Successful therapy of vitamin D-dependant rickets in a kitten.

A 7 mo old, 2.4 kg, intact female kitten was evaluated for an inability to walk after falling out of the owner's arms. Diagnostic testing abnormalities included hypocalcemia, low ionized calcium, and elevated intact parathyroid hormone concentration. The 25-hydroxyvitamin D level was normal. Radiographic abnormalities included generalized osteopenia, a nondisplaced, folding fracture of the proximal right fibula, and sclerosis with a compression fracture of the proximal right tibia. Based on these findings and response to calcium carbonate and calcitriol therapy, a diagnosis of vitamin D-dependent rickets was made. Reports of similar cases in veterinary medicine are sparse and no other reports to date document radiographic abnormalities with a successful therapeutic outcome.