The Silent Autoimmune: Sjögren's Syndrome in a Young Male

Background: Sjögren's syndrome (SS) is a systemic autoimmune exocrinopathy primarily targeting salivary and lacrimal glands. Its occurrence in young males is uncommon, and its association with hypokalemic paralysis mediated by distal renal tubular acidosis (dRTA) type 1 is an exceptionally rare and diagnostically challenging presentation. Anti-Jo-1 antibody positivity further distinguishes this case as a unique overlap with inflammatory myopathy. Case Presentation: We report a 27-year-old male who presented with dry eyes and dry mouth, with a prior hospitalization for hypokalemic quadriplegia. Ophthalmological assessment confirmed severe bilateral keratoconjunctivitis sicca (Schirmer's test: <5 mm/5 min bilaterally). Serological workup revealed isolated Anti-Jo-1 antibody positivity on ENA/ANA qualitative profile, while Anti-Ro/SSA and Anti-La/SSB antibodies were negative. Labial minor salivary gland biopsy demonstrated focal lymphocytic sialadenitis consistent with primary Sjögren's syndrome. The 2016 ACR/EULAR classification criteria were fulfilled with a score of ≥5. Conclusion: This case underscores the importance of considering Sjögren's syndrome in young male patients presenting with hypokalemic paralysis. Seronegativity for classical antibodies does not exclude the diagnosis. Minor salivary gland biopsy remains the histopathological cornerstone, and the oral pathologist plays a pivotal diagnostic role. Multidisciplinary management is essential to address both glandular and extraglandular manifestations.