This 4 month old infant had slow fetal heart rate throughout 2nd & 3rd trimester of pregnancy. What's the likely cause?
Answer: Neonatal lupus erythematosus -: fading facial lesions in characteristic periorbital distribution, with residual atrophy, in a 4-month-old infant. Discussion Definition Neonatal LE is a rare syndrome comprising transient skin lesions resembling subacute cutaneous LE, and/or congenitalheart block, occurring in the babies of mothers with clinical or subclinical autoimmune connective tissue disease, and associated with the transplacental passage of maternal autoantibodies to the ribonucleoproteins (RNPs), Ro-SSA, La-SSB or U1-RNP. Aetiology It is now accepted that this disease is provoked in the fetus or newborn infant by maternal IgG autoantibodies that have crossed the placenta. In 95% of cases, these are of IgG1 class and are directed against the Ro RNP antigen. These antibodies are relatively prevalent in young women, and appear to be compatible with apparently normal health. Prognosis Infants with skin lesions alone, or with skin lesions and systemic features other than heart block, generally show little sign of residual disease after the age of 1 year. However, their long-term prognosis must remain slightly guarded in the light of reports of the later development by some of full-blown connective tissue disease. Conduction defects of the heart tend to be permanent, and when severe are associated with a significant mortality. The risk of recurrence in further pregnancies appears to be about 25%. This risk appears to be infl uenced by immunogenetic factors. Spontaneous abortion and stillbirth do not appear to be more frequent in further pregnancies of mothers who have had a previous child with neonatal LE. Mothers with Roantibody may experience recurrent fetal loss if they do not have SLE, but do not appear to do so if they do have SLE. Ref: Rook's textbook of dermatology 17.17 Atopic dermatits is a strong differential, but the characteristic spectacle distribution and the association of bradycardia in 2nd and 3rd trimester, clinches the diagnosis in favor of 'Neonatal lupus'. Credit to Elias and E M Mike (Y)
