Hey there everyone! This is Melanie, welcome back to the Nursing School Week by Week podcast. I know it’s been a minute since I’ve made a podcast, and I’m so sorry. I just, you know, real life happened, and when you’re in nursing school, real life can be a struggle. I did wind up getting all A’s in my 1st semester, and now I’m back to help you do the same.
Alright. So for this week, the most high-yield topic is hyper and hypothyroidism. You’ll see a lot of your test questions coming from this subject.
I’m gonna talk about hyperthyroidism first, and then I’ll cover hypothyroidism.
So, What is hyperthyroidism? It’s when your body makes too much of the thyroid hormones T3 and T4. I’m not sure how much of the A&P you remember from forever ago, so to review how T3 & T4 are made, your hypothalamus in your brain releases Thyroid Releasing Hormone; this makes the Pituitary gland release TSH, or Thyroid Stimulating Hormone, and that makes the thyroid, the little butterfly-shaped gland on your neck, produce T3 and T4.
In both hyper and hypothyroidism, the main causes are autoimmune disorders. The autoimmune disorder that causes hyperthyroidism is called Graves disease. With Graves disease, the patient will have a goiter, or an enlarged thyroid gland, that’s sometimes so big, you can see it from the door of their room. They’ll also have the characteristic bulging eyes, or exophthalmos. This will also be very noticeable, cause it’ll look like they are staring at you in a creepy way, and their eyes are protruding out of the sockets. Usually, our upper eyelids cover the top half of our iris. But in a patient with exophthalmos, you’ll be able to see the white of their eyeball above their iris, below their upper eyelid. So, if the patient has green eyes, you’d be able to see some white between the green and their upper eyelid. Sometimes the exophthalmos will be so bad that they can’t even close their eyelids all the way.
Other causes of hyperthyroidism are tumors, like a pituitary tumor, or a toxic nodular goiter, or thyroiditis, which is inflammation of the thyroid. Also, if someone is taking medication to treat hypothyroidism and they take too much, that can cause them to go into a state of hyperthyroidism.
The people who are most at risk are: women ages 20-40, people with a family history of Graves disease, and smokers. In fact, the only modifiable risk factor is smoking, so if someone does have a history of Graves disease in the family, they should be advised to avoid cigarette smoke like the plague. Like cross over to the other side of the street, if they see someone smoking. That’s how much of a factor it is.
Other signs and symptoms we’ll see in someone who has hyperthyroidism are almost all related to their increased metabolism. These patients are going to be super skinny. When you think of hyperthyroidism, I want you to think “High and Hot.” They have high metabolism, and they are hot. They have heat intolerance, which means they're hot all the time. They will have hypertension and tachycardia. They will have warm, moist skin and silky hair, because of the increased blood circulation going on. They will have diarrhea because their GI system is in overdrive. They could have tremors. The way to test for this is to have them hold up their hand in front of their face and stretch their fingers apart. You can also place a sheet of paper on top of their hand to make the tremor easier to see. If they have tremors, the paper will shake. They may also not get their period at all. This is called Amenorrhea. Remember, the prefix A means absence of, and menorrhea means menstruation. So Amenorrhea is the absence of menstruation.
If the hyperthyroidism goes untreated, it can turn into something called a Thyroid Storm. This is a life-threatening condition that will present with a high fever, an altered mental status, and severe tachycardia.
To diagnose hyperthyroidism, we will do a blood test and if it shows elevated levels of T4, but decreased levels of TSH, then we’ve got hyperthyroidism. Remember the TSH is released by the pituitary gland to tell the thyroid gland to make T3 and T4. But if there is already a ton of T3 and T4 in the blood, the pituitary gland is going to try to slow that down by making very little if any TSH.
If the blood test does indicate hyperthyroidism, they may do a radioactive iodine uptake test, or RAIU. For this test, the patient takes a small amount of radioactive iodine by mouth and then has their blood drawn after 2, 6, and 24 hours to see how much of the iodine the thyroid has absorbed. This test will show whether the patient’s hyperthyroidism is caused by Graves disease, or another form of thyroiditis. If less than 2% of the iodine is absorbed by the thyroid gland, then it is not Graves disease.
The medications we use to treat hyperthyroidism are antithyroid meds, iodine, and beta blockers. The main antithyroid medication is Methimazole. But if the patient’s pregnant, she’ll get propylthiouracil. Both of these antithyroid medications inhibit the production of thyroid hormones. Potassium Iodide is iodine that’s given usually as preparation for a thyroidectomy, or the surgical removal of part of the thyroid, because the iodine slows down the blood flow in the thyroid, which decreases blood loss during surgery.
Beta blockers are also prescribed to treat the cardiac issues that these patients face. Remember they have tachycardia and hypertension, so they’ll get a beta blocker, usually propranolol or atenolol (if they’ve got asthma or heart disease), and this will slow down their heart rate and lower their blood pressure.
Other treatments for hyperthyroidism are Radioiodine Ablation, and a thyroidectomy. The word “Ablation” means the destruction of a body part, so in Radioiodine ablation, we are basically destroying the thyroid gland, so it can’t make as much T3 and T4. The thyroid gland is going to suck up iodine in any form, so we give the patient radioactive iodine by mouth, and it’s absorbed by the thyroid gland, which makes it shrink and destroys it. But, the downside of this is, because this is not an exact science, we can’t control how much of the thyroid gland is destroyed, and in 80% of cases, we’ll see them go from having hyperthyroidism to having hypothyroidism. And then they’ll need to be on life-long T4 replacement meds.
The thyroidectomy, or surgical removal of the thyroid, is done if the patient can’t get the radioactive iodine for some reason, or if their thyroid is so enlarged that it’s putting pressure on the trachea or esophagus and making it hard for them to breath or swallow. Usually a subtotal thyroidectomy will be done to leave enough of the gland to still produce some T3 and T4. A total thyroidectomy is done if the patient has thyroid cancer, in which case they’ll have to take lifelong hormone replacements. A lot of test questions may come from how to care for a patient who’s just had a thyroidectomy. We want to remember to check their calcium levels, since hypocalcemia can occur if the parathyroid glands are damaged during surgery. Remember the parathyroid glands are 4 tiny little glands that are attached to the thyroid gland, and it’s super easy to accidentally damage them when the surgeon is taking out part of the thyroid. The parathyroid is what constantly monitors the calcium level in the blood and can adjust accordingly, but if it’s damaged or straight up missing, we’re gonna see low calcium levels. Remember the normal range of calcium is 8.5-10.5, so anything below 8.5 is too low. So, If you remove the T, then check the C! If you remove the thyroid, then check the calcium. Another thing we want to do with the post-thyroidectomy patient is to always have an endotracheal tube ready to go at the bedside because they just had surgery on their neck, and their airway may try to close up on you. You also want to listen for sounds of stridor which is caused by laryngeal edema and means they’re having difficulty breathing.
So how do we take care of the patient who’s got hyperthyroidism?
We’re going to monitor their cardiac output. Their blood pressure, pulse, breath sounds. Monitor for peripheral edema, JVD, and arrhythmias. We want to keep their environment calm, and cool. Remember, they are hot, and hyper, so give them a nice cool room, with the lights dimmed and speak in a calm voice.
Check their eyes closely. They will probably be referred to an ophthalmologist, but you still want to monitor for dryness, or any infection, like pink eye. They will need artificial tears eye drops, and you may need to cover their eyes with a dome-shaped eye cover and actually tape them closed at night, so they can sleep. They will need to wear glasses during the day to make sure no debris gets into their eyes and injures them.
We want to keep the head of their bed elevated to 45 degrees, even at night, because gravity will make more fluid go to their eyes and increase the swelling even more.
Make sure they’re eating enough food. They’re bodies are in high metabolism mode so they need a high calorie, high protein diet until their T3 and T4 levels are in check. You want them to eat frequent meals and snacks. Also, no coffee! They need to avoid any caffeine or spicy foods, as these can make your heart beat faster, and these patients already have tachycardia.
Talk to them about the feelings they are having about their bodies. The biggest concern most patients with Graves disease have is their bulging eyes. The exophthalmos. It’s embarrassing for them and sometimes it doesn’t go away, even after treatment. So this is something that would need some therapeutic communication.
Alright. Now we’re gonna talk about hypothyroidism. Hypothyroidism is when the thyroid gland doesn’t make enough T3 and T4. So just the opposite of hyperthyroidism. The most common cause is the autoimmune disorder, Hashimoto’s thyroiditis. I remember that Hashimoto’s causes hypothyroidism like hypO, HashimOto. Hashimotos is when your body makes antibodies that destroy your thyroid gland, which decreases T3 and T4. This causes the gland to grow bigger to compensate, which creates a goiter. So you can have a goiter with both hyper and hypothyroidism.
Another cause of hypothyroidism is simply not getting enough iodine in your diet, but this isn’t an issue here in the US, because we put iodine into our salt.
Also, if someone is getting treated for hyperthyroidism, like they get a thyroidectomy, or radioactive iodine ablation, those can both overcorrect to lead to hypothyroidism. Even if they are just taking antithyroid medication, and they take too much.
Women over 50 years old who’ve had a close relative with an autoimmune disorder are most at risk for developing hypothyroidism. Also, studies are now showing that the use of the cardiac drug, amiodarone, can cause hypothyroidism, since it contains high levels of iodine.
People with hypothyroidism are gonna be “Low and Slow”. They’ll have gained a lot of weight recently, because their metabolism is slow. They will be bradycardic, and have slowed thinking and depression. They’ll be cold all the time, or have what’s called “cold intolerance”. They’ll be tired and have constipation. Their nails will be brittle and their skin will be dry. They’ll have hypertension, and possibly a goiter on their neck.
If the hypothyroidism goes untreated, the patient could fall into a myxedema coma, which can be life-threatening. With myxedema coma, you’ll see a very low body temperature, hypotension, and a decreased respiratory drive. You’re going to want to keep a tracheostomy kit at the bedside to maintain that open airway, check acid-base balances, increase the body temperature, and increase the T3 and T4 levels with thyroid hormones given IV.
To diagnose hypothyroidism, the patient will get blood tests that’ll show decreased levels of free T4 and increased levels of TSH. Normal TSH levels are between 0.35-5.5 mU/mL, so anything above 5.5, would be increased.
The main medication given to treat hypothyroidism is Levothyroxine, which is a synthetic form of T4. You may wonder why we only give T4 and not T3 also, but that’s because your body will use T4 to make its own T3. Levothyroxine should always be taken early in the morning, 30-60 minutes before breakfast, with a full glass of water. Remind your patient that it’s gonna take about 3 weeks before they’ll see the full effects of the Levothyroxine, but that they should never stop taking it abruptly, since that could put them in a state of myxedema coma.
Patients with a large goiter on their neck may need to have part of it surgically removed in a subtotal thyroidectomy if it’s causing difficulty breathing or swallowing.
So how do we take care of the patient with hypothyroidism?
We want to monitor their blood pressure, pulse, breath sounds, and respiratory rate. Check for cardiac arrhythmias. Keep the patient warm, cause remember they’re gonna feel like an ice cube from the cold intolerance. Alternate periods of rest and activity because they will get tired easily. Since these patients are prone to constipation, we want to encourage them to drink at least 2000 mL/day and to eat high fiber foods so they have regular bowel movements.
The patients pretty much just look at food, and they gain weight because their metabolism has slowed down, so we want to encourage them to eat a low calorie, low fat diet.
Educate them that there is no cure for hypothyroidism and that they’ll need to take their thyroid replacement meds for the rest of their lives and have routine blood work done to check their thyroid levels. They also need to stick with the same brand of medication that they’re on. No switching brands, because the thyroid is very sensitive to different brands.
Also, make sure they understand that they cannot stop taking the Levothyroxine suddenly, or that can put them into myxedema coma.
OK. So a little recap on the two life-threatening conditions, thyroid storm and myxedema coma. How are you going to remember which one goes with hyper and hypothyroidism? I picture a storm as being wild and chaotic and hyper, so the thyroid storm goes with hyperthyroidism. But when you’re in a coma, everything is slowed down and low, so myxedema coma goes with hypothyroidism.
Alright y’all. I hope that helps. Next week I’ll be talking about heart failure, so I hope you join me for that one too. Thank you so much for listening, have a great week, and I’ll talk to you soon.