USMLE Internal Medicine Review 12 03 Total Thyroid Block

USMLE Internal Medicine Review 12 03 Total Thyroid Block

On these “Gold Standard Internal Medicine Facts” pages you will find Free:

  • USMLE Audio Review files from our “Gold Standard USMLE Reviews”
  • Transcriptions of those files
  • And videos (as they become available)

The idea is that you can review for the USMLE online by:

  • Listening to the Audio
  • Following along with the transcription
  • Or by watching the video (if available)

If you like what you here, you can purchase the entire Gold Standard Foundations of Medicine MP3 Audio USMLE review for your iPhone, iPod, or computer here.

Let’s start our USMLE Review with Hypothyroidism and Hyperthyroidism from the Gold Standard USMLE Foundations of Medicine Audio Review program.

 

Play USMLE Audio MP3 12 03 Total Thyroid Block Below

 

Begin 12 03 Total Thyroid Block Transcription

Probably the most effective way of reducing the relapse rate with antithyroid drug use for Graves’ disease is with total thyroid block.

In this method the patient is treated with Methimazole until euthyroid, usually 3-6 months, then instead of further tapering Methimazole, which other agent is added to the regimen?

  • Levothyroxine is added at about 0.1mg qd.

The patient then continues on the combination of Methimazole about 10mg qd and Levothyroxine for 1-2 years.

When the thyroid gland has returned to normal size, which of the two agents is continued and which is discontinued?

  • In a total thyroid block regimen, Methimazole is discontinued at that time and Levothyroxine is continued for another year.

With this therapy there is a striking fall in antithyroid antibody titer. With long term remission occurring in about what percentage of treated Graves’ disease patients?

  • 40-50%.

Student doctor please pause the tape and summarize the strategy of total thyroid block in antithyroid drug therapy for Graves’ disease. Please include a particular advantage of this strategy along with the dosing schedules for Methimazole and Levothyroxine.

  • Total thyroid block is an alternative method of antithyroid drug therapy for Graves’ disease with a goal of total block of thyroid activity. A distinct advantage of this strategy is that it reduces the high relapse rate associated with more conventional antithyroid drug therapy. A patient is treated with Methimazole until euthyroid, usually taking 3-6 months. Then, Levothyroxine is added to the regimen. The combination of Methimazole 10mg qd and Levothyroxine 0.1mg qd is continued for 1-2 years or until the thyroid gland has returned to normal size. At that time, Methimazole is discontinued and Levothyroxine continued for another year. With this regimen, there’s a striking fall in antithyroid antibody titer and long term remissions occur in 40-50% of treated patients. The duration of therapy with antithyroid drugs in Graves’ disease is quite variable from 6 months to 20 years or more. But a sustained remission can be predicted in about 80% of treated patients if 4 qualifications are met.

First, regarding the gland size. If the thyroid gland returns to normal size.

Second, regarding control of the disease. If the disease can be controlled with a relatively small dose of antithyroid drug.

Third, if which antibody is no longer detectable in the serum?

  • If TSH-R is no longer detectable in the serum.

And fourth, if what occurs following administration of Liothyronine?

  • If the thyroid gland becomes normally suppressible following administration of Liothyronine.

Student doctor please pause the tape and repeat the 4 conditions under which 80% of Graves’ disease patients treated with antithyroid drugs will experience a sustained remission.

  • The duration of therapy with antithyroid drugs in Graves’ disease is variable. From 6 months to 20 years or more, but 80% of treated patients will enjoy a sustained remission if: the thyroid gland returns to normal size, the disease can be controlled with a relatively small dose of antithyroid drug,TSH-R antibody is no longer detectable in the serum, and if the thyroid gland becomes normally suppressible following administration of Liothyronine.

****END OF TRANSCRIPTION****

 

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