Vol.
2, No. 1 (23-36) 2004
Department of Allergy, Rheumatology and
Clinical Immunology, University Children’s Hospital, University Medical Center
Ljubljana, Ljubljana, Slovenia
E-mail: tadej.avcin@kclj.si
Neonatal lupus is a
rare disease of the developing fetus and neonate acquired from the
transplacental passage of specific maternal autoantibodies, in particular those
directed against the extractable nuclear antigens Ro (also called SSA) and La
(also called SSB) [1, 2]. Anti-Ro/La antibodies are present in a high
percentage of patients with systemic lupus erythematosus (SLE) and Sjögren’s
syndrome, but mothers with a known connective tissue disease and positive
anti-Ro/La antibodies have only about 1-5% risk of delivering a child with
neonatal lupus [5, 6]. On the other hand, neonatal lupus can be seen in the
offspring of mothers who do not have any signs or symptoms of a connective
tissue disorder, and the first demonstration of anti-Ro/La antibodies in these
mothers occurs during the pregnancy or after delivery of an affected
child.
The clinical features
most clearly associated with neonatal lupus include cardiac disease, skin
disease, hepatobiliary disease and cytopenia. The noncardiac manifestations of
neonatal lupus are generally transient, resolving by 6 months of life
coincident with the disappearance of maternal autoantibodies from the infant’s
circulation. The most frequent lesion of cardiac neonatal lupus is complete
(i.e., third degree) heart block, which is almost always permanent.
The classic presentation of neonatal lupus is one of a
fetus or newborn discovered to have a slow heart rate due to congenital heart
block in the absence of a structural heart disease. Many cases are discovered in
utero, most commonly between 18 and 24 weeks of gestation [7]. The
identification of fetal bradycardia (i.e., heart rate less than 120 per minute)
by either auscultation or routine obstetric ultrasound requires that the mother
be referred for immediate fetal echocardiography to confirm the presence of
heart block and to document the degree of the block. Autoimmune-associated
congenital heart block can be first, second, or third degree, and may or may
not be progressive after detection in utero or postnatally [8]. Only
second or third degree heart block is clinically manifested as bradycardia. It
is estimated that up to one third of pregnancies complicated by fetal complete
heart block result in intrauterine death, which is usually related to
intractable heart failure and development of hydrops fetalis. Besides
congenital heart block, other cardiac manifestations have been reported, such
as myocarditis, dilated cardiomyopathy, sinus bradycardia, QT interval
prolongation and, rarely, structural heart defects [9, 10].
The skin rash of neonatal lupus
characteristically appears a few days or weeks after birth, particularly after
sun exposure. It consists of annular (Figure 1 and Figure 2) or
elliptical erythematosus plaques (Figure 3) most often located on the scalp, face and
extremities. Skin lesions are transient, lasting weeks to months; these usually
resolve without scarring. Hypopigmentation is frequent and may be a prominent
feature. Rarely, remnant telangiectasias can occur at previously affected sites
[11]. The differential diagnosis of isolated cutaneous neonatal lupus includes
tinea faciei, a photosensitive drug eruption, urticaria, seborrheic dermatitis
and annular erythemas.
Hepatic dysfunction occurs in
approximately 15% of cases with neonatal lupus and can present as severe liver
failure in utero or after birth, transient cholestatic hepatitis and transient
elevations of aminotransferases. Hepatobiliary disease may occur as the sole
clinical manifestation, but is commonly associated with other manifestations of
neonatal lupus [12, 13].
Occasionally, newborns of mothers
with anti-Ro/La antibodies may present with hematological manifestations
including thrombocytopenia, anemia and neutropenia [14]. There have also been
several case reports of various neurological manifestations associated with
neonatal lupus [15, 16].
Presumably, the fetus
develops normally until maternal IgG antibodies against the Ro and La proteins
are actively transported across the placenta beginning at 12 weeks of
gestation. Although the Ro and La proteins are normally intracellular and thus
inaccessible to circulating antibodies, they are expressed on the developing
fetal heart at different stages of gestation. It has been demonstrated that
anti-Ro/La antibodies bind to fetal but not adult heart, and direct binding to
fetal cardiac proteins may trigger an inflammatory response and cause tissue
damage [17]. Despite exposure to the identical circulating autoantibodies, the
maternal heart is never affected.
The exact pathogenetic
mechanism of non-cardiac manifestations is still unknown, but it has been hypothesized
that the timing of transplacental passage of maternal autoantibodies coincides
with the period of maximal vulnerability of selected fetal organs [18].
Finally, it should be emphasized that specific
maternal autoantibodies are probably necessary, but are not sufficient, for
development of neonatal lupus. Several concomitant maternal, fetal or
environmental risk factors may contribute to the pathogenesis of this disease.
Management
Prior to the development of fetal
echocardiography, auscultatory evidence of regular bradycardia alerted the
clinician to the congenital heart block, which could only be confirmed after
birth. Fetal echocardiography is now used to establish the diagnosis of
congenital heart block and it is recommended that the fetuses of all women with
anti-Ro/La antibodies be evaluated by serial echocardiography. Echocardiograms
are done weekly from 16 to 26 weeks and every other week until 32 weeks. A
recent major advance in echocardiography was the development of a new
non-invasive Doppler technique to measure the mechanical PR interval, which has
made possible the in utero detection of first-degree heart block in the
absence of an electrocardiogram. This technique allows earlier diagnosis and
has paved the way for effective prenatal treatment in fetuses with incomplete
heart block [19, 20].
The most common prenatal
interventions attempted are systemic glucocorticosteroids and medications to
treat heart failure. The rationale for treatment of identified heart block with
glucocorticosteroids is to diminish the cardiac inflammatory injury and to
lower the maternal autoimmune response. Dexamethasone, which is not metabolized
by the placenta and is available to the fetus in an active form, is given at a
dose of 4 mg/day. Fetal risks secondary to dexamethasone include
oligohydramnios, intrauterine growth retardation and adrenal suppression.
Sympathomimetics, diuretics and fetal pacing are reserved for those cases where
the fetus is in a life-threatening situation with hydrops and deteriorating
cardiac function [21, 22].
Postnatal treatment of the
symptomatic infant with complete heart block is based on pacemaker
implantation, and supportive treatment for low output or congestive heart
failure.
Cutaneous manifestations of neonatal
lupus generally do not require any treatment; however; topical application of a
mild glucocorticosteroid cream may hasten the resolution of the lesions and be
used for cosmetic reasons. All infants whose mothers have anti Ro/La antibodies
should be protected from excessive exposure to the sun, which may induce or
exacerbate skin lesions. In most cases, hepatobiliary and hematological
manifestations are self-limited and the usual approach to management is
reassurance to the parents and continued observation of the infant (including
determination of titers for antinuclear antibodies and antibodies against
extractable nuclear antigens, liver function tests, complete blood count and
electrocardiogram) at least until transplacentally acquired autoantibodies
become undetectable.
Prognosis
Nearly all children with complete
heart block require implantation of a pacemaker at some point in their lives,
frequently in the neonatal period [7]. Despite early pacing, complete heart
block carries high neonatal morbidity and high mortality during the first 12
months of life [23].
If a mother has already had one
child with congenital heart block, there is approximately a 15 to 20% risk of
having another child with the same problem, supporting close fetal
echocardiographic monitoring and considering therapeutic interventions [7].
Apart from cardiac disease, children
with neonatal lupus grow and develop normally. They have only a slightly higher
risk for developing autoimmune disease later in life attributable to the genetic
predisposition [24, 25]. Parents of these infants should be counseled that the
risk of their offspring developing autoimmune diseases is similar to the risk
in children of women with SLE or another connective tissue disease.
NEONATAL
ANTIPHOSPHOLIPID SYNDROME
Neonatal antiphospholipid syndrome
(APS) is a rare clinical entity characterized by neonatal thrombotic disease
[3]. Autoantibodies that have been causally associated with neonatal APS
include antiphospholipid antibodies (aPL), namely the β2 glycoprotein
I - dependent anticardiolipin antibodies and lupus anticoagulants. These
autoantibodies have a well-recognized pathogenic role in thrombotic diathesis
and have been associated with a number of obstetric complications such as
recurrent pregnancy loss, pre-eclampsia, fetal growth retardation and pre-term
delivery [26]. While women with aPL show
an unusually high incidence of pregnancy complications, the aPL-related
thrombosis in their offspring seems to be exceedingly rare. The low frequency
of neonatal thrombosis has been attributed to the lack of the most known
“second hit” risk factors in infants (such as atherosclerosis, cigarette
smoking, oral contraceptives etc.), and to a low transplacental passage of IgG2
subclass of aPL, which are responsible for most clinical pathogenicity [28,
29].
Neonatal thromboses associated with
transplacentally acquired aPL were most commonly described in cerebral vessels
and abdominal organs; however, vascular occlusion in APS may involve the
arteries and veins at any level of the vascular tree and in all organ systems
[3]. Special concern is needed particularly when dealing with aPL-positive
infants who are exposed to other acquired thrombotic risk factors (i.e.,
central vascular catheters, sepsis, prematurity, congenital heart disease), and
possibly inherited prothrombotic disorders (i.e., deficiencies of antithrombin
III, protein C, protein S, factor V Leiden mutation). There have also been
scattered reports of thrombotic events in the fetuses of aPL-positive women,
resulting from intra-uterine exposure to aPL [30, 31].
Both aPL and anti-Ro/La antibodies
may be simultaneously present in a woman with connective tissue disease making
the distinction between neonatal lupus and neonatal APS sometimes difficult
[32, 33]. In fact, some of the hematological and neurological manifestations
reported in neonatal lupus could be related to the presence of aPL [34, 35]. At
the present time, however, the exact clinical criteria for these clinical
entities are not available.
CHRONIC INFANTILE
NEUROLOGIC CUTANEOUS AND ARTICULAR (CINCA) SYNDROME
We wish to thank Dr. Rolando Cimaz (Department of Pediatrics, Istituti
Clinici di Perfezionamento,