Tubulointerstitial nephritis-induced hypophosphatemic osteomalacia in Sjögren's syndrome: a case report and review of the literature

Recommendations for evaluation and diagnosis of extra-glandular manifestations of primary sjogren syndrome: results of an epidemiologic systematic review/meta-analysis and a consensus guideline from the Brazilian Society of Rheumatology (articular, pulmonary and renal)

Sjogren's Syndrome (SS) is an autoimmune disease characterized by lymphocytic infiltration of the exocrine glands and other organs, associated with sicca syndrome but also with systemic involvement with varying degrees of severity. Despite their importance, these systemic manifestations are not routinely evaluated and there is no homogenous approach to their diagnosis or evaluation. To close this gap, a panel of experts from the Brazilian Society of Rheumatology conducted a systematic review and meta-analysis on the identification of epidemiologic and clinical features of these manifestations and made recommendations based on the findings. Agreement between the experts was achieved using the Delphi method. The first part of this guideline summarizes the most important topics, and 11 recommendations are provided for the articular, pulmonary, and renal care of SS patients.

Musculoskeletal Manifestations in Sjogren's Syndrome: An Orthopedic Point of View

Sjogren's syndrome (SS) is a frequent entity with a broad symptomatology spectrum, mainly affecting the salivary and lachrymal glands. The disease also affects the musculoskeletal system targeting bones, specific joints, muscles, and the peripheral nerve system. Disease related clinical manifestations canhave an accumulative impact, as the syndrome is commonly associated with other rheumatic diseases. A literature review was performed with the aim to assess the in-depth association of Sjogren's syndrome and its treatment agents with the musculoskeletal system and further investigate its potential relevance with common orthopedic postoperative complications.

A loosening prosthesis in a dialysis patient

A haemodialysis patient with periprosthetic fractures and a history of corticosteroid use was referred for assessment for bone mineral disorders. Mixed renal osteodystrophy was diagnosed following a bone biopsy. Correction for vitamin D insufficiency did not improve the clinical signs, which prompted a potential diagnosis of hypophosphataemic osteomalacia to be considered. No causes for hypophosphataemia were found, except for phosphate dietary restrictions. Phosphorus supplementation was administered, resulting in an upturn in bone biochemical and histological parameters and increased bone mineral density, thus confirming the diagnosis of hypophosphataemic osteomalacia due to low phosphate intake. Characteristic features related to this diagnosis are shown from three repeated bone biopsies performed during the course of patient follow-up.

Biomarkers and Diagnostic Testing for Renal Disease in Sjogren's Syndrome

Primary Sjogren's syndrome (pSS) is an autoimmune disorder in which lymphocytic infiltration leads to lacrimal and salivary glands dysfunction, which results in symptoms of dryness (xerophthalmia and xerostomia). Extraglandular features are common and may affect several organs. Renal involvement has long been known as one of the systemic complications of pSS. The most classical lesion observed in pSS is tubulointerstitial nephritis (TIN) and less frequently membranoproliferative glomerulonephritis (MPGN), which is related to cryoglobulinemia. In some cases, renal biopsy is necessary for the definitive diagnosis of kidney involvement. Patients may present with proximal renal tubular acidosis, distal renal tubular acidosis and chronic kidney disease. Response to treatment is usually favorable. However, occasionally severe and rarely lethal outcomes have been described. Recently, several case series and cross-sectional studies have been published which investigated the factors associated with renal involvement in pSS and the most accurate screening tests for early detection. The presence of xerophthalmia, anti-SSA and rheumatoid factor positivity, low C3 levels and other features have all shown either positive or inverse associations with the development of renal complications. Serum creatinine, alpha-1-microglobulin, cystatin-C have been evaluated as early detection biomarkers with variable accuracy. More advanced techniques may be necessary to confirm proximal and distal renal tubular acidosis, along with nephrogenic diabetes insipidus. The aim of the current paper is to summarize and critically examine these findings in order to provide updated guidance on serum biomarkers and further testing for kidney involvement in pSS.

Current State of Knowledge on Primary Sjögren's Syndrome, an Autoimmune Exocrinopathy

Primary Sjögren's syndrome (pSS) is a chronic systemic autoimmune rheumatic disease characterized by lymphoplasmacytic infiltration of the salivary and lacrimal glands, whereby sicca syndrome and/or systemic manifestations are the clinical hallmarks, associated with a particular autoantibody profile. pSS is the most frequent connective tissue disease after rheumatoid arthritis, affecting 0.3-3% of the population. Women are more prone to develop pSS than men, with a sex ratio of 9:1. Considered in the past as innocent collateral passive victims of autoimmunity, the epithelial cells of the salivary glands are now known to play an active role in the pathogenesis of the disease. The aetiology of the "autoimmune epithelitis" still remains unknown, but certainly involves genetic, environmental and hormonal factors. Later during the disease evolution, the subsequent chronic activation of B cells can lead to the development of systemic manifestations or non-Hodgkin's lymphoma. The aim of the present comprehensive review is to provide the current state of knowledge on pSS. The review addresses the clinical manifestations and complications of the disease, the diagnostic workup, the pathogenic mechanisms and the therapeutic approaches.

Prevalence and factors associated with osteoporosis and fragility fractures in patients with primary Sjögren syndrome

This study aimed at determining socio-demographic and clinical factors of primary Sjögren syndrome (pSS) associated with osteoporosis (OP) and fragility fracture. SJOGRENSER is a cross-sectional study of patients with pSS, classified according to American European consensus criteria developed in 33 Spanish rheumatology departments. Epidemiological, clinical, serological and treatment data were collected and a descriptive analysis was conducted. Bivariate and multivariate analyses were performed using a binomial logistic regression to study the factors associated with OP and fragility fracture in pSS. 437 patients were included (95% women, with a median age of 58.6 years). 300 women were menopausal (76.4%). Prevalence of OP was 18.5% [in men (N = 21) this measured 19%]. A total of 37 fragility fractures were recorded. In the multivariate analysis, there was an association between OP and age: in the 51-64 age range (menopausal women), the OR measured 9.993 (95% CI 2301-43,399, p = 0.002); In the age > 64 years group, OR was 20.610 (4.679-90.774, p < 0.001); between OP and disease duration, OR was 1.046 (1.008-1085, p = 0.017); past treatment with corticosteroids, OR 2.548 (1.271-5.105, p = 0.008). Similarly, an association was found between fragility fractures and age: in the 51-64 age group, OR measured 5.068 (1.117-22,995, p = 0.035), age > 64 years, OR was 7.674 (1.675-35,151, p < 0.009); disease duration, OR 1.049 (CI 1.003-1097, p < 0.036) and the ESSDAI index, OR 1.080 (1.029-1134, p = 0.002). Patients with pSS can develop osteoporosis and fragility fractures over the course of the disease. Age, corticosteroids treatment and disease duration were associated with the development of OP. Disease duration and ESSDAI were associated with the development of fractures in patients with pSS.

Renal Tubular Acidosis in Patients with Primary Sjögren's Syndrome

Primary Sjögren's syndrome (pSS) is characterized by lymphocytic infiltration of the exocrine glands resulting in decreased saliva and tear production. It uncommonly involves the kidneys in various forms, including tubulointerstitial nephritis, renal tubular acidosis, Fanconi syndrome, and rarely glomerulonephritis. Its clinical symptoms include muscle weakness, periodic paralysis, and bone pain due to metabolic acidosis and electrolyte imbalance. Herein, we describe the cases of two women with pSS whose presenting symptoms involve the kidneys. They had hypokalemia and normal anion gap metabolic acidosis due to distal renal tubular acidosis and positive anti-SS-A and anti-SS-B autoantibodies. Since one of them experienced femoral fracture due to osteomalacia secondary to renal tubular acidosis, an earlier diagnosis of pSS is important in preventing serious complications.