A 75-year-old woman comes to the physician because of fatigue and low back pain. She takes ibuprofen as needed for lower back pain. She has no prior medical history and takes no medications. Physical examination shows tenderness to palpation over the lumbar spine. There is pedal edema. Radiographs reveal lytic bone lesions in the L4 and L5 vertebrae. Laboratory results are as follows:
Serum protein electrophoresis reveals a monoclonal gamma globulin spike. Further studies are most likely to show which of the following?

Question

A 75-year-old woman comes to the physician because of fatigue and low back pain. She takes ibuprofen as needed for lower back pain. She has no prior medical history and takes no medications.  Physical examination shows tenderness to palpation over the lumbar spine. There is pedal edema. Radiographs reveal lytic bone lesions in the L4 and L5 vertebrae. Laboratory results are as follows: 
Serum protein electrophoresis reveals a monoclonal gamma globulin spike.  Further studies are most likely to show which of the following?

Quizplus · Accepted Answer

Eductional Objective: Multiple myeloma is associated with increased bone resorption due to the production of tumor-related cytokines.  This results in elevated serum calcium levels, which reduce parathyroid hormone (PTH) production.  Low PTH decreases renal calcium reabsorption (hypercalciuria), and, in combination with renal insufficiency, reduces 1,25-dihydroxyvitamin D synthesis.

A 75-Year-Old Woman Comes to the Physician Because of Fatigue