Chondrocalcinosis and osteoporosis in a patient with renal tubular disorder

Abstract

We report the case of a 50-year old male patient presenting with a combination of chondrocalcinosis and osteoporosis related to a renal tubular disorder. Laboratory studies revealed hypokalemia, hypomagnesemia, hypocalcemia with renal wastage and metabolic alkalosis, compatible with a renal tubular transport disorder with similarities to Bartter's and Gitelman's syndrome. Calcifications of the menisci and cartilage on X-rays of knee joints suggested chondrocalcinosis, which has been associated with Gitelman's syndrome. Radiologically suspected osteopenia was confirmed by a bone density scan that revealed osteoporosis of the vertebral column. An association of osteoporosis with hypercalciuria, which commonly occurs in Bartter's syndrome patients, has been reported. Upon treatment of the renal tubular disorder with spironolactone and a thiazide diuretic in combination with calcium and magnesium supplementation, the electrolyte abnormalities resolved and arthralgias disappeared. Our case demonstrates a renal tubular dysfunction with features of both Bartter's and Gitelman's syndrome along with concurrent chondrocalcinosis and osteoporosis. Furthermore, the occurrence of osteoporosis in this relatively young patient, in the absence of other risk factors, demonstrates that renal tubular disorders should be suspected in presenile osteoporosis. Vice versa, since osteoporosis usually is asymptomatic before fracturing, patients with renal tubular disorders should be examined for osteoporosis.