Abstract | CLINICAL PRESENTATION:
Congenital heart block (CHB) in the absence of major structural abnormalities is associated with maternal antibodies to Ro (SS-A) and La (SS-B). CHB is most commonly diagnosed between 18 and 24 wk of gestation, and may be first, second or third degree (complete). Mortality approaches approximately 20%, and most surviving children require pacemakers. Affected infants may develop cardiomyopathy. Abnormalities in the skin, liver and blood of neonates are also associated with anti-Ro/La antibodies, and are usually self-limiting; these manifestations and CHB are collectively referred to as neonatal lupus syndromes (NLS). INVESTIGATION OF PATHOGENESIS: Recent studies demonstrate that Ro/La ribonucleoproteins appear on the surface of apoptotic fetal cardiocytes and are recognized by their cognate antibodies, promoting an inflammatory response. Mice immunized with Ro/La proteins have offspring with conduction abnormalities. In vitro, human serum and IgG with anti-Ro/La antibodies affect the conducting properties of isolated animal heart tissue. DIAGNOSTIC PROBLEMS: If fetal bradycardia is identified, a 2-dimensional and M-mode fetal echocardiographic and Doppler ultrasound should be obtained to determine whether there is an atrial arrhythmia or atrioventricular ( AV) block, and to what degree, and whether there are major structural abnormalities of the heart. The mother's serum should be tested by ELISA for anti-Ro and/or anti-La antibodies. THERAPEUTIC OPTIONS: To date, only anecdotal and retrospective evidence guides in utero therapy of CHB. A prospective trial is currently underway to evaluate the efficacy of maternal oral dexamethasone in treating newly identified first, second or third degree block. Established third-degree block appears to be irreversible. Dexamethasone and sympathomimetics may be of some benefit in treating hydrops fetalis. In pregnant women with anti-Ro/La antibodies, prophylactic therapy is not indicated but serial echocardiographic analysis is strongly recommended, with emphasis on the mechanical PR interval to identify a reversible block. CONCLUSION: CHB occurs in approximately 1-5% of pregnancies in mothers with anti-Ro/La antibodies, independent of the mother's disease status, and in approximately 15-20% of pregnancies following the birth of a child with NLS. Treatment of CHB identified in utero is not established but guidelines are provided. Serial echocardiographic monitoring of high-risk pregnancies, using the mechanical PR interval to identify first degree block, may afford the earliest opportunities for therapeutic intervention.
|
Authors | Deborah M Friedman, Ann Rupel, Julie Glickstein, Jill P Buyon |
Journal | Indian journal of pediatrics
(Indian J Pediatr)
Vol. 69
Issue 6
Pg. 517-22
(Jun 2002)
ISSN: 0019-5456 [Print] India |
PMID | 12139139
(Publication Type: Journal Article, Research Support, U.S. Gov't, P.H.S., Review)
|
Chemical References |
- Antibodies, Antinuclear
- SS-A antibodies
- SS-B antibodies
|
Topics |
- Antibodies, Antinuclear
(immunology)
- Autoimmune Diseases
(immunology)
- Female
- Heart Block
(congenital, diagnosis, immunology, therapy)
- Humans
- Infant, Newborn
- Lupus Vulgaris
(immunology)
- Pregnancy
- Pregnancy Complications, Cardiovascular
|