Neonatal Lupus Erythematosus

Syndrome in newborns characterized by congenital heart block and/or cutaneous lupus erythematosus in the presence of maternal autoantibodies.

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Estimated to be 1:12,500 live births. An infant born of an anti-Ro(SSA) antibody-positive mother has a 1:20 chance of developing a neonatal lupus syndrome.

No racial or sexual predilection, but there is an increased frequency of the HLA-DR3 phenotype in mothers of infants with neonatal lupus.

Believed to be caused by transplacental passage of specific autoantibodies (primarily anti-Ro/SSA and anti-La/SSB) from the mother with systemic lupus erythematosus to the fetus. These autoantibodies bind to fetal Ro and La autoantigens and induce an inflammatory infiltrate in the skin or heart. The latter results in scarring with fibrosis and calcification, causing complete congenital heart block.

Characteristic skin lesions and/or congenital complete heart block with positive maternal anti-Ro and anti-Ra antibodies.

Approximately 50% of infants with neonatal lupus have characteristic skin lesions, with predilection for involvement around the eyes—“raccoon eyes” appearance. In the other 50% of affected infants, cardiac lesions predominate. In approximately 10%, both cutaneous and cardiac lesions are present. The skin lesions (generalized, erythematous, nonscaling, sharply demarcated) develop in the first month or later in life, and they generally disappear by 6 months, which corresponds to the disappearance of the maternal IgG antibodies from the infant's serum. Neonatal lupus dermatitis responds to topical steroids. Avoidance of sunlight exposure is recommended because exacerbation and induction of skin lesions follow ultraviolet light exposure. Congenital abnormalities include patent ductus arteriosus, ventricular septal defect, transposition of the great arteries, atrial septal defect, coarctation of the aorta, and tetralogy of Fallot. The first cause of mortality (15-35%) and morbidity of neonates affected with lupus is complete congenital heart block. A pacemaker is required in one third of infants. Thrombocytopenia and liver involvement occur but are normally mild and transient.

Check drug history (steroids, cardiac drugs). Investigations include ECG, echocardiography, chest radiography, arterial blood gases, and levels of electrolytes, urea, creatinine, and hemoglobin. In patients with preexisting permanent pacemaker, ascertain pacemaker function according to institution protocol. A magnet or reprogramming device and expertise that can be used to convert the pacemaker to asynchronous mode should be available. In patients without preexisting permanent pacemaker, measures and expertise for temporary pacing (cardiologist, transcutaneous pacing, transesophageal pacing, transvenous pacing) should be available prior to induction of anesthesia. Chronotropic drugs (atropine, isoprenaline) should be available.

When transporting and positioning patients with temporary pacing devices, take care to prevent accidental dislodgment of the leads. Acute acid-base or electrolyte imbalance (K+, PaCO2, glucose, PaO2) that can increase pacing thresholds should be prevented. Hypothermia also increases pacing threshold, so normothermia should be maintained for optimal pacemaker function. Intraoperative and postoperative normothermia should minimize the development of postanesthetic shivering, which may cause pacemaker failure. Anesthetic considerations specific for the congenital heart defect present should be adapted for clinical management.

Suxamethonium-induced fasciculations may cause physiologic rate-responsive pacemaker failure and should be avoided. If necessary, precurarization with a nondepolarizing agent may be used. Halothane should be avoided because it slows the heart rate and sensitizes the myocardium to arrhythmias more so than isoflurane or sevoflurane. Anesthetic agents with effects on heart conduction and contractility should be avoided.