Monday, October 03, 2011

An Interesting Hypercalcemia Case

I thought I'd share this case I saw not too long ago. The patient, Mr. P, was a 52 year old man who was found incidentally to be hypercalcemic. His serum calcium was 10.9 mg/dL and on repeat 11.2 mg/dL (his albumin was normal, in case you medstudents out there were correctly asking that question).
While the workup of hypercalcemia should include a parathyroid hormone level early on as this may obliviate many other tests if this was inappropriately high (recall that one does not need to have a high PTH to have hyperparathyroidism- a common mistake that I encounter), his PTH was appropriately on the lower end.
So, working along the lines of 'non-PTH mediated hypercalcemia', what is your differential diagnosis, and plan?
(and if you're friends with me on FB and already saw my earlier posting, don't spoil the surprise!)

7 Comments:

Blogger The Quilter's Bag said...

This comment has been removed by the author.

10:13 PM  
Anonymous Anonymous said...

Assessment: Ask patient if he has any heart burns and is taking calcium carbonate (Tums)for relief. GFR? check creatinine level. Check TSH for calcitonin.
Diff dx: muliple myeloma, breast ca (men can have breast ca, too).
Tx: IV NS with furosemide. Agressively. increase weight bearing exercise.

10:20 PM  
Blogger vagus said...

His Creatinine and TSH were normal. So that rules out hyperthyroidism, while milk-alkali syndrome (I assume that's what you were getting at with the Tums remark) would be unlikely (the classical triad of metabolic alkalosis, hypercalcemia and renal failure).
Other labs to help work this up?

7:59 PM  
Anonymous Anonymous said...

Check PTH-related protein, 25-hydroxyvitamin D, and 1,25-dihydroxyvitamin D.
eval for underlying malignancy, granulomatous disease, vit D intox

5:50 PM  
Blogger vagus said...

All good thoughts. His PTHrp was negative, while 25- and 1,25-Vit D, and SPEP were normal.
The possible granulomatous diseases are numerous but tends to cause extrarenal hydroxylation of 25- to 1,25-Vit D leading to increased gut absorption of Ca. So, if you see a disproportionately higher 1,25- to 25-OH Vit D especially in the context of a suppressed PTH, this is a big clue (since the renal conversion is usually PTH mediated). But no, that wasn't the case here. Also, for good measure his ACE levels were normal (for board purposes, they like to ask about sarcoidosis FYI). Also, remember that hypercalcemia of malignancy can be via numerous mechanisms: PTHrp, bone metastasis, or as with granulomas some blood cancers can hydroxylate Vit D.
At this point we're probably still in the investigational stage- at these calcium levels this is still an outpatient workup and so IV fluid/bisphosphonates are probably not necessary.

7:51 PM  
Anonymous Anonymous said...

how about checking upep, spep, vitamin A, 24 hr urine collection for calcium?

? family hx hypercalcemia

3:07 PM  
Blogger vagus said...

His 24-hour urine calcium was midnormal. Given the normal SPEP I did not pursue a UPEP.
His Vit A, however, came back elevated. As it turns out, he takes just a men's multivitamin, but because he felt that "if 1 is good, then 2 must be better", takes double the recommended dose and has done so for 5 years.
So, the presumptive diagnosis is hypercalcemia from Vit A toxicity- I have told him to cut down and we plan to repeat his labs in a few months. It's one of those things that has been reported to cause hypercalcemia via increased bone turnover, but I must say this was the first time I actually encountered this in clinic. I was somewhat surprised though that all it took was 2 multivitamin tablets!
Good thoughts, dear readers!

4:00 PM  

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