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What Causes Weight Gain When Getting Treated For Autoimmune Hypothyroidism And Hypopituitarism?

Posted on Mon, 12 Jan 2015

Question: I'm a medial research scientist. I have autoimmune thyroid and radiation over exposure 25 years ago. I was hypothyroid and hypopituitary. I was on Amour thyroid for 25 years and normal weight of 162 pounds. I became allergic to the Amour thyroid and switched to Synthroid a month ago. I've been gaining 1-2 pounds per day on an 1,137 calorie a day diet. I know my metabolism has increased because I'm taking 33% less insulin for type 1 diabetes. I'm on 175 mcg Synthroid. This makes no sense to me.

Answered by Dr. Binu Parameswaran Pillai (15 minutes later)

Brief Answer:
Hypopituitarism may be responsible

Detailed Answer:
Good day,
Noted your concern. You have Auto immune hypothyroidism and Hypopituitarism. Hence there are several causes for weight gain apart from hypothyroidism. There are several hormonal imbalances possible with Hypopituitarism. Low Testosterone and Growth hormone ( both due to hypopituitarism) can cause weight gain and respond well to treatment. Hence, besides treating Hypothyroidism, you should try to get following hormones on empty stomach preferably between 7 to 9 AM
1. IGF-1
2. LH
3. Serum Total and Free Testosterone
4. SHBG
5. Serum Cortisol ( 8 AM preferred)
6. Free T4 and TSH

This will give us a clearer picture

Regards
Binu

Above answer was peer-reviewed by : Dr. Chakravarthy Mazumdar

Follow up: Dr. Binu Parameswaran Pillai (1 hour later)

All those tests were normal, except TSH, was always low. The only thing that changed is going from Amour thyroid to Synthroid.

Answered by Dr. Binu Parameswaran Pillai (36 minutes later)

Brief Answer:
T4 levels

Detailed Answer:
Armour is derived from animals and contain both T3 and T4. Synthroid just contain T4. Current evidence says that there is no advantage of giving T3 and T4 together and T4 alone would suffice. Armour is not recommended by most endocrinologists as it is an animal product . Since you have a low TSH from hypopituitarism , monitoring TSH is not recommended in your case and is not helpful in monitoring the dose of Synthroid. You should try to maintain the Free T4 ( Ft4) in the upper half of normal range.

As one age, the metabolism slows down. You may need to further restrict your calories. The best thing is to talk to a nutritionist.

What is your latest Free T4 level?

Regards
Binu

Above answer was peer-reviewed by : Dr. Chakravarthy Mazumdar

Follow up: Dr. Binu Parameswaran Pillai (23 hours later)

Wrong answer. I told you I'm on an 1,127 calorie diet. Any lower will be dangerous. The correct answer is to add Cytomel (T3) because the hypothalamus regulates de novo lipogenesis. Administration of triiodothyronine (T3) leads to sympathetic nervous system activation and upregulation of brown adipose tissue thermogenesis via reduction in hypothalamic AMP-Activated Protein Kinase (AMPK) activity. Inhibition of hypothalamic AMPK pathway results in activation of lipogenic enzyme acetyl-CoA carboxylase and subsequent activation of its downstream targets acetyl-CoA carboxylase and fatty acid synthase.

Answered by Dr. Binu Parameswaran Pillai (44 minutes later)

Brief Answer:
T3 actions

Detailed Answer:
Dear Doctor,
Thank you for the information. I agree that Brown adipose tissue plays an important role in thermogenesis and weight regulation. And Thyroid hormone plays an important role in thermogenesis. That is why you feel cold in hypothyroidism.

T3 is the active hormone and T4 has to be converted by body to T3 before it can act. Even if you take just Synthroid, it will be converted to T3 by the body ( deiodinases in every tissue will do that conversion).

THERE IS NO RECOMMENDATION OF ADDING T3 in the routine management of hypothyroidism. It is only recommended in special situations like Myxedema coma etc.

However, many patients continue to have hypothyroidism symptoms despite having normal blood levels of T3 and T4 while on Synthroid alone. In those patients, we believe that there is a tissue level defect in conversion of T4 to T3 and it "may" be beneficial to add Cytomel. However, there is no evidence to support this argument. NO ENDOCRINE BODY ( Example: AACE, ENDO SOCIETY) supports such a treatment.

It may be worth observing if there is any improvement when you take Synthroid and Cytomel together.

Note: For more detailed guidance, please consult an Internal Medicine Specialist, with your latest reports. Click here..

Above answer was peer-reviewed by : Dr. Chakravarthy Mazumdar