Osteomalacic Myopathy

A 45-year-old woman reported the development of thigh pain followed within a year by proximal muscle weakness. Clinical findings included short stature, prominent kyphoscoliosis, proximal weakness, and brisk reflexes. Recognition of an increased level of serum alkaline phosphatase and hypophosphatemia led to the diagnosis of osteomalacia. Identification of iron deficiency anemia and hypocholesterolemia implicated previously unrecognized gluten-sensitive enteropathy with associated vitamin D malabsorption as the cause of the osteomalacia. Adherence to a gluten-free diet and treatment with vitamin D2 resulted in weight gain, resolution of pain, and improvement in strength within 3 months. Painful proximal weakness and hyperreflexia may be the initial and primary manifestations of osteomalacia, a readily treatable cause of muscle and bone disease.