[Pediatric therapeutic options in autoimmune neurologic diseases]. / Opciones terapéuticas para enfermedades neurológicas autoinmunes en pediatría.

The pediatric neuroimmunology field has made significant progress in the last decade. Now, is possible to recognize primary demyelinating diseases, paraneoplastic syndromes, inflammatory (vasculitis), and granulomatous disorders that affect the central nervous system; at the same time, it is important to exclude neurologic manifestations caused by infections, toxic agents, and metabolic problems. An early diagnosis is imperative to institute treatment as soon as possible, improving outcomes. Treatment may include both, specific drugs if the etiology has been established, as well as drugs to treat potential complications, for example anticonvulsants, anti-inflammatory drugs, transfusions, or albumin replenishment within others. The main objective of this review is to provide guidance about the therapeutic options in pediatric autoimmune neurological diseases. We review the evidence and recommendations for the use of steroids in autoimmune demyelinating diseases, acute disseminated encephalomyelitis, optic neuritis, neuromyelitis optica, multiple sclerosis, among others. We will focus on current therapies, including high doses of intravenous methylprednisolone, followed by its progressive reduction, as well as intravenous immunoglobulin or plasmapheresis as second line therapies. Early institution of these treatments can save the patient's life and decrease their risk of permanent disability.

El campo de la pediatría neuro-inmunológica ha progresado significativamente en la última década. Ahora es posible reconocer con prontitud enfermedades desmielinizantes primarias, síndromes para-neoplásicos, enfermedades inflamatorias, autoinmunes y granulomatosas, que afectan el sistema nervioso central. Excluir con gran rapidez posibles causas infecciosas, agentes tóxicos, problemas metabólicos que se presenten con manifestaciones neurológicas es imperativo, ya que al hacer un diagnóstico preciso y temprano del paciente se puede instituir un tratamiento lo más pronto posible e incrementar las probabilidades de éxito. El tratamiento puede ser dirigido a la etiología específica, si se conoce. Adicionalmente, es importante tratar las complicaciones relacionadas a la propia enfermedad o efectos secundarios de los tratamientos que se impongan. El tratamiento puede incluir tanto fármacos específicos si se ha establecido la etiología, así como medicamentos para tratar posibles complicaciones, por ejemplo, anticonvulsivos, antiinflamatorios, transfusiones, o reposición de albúmina dentro de otros. El objetivo principal de esta revisión es brindar una guía sobre las opciones terapéuticas en enfermedades neurológicas autoinmunes en fase aguda. Revisamos la evidencia y recomendaciones acerca del uso de esteroides en enfermedades autoinmunes desmielinizantes, encefalomielitis aguda diseminada, neuritis óptica, neuromielitis óptica, esclerosis múltiple, entre otras, donde altas dosis de metilprednisolona, seguida por su disminución progresiva son esenciales, así como el uso de inmunoglobulina humana intravenosa y plasmaféresis, como tratamiento de segunda línea. La institución temprana de estos tratamientos puede salvar la vida del paciente y disminuir su discapacidad permanente.

Early changes in gene expression and inflammatory proteins in systemic juvenile idiopathic arthritis patients on canakinumab therapy.

BACKGROUND: Canakinumab is a human anti-interleukin-1ß (IL-1ß) monoclonal antibody neutralizing IL-1ß-mediated pathways. We sought to characterize the molecular response to canakinumab and evaluate potential markers of response using samples from two pivotal trials in systemic juvenile idiopathic arthritis (SJIA). METHODS: Gene expression was measured in patients with febrile SJIA and in matched healthy controls by Affymetrix DNA microarrays. Transcriptional response was assessed by gene expression changes from baseline to day 3 using adapted JIA American College of Rheumatology (aACR) response criteria (50 aACR JIA). Changes in pro-inflammatory cytokines IL-6 and IL-18 were assessed up to day 197. RESULTS: Microarray analysis identified 984 probe sets differentially expressed (≥2-fold difference; P < 0.05) in patients versus controls. Over 50% of patients with ≥50 aACR JIA were recognizable by baseline expression values. Analysis of gene expression profiles from patients achieving ≥50 aACR JIA response at day 15 identified 102 probe sets differentially expressed upon treatment (≥2-fold difference; P < 0.05) on day 3 versus baseline, including IL-1ß, IL-1 receptors (IL1-R1 and IL1-R2), IL-1 receptor accessory protein (IL1-RAP), and IL-6. The strongest clinical response was observed in patients with higher baseline expression of dysregulated genes and a strong transcriptional response on day 3. IL-6 declined by day 3 (≥8-fold decline; P < 0.0001) and remained suppressed. IL-18 declined on day 57 (≥1.5-fold decline, P ≤ 0.002). CONCLUSIONS: Treatment with canakinumab in SJIA patients resulted in downregulation of innate immune response genes and reductions in IL-6 and clinical symptoms. Additional research is needed to investigate potential differences in the disease mechanisms in patients with heterogeneous gene transcription profiles. TRIAL REGISTRATION: Clinicaltrials.gov: NCT00886769 (trial 1). Registered on 22 April 2009; NCT00889863 (trial 2). Registered on 21 April 2009.

Phenotypic Characterization of Juvenile Idiopathic Arthritis in African American Children.

OBJECTIVE: Juvenile idiopathic arthritis (JIA) affects children of all races. Prior studies suggest that phenotypic features of JIA in African American (AA) children differ from those of non-Hispanic white (NHW) children. We evaluated the phenotypic differences at presentation between AA and NHW children enrolled in the Childhood Arthritis and Rheumatology Research Alliance (CARRA) Registry, and replicated the findings in a JIA cohort from a large center in the southeastern United States. METHODS: Children with JIA enrolled in the multicenter CARRA Registry and from Emory University formed the study and replication cohorts. Phenotypic data on non-Hispanic AA children were compared with NHW children with JIA using the chi-square test, Fisher's exact test, and the Wilcoxon signed-rank test. RESULTS: In all, 4177 NHW and 292 AA JIA cases from the CARRA Registry and 212 NHW and 71 AA cases from Emory were analyzed. AA subjects more often had rheumatoid factor (RF)-positive polyarthritis in both the CARRA (13.4% vs 4.7%, p = 5.3 × 10(-7)) and the Emory (26.8% vs 6.1%, p = 1.1 × 10(-5)) cohorts. AA children had positive tests for RF and cyclic citrullinated peptide antibodies (CCP) more frequently, but oligoarticular or early onset antinuclear antibody (ANA)-positive JIA less frequently in both cohorts. AA children were older at onset in both cohorts and this difference persisted after excluding RF-positive polyarthritis in the CARRA Registry (median age 8.5 vs 5.0 yrs, p = 1.4 × 10(-8)). CONCLUSION: Compared with NHW children, AA children with JIA are more likely to have RF/CCP-positive polyarthritis, are older at disease onset, and less likely to have oligoarticular or ANA-positive, early-onset JIA, suggesting that the JIA phenotype is different in AA children.

Novel method to collect medication adverse events in juvenile arthritis: results from the childhood arthritis and rheumatology research alliance enhanced drug safety surveillance project.

OBJECTIVE: Few data are available regarding the rates of serious adverse events (SAEs) and important medical events (IMEs) outside of product-based registries and clinical trials for juvenile idiopathic arthritis (JIA). The Enhanced Drug Safety Surveillance Project (EDSSP) was developed to pilot a novel system to collect SAEs/IMEs in children with JIA. This analysis reports the results from this 4-year (2008-2012) EDSSP. METHODS: Participating physicians were surveyed monthly to ascertain whether their JIA patients experienced an SAE or IME. Sites were surveyed every 6 months to determine the number of unique JIA patients seen at each site during that 6-month period. Reporting rates were calculated per 100 person-years and 95% confidence intervals (95% CIs) were calculated based on a Poisson distribution. RESULTS: Thirty-seven Childhood Arthritis and Rheumatology Research Alliance sites with 115 physicians participated. The mean response rate to the monthly surveys was 65%. There were 147 total SAEs and 145 total IMEs. The largest proportion of SAEs and IMEs occurred in children with polyarticular JIA (39% and 37%, respectively). The majority of SAEs and IMEs were reported for patients receiving therapy with biologic agents (76% and 69%, respectively). The total event rate for SAEs and IMEs combined was 1.07 events per 100 person-years (95% CI 0.95-1.19). The rates for SAEs and IMEs were 0.54 per 100 person-years (95% CI 0.45-0.63) and 0.53 per 100 person-years (95% CI 0.49-0.62), respectively. CONCLUSION: The EDSSP provided a simple tool for SAE/IME reporting within an established research network and resulted in a similar range of reported events as captured by a traditional product-based registry.

Risk markers of juvenile idiopathic arthritis-associated uveitis in the Childhood Arthritis and Rheumatology Research Alliance (CARRA) Registry.

OBJECTIVE: To characterize the epidemiology and clinical course of children with juvenile idiopathic arthritis-associated uveitis (JIA-U) in the Childhood Arthritis and Rheumatology Research Alliance (CARRA) Registry and explore differences between African American (AA) and non-Hispanic white (NHW) children. METHODS: There were 4983 children with JIA enrolled in the CARRA Registry. Of those, 3967 NHW and AA children were included in this study. Demographic and disease-related data were collected from diagnosis to enrollment. Children with JIA were compared to those with JIA-U. Children with JIA-U were also compared by race. RESULTS: There were 459/3967 children (11.6%) with JIA-U in our cohort with a mean age (SD) of 11.4 years (± 4.5) at enrollment. Compared to children with JIA, they were younger at arthritis onset, more likely to be female, had < 5 joints involved, had oligoarticular JIA, and were antinuclear antibody (ANA)-positive, rheumatoid factor (RF)-negative, and anticitrullinated protein antibody-negative. Predictors of uveitis development included female sex, early age of arthritis onset, and oligoarticular JIA. Polyarticular RF-positive JIA subtype was protective. Nearly 3% of children with JIA-U were AA. However, of the 220 AA children with JIA, 6% had uveitis; in contrast, 12% of the 3721 NHW children with JIA had uveitis. CONCLUSION: In the CARRA registry, the prevalence of JIA-U in AA and NHW children is 11.6%. We confirmed known uveitis risk markers (ANA positivity, younger age at arthritis onset, and oligoarticular JIA). We describe a decreased likelihood of uveitis in AA children and recommend further exploration of race as a risk factor in a larger population of AA children.

Prevalence of the metabolic syndrome in children with psoriatic disease.

Adults with psoriasis have a greater risk of developing metabolic syndrome (MetS) and cardiovascular disease (CVD), but few studies have investigated the prevalence of MetS and other risk factors for CVD in children with psoriasis. In an assessor-blinded study, 20 children ages 9-17 years with a current or previously documented history of psoriasis involving 5% or more of their body surface area or psoriatic arthritis were compared with a cohort of age- and sex-matched controls with benign nevi, warts, or acne. MetS, our primary endpoint, was defined by the presence of abnormal values in at least three of the following measures: triglycerides, high-density lipoprotein cholesterol (HDL-C), fasting blood glucose (FBG), waist circumference, and blood pressure. Secondary endpoints included high-sensitivity C-reactive protein (hs-CRP), total cholesterol (TC), and low-density lipoprotein cholesterol (LDL-C). Thirty percent (6/20) of children with psoriasis met the criteria for MetS, compared with 5% (1/20) of the control group (p < 0.05). Subjects with psoriasis had higher mean FBG (91.1 mg/dL) than the control group (82.9 mg/dL) (p = 0.01). There were no statistically significant differences in the other four components of MetS, BMI, BMI percentile, hs-CRP, TC, or LDL-C. The results of this trial demonstrate that children with psoriasis have higher rates of MetS than age- and sex-matched controls. It may therefore be important to evaluate children with psoriasis for components of MetS to prevent future CVD morbidity and mortality.

Evaluation of the association between Hispanic ethnicity and disease activity and severity in a large cohort of patients with juvenile idiopathic arthritis.

To examine the association between ethnicity and disease activity in patients with juvenile idiopathic arthritis (JIA), and to determine the association of ethnicity with disease severity and disability in this population. CARRAnet, a US database containing information (collected between May 2010 and June 2011) on almost 3,000 subjects with JIA, was used. Demographic variables were compared between Hispanic patients and non-Hispanic patients. Mann-Whitney and chi-square tests were used to compare indicators of disease activity, as well as imaging evidence of joint damage, and Childhood Health Assessment Questionnaire (CHAQ) scores between ethnicities. Two linear regression models were used to determine the association of ethnicity with number of active joints in JIA, and the association between ethnicity and disability (CHAQ scores). A total of 2,704 patients with JIA (277 Hispanic; 2,427 non-Hispanic) were included. Income and health insurance coverage were higher in non-Hispanics. RF-positive polyarticular JIA, positive RF and anti-CCP, as well as use of systemic steroids were more frequent in Hispanics. Imaging evidence of joint damage was present in 32 % of the Hispanic patients compared to 24 % of the non-Hispanic patients (p = 0.008). In multivariate linear regression analyses, the number of active joints was significantly higher in Hispanics than in non-Hispanics (p = 0.03), as well as CHAQ scores (p = 0.003), after adjusting for confounders. Hispanic patients with JIA had higher disease activity than non-Hispanic patients, as well as higher disease severity and disability. Since ethnicity influences disease activity, severity, and disability, different management and treatment plans should be planned accordingly.

Obesity and disease activity in juvenile idiopathic arthritis.

BACKGROUND: Children with physical disabilities may have an increased risk for obesity and obesity might be a risk factor for inflammatory arthritis. The aims of this study were: to determine the prevalence of obesity in children and adolescents with juvenile idiopathic arthritis (JIA), and to examine the association between obesity and disease activity in this population. FINDINGS: A cross-sectional analysis of all patients with JIA attending a pediatric rheumatology clinic, between October 2009 and September 2010, was performed. A linear regression model was used to explore the association between obesity and disease activity in patients with JIA. A total of 154 subjects were included in the analysis; median age was 10.6 years, 61% were female, and 88% were white. Obesity was found in 18%, 12% were overweight, and 3% were underweight. There was no association between obesity and JADAS-27 (Juvenile Arthritis Disease Activity Score 27), physician's assessment of disease activity, parent's assessment of child's well-being, erythrocyte sedimentation rate, number of active joints, or C-reactive protein (p-value range 0.10 to 0.95). CONCLUSIONS: Although 18% of patients with JIA were obese, we did not find an association between obesity and disease activity. As obesity confers an additional health risk in children with arthritis, addressing this co-morbidity should be a health priority in patients with JIA. Future studies are necessary to further explore potential associations between obesity, development of JIA, and disease activity.

Consensus treatment plans for induction therapy of newly diagnosed proliferative lupus nephritis in juvenile systemic lupus erythematosus.

OBJECTIVE: To formulate consensus treatment plans (CTPs) for induction therapy of newly diagnosed proliferative lupus nephritis (LN) in juvenile systemic lupus erythematosus (SLE). METHODS: A structured consensus formation process was employed by the members of the Childhood Arthritis and Rheumatology Research Alliance after considering the existing medical evidence and current treatment approaches. RESULTS: After an initial Delphi survey (response rate = 70%), a 2-day consensus conference, and 2 followup Delphi surveys (response rates = 63-79%), consensus was achieved for a limited set of CTPs addressing the induction therapy of proliferative LN. These CTPs were developed for prototypical patients defined by eligibility characteristics, and included immunosuppressive therapy with either mycophenolic acid orally twice per day, or intravenous cyclophosphamide once per month at standardized dosages for 6 months. Additionally, the CTPs describe 3 options for standardized use of glucocorticoids, including a primarily oral, a mixed oral/intravenous, and a primarily intravenous regimen. There was consensus on measures of effectiveness and safety of the CTPs. The CTPs were well accepted by the pediatric rheumatology providers treating children with LN, and up to 300 children per year in North America are expected to be candidates for the treatment with the CTPs. CONCLUSION: CTPs for induction therapy of proliferative LN in juvenile SLE based on the available scientific evidence and pediatric rheumatology group experience have been developed. Consistent use of the CTPs may improve the prognosis of proliferative LN, and support the conduct of comparative effectiveness studies aimed at optimizing therapeutic strategies for proliferative LN in juvenile SLE.

25-hydroxyvitamin D levels and juvenile idiopathic arthritis: is there an association with disease activity?

The aims of this study were to examine the association between serum levels of 25-hydroxyvitamin D [25(OH)D] and disease activity in juvenile idiopathic arthritis (JIA), to determine the prevalence of vitamin D (VD) deficiency [25(OH)D ≤ 19 ng/ml] and insufficiency [25(OH)D 20-29 ng/ml], and to determine factors associated with lower serum levels of 25(OH)D in this population. In this cross-sectional study, disease activity was measured using JADAS-27, as well as its individual components (physician global assessment of disease activity, parent global assessment of child's well-being, count of joints with active disease, and erythrocyte sedimentation rate). Linear regression models were developed to analyze the association between serum 25(OH)D levels and JADAS-27 and to determine variables associated with serum 25(OH)D levels. A total of 154 patients (61% girls, 88% whites) were included. Mean age was 10.6. VD deficiency was detected in 13% and insufficiency in 42%. In univariate and multivariate analyses, 25(OH)D levels were not associated with JADAS-27, neither with its individual components. However, in a subset analysis including all new-onset JIA patients (n = 27), there was a nonsignificant negative correlation between serum 25(OH)D levels and JADAS-27 (r = -0.29, P = 0.14). In the univariate and multivariate analyses, age, ethnicity, BMI, and season were significantly associated with serum 25(OH)D levels, but not total VD intake. More than 1/2 of JIA patients had serum 25(OH)D levels below 29 ng/ml; however, there was no association between serum 25(OH)D levels and disease activity. Future larger, long-term studies with new-onset JIA patients are needed to further explore the association between serum 25(OH)D levels and disease activity.

Adherence to methotrexate in juvenile idiopathic arthritis.

Non-adherence to treatments for chronic diseases may jeopardize patients' health, increase costs of care, and cause unnecessary clinic appointments and diagnostic studies, as well as additional treatments with potentially serious side effects. Little is known about adherence to methotrexate in pediatric rheumatology. Because this medication is commonly used in JIA, we assessed adherence among children receiving methotrexate in two countries. A total of 76 outpatients (M:F 21:55) with JIA seen in Rio de Janeiro (Brazil) and in Boston (US) taking methotrexate for >2 months were enrolled. Questionnaires were completed by the parents from both centers. Non-adherence was defined as omission of ≥3 prescribed doses in the previous 8 weeks. Patients' ages ranged from 1 to 17 years. Mean time on methotrexate was 20.5 months (±25). Overall rate of non-adherence was 18%. The rate of reported non-adherence was 8% in Boston and 24% in Rio de Janeiro (P = 0.012). The main reason for non-adherence in Boston was "child refused"; in Rio de Janeiro, the main reason was inability to obtain medication. Age had a negative association with adherence (P < 0.0001). Sex, time on methotrexate, route of administration, or concomitant use of other medications were not associated with adherence. Eighteen percent of children with JIA prescribed methotrexate were non-compliant. The difference in reasons for poor adherence between patients in Rio de Janeiro and Boston suggests that different strategies may be needed to improve adherence in these 2 settings. The rate of non-adherence warrants further investigation.

25-hydroxyvitamin D levels and vitamin D deficiency in children with rheumatologic disorders and controls.

OBJECTIVE: To evaluate the prevalence of vitamin D deficiency, as well as factors associated with serum 25-hydroxyvitamin D [25(OH)D] levels, in children attending a pediatric rheumatology clinic, and to determine whether there was a difference in serum 25(OH)D levels and in vitamin D deficiency between children with autoimmune disorders and nonautoimmune conditions. METHODS: Cross-sectional analysis of serum 25(OH)D levels of patients between the ages of 2 and 19 years, seen between November 2008 and October 2009. RESULTS: A total of 254 patients were studied (169 autoimmune disorders, 85 nonautoimmune conditions). The mean age of study patients was 12.3 years; 67% were female and 80% were white. In the autoimmune disorders group, 23% had vitamin D deficiency [serum 25(OH)D < 20 ng/ml], and in the nonautoimmune conditions group 14% were vitamin D deficient. The average level of serum 25(OH)D was 28.6 (± 11) ng/ml (range 2 to 59). Age, ethnicity, body mass index, use of supplements, and season were significantly associated with serum levels of 25(OH)D (all p ≤ 0.02). The OR of patients with autoimmune disorders being vitamin D deficient was 2.3, in relation to patients with nonautoimmune conditions (p = 0.04). CONCLUSION: Twenty percent of patients attending a pediatric rheumatology clinic were vitamin D deficient. Patients with autoimmune disorders were more likely to be vitamin D deficient than patients with nonautoimmune conditions. Screening of serum 25(OH)D levels should be performed for patients with autoimmune disorders.

Unusual finding in pediatric Churg-Strauss: renal lesions on CT.

After a 19-year-old female experienced several weeks of unrelieved fevers, an abdominal CT revealed multiple low-attenuation renal lesions. As the differential included lymphoma, infections and infarcts, a core biopsy of the kidney was performed, which revealed changes consistent with Churg-Strauss syndrome.

Adherence to secondary prophylaxis and disease recurrence in 536 Brazilian children with rheumatic fever.

BACKGROUND: More than 15 million people worldwide have rheumatic fever (RF) and rheumatic heart disease due to RF. Secondary prophylaxis is a critical cost-effective intervention for preventing morbidity and mortality related to RF. Ensuring adequate adherence to secondary prophylaxis for RF is a challenging task. This study aimed to describe the rates of recurrent episodes of RF, quantify adherence to secondary prophylaxis, and examine the effects of medication adherence to the rates of RF in a cohort of Brazilian children and adolescents with RF. METHODS: This retrospective study took place in the Pediatric Rheumatology outpatient clinic at a tertiary care hospital (Instituto de Puericultura e Pediatria Martagão Gesteira) in Rio de Janeiro, Brazil, and included patients with a diagnosis of RF from 1985 to 2005. RESULTS: 536 patients with RF comprised the study sample. Recurrent episodes of RF occurred in 88 of 536 patients (16.5%). Patients with a recurrent episode of RF were younger (p < 0.0001), more frequently males (p = 0.003), and less adherent (p < 0.0001) to secondary prophylaxis than patients without RF recurrence. Non-adherence to medication at any time during follow-up was detected in 35% of patients. Rates of non-adherence were higher in the group of patients that were lost to follow-up (42%) than in the group of patients still in follow-up (32%) (p = 0.027). Appointment frequency was inadequate in 10% of patients. Higher rates of inadequate appointment frequency were observed among patients who were eventually lost to follow-up (14.5%) than in patients who were successfully followed-up (8%) (p = 0.022). 180 patients (33.5%) were lost to follow up at some point in time. CONCLUSIONS: We recommend implementation of a registry, and a system of active search of missing patients in every service responsible for the follow-up of RF patients. Measures to increase adherence to secondary prophylaxis need to be implemented formally, once non-adherence to secondary prophylaxis is the main cause of RF recurrence. Detection of irregularity in secondary prophylaxis or in appointments should be an alert about the possibility of loss of follow-up and closer observation should be instituted.

Vitamin D and autoimmune rheumatologic disorders.

Vitamin D levels depend on many variables, including sun exposure, age, ethnicity, body mass index, use of medications and supplements. A much higher oral vitamin D intake than the current guidelines is necessary to maintain adequate circulating 25(OH)D levels in the absence of UVB radiation of the skin. In addition to the traditional known metabolic activities, vitamin D has been shown to modulate the immune system, and its deficiency has been linked to the development of several autoimmune disorders including type 1 diabetes and multiple sclerosis. Experimental use of vitamin D has revealed a novel role in the immunopathogenesis of autoimmune diseases. Disorders such as systemic lupus erythematosus, rheumatoid arthritis, Behçet's, polymyositis/dermatomyositis and systemic scleroderma have all been associated to some extent to vitamin D deficiency. If vitamin D deficiency occurs at a higher rate in patients with autoimmune disorders, then appropriate supplementation may be indicated.

Erroneous diagnoses in children referred with acute rheumatic fever.

We reviewed 53 patients referred to a pediatric rheumatology clinic in Asuncion, Paraguay. In 6 patients, a diagnosis of rheumatic fever was confirmed and in 47 patients other clinically significant diagnoses were made. Eighteen children had nonspecific findings and did not develop a rheumatologic condition on follow-up. Overdiagnosis of rheumatic fever can falsely inflate incidence and prevalence statistics and clinically significant diagnoses may be overlooked.

Prediction of resource use during acute pediatric illnesses.

BACKGROUND: Significant resources are used for acute illnesses in children. Identifying predictors of resource use can focus interventions to reduce this use. OBJECTIVE: To determine the relative effects of maternal, infant, social milieu, and demographic characteristics, the mother-child interaction, and perception of illness severity on the use of resources during acute illnesses in children. DESIGN: At the 2-week and 6-, 15-, and 24-month well-child care visits of a cohort of mother-infant dyads, the mother-well-child interaction was assessed by using the Biringen Emotional Availability Scales, and data were gathered regarding maternal depression and sense of competence, infant temperament, maternal social support, the home environment, and demographic characteristics. At each of the cohort's 1983 ill-child care visits during 30 months of follow-up, the mother-ill-child interaction was assessed by using the Emotional Availability Scales, and mothers and pediatricians independently assessed illness severity using the Acute Illness Observation Scales. Resources used during the illnesses-over-the-counter and prescription medications, tests, hospitalizations, follow-up visits, and the emergency department-were assessed. SETTING: A hospital primary care center and an urban and a suburban private practice. Patients Between February 1, 1995, and March 30, 1998, a consecutive sample of 380 dyads were asked to enroll at the 2-week well-child care visit; 316 (83.2%) consented, and complete data were available for analysis of 243 dyads. MAIN OUTCOME MEASURES: A path analytic framework using a structural equation model assessed the presence and strength of predictive relationships between demographic, maternal, infant, and social milieu data, the Biringen Emotional Availability Scales, and the Acute Illness Observation Scales and the main outcome measure, resource use. RESULTS: Three variables predicted greater mean resource use during each acute illness episode: a less optimal mother-child interaction (beta = -.53), lower scores for parenting sense of competence (beta = -.26), and greater perception of illness severity by mothers (beta =.33). By using the coefficient of determination (R2), these 3 predictors account for 55% of the reliable variance in resource use during acute illnesses. CONCLUSION: The quality of the mother-child interaction, maternal sense of competence, and maternal assessment of severity of the illness are major predictors of resource use during acute pediatric illnesses, and should be important foci of interventions to reduce resource use.