GCA and thyroid

[tgca]

Can anyone advise me as to whether possible thyroid problems are/could be related to pred? I am awaiting blood results. Have a good night everyone zzzzzzzzzzzz

[SheffieldJane]

Well they are both autoimmune diseases. I have Graves Disease, suppressed and wonder if that led to my body attacking itself another way.

[chloe13 in reply to SheffieldJane]

I had PMR, was on Prednisone and when I finally came off Prednisone, I developed Grave's Disease.

[Woodiesmum]

I have underactive thyroid and GCA and pmr x not sure if it is linked but I am convinced it does t help as I am so shattered all the time even after high doses of pred xx

[PMRpro Ambassador in reply to Woodiesmum]

The fatigue of autoimmune disease isn't improved by pred - except in a few individuals who develop the Duracell Energizer Bunny effect. Pred can also cause fatigue. You can't win really.

[PMRpro Ambassador]

"Many different drugs affect thyroid function. Most of these drugs act at the level of the thyroid in patients with normal thyroid function, or at the level of thyroid hormone absorption or metabolism in patients requiring exogenous levothyroxine. A small subset of medications including glucocorticoids, dopamine agonists, somatostatin analogs and rexinoids affect thyroid function through suppression of TSH in the thyrotrope or hypothalamus. Fortunately, most of these medications do not cause clinically evident central hypothyroidism. ...

Glucocorticoids have long been known to affect serum TSH levels in humans (3;4). Physiologic levels of hydrocortisone appear to play an important role in the diurnal variation of serum TSH levels with lower levels in the morning and higher levels at night (5;6). Wilber and Utiger showed that high dose glucocorticoids suppressed serum TSH in hypothyroid patients and normal subjects (3). This effect appeared to involve TSH secretion and was controlled at the level of the hypothalamus. Others have confirmed this effect, but long-term high dose glucocorticoids or Cushing’s syndrome cortisol excess do not appear to cause clinically evident central hypothyroidism requiring thyroid hormone replacement (4;7). Dexamethasone doses as low as 0.5 mg can lower serum TSH levels, while 30 mg of prednisone is likely required to significantly alter TSH levels (4). Glucocorticoids appear to suppress release of TSH from thyrotropes in a PKC-dependent manner through the protein annexin 1 (8). The effect of glucocorticoids on TSH secretion is likely through inhibition of TRH in the hypothalamus. Glucocorticoid receptors are found in the TRH neurons of the PVN and a glucocorticoid response element has been identified on the TRH gene (9). Alkemade and colleagues have more recently shown that high dose glucocorticoids decrease TRH mRNA levels in the human hypothalamus, which is likely the primary mechanism for lower TSH secretion from the pituitary (10).

In summary, glucocorticoids can lower serum TSH levels and decrease TSH secretion through direct effects on TRH in the hypothalamus. Chronic high dose glucocorticoids or severe Cushing’s syndrome do not appear to cause clinically significant central hypothyroidism."

So the blood tests may possibly be affected if you are at a dose above 30mg but that doesn't mean you are hypothyroid. If you have symptoms - it is more likely to be because you also have an autoimmune disorder that is affecting your thyroid function. Once you have one autoimmune disorder - you have a higher chance of developing another...