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Date of last update: 10/17/2017.

Forum Name: Endocrinology Topics

Question: hyperthyroidism with normal free T4 and ultrasound

 JOHANSCULLY - Mon Sep 22, 2008 10:11 am

Dear Dr,

In 2001 I had a facial paralysis and I was treated with prednisolone; this drug caused hypothyroidism and I was treated during 2 months with ertroxin. However,during 2008 I loss 20 pounds and my doctor order me blood test and it showed a 0.01 U of TSH and I was diagnosed with hyperthyroidism and I have been treated with 5 mg of metimazol. To figure out the causes my doctor ordered additional tests and I got a a normal free T4, antibodies anti-TSH are negatives, and a normal ultrasound. My doctor said it was idiopathicm but I need to clarify the origin of my disease What can be the causes?. What are the changes of going hyper/hipo o viceversa again?.
thanks for your help,
 Dr. Safaa Mahmoud - Thu Oct 16, 2008 3:23 pm

User avatar Hello,

The administration of corticosteroids was reported to cause suppression on thyroid function directly or indirectly in different studies.

This effect is known to be transient and the normal thyroid function is expected to be gradually regained after steroid withdrawal.

Thyroid hypofunction is treated with thyroid hormone replacement.

Thyroid-stimulating hormone TSH Normal range is 0.4–4.5mIU/L.
Thyroid hyperfunction is diagnosed by testing for:
-Thyroid-stimulating hormone (TSH), a low level of TSH means the thyroid gland is overactive and is making too much thyroxine.
- Thyroxine (T4), a high level of T4 confirms hyperthyroidism.

Borderline results are defined by a normal T4 with a low TSH. In this case, another blood test for another thyroid hormone named T3 is helpful.

A way to confirm is to repeat the tests a few weeks later, as sometimes borderline tests are caused by another illness. When TSH is lower than 0.1 mIU/L, repeating the measurement of TSH, as well as Free T4 and a total T3 or Free T3, within 4 weeks of the initial measurement or within a shorter interval if there are signs or symptoms of hyperthyroidism.

Other tests like Ultrasonography of the thyroid gland may show a nodule (or nodules) in the thyroid and a thyroid scan is done as needed.

Borderline hyperthyroidism is seen postviral infection and postpartum. Thyroid dysfunction is more common on those who have previous thyroid dysfunction or autoimmune diseases.

Subclinical hyperthyroidism due to destructive thyroiditis including postviral subacute thyroiditis usually resolves spontaneously. Treatment is usually initiated when concerning symptoms or signs are present.

I advise you to follow up with your doctor and to discuss with him all your concerns.

Hope you find this information useful.
Best regards.

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