Andersons pediatric cardiology 1573

inflammation results in vessel mural necrosis with subsequent fibrosis, thrombosis, and microaneurysm formation Myocarditis has also been reported.337 This may be the cause of the left ventricular systolic dysfunction and mitral valve regurgitation that are frequently seen.338 Supportive care coupled with immunomodulatory therapy are the mainstays of treatment Systemic Lupus Erythematosus Systemic lupus erythematosus is a generalized, progressive, multisystem connective tissue disease of unknown etiology During childhood, the mean age of onset is 12 years It very rarely presents before the age of 5 years.339 The cutaneous, osteoarticular, renal, hematopoietic, central nervous, pulmonary, and gastrointestinal systems are commonly affected Cardiac involvement is also very frequent and can be present at any time during the course of the disease The most common manifestations are pericarditis, myocarditis, Libman-Sacks endocarditis leading to valvar stenosis and/or incompetence, disturbances of rhythm, coronary artery disease, and systemic and pulmonary hypertension Any of these can lead to CHF, which carries a poor prognosis.340 Deposition of immune complexes and complement activation have a major pathogenic role in these lesions Pericarditis is the most common cardiac manifestation Up to three-quarters of patients have echocardiographic evidence of pericardial disease Clinical involvement is seen in one-third, generally as acute pericarditis, which may have a recurrent nature Serous effusions are common, and complement levels in the fluid are very low Chronic constrictive pericarditis and tamponade are thankfully rare Evidence of myocarditis can be seen in about half the patients at postmortem, but clinical involvement is generally silent Dyspnea is the most common symptom The presence of a gallop rhythm, cardiomegaly on the chest radiograph, and ventricular dilation on the echocardiogram complete the clinical picture The ECG is nonspecific T-wave inversion, ventricular premature beats, and first-degree atrioventricular block may all be present In approximately half the patients, there are nonbacterial verrucous vegetations on the cardiac valves, so-called Libman-Sacks endocarditis These are clumps of fibrin from 0.1 to 4 mm in diameter with lymphocytes and plasma cell infiltrates that are most frequently seen on the mitral and/or aortic valves Fibrous tissue, which may later become calcified, appears during the process of healing, sometimes leading to valvar dysfunction Mitral and aortic incompetence and less frequently stenosis are the most common lesions Echocardiographic evaluation is a useful noninvasive method for the assessment of valvar dysfunction Doppler examination should increase the sensitivity of early detection of valve disease The presence of Libman-Sacks vegetations predisposes to bacterial endocarditis, although peripheral embolism is rare The coronary arteries can be affected by an acute inflammatory arteritic process or, less frequently in childhood, by atherosclerosis Coronary arteritis can lead to aneurysmal dilation of the arteries, thrombosis, and myocardial infarction This is an uncommon cause of death Disturbances of rhythm and conduction are common Atrial fibrillation or flutter may be seen during acute pericarditis, whereas ventricular ectopic beats and first-degree atrioventricular block are seen in the course of active myocarditis Complete heart block may result from vasculitis of small vessels, and fibrosis of the conduction system has been described in adults Systemic hypertension is very frequent It is generally caused by lupus nephritis or by prolonged steroid therapy The revised criteria for the diagnosis of systemic lupus erythematosus require the presence of at least four of the following: malar rash; discoid rash; photosensitivity; oral ulcers; arthritis, pleuritis, or pericarditis; renal disorders such as proteinuria or cellular casts; neurologic disorders such as seizures or psychosis; hematologic disorders such as hemolytic anemia, leucopenia, lymphopenia, or thrombocytopenia; immunologic disorders such as positive lupus erythematosus cell preparations, antibodies against double-stranded DNA (anti-dsDNA) or Smith protein (anti-Sm), or antinuclear antibodies.341 A revision to the immunologic criteria was made in 1997 to include antiphospholipid and anticardiolipin antibodies.342 The long-term prognosis is variable Boys seem to have a more severe form of the disease than girls The most common causes of death are renal involvement and sepsis Death from cardiac lesions is not frequent, but aggressive therapy is warranted when myocarditis is evident, as its course can be fulminant and lethal.343 Corticosteroids are the basis of treatment Immunosuppressive therapy with azathioprine or cyclophosphamide can be used as a supplement when there is no response to high doses of steroids or when there is severe renal or central nervous system involvement Apart from this systemic form of therapy, the management of specific lesions does not differ from that of the patient without lupus erythematosus Neonatal lupus erythematosus is a rare variety of the systemic disease It is frequently associated with maternal lupus and characterized by cutaneous lesions with or without congenital complete heart block and systemic manifestations.344 Prolongation of the QT interval, sinus bradycardia, lower-grade heart block, and dilated cardiomyopathy can also occur Skin lesions develop within the first 3 months of life and occur mainly in areas exposed to light, thus suggesting photosensitivity They consist of erythematous macules, papules, or plaques that may exhibit the characteristics of discoid lupus, specifically scaling, atrophy, follicular plugging, and telangiectasia Later, they have residual hyper- or hypopigmentation and resolve completely within 12 months with minimal atrophy or scarring Systemic manifestations—including hepatosplenomegaly, anemia, leukopenia, and thrombocytopenia—occur within the first weeks of life and tend to be self-limiting Specific treatment is rarely necessary Congenital complete heart block, unlike the cutaneous and systemic manifestations, is irreversible There is a high correlation with the presence of anti-SSA/Ro antibodies in maternal serum, these having been demonstrated in over threequarters of patients.345 Approximately 5% of babies born to mothers with these antibodies will develop complete heart block.346 The autoantibodies are frequently found in patients with systemic lupus erythematosus and Sjögren syndrome, but they are rarely encountered in the general population AntiSSA/Ro or anti-SSB/La antibodies are immunoglobulin-G forms that reach the fetus by transplacental transfer They can be detected in babies with congenital complete heart block before 3 months of age but not after they are 6 months old The underlying mechanism producing heart block is not clear, but it produces fibrosis of the atrial component of the atrioventricular conduction axis Pacing may be required in approximately two-thirds of such patients.347 Complete heart block in the subsequent pregnancies of mothers with lupus is uncommon, affecting approximately one-sixth Treatment, both for the prevention of heart block and as a treatment for evident evolving heart block, has centered on fluorinated steroids This remains controversial and has yet to be proven beneficial.348 More recent evidence suggests that when used throughout pregnancy there is a role for hydroxychloroquine in preventing autoimmune congenital complete heart block.349