Question

PM is a 15-year-old young woman who had her menstrual period at age 11. Recently, she has been experiencing double vision, headaches, and amenorrhea. A skull MRI indicates a pituitary adenoma. Blood tests indicate low estrogen, progesterone, and TSH levels.

Discussion Questions

Discuss the relationship of the pituitary gland to the optic nerve and its role in controlling sex hormones and thyroxine.

Explain why this benign tumor must be surgically removed.

Explain the effects that you would expect to see in PM caused by the reduced TSH level. How will these be treated after surgery?

Explain the manifestations that PM has experienced in terms of the pathophysiology.

Answer 1

Pituitary gland to the Optic nerves: The most common problem which affects the pituitary gland is a benign growth of the gland, also known as an adenoma. Pituitary adenomas either produce excessive amounts of pituitary hormones themselves, or the growth actually interferes with the production of pituitary hormones.

Problem with your vision due to a pituitary macroadenoma. This is because a pituitary macroadenoma most commonly affects the optic nerves, chiasm or optic tracts before any other nerves of the visual system. These nerves lie directly above the pituitary fossa and are therefore the first structures affected by upward expansion of a macroadenoma. The most common problem with vision to result from a pituitary macroadenoma is a bitemporal hemianopia when the optic chiasm is involved; in other words, an inability to notice things to either side of what you are directly looking.

b. Role of Pituitary Gland: The pituitary gland also secretes hormones that act on the adrenal glands, thyroid gland, ovaries and testes, which in turn produce other hormones. Through secretion of its hormones, the pituitary gland controls metabolism, growth, sexual maturation, reproduction, blood pressure and many other vital physical functions and processes.  Anterior Pituitary gland produces luteinising hormone and follicle stimulating hormone, also known as gonadotrophins. They act on the ovaries or testes to stimulate sex hormone production, and egg and sperm maturity. The thyroid stimulating hormone, which stimulates the thyroid gland to secrete thyroid hormones.

c. Surgical removal of these tumors can restore normal hormone production in many cases. Non-secretory tumors do not overproduce hormones, but cause problems due to their size and location. This is because they can compress both the normal pituitary gland and the surrounding structures. Hormone deficiencies may result from compression of the normal pituitary gland. Non-secreting tumors can also cause vision problems by growing upwards and compressing the optic nerves and chiasm, nerves which are important for vision. This pressure can lead to loss of peripheral vision. Surgery can remove such tumors and relieve the pressure on surrounding structures.

d. Fatigue, nervousness, restlessness and weakness are common symptoms of low TSH. Because these symptoms can be felt with a variety of other conditions, they may not be attributed to low TSH initially. Muscle cramps may also occur but be attributed to another cause. People with low TSH may be very sensitive to the heat and unable to tolerate it. A warm summer day for most people may be unbearably hot for them. People with low TSH may also sweat more than others. An abnormal heart rhythm called atrial fibrillation may occur when TSH is low. Heart failure can occur with this condition.

The skin may be unusually warm and may even have a reddish hue from the increased blood flow that can occur with a low TSH. Skin may become darker or smoother than usual. Hair thinning may be noted. Hives and itching may also occur. People with low TSH have an enlarged thyroid gland, called a goiter. If the goiter is big enough, it can cause difficulty swallowing. Having more frequent bowel movements is fairly common, but people with low TSH rarely experience abdominal pain and vomiting.