Fifteen elderly patients with osteomalacia were investigated in 2½ years in a geriatric unit. Although they all had bone pain the diagnosis in some cases was overshadowed by other common diseases with which they were referred to hospital, such as impaired balance or mental confusion. The bone pain had been present for weeks or months and was often attributed to arthritis. Biochemical investigations showed a low serum calcium and low or low-normal serum phosphate levels and a moderate to large increase in alkaline phosphatase above 15 KA units/100 ml. Only six patients had radiological signs of osteomalacia but all had histological evidence on bone biopsy.
Five subjects died within 3 weeks of admission from pneumonia or myocardial infarction. In the other ten, relief of pain occurred within 2-4 weeks of starting vitamin D, and bone tenderness disappeared after 2-3 months. The earliest biochemical sign of recovery was the rise in serum phosphate. Calciferol 1·25 mg daily (50,000 units of vitamin D) was given for 2-4 weeks or until there was a rise in the serum phosphate or calcium. One woman of 74 showed resistance to vitamin D associated with renal insufficiency.
Dietary history in seven patients revealed daily vitamin D intakes below 100 units. Four of the fifteen patients had a previous history of partial gastrectomy.
In addition to routine biochemical and X-ray investigations in elderly patients with generalized bone pain, trephine biopsy of the bone is a useful procedure for the diagnosis of osteomalacia.