MCQ 14

A 90 year old male complains of hip and back pain. He has also developed headache, hearing loss, and tinnitus. On physical examination the skull appears enlarged, with prominent superficial veins. There is a marked kyphosis , and the bones of the leg appear deformed. Plasma alkaline phosphatase is elevated. A skull X-ray shows sharply demarcated lucencies in the frontal, parietal, and occipital bones. X-rays of the hip show thickening of the pelvic brim. The most likely diagnosis is

a. Multiple myeloma
b. Paget's disease
c. Hypercalcemia
d. Metastatic bone disease

Answer and explanation

The answer is "b"

This patient has widespread Paget's disease of bone. Excessive resorption of bone is followed by replacement of normal marrow with dense, trabecular, disorganized bone.

Hearing loss and tinnitus are due to direct involvement of the ossicles of the ossicles of the inner ear.

Plasma alkaline phosphatase levels represent increased bone turn over.

Neithe Myeloma nor metastatic bone disease would result in bony deformity such as skull enlargement. Alkaline phosphatase is a marker of bone formation and does not rise in pure lytic lesions such as multiple myeloma.