A 2,400g male infant was born to a multiparous New Zealand Māori woman in the upper North Island following spontaneous onset of labour at approximately 36 weeks gestation. The pregnancy was not recognised until 24 weeks gestation, resulting in incomplete antenatal screening. The infant was born in good condition with Apgar scores of 9 and 10 and was admitted to a Level 2 Special Care Baby Unit (SCBU) to establish feeding. He was discharged following an uncomplicated ten-day stay.

At 20 days of age, the infant was readmitted to hospital with a 24-hour history of decreased feeding, irritability, abdominal distension and jaundice. On admission, the infant appeared acutely unwell, irritable and deeply jaundiced with marked hepatomegaly. There were no signs of cardiorespiratory instability or seizure activity.

Initial investigations showed conjugated hyperbilirubinaemia (bilirubin 166umol/L), anaemia (haemoglobin 66g/L), thrombocytopenia (platelets 60x10[[9]]/L) and coagulopathy. C-reactive protein  was elevated at 127mg/L. A blood gas demonstrated lactic acidosis (4mmol/L) and hypoglycaemia (blood glucose 2.7mmol/L). Anti-infectives were commenced for suspected late-onset neonatal sepsis (amoxicillin, cefotaxime and aciclovir).

Several hours after presentation the infant’s condition deteriorated with tachycardia and hypotension and he was urgently transferred to the paediatric intensive care unit (PICU) at Starship Children’s Hospital. The infant required further fluid resuscitation, and an adrenaline infusion and non-invasive ventilation were commenced. Blood cultures flagged positive after several hours with a gram-negative bacillus, later confirmed as Escherichia coli resistant to amoxicillin. In PICU, respiratory support and inotropes were discontinued within several hours, but the infant developed worsening conjugated hyperbilirubinaemia, significant lactic acidosis and severe hyponatraemia. Abdominal ultrasound demonstrated unilateral hydronephrosis with pelvico-ureteric junction (PUJ) obstruction, hepatosplenomegaly and a small volume of ascites. The gallbladder appeared normal. Urine showed nephrotic-range proteinuria. Extensive viral testing was negative, including for herpes simplex virus by polymerase chain reaction (PCR).

The infant was assessed by the metabolic, surgical, gastroenterology and infectious disease teams. During an infectious diseases consultation, a subtle desquamating rash on the soles of the feet was noted and urgent treponemal serology requested. On day five in PICU, positive reactive rapid plasma reagin (RPR) titre of 1:32 and Treponema pallidum particle agglutination assay (TTPA) results became available. On further questioning, the infant’s mother revealed a history of syphilis diagnosed several years prior with incomplete treatment. She was then lost to follow-up by her local sexual health service. Additionally, antenatal syphilis serology was not documented during her current pregnancy. Further infant investigations included abnormal long bone x-rays showing periostitis and extensive bony sclerosis involving the lower and upper limbs, scapulae, clavicles and ribs. A lumbar puncture was grossly bloodstained but showed a mild cerebrospinal fluid (CSF) pleocytosis (WBC 200x10[[6]]/L, 74% polymorphs, RCC 31,000 x10[[6]]/L, VDRL not performed due to bloodstaining, culture negative). Cranial ultrasound, ophthalmology and audiology evaluations were normal.

Congenital syphilis was diagnosed on the basis of positive serology and the constellation of consistent clinical features. The infant was treated with a ten-day course of IV benzylpenicillin, in addition to completing seven days of cefotaxime for E. coli bacteraemia. He made an excellent clinical recovery with jaundice, proteinuria and oedema all resolving by the time of discharge. His parents were referred to the local sexual health service.

Discussion

The recognition of congenital syphilis remains challenging for clinicians.[[1–3]] Like the majority of infants at risk of congenital syphilis, this infant was asymptomatic at birth. However, he went on to develop life-threatening manifestations in the first weeks of life. Clinicians need to maintain a low index of suspicion for congenital syphilis, especially where there is an absence of documented antenatal serology and where a unifying explanation for multi-organ dysfunction is not apparent.

This infant’s presentation was initially thought to be caused by E. coli bacteraemia with a predisposing renal tract abnormality. However, the severity of his multi-organ involvement with conjugated hyperbilirubinaemia, nephrotic-range proteinuria and haematologic abnormalities was not typical of E. coli infection, particularly as he required only a brief period of non-invasive ventilation and inotropic support. The rapid deterioration with haemodynamic instability and lactic acidosis occurring several hours after initiation of IV antibiotics may have been due to the Jarisch-Herxheimer reaction, a transient immunologic response following initiation of antibiotic treatment for syphilis that has occasionally been described in neonates. In a case series from Bejing, 11 infants with congenital syphilis who developed the Jarisch-Herxheimer reaction all had multi-organ involvement with high spirochete load.[[4]]  

New Zealand has seen a concerning increase in congenital syphilis in recent years. Between April 2018 and June 2020, prospective surveillance by the New Zealand Paediatric Surveillance Unit (NZPSU) identified 32 exposed infants and 12 probable/confirmed cases; seven of these infants’ mothers were not diagnosed with syphilis in pregnancy. The annual incidence was 9.4 per 100,000 live births.[[5]] In contrast, there were no notifications of congenital syphilis between 2011 and 2016.[[6]] Marked ethnic inequities are evident among congenital syphilis cases in New Zealand. This infant was Māori, as were 43% of cases notified to the NZPSU.[[5]]

The increase in congenital syphilis mirrors a dramatic rise in syphilis in adults. There were 727 cases in 2019, compared to only 82 in 2013.[[6]] Cases are concentrated in the Auckland region[[7]] and upper North Island. Although the majority of new cases are in men who have sex with men (MSM), numbers are rising among women of childbearing age, a particular concern given the potential for mother-to-child transmission.[[6]]

This resurgence in syphilis is occurring around the globe,[[8]] including other high-income countries such as Australia, where there was a 146% increase in infectious syphilis cases between 2014 and 2018,[[9]] and the United Kingdom.[[10]]

Congenital syphilis is preventable by antenatal screening and maternal treatment in early pregnancy. The steady rise in national notifications of congenital syphilis in recent years highlights critical deficiencies in maternity and sexual health services, particularly impacting wahine hapū.

This case highlights the importance of reviewing maternal serology results as part of routine newborn management. Urgent consideration should also be given to the introduction of universal third-trimester syphilis testing, which aligns with recommendations in the recently published New Zealand Sexual Health Society national guidelines[[11]] and antenatal screening practices in other high-incidence populations. Given the current situation in New Zealand, we strongly favour a universal rather than risk-based approach to third-trimester testing. Testing of the mother at delivery should be universally performed in the absence of antenatal testing, in particular for syphilis, HIV and hepatitis B, where immediate clinical management may prevent mother-to-child transmission. Infant testing should be performed at any time upon clinical suspicion of syphilis, as maternal infection may have been acquired after the time of maternal serologic screening.

For women in the childbearing years who are diagnosed with syphilis, follow-up care should include explicit guidance regarding the need for antenatal care and testing in future pregnancies, along with identification and treatment of sexual partners.

The recently announced health system reforms and Māori Health Authority present a timely opportunity to re-prioritise and re-design sexual health and maternity services for wahine Māori, in a culturally responsive manner with barriers to access removed.

Figure 1.