Thyroid Hormone Fluctuations: From Hyperthyroidism to Hypothyroidism

Hyperthyroidism has transitioned to hypothyroidism: Free T4 0.884 / TSH 27.07?

Hello, I was diagnosed with hyperthyroidism at the end of last year during a health check-up (T4 2.91/TSH 0.005).
I have been taking medication in several phases: Carbimazole 10 mg/tab, one tablet each time, and Inderal 10 mg/tab, half a tablet each time.
The records are as follows:
1.
First phase: 9 weeks, both medications taken three times daily (blood test results: T4 1.06/TSH 1.32) - normal.
2.
Second phase: 8 weeks, both medications taken three times daily (blood test results: T4 0.958/TSH 7.75) - slightly low.
3.
Third phase: 8 weeks, reduced medication, Carbimazole taken once daily, Inderal taken three times daily (T4 0.884/TSH 27.07) - too low.
Currently, the physician has prescribed stopping Carbimazole and continuing with Inderal three times daily (half a tablet), with no other treatments, and instructed me to return for a follow-up in two months.
A.
Is such variation common?
B.
Is the current level (T4 0.884/TSH 27.07) considered severe? (The reference range for the tests indicates T4 1.72-0.932 / TSH 4.2-0.27 (ng/dL))
C.
Would you recommend that I actively seek a second opinion from another physician regarding this? I look forward to your response.

Tom, 50~59 year old female. Ask Date: 2023/06/29

Dr. Li Jian reply Internal Medicine

It is recommended that you consult an endocrinologist to determine whether there are positive TSH receptor antibodies.
Thank you for your inquiry.

Reply Date: 2023/06/29

More Info

Understanding fluctuations in thyroid hormone levels, particularly in the context of transitioning from hyperthyroidism to hypothyroidism, is crucial for managing thyroid health effectively. Your situation, characterized by a history of hyperthyroidism followed by a significant drop in thyroid hormone levels (T4) and a rise in thyroid-stimulating hormone (TSH), is indeed a common scenario in thyroid management.

A. Is this fluctuation common?
Yes, fluctuations in thyroid hormone levels are quite common, especially in individuals undergoing treatment for hyperthyroidism. When hyperthyroidism is treated, either through medication like Carbimazole (Carbizo) or other interventions, the goal is to normalize thyroid hormone levels. However, the process can lead to overshooting, resulting in hypothyroidism, which is characterized by low T4 levels and elevated TSH. This is due to the feedback mechanism between the thyroid gland and the pituitary gland. When T4 levels drop, the pituitary gland increases TSH production in an attempt to stimulate the thyroid to produce more hormones.
In your case, the transition from a hyperthyroid state (with low TSH and high T4) to a hypothyroid state (with high TSH and low T4) indicates that your body is responding to the treatment, but it may also suggest that the dosage of your medication needs to be carefully adjusted. It’s not unusual for patients to experience these fluctuations, and it often requires close monitoring and adjustments in medication.

B. How serious are the current levels (T4 0.884/TSH 27.07)?
Your current levels indicate a significant hypothyroid state. A T4 level of 0.884 ng/dL is below the normal range, and a TSH level of 27.07 IU/mL is considerably elevated. According to the reference ranges you provided, your T4 is below the lower limit, and your TSH is well above the upper limit. This suggests that your thyroid is not producing enough hormones, and your pituitary gland is responding by producing more TSH in an attempt to stimulate the thyroid.

In clinical practice, a TSH level above 10 IU/mL is often considered indicative of hypothyroidism, and levels above 20 IU/mL can be seen as severe. Therefore, your current TSH level is concerning and warrants further evaluation and possibly treatment adjustments.

C. Should you seek a second opinion?
Given the significant changes in your thyroid hormone levels and the current state of hypothyroidism, it would be prudent to seek a second opinion, especially if you have concerns about your treatment plan. A second opinion can provide additional insights into your condition and treatment options. It’s essential to have a healthcare provider who is attentive to your symptoms and willing to adjust your treatment as necessary.

In addition to consulting another physician, consider discussing the following:
1. Thyroid Hormone Replacement Therapy: If your T4 levels remain low, your doctor may consider starting you on levothyroxine, a synthetic form of T4, to help normalize your hormone levels.

2. Regular Monitoring: Ensure that you have regular follow-up appointments to monitor your thyroid levels. This is crucial for adjusting medication dosages appropriately.

3. Symptoms of Hypothyroidism: Be aware of symptoms such as fatigue, weight gain, cold intolerance, and depression, which may indicate that your hypothyroid state is affecting your quality of life.

4. Comprehensive Evaluation: Discuss with your healthcare provider the possibility of conducting a comprehensive evaluation of your thyroid function, including tests for thyroid antibodies, to rule out autoimmune thyroid disease, which could complicate your condition.

In summary, fluctuations in thyroid hormone levels during treatment are common, but your current levels indicate a significant hypothyroid state that should be addressed promptly. Seeking a second opinion and discussing potential treatment adjustments with your healthcare provider is advisable to ensure optimal management of your thyroid health.

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