[A case of pseudo-Bartter's syndrome associated with hypokalemic myopathy]

A case of pseudo-Bartter's syndrome associated with hypokalemic myopathy was presented. A 37-year-old housewife was admitted to our hospital because of muscle cramps with muscle weakness and tetany. There was a history of facial edema and constipation, which have been managed with "Kanpo medicine (Chinese medicine)" and laxatives for several years. The patient was amenorrhea 3 months before entry. She began to experience muscle weakness and muscle cramps associated with gait disturbance 2 or 3 months before admission. On physical examination, she was thin with positive Trousseau's and Chvostek's signs. Laboratory studies revealed hypokalemia, low urinary excretion of potassium, hypocalcemia, metabolic alkalosis, elevated creatine phosphokinase (CPK), increased levels of plasma renin activity and plasma aldosterone concentration, and decreased sensitivity to pressor effect of angiotensin II. Potassium supplementation resulted in restoration of her symptoms and normalization of low serum calcium and elevated CPK levels. She was diagnosed to be pseudo-Bartter's syndrome due to anorexia nervosa. The mechanism(s) of hypokalemia in our case was discussed.