Hypothyroidism and Hyperthyroidism: What’s the Difference? with Ossama Lashin, MD, PhD

Podcast Transcript

John Horton:

Hey there, and welcome to another Health Essentials Podcast. I'm John Horton, your host.

Your thyroid is a small gland in your neck that can cause serious problems when it gets out of whack. The two most common types of thyroid disease are hypothyroidism and hyperthyroidism — two conditions that sound similar but exist on opposite ends of the spectrum. So what's the difference? That's a question we'll tackle today with endocrinologist Ossama Lashin, Medical Director of Cleveland Clinic's Thyroid Center. He's one of the many experts at Cleveland Clinic who visit us weekly to unravel the mysteries of health.

Now, let's find out how a slight difference in spelling can make a big difference when it comes to thyroid disease. Dr. Lashin, welcome back to the podcast. It's always great to have you on.

Dr. Ossama Lashin:

Thank you, John, thank you for having me.

John Horton:

So you're here today to talk about hypothyroidism and hyperthyroidism. Can you give us a basic rundown of what separates the two, aside from a few letters?

Dr. Ossama Lashin:

All right, so the thyroid gland is a small, butterfly-shaped gland that sits here in the lower neck, and the main task of that gland is to produce a hormone called thyroid hormone. The gland produces that thyroid hormone in a specific amount. That specific amount is necessary for the function of that hormone — meaning the body requires an exact amount of that thyroid hormone to be able to do its function. Every cell in the body requires that hormone. When that hormone is too high — meaning that the gland is producing too much or secreting too much — or too low because the gland is not able to produce the right amount, it's underactive, it's crippled, it's sluggish for some reason, then it produces too little thyroid hormone and that can cause what we call hypothyroidism or low thyroid levels.

And the other end of the spectrum is hyperthyroidism if the hormone level is too high. That's the difference between hypo and hyperthyroidism.

John Horton:

It's very much of a Goldilocks thing, so it can't be too much, not too little — you want everything to be just right.

Dr. Ossama Lashin:

Yeah, moderation is key.

John Horton:

So as we're talking about getting that level right, and obviously, you don't want it to be too high or too low, if you are in either one of those extremes, do you get really different symptoms if you're high or low, or are they similar?

Dr. Ossama Lashin:

No, there are several symptoms that differentiate both entities from each other. Some are not just symptoms but clinical manifestations that your healthcare professional will uncover even if you are not aware that it is related to the thyroid. And that's why we usually recommend if there is some suspicion that there is a thyroid condition, you see your primary care doctor, you get a physical exam, you get some testing, preliminary testing. And if a thyroid condition is still suspected by your healthcare professional, then you would see a specialist if necessary.

The symptoms of both entities are usually different, but there are a few symptoms that overlap. For example, and we've talked about this before, feeling tired or fatigue in general as an unspecific symptom can happen in either condition. You can be tired if you are hyperthyroid, with high levels of thyroid hormone because that high level is exhausting your body's cells. And consequently, you feel as tired as somebody who finished running a marathon.

Versus hypothyroidism, when you have little amount of thyroid hormone that is not enough for your body's cells to perform their job, your metabolic rate is low. So you have the fatigue of somebody who has not slept in four days. You're sleepy, you're sluggish and your body systems are basically coming to a standstill.

John Horton:

What other symptoms might be shared between hypo and hyperthyroidism?

Dr. Ossama Lashin:

There is one symptom that I want to mention in this specific segment, which is weight gain. Just from my experience in clinical practice as a thyroidologist, I get a lot of consultations about weight gain, the suspicion that it could be related to a thyroid disorder.

There is a general conception that if you have an underactive thyroid, you will gain weight but if you have an overactive thyroid, you'll lose weight. And 90% of the time that's true — at least, the thyroid will be a factor or play a role in a weight change in that manner. However, people with hyperthyroidism, not all of them lose weight. Some of them do gain weight because hyperthyroidism not just stimulates your metabolism to burn more calories, but it also stimulates your hunger centers. It stimulates your appetite. So if somebody eats way more than what the overactive metabolism is burning, they will gain weight.

John Horton:

That makes sense.

Dr. Ossama Lashin:

So not everybody with hyperthyroidism would lose weight, and that can be a common symptom. Weight gain can be a symptom of both.

However, there are defining symptoms. For example, if somebody has a hyperthyroidism they will have a rapid heart rate. An underactive thyroid person would not have a rapid heart rate, would have a slow heart rate. They may have some irregular beats because those heart cells are not functioning optimally because thyroid hormone levels are suboptimal. But they will have a slow heart, not a rapid heart. So these are called “defining symptoms” or “differentiating symptoms.”

John Horton:

And I've seen other things with thyroid issues, too, where you're on opposite ends there — the hyper versus hypo, where you can feel cold or hot or be constipated or have diarrhea. It sounds like there's kind of a yin and a yang to all of these.

Dr. Ossama Lashin:

Yeah. And this is the reality of both conditions.

So with hyperthyroidism, the excess thyroid hormone is making all your body systems work over time. So your GI tract is moving faster, so food is going through it faster. So the chances of frequent bowel movement or loose bowels are higher as opposed to hypothyroidism or the GI tract is more sluggish, is more slower. So the risk of constipation and the food transit time is slower.

The same thing applies to almost all the body organs. In hypothyroidism, you have dry skin and not the usual dryness that we get in the winter, but really dry skin that nothing works for. You don't see that with hyperthyroidism. You may see other skin changes in hyperthyroidism, but not the same as hypothyroidism. And if you think of the thyroid hormone as one protein that has an effect on everything in the body, then the symptoms or the clinical manifestations are many. You just have to see or be taken care of by the right healthcare professional who can define what these symptoms are related to.

John Horton:

So it sounds like … in looking at it, there's a lot of things where they're exact opposites, which is kind of what you'd expect given that the two conditions are kind of opposite — either too much or too little. And then there's also some that are shared, like you said, fatigue and sometimes weight gain.

One thing I want to make sure to ask you about is, what about mood changes? Since we're talking about hormones, I'd imagine both of them can lead to some pretty drastic swings there.

Dr. Ossama Lashin:

Yeah. And that's right. And we see this sometimes as the presenting symptom. Somebody all of a sudden feels that they are more irritable, more easy to snap on the opposite if they're hyper, if they have too much thyroid hormone. As opposed to hypothyroidism when they're feeling more subdued, more depressed, they don't want to get up and do anything, their drive is low. But let's also remember that the majority of these symptoms are non-specific. So when they are happening, you want to investigate whether it's truly related to a thyroid issue or not because they may be happening because of something else. But it does have an effect on the mood.

And also, we have to remember that an abnormal thyroid hormone level can have an impact on other hormones in the body that lead to more changes such as testosterone levels, estrogen levels and so forth.

And also keep in mind that thyroid hormone is a hormone that controls the metabolism, growth and development of the cells of the body, including the nervous system cells. So it makes sense that an abnormal thyroid level will have an impact on the brain chemistry, on the neurons of the brain that secrete certain neurotransmitters and certain chemicals that control the person's mood.

John Horton:

This is all just so fascinating — what's going on in our bodies just constantly, it just never ceases to amaze me.

So as we're looking at these issues, either hypo or hyper, they seem so different. But do they have different causes that can trigger each one? And are there specific risk factors we should be aware of for hypothyroidism or hyperthyroidism?

Dr. Ossama Lashin:

Well, in this day and age, the common reason for a thyroid function problem leading the thyroid to be overactive or underactive is an autoimmune issue. Meaning the immune system produces antibodies, which are small proteins that the immune system manufactures mainly as a tool to fire off infection. But in certain disorders, the immune system makes a mistake and makes these antibodies or proteins against the component or protein in the thyroid gland. And because of that antibody or protein attacking that component of the thyroid gland, it can lead to either the thyroid becoming sluggish, dysfunctional, unable to perform its job at the optimal level or overactive, hyper-functioning and producing too much of the hormone that it's supposed to produce at a specific level.

John Horton:

Can an illness kick that off, like if you get a nasty flu bug? Can you have something that, say, attacks the thyroid or does something to it that kind of causes some of these problems?

Dr. Ossama Lashin:

Well, that's related to a theory in the field of thyroidology called “the innocent bystander theory.” It indicates that the thyroid is just an organ in the body, and while the body is fighting off an infection such as a virus, the immune system is so consumed by that war between itself and the infectious agent that it can sometimes make a mistake and produce the wrong soldiers that would attack the thyroid. It's one of the theories for why thyroid autoimmunity develops. But the true reason why the immune system can sometimes attack the thyroid and cause dysfunction is not really pinpointed yet. There are theories, but the exact reason ... and in my own understanding of things, everybody's different, everybody's trigger for autoimmune thyroid disease is different. And I believe also that people are genetically predisposed to having autoimmune thyroid disease or not because so many of us would get viral infections, flu and COVID and other infections without ever developing autoimmune thyroid disease. It leads me, in summary, to believe that there are different factors that make people susceptible to autoimmune thyroid disorders based on our genetic makeup.

John Horton:

So given that, if you have a family history of some thyroid issues, are you maybe more likely to see them yourself?

Dr. Ossama Lashin:

Yeah. And we see that in some families, too. So it is not unusual, mostly in females because as you may know, thyroid disease is more common in females than males for some reason — and that's another reason we do not understand why is there more gender bias, if you will, that females suffer from more thyroid disorders than males — but we commonly see it is running in several generations in the same family. So it is not unusual to see somebody with autoimmune thyroid disease leading to hypothyroidism. And that patient would tell me that her mom and her aunt on her mom's side, for example, they both have been diagnosed with this condition.

John Horton:

But then, since the thyroid seems to be such a mysterious and vexing organ in there, it also seems like you can just come out … out of the blue, too, you could have an issue.

Dr. Ossama Lashin:

Yeah, of course. So it doesn't necessarily have to run in the family, but when there is a family history it definitely raises the risk of an individual to suspect that they do have the same thyroid condition. Especially if they're female and especially if they have a mother or aunt or somebody else in their immediate family with the same condition.

The other thing that I wanted to mention is, I think I've mentioned this before in our previous podcast, is that there is a difference between having a thyroid that doesn't work — meaning the function of the gland is abnormal — and a thyroid that works well but it does have a structural problem — has a lump, has a tumor, has a nodule that needs to be investigated — because those are two separate entities. You can have a structured disease that is probably nothing, probably a benign lesion. But you have to go through the workup to make sure it's not thyroid cancer, for example. As opposed to having a functional problem where you have a thyroid that when we do an ultrasound, it looks pristine, doesn't have any blemishes or nodules or anything, but it doesn't work well. That's a functional problem that we need to treat medically.

John Horton:

So when we talk about treating and managing these kinds of functional conditions or issues, I'm assuming that each one of these has a different approach.

Dr. Ossama Lashin:

In a sense, yes. So because we're dealing with two conditions, one that includes having too high thyroid hormone levels and one that includes having too low thyroid hormone levels, and we cannot really treat the reason for why they happened. So we cannot relieve that. The only solution that we have is to optimize the thyroid hormone levels. So if the gland is overactive and producing too much, we have to either give a medicine to slow it down to where it should be or get rid of the gland completely if we're not able to do that. On the other side, if the gland is underactive and producing too little thyroid hormone, then we supplement with exogenous thyroid hormone or thyroid hormone in a pill form that the person takes to supplement their body with the amount that is missing that the thyroid cannot make any more.

So the key is to optimize that level, bring it back where the body likes it. And that level is different. There's a general range for where that level should be, but your optimal level is a little different than mine. So this is where the professional comes in, works with the patient to get them optimized to the best level they should be at.

John Horton:

So it sounds like medication is usually the means to level things out.

Now, you had mentioned thyroid can actually be removed in some cases?

Dr. Ossama Lashin:

Yeah, especially in situations where the thyroid is either very overactive and using medical therapy is not quite effective in controlling its function. As a matter of fact, we only have one main medicine that we use to slow down a thyroid. It's usually recognized as a temporary solution to control the thyroid function until we get rid of the thyroid gland. However, more recent data and more recent evidence, from clinical practice, we're seeing that somebody can stay on that medicine with good control of their overactive thyroid back to normal, if they're able to achieve remission of the autoimmune thyroid condition leading to that. Or they can stay on a very small dose of that medicine long term. However, that's not the recommendation of most of the professionals in thyroidology. And the main way of dealing with an overactive thyroid is either by destroying the gland with radioactive iodine, which is a one-time pill of radioactive iodine that goes to the thyroid and burns the gland, or surgically removing the gland.

Those are the two main ways of dealing with an overactive thyroid. The question is, usually that we receive, what will that person do after we take their thyroid out? Well, we have thyroid hormone in a pill form that they will have to take every morning for the rest of their life.

John Horton:

If you have an overactive or an underactive thyroid and you do go and get treatment, is there one type that seems to be addressed more successfully than the other?

Dr. Ossama Lashin:

I think the treatment for thyroid conditions are really pretty straightforward and it's commonly very successful. Most of the time that I see patients in the clinic, whether it is a referral from a colleague in primary care or somebody's coming in for a second opinion about their condition, their thyroid condition treatment requires patience. And it requires not just patience, but accurate assessment of the response to the treatment. So the follow-up on how the treatment is working for the person and how the treatment is affecting how they feel and the resolution of their symptoms is very important to achieve that optimization of their thyroid hormone.

So it's not like, for example, treating chronic conditions where you are put on a certain medication and you're doing well and you continue to do well on that medicine forever or for a long time. And you only need to see your doctor very infrequently to renew medicine or get it changed.

Initially, when you start treatment for thyroid hormone, you have to be under close follow-up and monitoring and assessment of response of treatment to clinical manifestations to get optimized. And once you're optimized, it's pretty straightforward after that. You commonly do not need any further changes after that.

John Horton:

So it sounds like treatment is pretty effective for both of them, and I'd imagine then, I'd say one of them is not more dangerous or worse to have than the other. It sounds like they're just both issues with the thyroid and they can both be addressed.

Dr. Ossama Lashin:

Yeah, I wouldn't say that one of them is more dangerous than the other. But in our profession, we think of a hyperactive thyroid as a more urgent thing to deal with because that excess thyroid hormone is really exhausting your body and we're worried about your heart.

John Horton:

Well, that would make sense. It sounds like it's harder to slow things down than it is to maybe pump things up a little.

Dr. Ossama Lashin:

Yeah. And an underactive thyroid, you can slowly raise the thyroid hormone level with thyroid hormone pills gradually until you optimize the level. And you can take your time and you can monitor your patient and so forth. Somebody with excess thyroid hormone due to an overactive thyroid, you need more of an urgent solution. You need to treat them with certain medications to relieve the effect of that excess thyroid hormone off of the heart and other organs that may be suffering that continuous order to perform over time.

John Horton:

When it comes to thyroid disease, is there anything that we can do to protect the thyroid, keep it running right and guard against getting either one of these conditions?

Dr. Ossama Lashin:

Well, because the majority of time these conditions are related to an autoimmune thyroid disorder, we can't really do much about that. It's a mistake that the immune system makes and you cannot avoid that mistake. However, thyroid health like any other organ in the body, requires healthy living, healthy eating, good nutrition. In the past, decades ago, I would say, definitely more than 60 years ago, there was a degree of iodine deficiency in the United States, but we've managed to eliminate that. So we've fortified many of our food products and our ingredients that we use in cooking such as salt with iodine. So that is not a reason anymore. It's very hard to find iodine deficiency in the United States. However, in other parts of the world, it is still a problem. So iodine is necessary for the thyroid to perform at its optimal function. But keep in mind also that excess iodine … so if somebody makes more iodine than necessary, it's also detrimental to thyroid function. So the thyroid also requires the right amount of iodine. And in the United States, we don't have to worry about that.

John Horton:

It makes perfect sense with everything with the thyroid, it's all about balance, right?

Dr. Ossama Lashin:

Exactly.

John Horton:

So we've covered a lot of ground here today, Dr. Lashin. But if there's one thing in particular that folks should take from this discussion, what should it be?

Dr. Ossama Lashin:

Well, when you're not feeling well, do not dismiss how you're feeling and attribute it to something minimal until you see your healthcare professional and look into the situation. But at the same time, do not jump to conclusions either. Do not read information online that you may not be at a point where you can interpret that information well and just cause extra anxiety and concern for no reason.

Number two, the thyroid may be a factor in certain situations in how you feel but it may not be the only factor. And there are very easy tests and straightforward and accurate tests to check how the thyroid is working, and either exclude or confirm that there is a thyroid problem that we need to address.

And finally, I would say that in the field of thyroid disorders, there is always a straightforward, effective way of handling the condition. So treatments for thyroid conditions are very effective. And diagnosing thyroid conditions … we have many accurate tools to utilize to come to a conclusion about whether a thyroid is dysfunctional or has a problem that requires medical attention or not.

John Horton:

Well, that's great news. It sounds like whether your thyroid is overactive or underactive, there are ways to bring it back into the range where you need it.

So Dr. Lashin, thank you very much for coming on today. And just once again, really opening our eyes to everything that involves the thyroid.

Dr. Ossama Lashin:

Thank you, John. It's been a pleasure.

John Horton:

While there may be some overlap between hypothyroidism and hyperthyroidism, they are vastly different conditions. The good news: Both can be treated and managed. Talk to your doctor to find the best approach.

If you liked what you heard today, please hit the subscribe button and leave a comment to share your thoughts. Till next time, be well.

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