Current Review of Systemic Juvenile Idiopathic Arthritis: What Do Paediatricians Need to Know?

Systemic juvenile idiopathic arthritis is classified as an autoimmune entity and a subtype of juvenile idiopathic arthritis, although it has many features of autoinflammatory-type of diseases. This review article will elaborate on the disease’s pathogenesis and its proposed relation to autoinflammatory diseases including defective innate immunity and phagocytosis response leading excessive cytokine release. It also explains the disease’s epidemiology, clinical phenotype, diagnostic challenges, complications and current advancements in the treatment of systemic juvenile idiopathic arthritis, such as IL-1 and IL-6 antagonists and their impact on the disease trajectory. Care of patients with systemic juvenile idiopathic arthritis requires a comprehensive multidisciplinary team to optimize the care and avoid complications of the disease itself such as growth impairment, macrophage activation syndrome or the complications of immunosuppressant and immunomodulatory treatments.

Macrophage activation syndrome as a complication of dermatomyositis: A case report

BACKGROUND Macrophage activation syndrome(MAS)can be a fatal complication of rheumatic disorders,which occurs most commonly in patients with systemic juvenile idiopathic arthritis or systemic lupus erythematosus.It has rarely been reported in patients with dermatomyositis.Here,we describe a fatal case of MAS that developed in an adult patient with dermatomyositis.CASE SUMMARY A 44-year-old woman was admitted to our hospital with fever,generalized rash and muscle weakness.Fifteen days later,the fever persisted after the use of antibiotics,and repeat blood culture was negative.The patient then exhibited a typical Gottron sign and diffuse erythema on the face and neck,which were consistent with a diagnosis of dermatomyositis.The patient exhibited limb muscle strength of 2,and electromyography was suggestive of muscle-derived damage,which also supported a diagnosis of dermatomyositis.In addition,the patient exhibited high serum ferritin level,cytopenia,liver dysfunction,coagulopathy,enlarged spleen and hypertriglyceridemia,all of which are typical manifestations of MAS.The patient was diagnosed with dermatomyositis complicated by MAS.Although a high dose of methylprednisolone was administered for 15 d,the patient’s condition continued to deteriorate and central nervous system symptoms developed.Eventually,treatment was discontinued,and the patient died.CONCLUSION MAS is an important,potentially fatal,complication of dermatomyositis.Although MAS is rare in dermatomyositis,it should be considered in the differential diagnosis of an unexplained change of hemoglobin,platelet,fibrinogen,ferritin and triglyceride,which may complicate dermatomyositis.

Clinical and laboratory features,treatment,and outcomes of macrophage activation syndrome in 80 children:a multi-center study in China

Background Macrophage activation syndrome(MAS)is a major cause of morbidity and mortality in pediatric rheumatology.We aimed to further understand the clinical features,treatment,and outcome of MAS in China.Methods A multi-center cohort study was performed in seven hospitals in China from 2012 to 2018.Eighty patients with MAS were enrolled,including 53 cases with systemic juvenile idiopathic arthritis(SJIA-MAS),10 cases of Kawasaki disease(KD-MAS),and 17 cases of connective tissue disease(CTD-MAS).The clinical and laboratory data were collected before(pre-),at onset,and during full-blown stages of MAS.We compared the data among the SJIA-MAS,KD-MAS,and CTD-MAS subjects.Results 51.2%of patients developed MAS when the underlying disease was first diagnosed.In patients with SJIA,22.6%(12/53)were found to have hypotension before the onset of SJIA-MAS.These patients were also found to have significantly increased aspartate aminotransferase(AST)and lactate dehydrogenase(LDH),as well as decreased albumin(P<0.05),but no difference in alanine aminotransferase,ferdtin,and ratio of ferritin/erythrocyte sedimentation rate(ESR)at onset of MAS when compared to pre-MAS stages of the disease.In addition,ferritin and ratio of ferritin/ESR were significantly elevated in patients at full-blown stages of SJIA-MAS compared to pre-MAS stage.Significantly increased ferritin and ratio of ferritin/ESR were also observed in patients with SJIA compared to in KD and CTD.Receiver-operating characteristic analysis showed that 12,217.5μg/L of ferritin and 267.5 of ferritin/ESR ratio had sensitivity(80.0%and 90.5%)and specificity(88.2%and 86.7%),respectively,for predicting full-blown SJIA-MAS.The majority of the patients received corticosteroids(79/80),while biologic agents were used in 12.5%(10/80)of cases.Tocilizumab was the most commonly selected biologic agent.The overall mortality rate was 7.5%.Conclusions About half of MAS occurred when the underlying autoimmune diseases(SJIA,KD,and CTD)were first diagnosed.Hypotension could be an important manifestation before MAS diagnosis.Decreased albumin and increased AST,LDH,ferritin,and ratio of ferritin/ESR could predict the onset or full blown of MAS in patient with SJIA.