These are my notes from the presentation Endocrinology in Mast Cell Disease
given by Dr. Marla Barkoff for The Mast Cell Disease Society
The 3 areas of endocrinology that Dr Barkoff discusses are thyroid function, bone density, and blood sugar and insulin regulation. (MCD = Mast Cell Disease)
THYROID HEALTH
The thyroid gland sits at the base of the throat and secrets hormones that are like the “motor” of the body. When too much hormone is produced the metabolism speeds up, and you will see weight loss, body temp going up (feeling hot and sweaty), bowels speeding up (and possibly diarrhea), anxiety, and tremors. If not enough thyroid hormone is produced you will see slowing of the metabolism, feeling sluggish, depression, low body temp, heart rate slowing down, bowels slowing down (constipation), and weight gain.
The first line of treatment is hormone replacement, but this can be problematic for patients with MCD for several reasons. 95% of what the thyroid makes is T4 (meaning it has 4 iodine molecules attached). T4 is oral and may not be absorbed well in MCD patients because of intestinal inflammation. Signs of not absorbing T4 are if symptoms don’t improve and lab markers don’t improve. Trouble-shooting things to try-
-Calcium and iron supplements need to be dosed at least 2 hrs away from T4 to not interfere with absorption.
-Acid blockers, PPIs, and maybe H2 blockers may block absorption.
-If still not working calculate full replacement dose (weight in kg multiplied by 1.7 before menopause and 1.6 after).
-Can switch to a liquid form (tyrosynth) that tends to be much better absorbed. The solution form has no gelatin which can be better for allergies, halal, kosher, vegan, etc.
-If still not working, are they having a sensitivity? Levothyroxine, only the 50mg is white (note- this doesn’t mean no dyes!). Some brands of T4 are better tolerated including Levoxyl or Euthyrox (all doses are white). Levothyroxin can be compounded easily.
T4 is the inactive form of thyroid hormone, an enzyme removes one iodine to make T3 and that is the active form. Some mast cell mediators released with degranulation can halt or impede the conversion of T4 to T3. If this is happening it may help to add a low dose of T3 (2.5mcg, rarely need more than 5mcg in AM). T3 is short lived and fast acting, may need to be dosed again midday. Dose in ratio of 95%T4 to 5%T3. Reason not to use “natural” form, which is desiccated from pigs, is that it has a different ratio of T4 to T3. Never use T3 alone.
BONE HEALTH
Bone density is the result of two kinds of cells that work together to keep bone healthy and strong. Osteoblasts build new bone, and osteoclasts break down old bone that is no longer functioning well. The active process of these two kinds of cells working together is called bone remodeling, and the balance of the actions of these two kinds of cells is essential for bone to be both flexible and strong as it needs to be. There are many different factors that influence this balance including vitamin D, estrogen, and parathyroid hormone (PTH). The fact that estrogen is involved is why women lose bone density after menopause.
If a person is losing bone density, testing for vitamin D and parathyroid hormone (PTH) levels is a good place to start. Parathyroid glands sit above thyroid gland but are not involved in thyroid function. If vitamon D levels are inadequate, PTH kicks in. PTH triggers osteoclasts to degrade bone. Mast cells release RANK ligand when they degranulate which also stimulates osteoclasts. Vitamin D levels should be above 30 and PTH level should be less than 45. PTH can also trigger mast cell degranulation. The drug Forteo is pharmacological PTH, so might also trigger mast cell degranulation. What is safer in MCD is the anti-resorbtive including bisphosphonates and Prolea (a monoclonal antibody given in doctor’s office).
BLOOD SUGAR
Evidence suggests that mast cell degranulation releases pro-inflammatory mediators that can contribute to white fat growth and differentiation and insulin resistance, which causes blood sugar to rise and the body may struggle to produce enough insulin. Check fasting glucose level, normal is < 100, >126 is diabetes, in between is pre-diabetes. Also check HbA1c which is average blood sugar over 3 month period, normal <5.7, if >5.7 glucose tolerance test. Metformin may be good option for MCD patients because it is also anti-inflammatory.
