A Conundrum of Severe Hypokalaemic Quadriparesis, Acute Kidney Injury, and Lung Involvement as the Initial Presentation of Catastrophic Primary Sjögren's Syndrome: Is it a New Entity? A Case Report.

Sjögren's syndrome (SS) is a systemic chronic autoimmune disorder that classically affects the exocrine glands. Only 15% of the patients with primary SS (pSS) develop extraglandular symptoms involving the lungs, kidneys, joints, nervous system, and skin. Hypokalaemic paralysis is a rare presentation. The most common cause of hypokalaemia is distal renal tubular acidosis. The prevalence of clinically significant lung involvement in pSS is 9-20 %. Primary SS is an indolent disease leading to increased morbidity and poor quality of life. We present a case of a 40-year-old female with severe hypokalaemic paralysis, tubulointerstitial nephritis, and lung involvement as the initial presentation of catastrophic pSS without sicca symptoms. The course of hospitalisation was complicated by ventilator-associated pneumonia. She was managed with broad spectrum antibiotics, five sessions of plasma exchange and alternate-day haemodialysis followed by oral glucocorticoids and intravenous cyclophosphamide. To the best of our knowledge, this is the first case of catastrophic presentation of pSS with a favourable outcome.