Which of the following signs/symptoms are pathognomonic of hyperparathyroidism?

e. Osteitis fibrosa cystica

Manifestations of hyperparathyroidism are protean, but generally nonspecific and may be difficult to elicit in the history. The earliest complaints are often vague and include muscle weakness, anorexia, nausea, constipation, polyuria, and polydipsia. These nonspecific symptoms may or may not cause the patient to seek medical attention. Symptomatic patients generally have evidence of chronic disease involving the kidney or the skeleton. Renal complications develop because the hypercalcemia leads to increased urinary calcium excretion and PTH increases the excretion of phosphate. These events predispose to stone formation. Nephrolithiasis develops in about 30% of patients. Nephrocalcinosis occurs in 5% to 10% of patients. These are both nonspecific for hyperparathyroidism.

Parathyroid bone disease in its most classic and severe form, osteitis fibrosa cystica, is seldom seen. However, 5% to 15% of patients present with significant symptoms of skeletal disease. Only the skeletal disease is pathognomonic. Bone changes include subperiosteal resorption of bone on the radial aspect of the middle phalanx of the second or third finger. Tufting of the distal phalanges, bone cysts of the skull and long bones, “brown” tumors (i.e., localized proliferations of osteoclasts), and diffuse demineralization or granularity are seen as well. Atrophy of Type II muscle fibers, consistent with a neuropathic and not a myopathic cause, has been demonstrated in patients with hyperthyroidism, but this too is nonspecific.