# When should a neonatologist consult a rheumatologist?

## TL;DR

Neonatologists should consult rheumatologists when neonates show symptoms like fever or rash, as rare rheumatologic diseases and maternal autoimmune conditions can cause serious complications.

## Contribution

The paper introduces novel biomarkers and highlights the need for neonatal-specific scoring systems to improve diagnosis and outcomes in neonatal rheumatologic diseases.

## Key findings

- Persistent fever, rash, or joint involvement in neonates should prompt early referral to a pediatric rheumatologist.
- Maternal autoimmune diseases like SLE and APS can lead to neonatal complications such as thrombosis or heart block.
- Elevated cord biomarkers like C-reactive protein and NT-proBNP may aid in diagnosing cardiac neonatal lupus.

## Abstract

Pediatric rheumatologic diseases are complex conditions that can present with various clinical manifestations, including fever, rash, joint involvement, and diarrhea, impacting more than one organ system and affecting all pediatric age groups from 0 to 18 years. This review focuses on rheumatologic diseases in neonates, encompassing both primary neonatal-onset conditions and those influenced by maternal autoimmune diseases and treatments during pregnancy. Diagnosing rheumatologic diseases in neonates is challenging due to their nonspecific symptoms, which can overlap with other conditions. While primary neonatal-onset diseases such as cryopyrin-associated periodic syndromes (CAPS), deficiency of IL-1 receptor antagonist (DIRA), and neonatal-onset juvenile idiopathic arthritis (JIA) are rare, maternal autoimmune diseases and their treatments can also impact neonatal health. Conditions like systemic lupus erythematosus (SLE) and antiphospholipid syndrome (APS) may increase neonatal risks, leading to complications such as thrombosis or pregnancy loss. Identifying these conditions early and providing the proper care is crucial to reduce morbidity and mortality in this vulnerable group.

Conclusion: Persistent fever, rash, or unexplained joint involvement warrants early referral to a pediatric rheumatologist. A multidisciplinary approach involving obstetricians, rheumatologists, and neonatologists is essential for timely diagnosis and optimal neonatal outcomes.

What is Known:• Diagnosis of neonatal rheumatologic diseases is difficult because their symptoms are nonspecific and may overlap with other neonatal diseases.• Maternal autoantibodies transmitted through the placenta may lead to neonatal complications (e.g. congenital heart block, thrombosis).What is New:• Long-term follow-up of autoinflammatory diseases is essential, as the absence of neonatal-specific damage indices limits the ability to assess disease progression and treatment outcomes, underscoring the need for validated scoring systems tailored to neonates.• Novel biomarkers, such as elevated levels of cord C-reactive protein, NT-proBNP, MMP-2, uPA, uPAR, and plasminogen, have been identified, offering new insights into potential diagnostic tools for cardiac neonatal lupus.

What is Known:

• Diagnosis of neonatal rheumatologic diseases is difficult because their symptoms are nonspecific and may overlap with other neonatal diseases.

• Maternal autoantibodies transmitted through the placenta may lead to neonatal complications (e.g. congenital heart block, thrombosis).

What is New:

• Long-term follow-up of autoinflammatory diseases is essential, as the absence of neonatal-specific damage indices limits the ability to assess disease progression and treatment outcomes, underscoring the need for validated scoring systems tailored to neonates.

• Novel biomarkers, such as elevated levels of cord C-reactive protein, NT-proBNP, MMP-2, uPA, uPAR, and plasminogen, have been identified, offering new insights into potential diagnostic tools for cardiac neonatal lupus.