Identifying Parathyroid vs Thyroid Conditions to Optimize Thyroid Surgery

[Dr. Gopi Shah]
Can you expand a little bit? For the patients that come in for what you're working at, for example, parathyroid adenoma, and you do an ultrasound, you're also looking at the thyroid gland, what kinds of thyroid problems are you seeing? Is it just single nodules that then you have to get FNAs for? Then vice versa, the patients that come in for a thyroid problem that you're drawing labs on, you're like, "Oh, the PTH is high." What concurrent pathology or diagnosis are you also seeing?

[Dr. Michael Singer]
Yes. We'll start with just to keep it consistent with my prior comments, so just thyroid surgery. Certainly the most common thing that I see is secondary, particularly where I am at Michigan, vitamin D deficiency is insanely common. I think it's helpful in all patients to replete that. In my mind, there's really two primary reasons. This goes back to your question from before about hypoparathyroidism versus hypocalcemia.

I think that in patients who have total thyroidectomy, and are at genuine risk of hypoparathyroidism, the question with the hypoparathyroidism is do they become symptomatic and actually put at risk. We all know about tetany, "Oh my God, are they going to show up and they're not going to be able to breathe?" That's not from the hypoparathyroidism, that's from the hypocalcemia. Ultimately, and this is, studies have shown this consistently that the patients who do become hypoparathyroid, the ones who are at more at risk of becoming hypocalcemic and consequently then symptomatic are those patients who are vitamin D deficient.

Those patients, if you can replete them beforehand, there's some studies out there that suggest somehow that repleting it reduces the risk of hypoparathyroidism. I don't believe that's true. I'm not sure how that would possibly work from say a surgical perspective. If you devascularize the glands, if you traumatize the glands, they don't care whether the vitamin D is high or low. What I do think is that those patients are in fact more at risk of developing hypocalcemia as a result of the hypoparathyroidism and then becoming symptomatic. Those patients I replete for that reason.

The other reason, this may be sound strange to people, but even when I'm doing hemithyroidectomies, I like to know that level beforehand because if they have vitamin D deficiency, it's not unusual to get in there and find, guess what, enlarged parathyroid glands. You don't want to be in a situation where you go in there and you say, "Oh, look, I found enlarged parathyroid glands, the patient must have parathyroid disease too, I'm going to take these out."

To some extent it's repleting the vitamin D, to some extent it's recognizing what you're actually dealing with, but it is not unusual, particularly patients with mild hypercalcemia, where I'll see patients who've been walking around for years with mild hypercalcemia and no one's ever said, "Hey, do you know that your calcium levels are a little elevated?" I'll then check a concurrent PTH level and those patients have primary disease. In my mind, if I'm going to be going to the operating room, and someone needs to have both, you want to know that at the time you're there. You don't want to be like, "Oh, wait, I wish I had checked this beforehand. Now I don't know what to do."

To some extent, that's the same on the parathyroid surgery side of things. What I mean by that is, historically, the way parathyroid surgery was done, certainly in the age before all these imaging studies were performed, was patients were brought to the operating room, and the standard, because there was no information beforehand, was bilateral neck exploration. There was no preoperative localization that was obtained. Because of that, routinely, patients would be brought to the operating room, and in addition to finding maybe a parathyroid adenoma or parathyroid hyperplasia, people would find, "Oh, wait, here's a nodule. What is this? Is this malignant or not? Should I take this out?" Then you would see all these frozen sections being done, and then a patient maybe would end up with a hemithyroidectomy. The reality is, just like everything else, we want to go in with as much of a plan as possible. When you say like, "What thyroid disease am I finding?" Certainly the most common is thyroid nodule disease. Oftentimes, that's single disease, but sometimes it's multi-nodular disease, but certainly single nodule disease.

Then, in those patients, I go down the same pathway I would if they were presenting to me with a single thyroid nodule. Is this something that warrants biopsy? Is this something that should be at a minimum discussed with the patients? Because sometimes I mentioned it to patients and they're like, "I don't want to know about it. That's not why I came here. I came here to have parathyroid surgery. Why are you talking to me about thyroid?" That's fine. I don't want to ever say to a patient, "Oh, don't even think about it." Meanwhile, they have a thyroid cancer that I could have easily addressed at the same time.

In both cases, there are things that are just trying to give me as much information as possible before I go to the OR to know what I'm actually dealing with in a patient.

[Dr. Ashley Agan]
Moving forward with the conversation, we're focusing on finding parathyroids, whether that be during a thyroid surgery or if you're looking for a parathyroid adenoma or something like that. Before we get to the surgical part, can we touch a little bit about on as you're seeing patients and work up preoperatively that helps you? For example, what imaging do you like to prepare you for surgery?

[Dr. Michael Singer]
Yes. I'm going to keep hammering on this throughout probably this conversation. I apologize in advance if that becomes annoying-

[Dr. Ashley Agan]
Hammer it.

[Dr. Michael Singer]
-to one or both of you. Really, we have to talk about what surgery are we talking about. In thyroid surgery, patient comes to me, they've got a big goiter, they've got cancer, whatever else it is. There's no consideration in my mind of getting localizing studies in those patients. That's not the goal of the surgery. Now, that being said, I will tell you that on all my thyroid patients, I still check PTH levels, I still look for hypercalcemia because it's not unusual for those patients to have concurrent primary hyperparathyroidism.

I actually routinely check those labs on all my thyroid patients looking for parathyroid disease. Now that includes surgical parathyroid disease and by that is primary or say some forms of secondary that can be reversed prior to the surgery, say vitamin D deficiency. In thyroid surgery, I'm not thinking about localizing glands preoperatively. Now that's very different obviously than in parathyroid surgery where there really has become an emphasis, at least in my mind, sometimes excessive on people trying to focus on the idea of which gland is it and can I predict that before the surgery.

In patients with primary hyperparathyroidism in my practice, the one always absolute study that I'm getting is ultrasound, and that's for two reasons. First of all, I think particularly when it's surgeon performed, ultrasound is extraordinarily sensitive for finding adenomas, but particularly smaller adenomas, ones that you won't necessarily see on whether it's a 4DCT or say Sestamibi or nuclear medicine imaging.

The other thing that I think is critical in parathyroid patients in terms of getting ultrasound is, now this is the opposite of what I said before, you want to be looking for concurrent thyroid disease. In my practice, about 5% of the patients that I operate on, I end up doing both surgeries. That's how common these diseases are to run together. People argue a lot about what's the best imaging study for parathyroid disease. You'll see, at least in my mind, endless papers on what's the best study to get.

First of all, I tell people it's institutional. We all practice in different settings, different places. There are places where patients come from, where they come with Sestamibi scans to see me and I'm like, "I don't even need to look at it. It's going to be negative." I just know that they don't do Sestamibi scans frequently enough that it's going to be a positive result. At other institutions, 4DCT is amazing and other places, Sestamibi is great, whatever it is. I don't think there's an absolute. I know that in my practice, ultrasound is extremely sensitive for parathyroid localization, but again, I think it's important to point to recognize it's also looking for concurrent thyroid disease.