Occult anticonvulsant osteomalacia in North India

Serum calcium, inorganic phosphate and alkaline phosphatase, tubular reabsorption of phosphate (TRP) estimation and radiological examination of the skeleton were conducted in 40 cases (18-50 years of age) on anticonvulsant therapy and 20 controls. The epileptic group showed a statistically significant rise in serum alkaline phosphatase and a fall in TRP. In none of the cases, however, was there clinical or radiological evidence of osteomalacia. Biochemical abnormalities were seen mainly in the youngest individuals. It seems that the critical factor for the development of anticonvulsant osteomalacia is the lack of dietary vitamin D/solar exposure or increased body requirement of the vitamin.