Systemic lupus erythematosus (SLE) is a chronic and complex autoimmune disease which causes systemic inflammation and may involve any organ system. Childhood-onset SLE (cSLE) is rare, with an incidence of 0.36-0.9 per 100,000 children and a prevalence of 1.9-25.7 per 100,000 children-years worldwide. For classification of SLE the recently published European League Against Rheumatism (EULAR)/American College of Rheumatology (ACR) classification criteria can be used, which include occurrence of antinuclear antibodies (ANA) on at least one occasion, and additive clinical/immunological criteria. Validation of the recently published EULAR/ACR classification criteria in cSLE has only just begun, therefore the Systemic Lupus International Collaborating Clinics (SLICC) SLE classification criteria (published in 2012, validated in cSLE) are still more widely used. Most children with SLE are
diagnosed in adolescence, and the occurrence in young children (under 10 years) is rare. Early aggressive treatment with immunosuppressive treatment is required with specific attention for limiting exposure to corticosteroids, as these have been consistently associated with the development of damage. Mortality rates in cSLE have decreased significantly over the past two decades with 10-15 years survival rate exceeding 85-90%. However, with a median age of disease onset around 12 years, this means that by 25-30 years of age, up to 15% of cSLE patients will have died. The overall standardized mortality rate in SLE is 2.2 (across all ages), however in patients under the age of 18, the SMR is approximately three times higher at 6.5.
Specific attention for renal disease in cSLE is important as lupus nephritis is present in 50-60% of pediatric cases. When compared to adult-onset disease, lupus nephritis is more common in children with SLE, occurring earlier in disease course (the majority within 2 years after diagnosis) and with increased severity. Children with lupus nephritis accrue more renal organ damage than adults with SLE, with higher rates of children requiring dialysis and renal transplantation. Two of the main risk factors for death in SLE are disease onset in childhood and the development of renal disease, highlighting that lupus nephritis in children is a severe and potentially life-threatening disease. Renal abnormalities indicative of lupus nephritis includes renal failure, hypertension, macroscopic/microscopic hematuria and/or proteinuria. Renal biopsy should be performed in all patients with suspected renal disease, with the histological classification of lupus nephritis guiding treatment choices as clinical symptoms are not reliable enough to reflect severity of renal disease. Timely and accurate recognition of renal involvement combined with appropriate treatment are essential for prevention of renal damage associated mortality.
Guidance for lupus nephritis in children can be found in the recently published ‘European evidencebased recommendations for diagnosis and treatment of lupus nephritis in cSLE (2017). These recommendations are the first to specifically focus on evidence in cSLE with systematically reviewing the literature relating to diagnosis and treatment of all classes of lupus nephritis in children. These recommendations support clinicians caring for children with suspected lupus nephritis, taking them through a diagnostic process and guiding them in treatment choices and decision-making. A flowchart with preferred options for a management strategy and immunosuppressive medication is presented to guide treatment. Country-specific reimbursement policies however likely limit the application of this flowchart in a real-life setting in many countries. This has not been accounted for in these recommendations. Adding to this, as there is no robust evidence for the ideal dosing and tapering strategies of corticosteroids, the expert group only presented possible induction and tapering corticosteroid treatment regimens. This is troublesome as corticosteroids cause significant damage that extend into adulthood. The next step is to translate these recommendations into ready to use lupus nephritis management plans for clinical practice that are agreed upon and applicable in varying medical systems and country-specific reimbursement policies.
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