Neonatal Lupus

Neonatal lupus is passively acquired autoimmune disease in newborns from maternal IgG anti-Ro/SSA and anti-La/SSB antibodies crossing the placenta.

• Mothers may have SLE, Sjögren syndrome, or be asymptomatic (about half).

• Cardiac manifestations: congenital complete heart block (1 to 2% in first anti-Ro positive pregnancy; 15 to 20% recurrence), endocardial fibroelastosis, cardiomyopathy; mortality 15 to 20%, with 60 to 70% needing pacemaker.

• Cutaneous lupus (15% of infants), hepatobiliary disease, thrombocytopenia, anaemia, neutropenia.

• Rash and blood changes resolve by 6 to 8 months as maternal antibodies clear; heart block is permanent.

• Fetal bradycardia (under 100 beats per minute) at 18 to 24 weeks, hydrops fetalis.

• Newborn: annular erythematous periorbital and facial rash ("owl eyes"), photosensitive, scaling plaques; hepatomegaly with cholestasis; thrombocytopenia with petechiae.

• Congenital heart block: bradycardia, signs of heart failure.

• Mother often asymptomatic.

• Maternal anti-Ro/SSA (52 and 60 kDa) and anti-La/SSB antibodies (test all women with SLE, Sjögren, or prior affected child).

• Serial fetal echocardiography weekly from 16 to 26 weeks (PR interval over 150 ms, first degree block), then every 2 weeks to 28 weeks.

• Neonatal ECG (complete block), echocardiogram, full blood count, liver tests.

• Skin lesions: clinical, biopsy if needed. Neonatal anti-Ro/La antibodies.

• Exclude infection (TORCH), other causes of congenital heart block.

• Prevention in anti-Ro positive women: hydroxychloroquine 200 mg twice daily from before 10 weeks reduces recurrence of heart block (in women with prior affected child, reduces risk by about 50%).

• Fetal first or second degree block: dexamethasone 4 mg daily (fluorinated steroid crossing placenta) may reverse; no benefit for established complete block; weigh maternal risks. IVIG 400 mg/kg has limited benefit.

• Fetal heart failure or hydrops: maternal dexamethasone, terbutaline 5 mg orally every 8 hours for bradycardia under 55, delivery planning at tertiary centre.

• Complete heart block in neonate: pacemaker implantation if rate under 55 beats per minute, congenital heart disease, or symptoms, and later for wide QRS; ventricular dysfunction treated with heart failure care.

• Skin disease: sun avoidance, mild topical steroid (hydrocortisone 1%), sunscreen; resolves spontaneously.

• Cytopenias, liver disease: supportive and observation.

• Counsel future pregnancies; screen mother for evolving connective tissue disease.