Severe Thrombocytopenia as Initial Signs of Primary Sjögren Syndrome in a 9-Year-Old Female

Kidney manifestations of pediatric Sjögren's syndrome

Approximately 1% of all patients with Sjögren's syndrome (SS) are children. Unlike the adult form, in which sicca syndrome is the main presentation, in children, the most common clinical finding is recurrent enlargement of the salivary glands. In pediatric SS, extraglandular manifestations represent a significant feature and, among these, kidney manifestations are relevant. Kidney involvement is observed in 5-20.5% of children with SS, most frequently tubulointerstitial nephritis. This injury can lead to serious phenotypes, including distal kidney tubular acidosis with the development of severe hypokalemia, which can lead to ECG abnormalities, weakness, and hypokalemic periodic paralysis. Kidney implications in pediatric SS also include nephrolithiasis, nephrocalcinosis, and various types of glomerular damage, which often require immunosuppressive therapies. Laboratory findings are usually comparable to adults, including hyperglobulinemia and high rates of antinuclear antibodies (ANA, 63.6-96.2%), and anti-Ro/SSA (36.4-84.6%). The current classification criteria for SS are inaccurate for the pediatric population, and more specific criteria are needed to improve the diagnostic rate. Due to the rarity of the disease, strong recommendations for treatment are lacking, and several therapeutic strategies have been reported, mostly based on glucocorticoids and disease-modifying antirheumatic drugs, with different outcomes. The aim of this paper is to provide an overview of the kidney implications of pediatric SS based on the latest evidence of the medical literature.

Unique Aspects of Pediatric Sjögren Disease

Sjögren disease increasingly is recognized in pediatric patients. Clinical features, primarily parotitis and sicca symptoms, and results of diagnostic tests may be different from those in adult disease. Adult criteria fail to capture most pediatric patients. Pediatric-specific criteria are urgently needed to define the natural history of the disease, identify risk and prognostic factors, and evaluate the impact of therapeutics and other interventions on disease course in young patients.

Childhood Sjogren's syndrome: An Italian case series and a literature review-based cohort

OBJECTIVE

Sjogren's syndrome (SS) is a chronic autoimmune disease with a highly variable presentation. This study aims to describe childhood SS (cSS) features to help guide clinicians in their consideration of and workup for cSS.

METHODS

We retrospectively reviewed medical records of patients with cSS referred to three Italian pediatric rheumatology centers from 2015 to 2019 and we conducted a literature review of cSS. Statistical analysis was performed to detect associations between clinical/laboratory features.

RESULTS

We reviewed 12 cases (9 female) followed in 3 Italian centers and 240 cases (191 female) in the published literature reporting individual information. The median age at disease onset was 10 years for both cohorts. The most frequently reported clinical SS-specific feature was parotitis in both cohorts (67% each). Extraglandular manifestations were very common and joint involvement was the most frequent. In the cluster analysis, we identified a significant association between parotitis and younger patients (< 11 years). We verified the presence of the main SS features (exocrine gland inflammation, exocrine gland dysfunction, and presence of autoantibodies) in the Italian cohort and the literature review-based cohort: 92% and 80% of the cohorts, respectively, had at least 2/3 main characteristics.

CONCLUSION

We described cSS features with relative frequencies and we found that parotid involvement was related to cSS in younger patients. The majority of patients showed various combinations of exocrine gland inflammation, exocrine gland dysfunction, and presence of autoantibodies giving a theoretical basis for future research to pave the way for the development of cSS specific diagnostic criteria.