Rare Case of Central Pontine Myelinolysis: Etiological Dilemma.

Central nervous system (CNS) involvement in Sjogren's syndrome (SS) has a broad spectrum of presentations. We present a 33-year-old with sudden onset, rapidly progressive quadriplegia, severe dysarthria, bilateral facial palsy, bulbar palsy, and hypernatremia. The MRI of the brain revealed hyperintensity in the central pons diffusion-weighted imaging, T2-weighted imaging, and fluid-attenuated inversion recovery (FLAIR) without abnormal contrast enhancement, consistent with central pontine myelinolysis. However, there was no antecedent history of hyponatremia with rapid correction. The patient responded excellently to sodium correction and pulse methylprednisolone therapy and was erroneously diagnosed as idiopathic hypernatremic osmotic demyelination. One year later, she presented with vague constitutional symptoms, renal tubular acidosis type-1 (distal), hypokalemia with associated myopathy. Subsequent testing for anti-Sjögren's-syndrome-related antigen A (SSA)/Ro autoantibodies and a biopsy of the minor salivary gland established the diagnosis of primary Sjogren syndrome (pSS). Remission was achieved with oral prednisolone after her discharge. Neurological signs can be the initial presentation that precedes the classical systemic manifestations of multisystem autoimmune disorders like pSS. In the event of osmotic demyelination, when antecedent hyponatremia with rapid correction is not there, we suggest evaluating for possible autoimmune etiology.