Question about a Case

[turkeyjerky]

---

Members don't see this ad.

On family med right now, we had a lecture about osteoporosis today. The following is one of the cases that was presented (pretty sure it's not a real case, but it might be). Wanted to get some people's thoughts on it.

58 year old woman, non-contributory PMHx, gets a DEXA which shows T-score of -1.9 and a Z-score lower than T-score (suggestive of secondary osteoporosis). Labs are obtained:
BUN 13
Creatinine .8
Calcium 10.8 (uln 10.5)
TSH 1.6
PTH 6.3 (nml: 1.0-5.2)
1,25-dihydroxy vitamin D 29 (normal > 35)

Of note, the patient is a non-smoker, has no FHx of osteoporosis, takes 1500 mg Ca plus 400 IU of Vitamin daily and gets erratic sun exposure in a northern part of the country.

What's the diagnosis?
What's the recommended treatment?

 

[turkeyjerky]

This is most likely primary hyperparathyroidism. Further eval would include a serum phosphorus level, urinary calcium and possibly a serum ionized calcium. The low 1,25-Vitamin D is difficult to interpret in this setting; a 25-OH vitamin D level is the test to use to see if one is replete of vitamin d. The patient really doesn't meet great criteria for surgery; I'd probably offer it and if declined, start therapy with a bisphosphonate.

 

[turkeyjerky]

The professor (a family med doctor) told me that I was basically flat wrong. Here's what she said:

The patient is vitamin D deficient w/ a resulting secondary hyperparathyroidism. Treatment should be begun w/ 50,000 IU of D3 once weekly for 6-8 wks.


Anyone care to explain to me why I'm wrong??

 

[MilkmanAl]

I dunno, that sounds like the most reasonable thing I can think of, considering her labs. That said, her PTH isn't really that high. Most of the HPTH patients I've seen had PTH levels up around 100 before surgery. That might be where he got you.

 

[turkeyjerky]

(the values, which weren't given, must be different for this lab's reporting of pth)

yeah, but have you ever heard of vitamin D deficiency leading to hypERcalcemia? Hell, this case doesn't even demonstrate hypovitaminosis--that's diagnosed on the basis of the 25-OH Vitamin D lvl.

This person called me out and told me I was flat wrong--can anyone step up to the plate and tell me why?

 

[MilkmanAl]

Looking back, I suppose I was unclear; I meant that HPTH seems most reasonable. I have no clue why D deficiency would cause hypercalcemia. I don't know why you'd be wrong.

 

[turkeyjerky]

Looking back, I suppose I was unclear; I meant that HPTH seems most reasonable. I have no clue why D deficiency would cause hypercalcemia. I don't know why you'd be wrong.

thank you, I don't get it either. I don't like to get told I'm wrong, especially when I'm not, and I especially don't like to get talked down to like I'm some ******, which is how this went. Funny thing was, she said that "students always get this one wrong", yeah right!

 

[cabinbuilder]

Uptodate says that the final hydroxylation of vitamin D in the kidney is stimulated my PTH and other factors. So if your vitamin D is low, your brain will increase it's PTH in order to stimulate that final step in the reaction.

I think why you were deemed to be wrong, is that you are jumping to the conclusion that it's a parathyroid problem (hence the PTH) when it's really a insuffiicient vitamin D problem.

The easiest form of treatment is the mega dose vitamin D replacement 50,000units per week for 8 weeks, then recheck all your labs. This is much more cost effective than running after a parathyroid issue. Plus, unless the persons serum calcium is very high, I wouldn't start with the parathyroid.

 

[turkeyjerky]

Uptodate says that the final hydroxylation of vitamin D in the kidney is stimulated my PTH and other factors. So if your vitamin D is low, your brain will increase it's PTH in order to stimulate that final step in the reaction.

I think why you were deemed to be wrong, is that you are jumping to the conclusion that it's a parathyroid problem (hence the PTH) when it's really a insuffiicient vitamin D problem.

The easiest form of treatment is the mega dose vitamin D replacement 50,000units per week for 8 weeks, then recheck all your labs. This is much more cost effective than running after a parathyroid issue. Plus, unless the persons serum calcium is very high, I wouldn't start with the parathyroid.

thanks for responding, but that really doesn't make any sense to me. You're really just repeating, almost verbatim, what I was told in class w/o giving any reasoning or evidence whatsoever. Here's why your reasoning is incorrect, at least in my view:

You need a 25-OH Vitamin D level to say that the patient is actually vitamin D deficient. The patient in question is calcitriol deficient--we don't know anything about her vitamin D status. She could have tertiary hyperparathyrodism from renal failure; this seems very unlikely given the normal Cr and the fact she is asymptomatic.

Plus, show me one article or other source that lists vitamin D deficiency in the differential for hypERcalcemia. I've looked and cannot find one.

Another thing, I'm not sure why you have doubts about hyperparathyroidism--this is the most common cause of hypercalcemia in the community setting and I don't find it at all unusual for the calcium to be only mildly elevated.

 

[OCallag]

Dude, let it go.

 

[Rollo]

Uptodate says that the final hydroxylation of vitamin D in the kidney is stimulated my PTH and other factors. So if your vitamin D is low, your brain will increase it's PTH in order to stimulate that final step in the reaction.

I think why you were deemed to be wrong, is that you are jumping to the conclusion that it's a parathyroid problem (hence the PTH) when it's really a insuffiicient vitamin D problem.

The easiest form of treatment is the mega dose vitamin D replacement 50,000units per week for 8 weeks, then recheck all your labs. This is much more cost effective than running after a parathyroid issue. Plus, unless the persons serum calcium is very high, I wouldn't start with the parathyroid.

This is correct.

The patient is having secondary hyperparathyroidism due to deficiency in Vitamin D which causes decreased Ca levels which serves as a trigger for PTH release hence you see a slightly higher than normal Ca level. Reason for slightly higher than normal Ca is that PTH increases Ca levels 3 ways: 1) increase Ca levels from bone 2) increase reabsorption of Ca in distal tubule and 3) activate vitamin D. Since, it can't activate vitamin D because of vitamin D deficiency, it can only increase Ca levels 2/3 as efficiently as it would have if vitamin D was around. Therefore, you see slightly higher than normal Ca levels.

Renal re-absorption of calcium is also not as efficient because vitamin D is what increases absorption of calcium in the small intestines. Therefore, without Vitamin D around, small intestines can't absorb as much Ca and the only Ca to reabsorb from the kidneys is the one that was released by the bone.

Secondary osteoporosis is also explained, then, due to high PTH levels.

 

[cabinbuilder]

thanks for responding, but that really doesn't make any sense to me. You're really just repeating, almost verbatim, what I was told in class w/o giving any reasoning or evidence whatsoever. Here's why your reasoning is incorrect, at least in my view:

 

[turkeyjerky]

Seriously, it's not my reasoning. It's what uptodate says. I don't need to come up with someone's stupid article. OMG, I just hated argumentative types in medical school and residency. Go into internal medicine as an attending and prove everyone wrong. Glad I'm done with all that bull and don't have to answer anyone anymore. You can argue for the next 5 years until you get to be an attending, good luck with that. As some one else said, Dude- let it go.


In the real world vitamin D deficiency afflicts EVERYONE who walks through the door. Parathyroid disorders are the zebra. Move on.

Honestly dude? You take one line out of context from an article on uptodate and think that trumps all? Since that's the source de jour, here are some other quotes from it:

"Among all causes of hypercalcemia, primary hyperparathyroidism and malignancy are the most common, accounting for greater than 90 percent of cases"

"The degree of hypercalcemia also may be useful diagnostically. Primary hyperparathyroidism is often associated with borderline or mild hypercalcemia (serum calcium concentration often below 11 mg/dL [2.75 mmol/L])."

In the article about osteomalacia:
"The serum concentration of 1,25-dihydroxyvitamin D is not helpful because it may be normal, low, or high, depending upon the severity and duration of vitamin D deficiency "

Man, you are just so f*cking condescending--it kinda gets to me that your default position is that someone who's younger than you doesn't know jack.

 

[cabinbuilder]

Nothing like beating a dead horse!!! Probably gonna be an Internist. Just like those fleas to cling to that last hair shaft.

 

[turkeyjerky]

Nothing like beating a dead horse!!! Probably gonna be an Internist. Just like those fleas to cling to that last hair shaft.

don't get it

 

[Rendar5]

don't get it

He's saying that you've convinced yourself that you're right to the point that your brain will find any explanation to the contrary wrong, nonsensical, full of holes, or insulting. Now as to whether you're right or not, I don't know. I'd defer to an endocrinologist since I'm getting to the point that I realize there's a huge disconnect between textbook and real-world medicine.

 

[turkeyjerky]

He's saying that you've convinced yourself that you're right to the point that your brain will find any explanation to the contrary wrong, nonsensical, full of holes, or insulting. Now as to whether you're right or not, I don't know. I'd defer to an endocrinologist since I'm getting to the point that I realize there's a huge disconnect between textbook and real-world medicine.

the thing is, he never presented even one iota of evidence to suggest that I'm actually wrong. Do you actually see anything above I've posted that is incorrect? (please, let me know) Look--I don't like the idea that people above me in this field don't know what their talking about and are teaching wrong concepts; I spent a fair amount of time looking into this in an attempt to find something (a case report, anything) that lists vitamin d deficiency as a cause for hypercalcemia--couldn't find anything.

Plus, I don't really see where I was being insulting above. Nonsensical, well that's always a possibility.

 

[VA Hopeful Dr]

the thing is, he never presented even one iota of evidence to suggest that I'm actually wrong. Do you actually see anything above I've posted that is incorrect? (please, let me know) Look--I don't like the idea that people above me in this field don't know what their talking about and are teaching wrong concepts; I spent a fair amount of time looking into this in an attempt to find something (a case report, anything) that lists vitamin d deficiency as a cause for hypercalcemia--couldn't find anything.

Plus, I don't really see where I was being insulting above. Nonsensical, well that's always a possibility.

Maybe I can help you on that last bit. I think it wasn't what you said but how you said it that some might find insulting or rude - I know I did. I'll elaborate...

You: You're really just repeating, almost verbatim, what I was told in class w/o giving any reasoning or evidence whatsoever.

First, that's kind of a jackass way to say what you did. It sounds like you are accusing the other guy of parroting your attending without giving it any thought. I'd have gone with something like "Yeah, that's very similar to what my attending said, but I'm still having trouble understanding how that works". Its not as confrontational and people are more likely to help you out if you're nice about things.

You: Plus, show me one article or other source that lists vitamin D deficiency in the differential for hypERcalcemia. I've looked and cannot find one.

Again, its the way you worded it. Why couldn't you have said something like "I've looked for references about this and haven't been able to find anything, any idea where I can start looking?".

Basically, your tone is just very confrontational with someone who was trying to help you. After that person's second post, I can understand you getting a little snarky but not after an honest attempt to help you out.

Then again, maybe I've just trained out more congenial places.

 

[turkeyjerky]

Fair enough, I can see how one might interpret my words as, well I wouldn't go so far as to say insulting or rude, but how about brusque, impolite or even churlish. And, I'll freely admit, that I do tend to be more plain-spoken and to-the-point than some others, oh well--I guess that's how I was raised.

As for your re-wordings of my statements--had I said that I really would not have been sending the message I intended. I was accusing the poster of simply parroting the attending (whether he actually gave it any thought I can't comment on). And, on the second point, I wasn't hoping for guidance on how to go about a lit search--if fact I was challenging him to provide some sort of literature to back his point up. So, sorry if my tone was a little too confrontational for your tastes, but, in all honesty, I said what I meant.

 

[VA Hopeful Dr]

Fair enough, I can see how one might interpret my words as, well I wouldn't go so far as to say insulting or rude, but how about brusque, impolite or even churlish. And, I'll freely admit, that I do tend to be more plain-spoken and to-the-point than some others, oh well--I guess that's how I was raised.

As for your re-wordings of my statements--had I said that I really would not have been sending the message I intended. I was accusing the poster of simply parroting the attending (whether he actually gave it any thought I can't comment on). And, on the second point, I wasn't hoping for guidance on how to go about a lit search--if fact I was challenging him to provide some sort of literature to back his point up. So, sorry if my tone was a little too confrontational for your tastes, but, in all honesty, I said what I meant.

That is certainly your right, but don't be surprised if people get a little pissed off if this is your standard approach.

 

[ScubaStarved]

First, I think you're right that there may not be enough information to definitively answer the case. It's made more challenging by the supplementation of Ca and D.

In the article about osteomalacia:
"The serum concentration of 1,25-dihydroxyvitamin D is not helpful because it may be normal, low, or high, depending upon the severity and duration of vitamin D deficiency "

If you read this again, you'll see that it's stating that 1,25 D is not a sensitive test. It says nothing about the utility of a positive result (specificity or PPV).

IMO, the way to stick it to this guy is to keep your head down, get good evals, ace the shelf, and submit a negative eval of this person including specific instances in which they were not a good educator (if you think they deserve it).

 

[turkeyjerky]

First, I think you're right that there may not be enough information to definitively answer the case. It's made more challenging by the supplementation of Ca and D.


If you read this again, you'll see that it's stating that 1,25 D is not a sensitive test. It says nothing about the utility of a positive result (specificity or PPV).

IMO, the way to stick it to this guy is to keep your head down, get good evals, ace the shelf, and submit a negative eval of this person including specific instances in which they were not a good educator (if you think they deserve it).

See, a comment like that leads me to believe that you don't actually understand vitamin D metabolism. I'm starting to think that this is pretty common among people--they know vitamin D is 'activated' in the kidneys, but don't actually understand what that means. Maybe it'd be easier if we talked about cholecalciferol, calcidiol and calcitriol.

As for your second point, this wasn't my attending, it was a woman who gave us a single lecture on osteoporosis. Plus, "stick it to [her]", who cares? I started this thread b/c I was hoping that someone would either prove me wrong or confirm that I was right, because I don't want to graduate as someone who doesn't know their stuff.

 

[ScubaStarved]

See, a comment like that leads me to believe that you don't actually understand vitamin D metabolism. I'm starting to think that this is pretty common among people--they know vitamin D is 'activated' in the kidneys, but don't actually understand what that means. Maybe it'd be easier if we talked about cholecalciferol, calcidiol and calcitriol.

As for your second point, this wasn't my attending, it was a woman who gave us a single lecture on osteoporosis. Plus, "stick it to [her]", who cares? I started this thread b/c I was hoping that someone would either prove me wrong or confirm that I was right, because I don't want to graduate as someone who doesn't know their stuff.

Way to continue being condescending while completely missing the point. +1 you.

Your quoted sentence from uptodate is a poor explanation for why 1,25 D is a poor assay of Vit D status. Your quotation states exactly what I said, that the test is not sensitive. (Four minutes of pubmed abstract browsing shows that 1,25 D has a short half life and is best employed in testing renal ability to perform the final hydroxylation step, which is never done.) With that level of PTH and intact renal function, this person should have a normal-high 1,25 OH Vit D level. This person is vit D deficient, BUT I still agree that you cannot rule out other disorders such as primary hyperpara (a few abstracts report on cases in which the two occur together, those might be interesting to you). More likely, however, is that her Ca supplementation maintained a high Ca despite borderline low levels of active D.

Finally, you posted this thread because you got butt hurt over being called out. I merely suggested letting go. And my understanding of D metabolism is fine, thanks for your concern.

/rant