[A patient with Sjögren syndrome with central pontine myelinolysis and hypokalemic myopathy].

We report a 42-year-old woman who presented with intermittent episodes of muscular weakness lasting approximate 7 to 10 days, about once a year, since 1985. During these episodes of weakness, hypokalemia and elevation of serum creatine kinase were noted. On admission, xerostomia, keratoconjunctivitis sicca (positive Schirmer test), abnormal sialographic findings (apple tree-like appearance), and positive serum autoantibodies against ss-A and nucleus were noted. These findings were compatible with Sjögren syndrome. She also had hyperchloremic metabolic acidosis with normal anion gap, hypokalemia and renal calcifications. Therefore, she had renal tubular acidosis (type 1) in addition to Sjögren syndrome. Brain magnetic resonance imaging (MRI) demonstrated a symmetrical circumscribed lesion in the ventral part of the central pons. We considered this lesion to be central pontine myelinolysis (CPM), because of its typical location and characteristic MRI appearance. This CPM was clinically silent. Pathogenesis and etiology of CPM are obscure, and CPM associated with hypokalemia without hyponatremia has rarely been reported in the literature. However, this is the first report of CPM associated with Sjögren syndrome and hypokalemic myopathy complicated with renal tubular acidosis.