James T. Cassidy

Childhood dermatomyositis: Factors predicting functional outcome and development of dystrophic calcification

The medical records of 47 children with dermatomyositis who were seen in the pediatric rheumatology clinic at the University of Michigan between 1964 and 1982 were reviewed. Although most children with dermatomyositis have a good prognosis, the best predictor of both good functional recovery and minimal calcinosis is early treatment after the onset of symptoms, using high doses of prednisone for an adequate length of time. Of the children given such treatment, 78% had good functional outcomes, and disabling calcinosis was seen in 20% or less. Children given treatment late in the course of disease and with low doses of steroids are more likely to be functionally limited and have a greater amount of dystrophic calcium salt deposition. In our study, only 33% of patients given such treatment had a mild disease course with good functional outcome. We have identified a subgroup of children with dermatomyositis who appear to do poorly despite optimal therapeutic regimens. These patients are distinguished by a severe disease course responding minimally to corticosteroid therapy and manifested by persistent muscle weakness, elevations of muscle enzyme activity, and severe generalized cutaneous vasculitis. These children are at high risk for the development of exoskeleton-like calcification; consideration should be given to combined immunosuppressive therapy early in the course of disease.

CHAPTER 9 – CHRONIC ARTHRITIS IN CHILDHOOD

211 Chronic arthritis, the most common chronic rheumatic disease of childhood, is one of the more frequent chronic illnesses of children and an important cause of shortand long-term disability. It is not a single disease, but a group of related, genetically heterogeneous, phenotypically diverse immuno inflammatory disorders affecting joints and other structures, possibly activated by contact with an external antigen or antigens. Since its introduction in 1994, the term Juvenile Idiopathic Arthritis (JIA) has largely supplanted the terms Juvenile Chronic Arthritis (JCA) and Juvenile Rheumatoid Arthritis (JRA). However, it is necessary to understand the older classifications in order to interpret the literature on the subject. The intent of this chapter is to provide a general introduction to JIA. Each subtype of disease is discussed in separate chapters.

Prognosis in childhood dermatomyositis

The insidious onset of progressive muscle weakness in a child may go unnoticed until fever, rash, or muscle pain prompts the family to seek medical attention. Although the diagnosis of dermatomyositis may be suspected, and muscle biopsy and electromyography are later confirmatory, the single most useful method of assessment is determination of the concentration of the serum muscle enzymes. Prompt treatment with corticosteroids has undoubtedly contributed to the currently improved prognosis. Of the 18 children reported in this study, one died of trauma, and all of the remaining individuals have been maintained in functional independence.

Human serum immunoglobulin concentrations: Prevalence of immunoglobulin deficiencies

Classical antibody deficiency syndromes, such as sex-linked aggammaglobulinemia, are rare and relatively homogeneous in presentation. In the present investigation an unselected group of 3,213 individuals from a community health study was examined in an attempt to estimate the prevalence of the commoner and largely unclassified examples of immunoglobulin deficiencies defined by the lower 2.5 per cent of the population. The prevalence of selective IgA deficiency (an isolated absence of IgA) was 0.097 per cent and that for selective IgM deficiency was 0.03 per cent. No isolated absence of IgG was found. In addition to these deficiency syndromes, concentrations of each of the immunoglobulins were found to be highly correlated to each other.

Clinical correlates of antinuclear antibodies in juvenile rheumatoid arthritis

The presence of antinuclear antibodies (ANA) was determined by an immunofluorescent technique in 200 children with juvenile rheumatoid arthritis and was compared to that in 80 children with other connective tissue diseases, 164 children with nonconnective tissue diseases, and 90 normal children. The low frequency of positive tests in normal children (3 per cent) and in nonconnective tissue diseases (1 per cent) compared with the high seropositivity in children with systemic lupus erythematosus (100 per cent), polyarteritis (75 per cent), and juvenile rheumatoid arthritis (38.5 per cent) demonstrates that the method used to detect ANA is both sensitive and selective. In juvenile rheumatoid arthritis, ANA were found significantly more frequently in girls, in patients with early onset of disease or whose present age was young, and in those with polyarticular disease or with monarticular disease and iridocyclitis.

A syndrome of childhood polyarteritis

In this report the clinical, laboratory, and histopathologic findings of nine children with polyarteritis are reviewed. All have had evidence of systemic involvement. Eight presented with fever, calf pain, erythematous painful nodules, and elevation of the acute-phase reactants. All were treated with prednisone at a dosage of 2 mg/kg/day. All of the children are alive but have had relapses at least once during the course of tapering the dosage of corticosteroids. Serious complications of disease have included myocardial infarction, hypertension, and impaired renal function.

Antibodies against heart muscle and nuclear constituents in cardiomyopathy

Abstract The prevalence of HAB and ANA was determined in eight patients with idiopathic hypertrophic subaortic stenosis (IHSS) and 35 patients with cardiomyopathy (CM). HAB was found in 88 per cent of patients with IHSS and in 17 per cent of those with CM. Antinuclear antibody was found in 63 per cent of patients with IHSS and 43 per cent of those with CM. Aging alone was not responsible for the high prevalence of ANA in the former group, but may be partly so in the latter. There was an increased tendency for women in both groups to have ANA. An increased serum concentration of IgM was also observed in women in the IHSS and CM groups. Serum concentrations of IgG and IgA, precipitating antibodies to nuclear constituents, rheumatoid factors, and a positive serologic test for syphilis were not increased in patients with idiopathic cardiomyopathy. Positivity to HAB and ANA did not remain constant and was not present frequently in sera in follow-up studies of these patients. No instance of a negative test becoming positive was recorded for either HAB or ANA. The high prevalence of ANA in patients with IHSS and CM and an increased prevalence of HAB in patients with IHSS may suggest that an autoimmune disturbance is operative in these forms of cardiomyopathy.

Monarticular juvenile rheumatoid arthritis

A child with recent onset of arthritis in a single joint often presents a diagnostic problem of considerable magnitude. The diagnosis of rheumatoid arthritis may be made with certainty only after specific diseases such as tuberculosis have been clinically eliminated; even then, correct therapeutic management of this form of arthritis is complex. This report reviews 40 patients who had monarticular rheumatoid arthritis in childhood and examines the diagnostic and prognostic aspects of the disease.

Abnormalities in the Distribution of Serum Immunoglobulin Concentrations in Juvenile Rheumatoid Arthritis

Concentrations of serum IgG. IgA, and IgM were determined in 200 patients with juvenile rheumatoid arthritis. The relative frequency distribution of IgG and IgM approached that of a log-normal curve; however, there was marked skewing of the distribution of the serum concentrations of IgA. The prevalence of selective IgA deficiency was 4%. In order to permit further intragroup comparisons, the serum immunoglobulin concentrations were standardized by comparison to a sex-age matched control group. By this process it was found that there was concordance of the serum levels of IgG with IgA, and IgG with IgM. The standardized concentrations of IgA and IgM were less in females than males. The aberration in distribution of serum IgA concentrations found in this study, and the relative inability of females to respond to their disease by increasing specific serum immunoglobulin levels, add further data supporting the concept of immunodeficiency in the pathogenesis of juvenile rheumatoid arthritis.

Renal papillary necrosis in juvenile rheumatoid arthritis

Three patients who developed renal papillary necrosis while receiving long-term, high-dose aspirin therapy for juvenile rheumatoid arthritis are presented. It appears that aspirin alone or aspirin in combination with other drugs is the causative agent. The incidence and biologic significance of renal papillary necrosis are insufficient to alter the use of aspirin as the drug of choice in management of JRA. It is recommended that all children with JRA be encouraged to drink ample fluids and be followed with periodic urinalysis and blood pressure measurements. Those children who develop hematuria or hypertension should be evaluated by excretory urography.