Do You Continue Levothyroxine After Thyroidectomy

I received the following request for a post via email:

I am about to get my thyroid removed in the next couple months for a growing multinodular goiter. I have had one indeterminate FNA but the rest, over about 5 years, have been benign. But it has been growing to about 6 cm on each side, and the chances of missing a malignancy grow as it gets bigger, and now both the endocrinologist and surgeon are recommending thyroidectomy.[HD: The type of indeterminate cytopathology result is important here.  If it was "atypia of undetermined significance" or similar, followed by one or more benign biopsies of the same nodule, the risk of malignancy should be no more than 5-10%.  If it was a "follicular neoplasm" or "oncocytic neoplasm," followed by benign biopsies of the same nodule, the risk of malignancy is higher, 20-30%.  The risk of malignancy can also be adjusted up or down depending on the presence/absence of suspicious ultrasonographic features.]

I like your blog because frankly, the Internet is scaring me about thyroid issues. I am an RN and my husband is a scientist, so I am science focused. My question is, do you have any recommendations on how to treat patients post-thyroidectomy so that they get their levels optimized quickly? I am 42 and I feel great, lots of energy, completely euthyroid now, and frankly I am very worried that I am throwing away my energy and making a big mistake. But I don't see that I have any choice now with how the nodules have been growing.

Although treating postoperative hypothyroidism (thyroid removed) is mostly the same as treating primary hypothyroidism (thyroid slows or stops working), there are a few issues unique to the postsurgical patient.  The most important thing to know, however, is that most people do just fine after surgery on levothyroxine.

Beware the Post-Surgery Blues

I've had many patients come back to see me a couple of months after thyroidectomy, distraught over their "hypothyroid" symptoms. The whole situation is made worse by a sense of buyer's remorse, particularly when the thyroid was removed for noncancerous reasons. I've listen to patients lament the loss of their thyroids, understandably wondering if they've made a huge mistake by allowing the surgeon to excise a gland that may have been bulky and uncomfortable, but was working just fine.

The sense of urgency that my patients feel transfers directly over to me, and I feel strong pressure to "fix it." But if the postoperative TSH is comparable to the preoperative TSH, I am typically inclined to attribute symptoms like fatigue, weight gain, and mood changes to something other than uncontrolled hypothyroidism.

This is where the post-surgery blues may be playing a role. The challenging part about making this diagnosis is that it's a diagnosis of exclusion. In other words, there are no objective tests for this problem, so we just need to rule out everything else. Upping the difficulty factor is that most people are programmed to believe that a temporal relationship implies a causal relationship – i.e. "My thyroid was just removed, so anything I'm feeling must be directly linked to its absence." It can be extremely difficult to redirect this line of thought, in order to explore more likely culprits.

So, what to do? First, I need to review the chart. Did surgery go smoothly? Were there any complications that could have drained my patient's energy (e.g. prolonged hypocalcemia)?  Is she anemic at baseline?  Did the anemia get worse due to surgical blood loss (uncommon in thyroid surgery)?  Is it possible that she had undiagnosed sleep apnea prior to surgery?  Perhaps her decreased activity level after surgery has led to weight gain, and that weight gain has unmasked the sleep apnea.

What else is going on in her life right now?  Has there been family or job-related stress that has been exacerbated by her postoperative downtime?  Has she ever been prone to bouts of depression in the past?

If we seem to be coming up empty with respect to any other plausible cause of her symptoms, we need to consider that this could be postoperative depression.  A discussion of why this happens is outside the scope of this piece, not to mention outside my area of expertise.  Just know that it can happen, even if you don't consider yourself at risk for depression.  I think that recognizing this is more than half the battle, as you should feel reassured that it is most likely temporary and will pass soon.  In fact, knowing that there's nothing seriously wrong with your hormonal status may even accelerate your recovery, as that's one less thing about which to stress.  If your symptoms are moderate-severe, though, you may consider seeing your primary care provider or psychiatrist to get their take on whether anything else should be done.

Your TSH Target is Important

In patients without thyroid cancer, the postoperative TSH target is going to be the same as the preoperative TSH.  In thyroid cancer, however, the TSH target is often going to be lower – how low depends on the extent of disease.  The trouble with TSH suppression therapy – which can slow the growth of residual disease and reduce the risk of recurrence – is that it requires supraphysiologic doses of levothyroxine.

While many people will feel fine with these higher doses of levothyroxine, some will not.  And remember, the symptoms of too much thyroid hormone overlap significantly with the symptoms of too little thyroid hormone.  Both overlap with the symptoms of depression, which brings us back full circle.  We therefore need to balance our aims of decreasing cancer recurrence, minimizing symptoms of "over-suppression," and making sure that we're not missing something else, like postoperative depression.

I have had patients with thyroid cancer who needed to have their doses of levothyroxine decreased because of fatigue, weakness, insomnia, etc.  In those cases, if their symptoms did not get any better once the TSH normalized, then I increased the dose back to a level sufficient for cancer suppression, and we began looking for other causes of their symptoms.  On the other hand, if symptoms improved on the lower dose, then we discussed the balancing act of cancer suppression versus feeling well, and I let the patient make an informed decision about how to proceed.

The T3 Controversy

As I've previously written, most hypothyroid patients will fare no better with the addition of T3 to their regimen.  However, the occasional thyroidectomized person may be in that small subset of people who benefit from taking T3.  Remember that the thyroid makes some T3, while the rest is produced through conversion of T4 (remember that levothyroxine is T4) to T3 in your tissues.  Once the thyroid is removed, you are entirely dependent on peripheral conversion of T4 to T3.

What if your conversion is impaired?  Mind you, I'm not talking about pseudoscientific, widely discredited diagnoses like Wilson's (Low T3) Syndrome.  I'm referring to people who actually have a genetic polymorphism of one of the enzymes that converts T4 to T3; that has the potential to affect circulating and tissue T3 levels.  This topic is explored nicely in Section 13a of Guidelines for the Treatment of Hypothyroidism: Prepared by the American Thyroid Association Task Force on Thyroid Hormone Replacement.

Note that I amnot saying that non-hypothyroid people who are heterozygous or homozygous for these polymorphisms can now be diagnosed with hypothyroidism.  The research to date on these polymorphisms would suggest that the changes in circulating levels of thyroid hormones in otherwise normal people are subtle, and the clinical significance is probably minimal to zero.

What I am saying is, a person who loses her thyroid and has one of these polymorphismsmaynot respond optimally to standard levothyroxine therapy.  As we do not have the ability to test for these polymorphisms in routine clinical settings, doctors should recognize that some postsurgical patients might do better with slightly higher than normal doses of levothyroxine or with the addition of liothyronine to levothyroxine.  The most recent study I've read on this subject (it was a good study) can be found here.

Summary

Hopefully it's comforting to know that most people will feel just fine on levothyroxine alone after a total thyroidectomy.  There is no magic to getting the dose right and regulated quickly; beginning the medication after surgery at a dose of 1.6 mcg/kg is usually a good place to start (1.7 mcg/kg if cancerous).  If you feel relatively okay during the weeks after surgery, then checking a TSH about 6 weeks later is a good idea, so that a dose adjustment can be made if necessary.  If you feel very poorly in the weeks after surgery, then a TSH and FT4 (free T4) should be checked at that time, as it's possible that the dose may be much too high or low, in which case the blood work may be helpful.

Do you take thyroid hormone for postoperative hypothyroidism?  Has your experience been smooth or not?  If you're a doctor, what is your impression of how people do after thyroidectomy on T4 alone?  Comment below!

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Source: https://hormonesdemystified.com/optimizing-thyroid-hormone-replacement-after-surgery

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