Master the board step 3

Endocrinology
Hyperparathyroidism
The vast majority of cases present as asymptomatic hypercalcemia. Target
organ damage is as follows:
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Kidney stones
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Osteoporosis/osteomalacia/fractures
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Confusion
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Constipation and abdominal pain
Basic Science Correlate
Mechanism of Neural Inhibition in Hypercalcemia
High calcium levels make it harder for excitable tissue such as nerves to
depolarize. High calcium moves the threshold for depolarization away from
the resting membrane potential. Bowels are a long muscular tube. High
calcium inhibits smooth muscle contraction.
Low calcium = Hyperexcitable
Diagnostic Testing
Increased parathyroid hormone (PTH) level with hypercalcemia
Treatment
Surgical removal. Remember: Hyperparathyroidism may be a part of multiple
endocrine neoplasia (MEN) syndrome. The nature of cases is as follows:
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Solitary adenoma: 80 percent
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Four-gland hyperplasia: 19 percent
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Cancer: 1 percent
When is the answer to a question about hyperparathyroidism surgical removal of
the parathyroid gland?
Answer: Remove the gland under any of the following circumstances:
• Any symptomatic disease (“stones, bones, psychic moans, GI groans”)
• Renal insufficiency, no matter how slight
• Markedly elevated 24-hour urine calcium
• Very elevated serum calcium (> 12.5)
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