Hypothyroidism: Introduction (Nursing)

00:01 Hi, I'm Doctor Rhonda Lawes, and in this portion of our video series we're going to look at an introduction to hypothyroidism.

00:09 So we'll start with the definition and help you understand the difference between primary and secondary hypothyroidism.

00:15 So let's start with primary.

00:17 Now this happens when the thyroid gland can't make enough or adequate amounts of thyroid hormones known as T3 and T4.

00:26 Now what happens when you don't have enough T3 or T4 is it impacts the metabolic rate, it goes down and you also have reduced tissue oxygen consumption. Now finally you end up with altered protein carbohydrate and lipid metabolism. So that is primary hypothyroidism.

00:44 The gland can't produce enough T3 or T4, so you end up in a decreased metabolic rate.

00:49 You have less tissue oxygen consumption and you have altered metabolism of your proteins, carbohydrates, and lipids.

00:56 Now, because the patient is going through this, there's a long list of things they could experience. So you want to be on your toes when you're doing assessments of your patients and be listening for these signs and symptoms.

01:08 So of course they're going to feel tired.

01:10 They're going to feel fatigued and really lethargic.

01:13 They will not be able to tolerate cold because they don't have enough of those hormones to rev everything up.

01:18 They are very sensitive to cold temperatures.

01:21 They'll also notice a weight gain, which obviously is something no one wants.

01:23 They'll also notice a weight gain, which obviously is something no one wants.

01:23 You look at their skin and their hair.

01:25 It's drier than normal.

01:27 They may also experience things like depression, feelings of sadness. Their heart rate may be slower.

01:32 They may even be in a bradycardia.

01:34 That's not normal for them.

01:36 Now, as you think of things slowing down, they can also have constipation or menstrual irregularities.

01:43 So when you're looking at all these possible signs and symptoms, think of the body slowing down in ways that are not helpful.

01:51 So primary hypothyroidism is usually caused by some type of autoimmune condition.

01:56 Now this autoimmune condition, like something like Hashimoto's, it will slowly destroy the thyroid tissue.

02:03 In fact, it's so slow we often don't pick it up until a large majority of the thyroid gland has already been destroyed.

02:10 Now, secondary hypothyroidism is different.

02:13 This is related to damage to the pituitary gland.

02:16 Now that might have happened due to cancer, surgical injury, genetics or trauma. So primary hypothyroidism means that the thyroid gland itself can't produce enough T3 or T4.

02:29 Secondary hypothyroidism is because the pituitary gland has been damaged through either. Those things we talked about cancer, surgical injury, genetics, or trauma. And it's not going to stimulate the thyroid to produce those hormones. So that's the difference between primary and secondary hypothyroidism. Now it matters that you understand the distinctions of the underlying cause because we're going to treat it differently.

02:52 The medication doses will be different, and it's going to depend on whether the patient has primary or secondary hypothyroidism.

03:00 Now let's take a look at some lab values so you can be on the lookout for these.

03:04 Someone in primary hypothyroidism that means the thyroid isn't producing enough T3 or T4. They're going to have an elevated TSH be likely greater than 4.0. Now the reason is thyroid stimulating hormone is what tells the thyroid to put out T3 and T4.

03:22 When you have an elevated TSH, that's saying the body keeps kicking out more and more TSH to try to stimulate that thyroid gland.

03:30 But because we're in primary hypothyroidism, it can't respond.

03:34 You're also going to see a low free T4.

03:37 You might also see positive thyroid antibodies, particularly in Hashimoto's.

03:42 And you will notice normal or elevated TSH receptor antibodies.

03:46 Okay, so that's quite a package.

03:48 Remember primary hypothyroidism is a focus right on the thyroid function itself. So watch for these lab values when you're evaluating your patients.

03:58 Well that's it. That's an introduction to what hypothyroidism is and the difference between primary and secondary hypothyroidism.