[Effect of calcitriol, a vitamin D compound, in bone disease associated with distal renal tubular acidosis].

In a 47-year-old female patient distal renal tubular acidosis (dRTA) led to the development of osteomalacia following 13 years of the first episode of hypokalemic respiratory paralysis and 7 years of KHCO3 treatment. In spite of the musculoskeletal disability, intense bone pain and myopathy, the values of serum calcium (Ca++) and phosphorous (P) showed minimal deviation from the normal levels. The bone scintigraphy was the first indicator of the bone disease. As the disease progressed the serum level of alkaline phosphatase increased gradually and 25-hydroxyvitamin-D level decreased and bone scintigraphy showed multiple areas of increased radioisotope uptake. By that time the patient's condition deteriorated severely, she became almost unable to walk. Rocaltrol (calcitriol) therapy led to dramatic clinical improvement and the complete resolution of the laboratory values. When the alkaline therapy of dRTA does not prevent the development of osteomalacia, administration of a modern vitamin-D preparation can result complete healing of the bone disease.