"Rote Augen" und Hypokaliämie

Gitelman syndrome is a rare hereditary disorder of the thiazide-sensitive NaCl transporter in the distal renal tubular cells, but mimicking of such hereditary tubular disorders has been described in different autoimmune diseases (Sjogren syndrome, SLE,...). A 62-year-old woman with painful red eyes and sicca syndrome presented at the ophthalmological department. The diagnostic evaluation identified a Sjogren syndrome with early endophthalmitis as the reason for the red eyes. Results of laboratory examination indicated severe hypokalemia, metabolic alkalosis and hypomagnesemia, although this had not been seen years earlier. Together with the urine analysis, a rare case of an acquired Gitelman syndrome was diagnosed. Substitution with potassium and magnesium improved the initial symptoms of weakness, but renal electrolyte wasting persisted even after treatment of Sjogren syndrome. In patients with autoimmune disease, laboratory analysis of serum electrolytes should be performed because different acquired tubular disorders can lead to severe hypokalemia.