What is the appropriate treatment plan for a newborn diagnosed with congenital syphilis?

Complete SOAP for Congenital Syphilis

Subjective

Maternal History Assessment

• Document maternal syphilis treatment status: Was the mother untreated, inadequately treated, treated with non-penicillin regimen (e.g., erythromycin), or treated <4 weeks before delivery? 1
• Assess maternal serologic response: Did maternal nontreponemal titers decrease at least fourfold after treatment for early syphilis? 1
• Identify evidence of maternal relapse/reinfection: Has there been a fourfold or greater increase in maternal nontreponemal antibody titer? 1
• Verify timing and adequacy of prenatal care: Was there adequate serologic follow-up to ensure treatment response and lack of current infection? 1

Risk Stratification Based on Maternal History The infant requires treatment if the mother had any of the following: untreated syphilis at delivery, serologic evidence of relapse/reinfection, treatment with erythromycin or non-penicillin regimen, treatment ≤1 month before delivery, no documented treatment history, or inadequate serologic response to treatment 1.

Objective

Physical Examination Findings

• Examine for classic manifestations: nonimmune hydrops, jaundice, hepatosplenomegaly, rhinitis (snuffles), skin rash (maculopapular or vesiculobullous), and pseudoparalysis of an extremity 1
• Assess for subtle signs: lymphadenopathy, mucous patches, condyloma lata, or failure to thrive 2
• Note that >50% of infected infants are asymptomatic at birth, making clinical examination alone insufficient for diagnosis 3

Laboratory Evaluation

Serologic Testing

• Obtain quantitative nontreponemal test (RPR or VDRL) on infant serum—compare to maternal titer using the same test and preferably the same laboratory 1
• A fourfold higher infant titer than maternal titer indicates probable congenital syphilis 1
• Do NOT perform treponemal tests (TP-PA, FTA-ABS, EIA) on newborn serum as maternal IgG antibodies transfer transplacentally and make interpretation impossible 1, 4
• Never use umbilical cord blood for serologic testing due to contamination with maternal blood yielding false-positive results 4

Complete Evaluation for Proven or Highly Probable Disease (Scenario 1)

Required when infant has: (1) abnormal physical examination consistent with congenital syphilis, (2) serum nontreponemal titer fourfold higher than mother's, or (3) positive darkfield test of body fluids 1, 4, 5:

• CSF analysis: VDRL, cell count, and protein 1, 5
  • Normal CSF values in neonates can be difficult to interpret—values as high as 25 WBCs/mm³ and protein of 150 mg/dL may occur in normal neonates, though some specialists recommend 5 WBCs/mm³ and protein of 40 mg/dL as upper limits 1
• Complete blood count with differential and platelet count 1, 5
• Long-bone radiographs to assess for osteochondritis and periostitis 1
• Additional studies as clinically indicated: chest radiograph, liver function tests, cranial ultrasound, ophthalmologic examination, auditory brainstem response 1
• Pathologic examination of placenta or umbilical cord using specific fluorescent antitreponemal antibody staining 1
• Darkfield microscopy of suspicious lesions or body fluids (e.g., nasal discharge) 1

Evaluation for Possible Disease (Scenario 2)

For infants with normal physical examination and serum titer ≤fourfold maternal titer, but inadequate maternal treatment 1, 5:

• CSF analysis for VDRL, cell count, and protein 1, 5
• Complete blood count with differential and platelet count 1, 5
• Long-bone radiographs 1, 5

Note: A complete evaluation is not necessary if 10 days of parenteral therapy is administered, though CSF evaluation may document abnormalities prompting closer follow-up 1.

Assessment

Diagnostic Classification

Scenario 1: Proven or Highly Probable Congenital Syphilis

• Abnormal physical examination consistent with congenital syphilis, OR
• Serum quantitative nontreponemal titer fourfold higher than maternal titer, OR
• Positive darkfield test of body fluids 1

Scenario 2: Possible Congenital Syphilis

• Normal physical examination AND serum titer ≤fourfold maternal titer, BUT mother was untreated, inadequately treated, has no treatment documentation, received non-penicillin regimen, or was treated <4 weeks before delivery 1

Scenario 3: Lower Risk

• Normal physical examination, serum titer ≤fourfold maternal titer, AND mother received adequate treatment >4 weeks before delivery with appropriate serologic response 1, 4

Critical Caveat: The absence of a fourfold or greater titer in an infant does not exclude congenital syphilis 1.

Plan

Treatment Regimens

For Scenario 1 (Proven or Highly Probable Disease):

Aqueous crystalline penicillin G is the first-line treatment 1, 5, 6:

• Dosing: 100,000-150,000 units/kg/day IV, administered as 50,000 units/kg/dose every 12 hours during the first 7 days of life, then every 8 hours thereafter for a total of 10 days 1, 6

Alternative regimen:

• Procaine penicillin G 50,000 units/kg/dose IM once daily for 10 days 1

Critical treatment principles:

• If more than 1 day of therapy is missed, restart the entire 10-day course 1
• A full 10-day course of penicillin is strongly preferred even if ampicillin was initially given for possible sepsis 1
• Data are insufficient regarding other antimicrobial agents (e.g., ampicillin, ceftriaxone)—use of non-penicillin agents requires close serologic follow-up 1

For Scenario 2 (Possible Disease with Inadequate Maternal Treatment):

Two treatment options 1, 5:

1. Aqueous crystalline penicillin G or procaine penicillin G for 10 days (preferred if any part of evaluation is abnormal, CSF is uninterpretable, CSF was not performed, or follow-up is uncertain) 1

2. Benzathine penicillin G 50,000 units/kg IM as a single dose—ONLY if the infant is fully evaluated (CSF examination, long-bone radiographs, CBC with platelets), the full evaluation is normal, and follow-up is certain 1, 5

For Older Infants/Children (After Newborn Period):

Any child with suspected congenital syphilis or neurologic involvement:

• Aqueous crystalline penicillin G 200,000-300,000 units/kg/day (administered as 50,000 units/kg every 4-6 hours) IV for 10-14 days 1, 5, 6
• Consider single dose of benzathine penicillin G 50,000 units/kg IM after completing the 10-day IV course 1

For children without clinical manifestations, normal CSF, and negative CSF VDRL:

• Benzathine penicillin G 50,000 units/kg IM weekly for up to 3 doses can be considered 1

Penicillin Allergy Management

Infants and children with penicillin allergy history must be desensitized and then treated with penicillin 1, 5. Data are insufficient for alternative agents; if non-penicillin agents are used, close serologic and CSF follow-up are mandatory 1.

Penicillin Shortage Alternatives

During penicillin shortages 1:

• For Scenario 1: Substitute some or all daily doses with procaine penicillin G (50,000 units/kg/dose IM daily for 10 days) 1
• If no penicillin available: Ceftriaxone (75 mg/kg IV/IM daily for infants ≥30 days; 100 mg/kg daily for older infants) for 10-14 days—use with caution in jaundiced infants and only in consultation with a specialist 1
• A single dose of ceftriaxone is inadequate therapy 1

Follow-Up Protocol

All seroreactive infants require:

• Careful follow-up examinations and nontreponemal serologic testing every 2-3 months until nonreactive or titer has decreased fourfold 1, 5
• Nontreponemal titers should decline by 3 months and be nonreactive by 6 months if the infant was not infected (passive maternal antibody transfer) or was adequately treated 1, 5
• If titers are stable or increase after 6-12 months: Perform CSF examination and treat with 10-day course of parenteral penicillin G 1, 5
• If infant remains seroreactive at 18 months: Fully (re)evaluate and treat for congenital syphilis 1

For infants with abnormal initial CSF:

• Repeat lumbar puncture approximately every 6 months until results normalize 1, 5
• Reactive CSF VDRL or abnormal CSF indices not attributable to other illness requires retreatment for possible neurosyphilis 1

Special Monitoring Considerations

• Periodic assessment of organ system function including electrolyte balance, hepatic, renal, hematopoietic systems, and cardiac/vascular status during prolonged high-dose IV penicillin therapy 6
• Penicillin G potassium contains 65.8 mg potassium (1.68 mEq) per million units—monitor for electrolyte imbalance with high doses 6
• All newborns treated with penicillin should be monitored closely for clinical and laboratory evidence of toxic or adverse effects 6

Common Pitfalls to Avoid

• Never rely solely on clinical examination as >50% of infected infants are asymptomatic at birth 3
• Do not use umbilical cord blood for serologic testing 4
• Do not perform treponemal tests on newborn serum 1, 4
• Do not assume adequate treatment if maternal titers did not decrease fourfold after treatment for early syphilis 1
• Do not use single-dose benzathine penicillin unless infant is fully evaluated, evaluation is completely normal, and follow-up is certain 1
• Recognize that treatment failures can occur even with regimens exceeding CDC guidelines—adequate follow-up is essential 7