Ferritin levels in children with juvenile idiopathic arthritis of systemic onset and children with other causes of fever of unknown origin: A multicenter study of diagnostic tests / Niveles de ferritina en artritis idiopática juvenil de inicio sistémico comparada con otras fiebres de origen desconocido: estudio multicéntrico de pruebas diagnósticas

Introduction: There are no sensitive or specific tests available to diagnose systemic juvenile idiopathic arthritis (sJIA). Objective: To assess the utility as diagnostic tests of total ferritin (TF) levels greater than 5 times the normal value (TF>5N) and the decreased percentage (less than or equal to 20% of TF) of glycosylated ferritin (GF≤20%) for the diagnosis of sJIA in patients with fever of unknown origin evaluated by pediatric rheumatology. Materials and methods: We conducted an observational, cross-sectional study of diagnostic tests in children under 16 years of age hospitalized between 2010 and 2014. The reference diagnostic standard was the fulfillment of the classification criteria or confirmed diagnosis at follow-up. We determined the measures of utility of the tests. Results: We included 40 patients with fever of unknown origin, 11 with sJIA, and 29 with other diagnoses. The median TF was higher in sAIJ (3992 ng/ml) versus other causes of fever of unknown origin (155 ng/ml) (p=0.0027), as well as TF>5N (90.91% versus 51.72%) (p=0.023). The percentage of GF≤20% was higher in patients with other causes of fever of unknown origin (96.5%) compared to sJIA (81.8%) (p=0.178). TF>5N had a sensitivity of 91%, specificity of 48%, positive likelihood ratio (LR) of 1.76, and negative LR of 0.19 demonstrating greater utility for the diagnosis of sJIA than the combination of FT> 5N with GFR <20%, with a sensitivity of 81.8%, specificity of 48.3%, positive LR of 1.58, and negative LR of 0.38. Conclusion: In patients with FUO evaluated by pediatric rheumatology, TF> 5N proved useful as a screening test for the diagnosis of sJIA.

Introducción. No se dispone de pruebas sensibles ni específicas para diagnosticar la artritis idiopática juvenil sistémica. Objetivo. Evaluar la utilidad diagnóstica de niveles de ferritina total cinco veces por encima del valor normal (ferritina total>5N) y el porcentaje disminuido (menor de o igual a 20 % de la ferritina total) de la ferritina glucosilada (ferritina glucosilada<20 %) para el diagnóstico de artritis idiopática juvenil sistémica en pacientes con fiebre de origen desconocido evaluados por reumatología pediátrica. Materiales y métodos. Se hizo un estudio observacional de pruebas diagnósticas de corte transversal en menores de 16 años hospitalizados entre el 2010 y el 2014. El patrón diagnóstico de referencia fue el cumplimiento de los criterios de clasificación o diagnóstico confirmado en el seguimiento. Se determinaron las medidas de utilidad de las pruebas. Resultados. Se incluyeron 40 pacientes con fiebre de origen desconocido: 11 con artritis idiopática juvenil sistémica y 29 con otros diagnósticos. La mediana de la ferritina total fue mayor en la artritis idiopática juvenil sistémica (3.992 ng/ml) comparada con otras causas de fiebre de origen desconocido (155 ng/ml) (p=0,0027), así como la ferritina total>5N (90,91 % Vs. 51,72 %) (p=0,023). El porcentaje de ferritina glucosilada≤20 % fue de 96,5 % en otras fiebres de origen desconocido en comparación con la artritis idiopática juvenil sistémica (81,8 %) (p=0,178). La ferritina total>5N tuvo una sensibilidad del 91 %, una especificidad del 48 %; un cociente de probabilidades (Likelihood Ratio, LR) positivo de 1,76 y uno negativo de 0,19, demostrando mayor utilidad para el diagnóstico que la combinación de la ferritina total>5N y ferritina glucosilada≤20 %, cuya sensibilidad fue del 81,8 %, la especificidad del 48,3 %, un cociente de probabilidades LR positivo de 1,58 y un LR negativo de 0,38. Conclusión. En pacientes con fiebre de origen desconocido evaluados por reumatología pediátrica, la ferritina total>5N demostró ser útil como prueba de tamización para el diagnóstico de artritis idiopática juvenil sistémica.

Niveles de ferritina en artritis idiopática juvenil de inicio sistémico comparada con otras fiebres de origen desconocido: estudio multicéntrico de pruebas diagnósticas / Ferritin levels in children with juvenile idiopathic arthritis of systemic onset and children with other causes of fever of unknown origin: A multicenter study of diagnostic tests

Resumen | Introducción. No se dispone de pruebas sensibles ni específicas para diagnosticar la artritis idiopática juvenil sistémica. Objetivo. Evaluar la utilidad diagnóstica de niveles de ferritina total cinco veces por encima del valor normal (ferritina total>5N) y el porcentaje disminuido (menor de o igual a 20 % de la ferritina total) de la ferritina glucosilada (ferritina glucosilada<20 %) para el diagnóstico de artritis idiopática juvenil sistémica en pacientes con fiebre de origen desconocido evaluados por reumatología pediátrica. Materiales y métodos. Se hizo un estudio observacional de pruebas diagnósticas de corte transversal en menores de 16 años hospitalizados entre el 2010 y el 2014. El patrón diagnóstico de referencia fue el cumplimiento de los criterios de clasificación o diagnóstico confirmado en el seguimiento. Se determinaron las medidas de utilidad de las pruebas. Resultados. Se incluyeron 40 pacientes con fiebre de origen desconocido: 11 con artritis idiopática juvenil sistémica y 29 con otros diagnósticos. La mediana de la ferritina total fue mayor en la artritis idiopática juvenil sistémica (3.992 ng/ml) comparada con otras causas de fiebre de origen desconocido (155 ng/ml) (p=0,0027), así como la ferritina total>5N (90,91 % Vs. 51,72 %) (p=0,023). El porcentaje de ferritina glucosilada≤20 % fue de 96,5 % en otras fiebres de origen desconocido en comparación con la artritis idiopática juvenil sistémica (81,8 %) (p=0,178). La ferritina total>5N tuvo una sensibilidad del 91 %, una especificidad del 48 %; un cociente de probabilidades (Likelihood Ratio, LR) positivo de 1,76 y uno negativo de 0,19, demostrando mayor utilidad para el diagnóstico que la combinación de la ferritina total>5N y ferritina glucosilada≤20 %, cuya sensibilidad fue del 81,8 %, la especificidad del 48,3 %, un cociente de probabilidades LR positivo de 1,58 y un LR negativo de 0,38. Conclusión. En pacientes con fiebre de origen desconocido evaluados por reumatología pediátrica, la ferritina total>5N demostró ser útil como prueba de tamización para el diagnóstico de artritis idiopática juvenil sistémica.

Abstract | Introduction: There are no sensitive or specific tests available to diagnose systemic juvenile idiopathic arthritis (sJIA). Objective: To assess the utility as diagnostic tests of total ferritin (TF) levels greater than 5 times the normal value (TF>5N) and the decreased percentage (less than or equal to 20% of TF) of glycosylated ferritin (GF≤20%) for the diagnosis of sJIA in patients with fever of unknown origin evaluated by pediatric rheumatology. Materials and methods: We conducted an observational, cross-sectional study of diagnostic tests in children under 16 years of age hospitalized between 2010 and 2014. The reference diagnostic standard was the fulfillment of the classification criteria or confirmed diagnosis at follow-up. We determined the measures of utility of the tests. Results: We included 40 patients with fever of unknown origin, 11 with sJIA, and 29 with other diagnoses. The median TF was higher in sAIJ (3992 ng/ml) versus other causes of fever of unknown origin (155 ng/ml) (p=0.0027), as well as TF>5N (90.91% versus 51.72%) (p=0.023). The percentage of GF≤20% was higher in patients with other causes of fever of unknown origin (96.5%) compared to sJIA (81.8%) (p=0.178). TF>5N had a sensitivity of 91%, specificity of 48%, positive likelihood ratio (LR) of 1.76, and negative LR of 0.19 demonstrating greater utility for the diagnosis of sJIA than the combination of FT> 5N with GFR <20%, with a sensitivity of 81.8%, specificity of 48.3%, positive LR of 1.58, and negative LR of 0.38. Conclusion: In patients with FUO evaluated by pediatric rheumatology, TF> 5N proved useful as a screening test for the diagnosis of sJIA.

Síndrome de activación de macrofágica como complicación de la artritis idiopática juvenil sistémica / Macrophage activation syndrome as a complication of systemic juvenile idiopathic arthritis

RESUMEN La artritis idiopática juvenil sistémica, también conocida como enfermedad de Still, se considera un trastorno autoinflamatorio y suele ser la más compleja y grave entre todas las formas clínicas de la enfermedad. Cursa generalmente en forma de brotes de actividad repetidos, intercalados por periodos de remisión. Se presenta el caso de una paciente femenina de 4 años de edad, con diagnóstico de enfermedad de Still a los 2 años. Actualmente tiene tratamiento con triple terapia de inducción: cloroquina, metotrexato y salazosulfapiridina con actividad de la enfermedad persistentemente alta por JADAS 27. Acudió a consulta por presentar fiebre, toma del estado general y manifestaciones respiratorias de tres días de evolución que se interpretó como una infección respiratoria baja. Se prescribió tratamiento con antibióticos sin signos de mejoría. A los 7 días se agravó el cuadro clínico y se planteó el diagnóstico de síndrome de activación macrofágica. Se comenzó protocolo de tratamiento con esteroides en combinación con otros fármacos de probada eficacia para esta situación clínica (etopósido, ciclosporina, metotrexato). Se revaloró política de antibióticos sin lograrse respuesta satisfactoria y se decidió introducir el rituximab que aporta excelentes resultados. Después de 3 meses de difícil manejo, la paciente egresó del hospital recuperada de esta complicación y con bajo nivel de actividad de la enfermedad de base.

ABSTRACT Systemic Juvenile Idiopathic Arthritis, also known as Still's disease, is considered an autoinflammatory disorder and is often the most complex and severe of all clinical forms of the disease. It usually takes the form of repeated bouts of activity, interspersed with periods of remission. We present the case of a 4-year-old female patient, diagnosed with Still's disease at 2 years of age. Currently undergoing treatment with triple induction therapy: chloroquine, methotrexate and salazosulfapyridine with persistently high disease activity due to JADAS 27. He comes to the clinic due to fever, general condition, and respiratory manifestations of three days of evolution interpreted as an infectious respiratory process under. Antibiotic treatment is started without signs of improvement. At 7 days the clinical picture worsens, and the diagnosis of Macrophage Activation Syndrome is raised. A steroid treatment protocol is started in combination with other drugs of proven efficacy for this clinical situation (ethopside, cyclosporine, methotrexate). Antibiotic policy was reassessed without achieving a satisfactory response and it was decided to introduce rituximab, which provides excellent results. After three months of difficult management, the patient was released from the hospital recovered from this complication and with a low level of activity of the underlying disease.

Sudden Hypotension and Increased Serum Interferon-γ and Interleukin-10 Predict Early Macrophage Activation Syndrome in Patients with Systemic Juvenile Idiopathic Arthritis.

OBJECTIVE: To identify clinical and laboratory predictors for early macrophage activation syndrome (MAS) associated with systemic juvenile idiopathic arthritis (sJIA). STUDY DESIGN: This is a retrospective cohort study of 149 patients with sJIA, of whom 27 had 31 episodes of MAS. We evaluated the clinical and laboratory features of patients with sJIA and MAS and compared them with those without MAS. We focused our analysis on the overall process of MAS development, especially MAS onset. RESULTS: As shown in previous studies, we found a high percentage of fever, absence of arthritis, and central nervous system dysfunction at MAS onset in our study cohort. We also found that 35% of patients with MAS had hypotension although not shock, and 22.6% of patients with MAS had gastrointestinal involvement at MAS onset. Compared with patients with MAS without hypotension, patients with MAS and hypotension had greater rates of admission to the intensive care unit; presented with more arthritis, serositis, pneumonia, and gastrointestinal involvement; and had greater white blood cell and absolute neutrophil counts and serum bilirubin levels and lower serum total protein. We confirmed laboratory markers such as platelet counts, lactate dehydrogenase, and aspartate aminotransferase can help to identify early MAS and that ferritin/erythrocyte sedimentation rate ratio of approximately 20.0 had a high diagnostic sensitivity and specificity for MAS. In addition, we discovered that the combination of interferon-γ >17.1 pg/mL and interleukin-10 >7.8 pg/mL appeared to be a good cytokine pattern for the recognition of MAS onset. CONCLUSIONS: Sudden hypotension, elevated ferritin/erythrocyte sedimentation rate ratio, and the cytokine pattern of significantly increased interferon-γ and interleukin-10 levels are important markers for early identification of MAS in addition to the traditional characteristics of sJIA-associated MAS.

Predictors of Effectiveness of Anakinra in Systemic Juvenile Idiopathic Arthritis.

OBJECTIVE: To seek predictors of therapeutic response to the interleukin (IL)-1 inhibitor anakinra in children with systemic-onset juvenile idiopathic arthritis (sJIA). METHODS: The clinical charts of all patients with sJIA who were newly treated with anakinra at our center between 2004 and 2017 were reviewed retrospectively. Predictors included baseline demographic, clinical, and laboratory variables as well as previous or concomitant therapies. The effectiveness of anakinra was assessed at 1 year after treatment start. Complete clinical response (CCR) was defined as absence of fever, physician's global assessment ≤ 1, count of active joints ≤ 1, negative C-reactive protein, and ≥ 75% reduction of corticosteroid dose. According to the intention-to-treat principle, patients who had anakinra discontinued before 1 year for any reasons other than disease remission were classified as nonresponders. Statistics included univariate and multivariable analyses. RESULTS: Of the 62 patients included in the study, 24 (39%) met the criteria for CCR at 1 year, whereas 38 (61%) did not. On multivariable analysis, independent correlations with achievement of CCR were identified for shorter disease duration, lower active joint count, higher ferritin level, and greater activity of systemic manifestations. The area under the curve of the model was 0.83. CONCLUSION: Our findings help to delineate the clinical profile of patients with sJIA who are more likely to benefit from IL-1 blockade. They also underscore the need for studies aimed at examining the therapeutic role of early IL-1 inhibition and to identify biomarkers predicting response to either IL-1 or IL-6 antagonists.