Thyroid & Adrenal
Osteitis fibrosa cystica is associated with:
a. Bone disease, including osteopenia, osteoporosis, and osteitis fibrosa cystica, is found in approximately 15% of patients with PHPT.
b. Increased bone turnover can usually be determined by documenting an elevated blood alkaline phosphatase level.
c. Advanced PHPT and/or vitamin D deficiency leads to osteitis fibrosa cystica, a condition that previously was more common, but which now occurs in less than 5% of patients.
d. It is characterized by pathognomonic radiologic findings, which are best seen on x-rays of the hands that demonstrate subperiosteal resorption (most apparent on the radial aspect of the middle phalanx of the second and third fingers), bone cysts, and tufting of the distal phalanges.
e. The skull may also be affected and appears mottled (salt and pepper) with a loss of definition of the inner and outer cortices.
f. Brown or osteoclastic tumors and bone cysts may also be present. Reductions of bone mineral density (BMD) with osteopenia and osteoporosis are more common.
g. Patients with normal serum alkaline phosphatase levels almost never have clinically apparent osteitis fibrosa cystica.
h. Hyperparathyroidism typically results in a loss of bone mass at sites of cortical bone, such as the radius and relative preservation of cancellous bone such as that located at the vertebral bodies.
i. Patients with PHPT, however, may also have osteoporosis of the lumbar spine (trabecular bone) that improves dramatically following parathyroidectomy.
j. Fractures also occur more frequently in patients with PHPT and the incidence of fractures decreases beginning 1 year after parathyroidectomy.