Well what, you may be wondering, does the pituitary gland have to do with the thyroid gland? Turns out, it has a lot to do with it.
It is amazing how much I've had to learn in dealing with Chiari and EDS. Here is an explanation of what the pituitary gland does:
"The pituitary gland is a tiny organ, the size of a pea, found at the base of the brain. As the master gland of the body, it produces and secretes many hormones that travel throughout the body, directing certain processes stimulating other glands to produce different types of hormones. The pituitary gland controls biochemical processes important to our well-being.
The pituitary gland makes these types of hormones:
Prolactin - Prolactin stimulates milk production from the breasts after childbirth to enable nursing. It also affects sex hormone levels from ovaries in women and from testes in men. Growth hormone (GH) - GH stimulates growth in childhood and is important for maintaining a healthy body composition and well-being in adults. In adults it is important for maintaining muscle mass as well as bone mass. It also affects fat distribution in the body.
Adrenocorticotropin (ACTH) - ACTH stimulates the production of cortisol by the adrenal glands. Cortisol, a so-called "stress hormone" is vital to our survival. It helps to maintain blood pressure and blood glucose levels.
Thyroid-stimulating hormone (TSH) - TSH stimulates the thyroid gland, which regulates the body's metabolism, energy, growth, and nervous system activity. This hormone is also vital to our survival.
Antidiuretic hormone (ADH) - ADH, also called vasopressin, regulates water balance. If this hormone is not released properly, it can lead to too little hormone (called diabetes insipidus), or too much hormone (called syndrome of inappropriate ADH). Both of these conditions affect the kidneys. Diabetes insipidus is different from the more well-known diabetes mellitus (or type II diabetes), which affects the levels of glucose in our bodies.
Luteinizing hormone (LH) - LH regulates testosterone in men and estrogen in women.
Follicle-stimulating hormone (FSH) - FSH promotes sperm production in men and stimulates the ovaries to enable ovulation in women. Luteinizing hormone and follicle-stimulating hormone work together to cause normal function of the ovaries and testes." - From http://www.hormone.org/Pituitary/overview.cfm
So you see, the pituitary is in charge of lots of things. I'm not a doctor, but I did get copies of my own MRIs to study. I stared at them for hours until I could see my pituitary and if I was looking right, my pituitary does look "squished." People with Chiari get fluid buildup in their brains because the area where the spinal cord descends (the foramen magnum) is too blocked up for the fluid to flow out at the proper rate. The pressue of the fluid and the fact that the brain is overcrowded causes the pituitary to be damaged and/or not operate correctly.
I asked a neurosurgeon who knows about Chiari, if he thought my hormone imbalances could be caused by this pressure. He said it very well could be, and there was no way to tell if I had surgery if the function would return to normal.