Not Just PLAIN Old Sjögren's: A Case of Acute Interstitial Nephritis Secondary to Sjögren's Syndrome

Summary: Author(s): Tiffany Laitano, MD1; Kathryn Weston, DO1; Ryan Kavilaveettil, DO2; Robert DiGiovanni, DO1 Affiliation(s): HCA Healthcare/USF Morsani College of Medicine GME: HCA Florida Largo Hospital1; Rheumatology Associates Grapevine, Texas2 Disclaimer: This research was supported (in whole or in part) by HCA Healthcare and/or an HCA Healthcare affiliated entity. The views expressed in this publication represent those of the author(s) and do not necessarily represent the official views of HCA Healthcare or any of its affiliated entities. This work has not been submitted for publication elsewhere. Financial Disclosures: None Conflict of interest: None Clinical Case Abstract Introduction: Acute interstitial nephritis (AIN) is a rare extra-glandular manifestation of Sjögren's Syndrome occurring in less than 5% of patients. Acute interstitial nephritis, if not treated promptly, can give rise to prolonged kidney failure, leading to a decreased probability of recovery. Case Presentation: A 45-year-old Haitian male with no PMH, presented with symptoms of generalized weakness, swelling of his legs, nausea and vomiting for 3 days. The patient also endorsed a history of dry mouth, pain and swelling of his hands. Vitals upon presentation were BP 67/58mmHg, HR 150bpm, O2 Sat 96% on RA, temperature 36.4 °C. Physical exam showed distended and tender abdomen and bilateral moderate lower extremity edema. Labs were significant for leukocytosis, thrombocytopenia, elevated creatinine, GFR in kidney failure range, urinalysis revealed proteinuria and hematuria, elevated CRP, positive ANA, positive SS-A/RO antibody and decreased complements. CTA of abdomen and pelvis revealed normal kidneys without evidence of hydronephrosis or stone formation. A kidney biopsy was done and showed features consistent with acute interstitial nephritis. The patient was started on hemodialysis and high dose steroids, with improvement of renal function. Upon discharge, the patient no longer required hemodialysis. Discussion: The typical presentation of Sjögren’s Syndrome is xeropthalmia and xerostomia. Renal disease is a known extra-glandular manifestation associated with Sjögren’s. The prevalence of renal disease varies, from 1-33%. Acute interstitial nephritis in Sjögren’s is described as an invasion of mononuclear lymphocytes, predominately CD4+ T cells. Of note, the pattern of epithelial inflammation is similar to that in labial salivary glands. Clinically, patients present with a prior diagnosis of primary Sjögren’s, elevated BUN/Cr, hypokalemia, proteinuria, and hematuria. Autoantibodies SSA and SSB are specific for Sjögren’s and, if present, can help confirm the diagnosis. Kidney biopsy shows interstitial lymphoplasmacytic infiltrates and fibrosis surrounding the tubules, occasionally with lymphoid follicle formation, distinguishing it from other non-autoimmune causes of acute interstitial nephritis. Treatment for Sjögren’s is methotrexate and hydroxychloroquine for lacrimal, salivary and joint involvement. Acute interstitial nephritis specifically has been treated with high dose corticosteroids and azathioprine or low dose MMF. Conclusion: Our case highlights the importance of considering Sjögren's Syndrome as a possible etiology for acute interstitial nephritis, when other causes, such as medications and infections, have been ruled out. Early recognition and appropriate management with high dose steroids and immunosuppressants, such as azathioprine or low dose MMF, can improve outcomes for patients with this condition. References: 1. Jai Radhakrishnan, MD, MS. Kidney disease in primary Sjögren syndrome Post TW, ed. UpToDate. Waltham, MA: UpToDate Inc. http://www.uptodate.com. Accessed January 2023. 2. Evans RD, Laing CM, Ciurtin C, Walsh SB. Tubulointerstitial nephritis in primary Sjögren syndrome: clinical manifestations and response to treatment. BMC Musculoskelet Disord. 2016 Jan 5;17:2. doi: 10.1186/s12891-015-0858-x. PMID: 26728714; PMCID: PMC4700638. 3. Koratala, Abhilash MD; Reeves, Westley H. MD; Segal, Mark S. MD. Tubulointerstitial Nephritis in Sjögren Syndrome Treated With Mycophenolate Mofetil. JCR: Journal of Clinical Rheumatology 23(7):p 402-403, October 2017. | DOI: 10.1097/RHU.0000000000000595