Abstract
A 34-year-old man with adult-onset Still's disease developed a striking hypercalcaemia during a rapidly destructive polyarthritis with extensive osteoporosis. The hypercalcaemia seemed to be primarily caused by inflammation-induced bone resorption. On prednisone the polyarthritis went into remission and the plasma calcium levels became normal. Other remarkable features in this case were a subluxation of the atlantoaxial joint, a brain-stem haemorrhage, transient hyperuricaemia and hyperuricosuria, and urolithiasis.