower extremities with swelling of the wrist and knee joints for a week.  She was born at 38 weeks gestation via an uncomplicated vaginal delivery and had an unremarkable neonatal course with no history of birth trauma or excessive bleeding.  The mother had inconsistent prenatal care.  The patient is exclusively breastfed.  Examination shows swelling with no warmth or erythema of the bilateral wrist and knee joints.  Spontaneous limb movements are decreased; the patient cries on passive movement of the joints.  Mild pallor, generalized lymphadenopathy, and hepatosplenomegaly are present.  X-rays of the wrist and knee joints reveal metaphyseal erosions with periosteal reaction.  Which of the following is the most likely cause of this patient's illness?

Quizplus · Accepted Answer

11ec160b_3860_01f1_9249_6bbec637b808_MD0001_00 This infant with hepatosplenomegaly and lymphadenopathy has multifocal bony erosions, findings worrisome for congenital syphilis. This infection is acquired via transplacental transmission of the spirochete Treponema pallidum. Although routine first-trimester screening and treatment when indicated help decrease the risk of in utero transmission, lack of prenatal care increases the risk of fetal transmission. Classic neonatal findings include copious rhinorrhea and a maculopapular rash involving the palms and soles; however, skeletal abnormalities due to spread of T pallidum to the bone may be the primary reason for evaluation. Typical signs and symptoms include the following: Nonspecific findings in congenital syphilis include fever, hepatosplenomegaly, and lymphadenopathy. Pancytopenia can also occur, and anemia is the most likely cause of this patient's pallor. (Choice A) Maternal Chlamydia infection is transmitted to the neonate via exposure to genital secretions during delivery. Symptomatic infection in the infant includes conjunctivitis or pneumonia; bony lesions, hepatosplenomegaly, and diffuse lymphadenopathy do not occur. (Choice B) Transmission of HIV may occur through breastfeeding, and infection should be considered in an infant who has hepatosplenomegaly and lymphadenopathy and whose mother received inconsistent prenatal care. Acute infection may be associated with joint or muscle pain, but metaphyseal erosions and periosteal inflammation make this diagnosis less likely. Moreover, symptomatic infants with HIV typically have persistent diarrhea and recurrent infections (eg, thrush, pneumonia). (Choice C) Osteomyelitis in infants leads to extremity pain and decreased movement, and Staphylococcus aureus is the most common cause. Most young infants with nosocomial transmission have risk factors (eg, prematurity, prior bacterial infection, history of central line), none of which are seen here. In addition, patients usually have fever, particularly if the infection is multifocal, and hepatosplenomegaly would not be expected. (Choice E) Infection due to transplacental transmission of a tachyzoite describes congenital toxoplasmosis, which may cause hepatosplenomegaly and lymphadenopathy; chorioretinitis and intracranial calcifications are typical. However, tender, swollen joints with bony erosions would not be seen. Educational objective: Congenital syphilis is acquired via transplacental transmission of the spirochete Treponema pallidum and may present with pain and limited extremity movement due to long bone involvement (eg, metaphyseal erosions, periosteal inflammation). Nonspecific manifestations include hepatosplenomegaly and lymphadenopathy. __________ References: Congenital syphilis: a U.S. perspective. (http://www.ncbi.nlm.nih.gov/pubmed/33137962)

A 2-Month-Old Girl Is Brought to the Office Due to Restricted