Examkin

Question

Difficulty: MediumNeonatal Disorders

A 12-hour-old male neonate is evaluated in the newborn nursery due to respiratory difficulty and a skin eruption. The infant was born at 38 weeks of gestation via uncomplicated vaginal delivery to a 19-year-old primigravida who recently immigrated and received no prenatal care.

Birth weight is 2100 g (4 lb 10 oz). APGAR scores were 7 and 8 at 1 and 5 minutes, respectively. Vital signs show a temperature of 37.3°C (99.1°F), heart rate of 165/min, and respiratory rate of 55/min.

Physical examination reveals a small-for-gestational-age infant with copious, clear nasal discharge. The abdomen is distended, and the liver edge is palpable 4 cm below the right costal margin along with a palpable spleen tip. Skin examination shows a widespread maculopapular rash with prominent desquamation involving the palms and soles.

Initial laboratory evaluation reveals the following:

TestResult
Maternal rapid plasma reagin (RPR)Reactive, 1:64
Maternal *Treponema pallidum* particle agglutination (TP-PA)Positive
Infant rapid plasma reagin (RPR)Reactive, 1:128
Infant platelet count80,000/mm³

Which of the following is the most appropriate next step in pharmacologic management for this infant?

  1. Initiate intravenous aqueous crystalline penicillin G for 10 daysAnswer
  2. B
    Initiate intravenous ampicillin and gentamicin for 10 days
  3. C
    Administer a single dose of intramuscular benzathine penicillin G
  4. D
    Initiate intravenous acyclovir for 14 days
  5. E
    Provide routine nursery care with topical emollients

Answer

Initiate intravenous aqueous crystalline penicillin G for 10 days
This infant has classic signs of symptomatic congenital syphilis, including 'snuffles' (syphilitic rhinitis), hepatosplenomegaly, and a maculopapular desquamating rash on the palms and soles. The diagnosis is confirmed by the lack of maternal prenatal care (untreated infection) and an infant RPR titer (1:128) that is higher than the maternal titer (1:64), indicating active fetal infection rather than passive transfer of maternal antibodies. According to CDC guidelines, infants with proven or highly probable congenital syphilis (defined by an abnormal physical exam consistent with syphilis, a positive darkfield test, or an infant serum quantitative non-treponemal titer fourfold higher than the mother's) must be treated comprehensively. The strict standard of care for these highly symptomatic infants is 10 days of intravenous aqueous crystalline penicillin G (or intramuscular procaine penicillin G).

Step-by-Step Solution

1
Analyze the clinical presentation.
The triad of 'snuffles', hepatosplenomegaly, and a desquamating maculopapular rash on the palms and soles in a small-for-gestational-age infant strongly suggests congenital syphilis.
To establish a preliminary clinical diagnosis based on classic pathognomonic signs.
2
Interpret the laboratory findings.
The mother has untreated syphilis. The infant has a reactive RPR at a higher titer (1:128) than the mother (1:64) alongside thrombocytopenia, confirming active fetal infection rather than passive maternal antibody transfer.
To definitively confirm the transmission and severity of the infection.
3
Determine the appropriate treatment protocol.
Infants with proven or highly probable symptomatic congenital syphilis require a 10-day course of intravenous aqueous crystalline penicillin G.
To eradicate the spirochete completely and prevent long-term neurological sequelae.

Key Concept

Diagnosis and management of symptomatic congenital syphilis
Rate this question

Topics

Neonatal Disorders

More questions from this topic