Severe Hypothyroidism: Treatment of Myxedema Coma (Nursing)

00:01 Myxedema coma is a life threatening event, but I want you to understand what we do to treat it now.

00:07 The overall treatment goals is there going to be admitted to ICU? They need extreme monitoring and they need supportive care.

00:13 So they have to be in a critical care unit.

00:15 So you're going to watch their labs and their ABCs very closely because their thyroid gland is not putting out the thyroid hormones.

00:24 You're going to need to replace with levothyroxine T3 and hydrocortisone. Also, you're going to do supportive and assessment measures. Remember those ABCs.

00:33 Is their airway safe? Are they breathing adequately and are they well perfused for circulation. So you'll specifically monitor T4, TSH and cortisol levels.

00:44 Now when you're drawing blood for T4, TSH and cortisol, remember these labs are essential for diagnosis and monitoring throughout the client stay. So T4 and TSH confirm that yes, it is severe hypothyroidism, right? If you don't have enough T4, it's not going to be able to be converted to T3 in the peripheral tissues.

01:03 And you've got the TSH will tell us like, wow, the thyroid gland just can't respond.

01:08 Cortisol levels are crucial because a myxedema coma often involves adrenal insufficiency.

01:14 So what the lab work is will guide how the health care team decides to do hormone replacement and what doses they use.

01:22 Now, levothyroxine is usually given 200 to 400mg IV.

01:27 Then they get daily doses of around 500.

01:29 There's two medications, two hormones that need to be immediately replaced in the intensive care environment.

01:35 At first you'll be given IV and then they can be switched to another route.

01:40 Now, levothyroxine and triiodothyronine are the two medications that will need to be administered.

01:47 Now it's given IV because we need immediate replacement.

01:51 Also, GI absorption is impaired in a myxedema coma.

01:55 You know, if we have poor absorption, the hormone replacement will be inadequate.

01:59 So you need rapid hormone replacement, which is why it's done immediately through IV administration.

02:06 Now both T4 and T3 are given because that T4 will give you the steady, long acting hormone source, and T3 will act more quickly to give you that immediate hormone activity.

02:19 Now, conversion of T4 to T3 may also be impaired, so you want to keep that in mind since the patient has severe illness.

02:26 Now you'll be able to change to oral levothyroxine when the patient can tolerate oral medications. Now the oral dose is approximately the IV dose divided by 0.75. But that's just to give you a reference range.

02:39 Hydrocortisone is also given IV every eight hours until possible adrenal insufficiency has been resolved.

02:46 Now let's talk about that for a minute.

02:48 Someone with hypothyroidism, their body can kind of mask the underlying adrenal insufficiency that might be there, but we weren't aware of it.

02:58 There's a couple things to keep in mind.

03:00 Thyroid hormone replacement can increase cortisol metabolism.

03:04 Therefore less is available.

03:06 Less cortisol to the body.

03:08 Also, the stress of a severe illness requires adequate cortisol levels.

03:13 So you give the hydrocortisone until adrenal insufficiency is ruled out. Because, you know, thyroid hormone replacement therapy can increase the metabolism of cortisol and the stress of severe illness.

03:26 In order to recover, the client needs adequate cortisol levels, and that's why we replace it via IV.

03:33 Now, thinking about the supportive measures when we say that, that would be things like keeping their airway safe with mechanical ventilation, this will help you address the respiratory depression that is common in myxedema coma. Now for circulation, you might give fluids and vasopressor drugs to correct that really low hypotension.

03:52 We use these fluids extra volume in their intravascular space and the vasopressors that constrict those vessels.

03:59 This will help us improve the perfusion and correct that hypotension. Now, because they have a risk for cardiovascular problems, that's why they're on a monitor. And you're going to watch them closely for dysrhythmias if you're going to rewarm them, it's a passive rewarming.

04:16 This will help address that hypothermia without causing vasodilation shock, which would further drive their blood pressure down lower.

04:24 And finally, in this category, we know that infections can trigger a myxedema coma. So empirical antibiotic treatment will be considered because infection is often a trigger and can sometimes be masked in this experience.

04:41 and for patients who develop a myxedema coma, there's a lifespan issue I wanted to bring up.

04:47 You'll notice in an older adult, the dosage is lower for hormone replacement. There's a really important reason for that.

04:55 If the hormones are replaced too rapidly, this puts an older adult patient at an increased risk to precipitate a cardiac complication. So keep that in mind.

05:07 You'll notice a difference in how someone 42 years who is treated, and how someone who is an older adult is treated, they will have lower dosages.

05:17 So thank you for joining us in this discussion.

05:20 I hope this gives you a better understanding of what you'll see in the clinical setting for a myxedema coma.