Severe Hypokalemia and Respiratory Muscle Paralysis: An Atypical Manifestation of Primary Sjögren's Syndrome

Primary Sjögren's syndrome (SS) is a systemic autoimmune disorder primarily affecting exocrine glands, that may occasionally present with severe extra-glandular manifestations. Although rarely, severe hypokalemia and respiratory muscle paralysis may be initial presentations. We report the case of a 33-year-old woman with a recent history of severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) infection who presented with headache and generalized muscle weakness. An evaluation revealed severe hypokalemia, acute kidney injury, and metabolic acidosis. Despite intravenous potassium supplementation, her condition rapidly deteriorated, leading to respiratory failure requiring invasive ventilation. Further investigations showed a urinary pH >5.5, indicating distal renal tubular acidosis (dRTA). Positive antinuclear antibody (ANA) titers, SS-related antigen A antibody (anti-Ro/SSA), and lymphocytic infiltration on parotid gland biopsy confirmed a diagnosis of primary SS. Treatment with bicarbonate, potassium supplementation, and oral corticosteroids was initiated, leading to clinical improvement. This case underscores the importance of considering SS in patients with unexplained dRTA and severe hypokalemia, emphasizing the importance of timely diagnosis and tailored therapy in managing systemic manifestations.