A 6-week-old girl is brought to the emergency department due to a rash. Her parents first noticed several red spots on her feet, hands, and buttocks several weeks ago; the spots have now spread to her arms and legs. The patient has been breastfeeding well, with regular stooling and voiding. She has had no fever. The family lives on a rural farm, and the patient was delivered at home at approximately 39 weeks gestation via an uncomplicated, spontaneous vaginal delivery. The mother was evaluated only once during pregnancy, at 10 weeks gestation, and her examination, blood work, and ultrasound were normal. Today, the patient's temperature is 37.3 C (99.1 F). She is not in acute distress. Mucous membranes have no lesions. Heart, lung, and abdominal examinations are unremarkable. Numerous small, nonblanching, erythematous maculopapular spots are distributed over the arms and legs, including the dorsal and ventral surfaces of the hands and feet. Which of the following is the best next step in evaluation of this patient?

Question

A 6-week-old girl is brought to the emergency department due to a rash.  Her parents first noticed several red spots on her feet, hands, and buttocks several weeks ago; the spots have now spread to her arms and legs.  The patient has been breastfeeding well, with regular stooling and voiding.  She has had no fever.  The family lives on a rural farm, and the patient was delivered at home at approximately 39 weeks gestation via an uncomplicated, spontaneous vaginal delivery.  The mother was evaluated only once during pregnancy, at 10 weeks gestation, and her examination, blood work, and ultrasound were normal.  Today, the patient's temperature is 37.3 C (99.1 F).  She is not in acute distress.  Mucous membranes have no lesions.  Heart, lung, and abdominal examinations are unremarkable.  Numerous small, nonblanching, erythematous maculopapular spots are distributed over the arms and legs, including the dorsal and ventral surfaces of the hands and feet.  Which of the following is the best next step in evaluation of this patient?

Quizplus · Accepted Answer

11ec25c8_d6d6_53ab_bc81_5b78ea6926e7_MD0003_00 This patient developed a prolonged and progressive, nonblanching maculopapular rash in the neonatal period with involvement of the palms and soles, findings that warrant evaluation for congenital syphilis. Patients are often asymptomatic at birth and may develop snuffles (ie, persistent rhinorrhea) and/or the characteristic rash weeks later. The rash usually begins on the distal extremities, buttocks, and back but can spread anywhere. It often desquamates after several weeks, leaving hyperpigmented lesions. Congenital syphilis is usually caused by the transplacental spread of Treponema pallidum from mother to fetus. Preconception infection is often identified on routine, first-trimester screening and treated with maternal penicillin. However, primary maternal infection acquired during pregnancy, which has the highest likelihood of transmission, may result in falsely reassuring negative screening, as is likely the case in this patient, so a high index of suspicion for congenital syphilis is required. Infants with suspected syphilis should undergo a nontreponemal test, such as the rapid reagin test or VDRL. Compared to maternal levels, a significantly elevated neonatal titer is consistent with congenital syphilis. Visualization of T pallidum in infectious material (eg, nasal discharge, skin lesions) on dark-field microscopy is also diagnostic. (Choices A and E) A rash involving the palms and soles may warrant blood culture for suspected meningococcemia or skin biopsy for suspected Rocky Mountain spotted fever. However, both conditions are associated with fever and a rash that is often petechial. Moreover, rapid clinical deterioration is typical, and a rash lasting weeks would not be seen. (Choice B) No workup is required for hand-foot-and-mouth disease, a coxsackievirus infection that causes discrete maculopapular or vesicular lesions on the palms and soles. Unlike in this patient, however, oropharyngeal lesions and fever are usually present, and symptoms typically resolve within a week. Given the prolonged rash and minimal prenatal care in this patient, further evaluation is required. (Choice C) Erythema infectiosum caused by parvovirus can cause a rash after prodromal symptoms (eg, fever, diarrhea, coryza), which were not seen in this patient. In addition, examination typically shows a slapped-cheek appearance and a lacy, reticular rash on the trunk, not diffuse maculopapular lesions. Educational objective: Congenital syphilis classically causes a nonblanching, maculopapular rash in the neonatal period that involves the palms and soles. Evaluation begins with rapid plasma reagin testing. A high index of suspicion is required because primary maternal infection in pregnancy may lead to falsely reassuring negative screening. References: A review of the guidelines for the evaluation and treatment of congenital syphilis. (http://www.ncbi.nlm.nih.gov/pubmed/25996197) TORCH complex. (http://www.ncbi.nlm.nih.gov/pubmed/32809363)

A 6-Week-Old Girl Is Brought to the Emergency Department Due