Urinary sodium, potassium and aldosterone in Duchenne muscular dystrophy.

Four adolescent boys with Duchenne (progressive) muscular dystrophy (DMD) of 10-11 years duration and six normal boys of similar age were studied on a metabolism ward for 22 days. Sodium and potassium intake was as follows: Period I, Na 60 mEq, K 60 mEq; Period II, Na 10, K 60; Period III, Na 10, K 95-150; Period IV, Na 60, K 60. The differences between the DMD group and the group of normal boys for sodium and potassium in serum and urine and for urinary aldosterone were not significant. These findings show that the pathologically elevated sodium-potassium ratio in skeletal muscle of patients with DMD is not due to increased aldosterone or other causes of renal wastage of potassium.