[Paget's osteitis deformans. Epidemiology and clinical picture].

Osteitis deformans is a focal disease of the osteoclasts characterised by increased bone resorption subsequently followed by increased bone formation leading to abnormal bone. A viral etiology seems increasingly probable, but remains unproven. 5-30% of the patients present with symptoms such as pain, deformity and fracture. Hearing loss, nerve- or root-compression, arthrosis and hyperuricaemia may complicate the disease while malignant degeneration, hypercalcemia and high output cardiac failure are rare. The diagnosis is based on X-ray findings but biopsy may be necessary in selected cases. The extent of the disease is revealed by bone scintigraphy and the activity of the disease reflected by urine hydroxyproline excretion and serum alkaline phosphatase.