Let's go on to a case.
On routine exam, a 68-year old female patient is
discovered to have a serum calcium level of 11.5 mg/dL.
Follow up lab test show an elevated PTH level with a low
serum phosphorus and mildly elevated alkaline phosphatase.
24-hour urine calcium
level is elevated.
Review of symptoms includes complaints of fatigue, constipation,
diffuse bone pain for which she has been taking vitamin D.
Past medical history is significant for
type 2 diabetes mellitus for 25 years
and essential hypertension
for around 15 years.
The patient has a history of kidney stones.
The family history is unremarkable.
What is the most likely diagnosis
and what should you do next?
Here we have an incidentally
discovered elevated calcium level.
When a more in-depth history is
taken and the systems are reviewed,
we appear to have the classic symptoms of stones,
bones, abdominal groans but no psychiatric overtones.
In association with an increase serum calcium,
she has also elevated parathyroid hormone levels,
a low serum phosphorus and an
increased alkaline phosphatase.
She also has increased urinary
secretion of calcium.
The conclusion here that this
constellation of symptoms and signs,
presentation of hypercalcemia with the association
of low phosphorus, high calcium and elevated PTH
is classic for the diagnosis of
Let's talk a little bit about
Repeat measurements of calcium and PTH
should be confirmed to make the diagnosis.
The serum phosphorus level may be low
or in the lower range of normal.
We should also check a 25-hydroxyvitamin
D level because decreased vitamin D
may lead to a compensatory increase
in PTH and worsen the condition.
It certainly doesn't help in this patient that
she's taking vitamin D supplementation as well.
Urinary calcium measurement should be performed
with the 24-hour measurement of urinary calcium
to differentiate primary hyperparathyroidism from the
much rarer familial hypocalciuric hypercalcemia.
And we'll review this at the
end of the section in a table.