In multiple myeloma following are seen -(

In multiple myeloma ,hypercalcemia occurs due to destruction of bone. Bone pain is the most common symptom.The pain usually involves the back & ribs. Pathological fracture may occur causing localised pain.Bone pain results from the proliferation of tumour cells in the marrow & activation of osteoclasts which destroy the bone. Renal failure occurs due to hypercalcaemia, glomerular deposits of amyloid,hyperuricaemia, & infiltration of kidney by myeloma cells.Reference:Harsh mohan textbook of pathology sixth edition pg no 383.