What Causes Weight Gain And Tiredness After Treated Thyroid Cancer?

Posted on Wed, 30 Apr 2014

Medically reviewed by Ask A Doctor - 24x7 Medical Review Team

Wed, 30 Apr 2014 Answered on

Wed, 21 May 2014 Last reviewed on

Question : I had thyroid cancer an was treated in 2007 with surgery and radiation, I lost one parathyroid gland at time of surgery. Now I am having symptoms of weight gain extreme tiredness, an for over a year my blood shows very low Vitaman D levels an high white blood cell count, not sure about Calcium levels. My reg dr wants me to just take anti depressant and a Vitaman D 5000mg once a week something prescribed. I am currently taking 1200 daily now? was wondering if problem could be my parathyroid glands?
Also my TSH stays high even though my thyroid meds have been taken from 275mcg to 112mcg ?

Answered by Dr. Binu Parameswaran Pillai (27 minutes later)

Brief Answer:
Could you attach the blood reports ?

Detailed Answer:
Hello,
Good day.
What type of thyroid cancer was it ? ( Follicular/Papillary/undifferentiated/Medullary)
You may find out that in the histopathology report.

The tiredness may be due to low calcium levels or due to hypothyroidism ( you mentioned that the TSH is high and you have weight gain).

Ideally, in many thyroid cancers, we want the TSH to be below normal . Hence we give higher dose of Levothyroxine( you are just on 112 mcg and I doubt if that dose is adequate). If the TSH remains high, it may promote the growth of thyroid tissue in the operated thyroid bed. ( TSH is Thyroid Stimulating Hormone, which is a hormone produced In pituitary gland).

Please do a blood test for fasting calcium, phosphorus and albumin. Could you also tell me the exact TSH value ? Could you also tell the exact value of White cell count ? ( If possible, attach the recent blood reports and the previous thyroid biopsy reports ).

I hope to hear from you soon

Regards
Binu

Above answer was peer-reviewed by : Dr. Yogesh D

Follow up: Dr. Binu Parameswaran Pillai (3 hours later)

My cancer was follicular, I had a complete removal of thyroid. They did not take any lymph nodes due to miss reading of the the first pathology report done after the first surgery, it did say there was lymph node /venous invasion? I don't have the reports but can get a copy an send it, I do know my vitamin D has been high teens an lo 20's going on for a year, the las test was 22. Also how can it be hypothyroidism if I have no thyroid? Do you have any idea what it could be? I will try to get my dr to run the test that you have suggested.

Answered by Dr. Binu Parameswaran Pillai (8 hours later)

Brief Answer:
KEEP YOUR TSH SUPRESSED.

Detailed Answer:
Hello,
Good day.
Follicuar cancer usually need the TSH to be supressed to less than normal for a number of years after the surgery. This is to prevent the regrowth of the thyroid tissue/cancer ( even after complete removal and radio iodine ablation).

If you have no thyroid gland left, there is no hormone production. That is hypothyroidism. We have to supplement the levothyroxine. I hope you are under the care of an endocrinologist ( not an internist). It is very important to keep the TSH supressed. This requires a higher dose of medicine, usually above 150 mcg of levothyroxine, depending on your weight.

Parathyroid hormone is important to convert Vitamin D to actiated Vitamin D.
If your parathyroid is not working, Vitamin D will not be converted to activated Vitamin D ( no matter how high the vitamin D levels are). Since you have low vitamin D, the current dose of 1500 units a day is inadequate. You should take 50000 units weekly once for 6 weeks followed by 2000 units a day. You need sun expourse for 20 minutes daily between 9 am to 4 pm.

The simple test to know if your parathyroid is working or not is by doing a fasting calcium, albumin and phosphorus. ( direct estimation of Parathyroid hormone(PTH) is possible, but expensive).

Regards
Binu

Above answer was peer-reviewed by : Dr. Prasad