An Atypical Case of Sjögren's Syndrome: A Surprise Diagnosis.

Distal renal tubular acidosis (RTA) presenting as hypokalemia, metabolic acidosis, and hypokalemic periodic paralysis is a common manifestation of tubulointerstitial nephritis (TIN) in Sjögren's syndrome. Sjögren's syndrome is a chronic, progressive, systemic autoimmune inflammatory disease characterized by lymphocytic infiltration of exocrine glands, which results in sicca syndrome, i.e., xerostomia and keratoconjunctivitis sicca. Some patients can express sicca symptoms with other autoimmune diseases. It is mostly seen in females, and middle-aged women are more likely to be affected. Some patients can present with extra-glandular (systemic) manifestations, of which renal involvement is the most common. Renal involvement in the form of TIN is more common compared to glomerular involvement. We report a case of a 37-year-old female presenting with hypokalemic periodic paralysis, later diagnosed as distal RTA secondary to Sjögren's syndrome, which requires high clinical suspicion based on hypokalemia refractory to treatment. Further evaluation is necessary to confirm the diagnosis.