Consequences of a Brain Tumor-Life for our little boy with pan-hypopit

What is meant by a "benign" brain tumor? In our opinion it is a bit misleading. What we do know is that our son's life is not directly threatened (at least now that he has been diagnosed and is receiving treatment). This is unfortunately not the reality for so many other children diagnosed with brain tumors, most of which are malignant and very difficult to treat. With every visit to the neuo-oncology clinic, which shares space with the heme-onc clinic (that's kids with leukemia, lymphoma and other blood cancers), we are reminded how lucky we are, how lucky Eli is. Although he has scars on his head and belly and patchy hair, he has hair and it is growing. He runs around the clinic full of energy because while he is there for a chemo treatment too, his chemo is not systemic. His treatment will last 2-3 minutes, not 2-3 hours.

But then I begin to think about Eli's future and the "chronic" condition of this "acute" illness. Like many childhood cancers Eli will recover. The tumor will one day disappear. And for more and more children every year their tumors and blood cancers will be cured (not just remission). All of these children, as they grow will deal with the fear of reoccurance, for some the chances are greater than others. For Eli, he will require an MRI every year or so, well...forever! But on top of managing the tumor, Eli will have to deal with something that I feel is much more difficult and life altering - being pan-hypopituitary.

The most accurate description I have come across to describe what a benign brain tumor really is went something like this; "A craniopharyngioma is a benign tumor in a malignant location." Why malignant? Because the brain if full of vital organs and a tumor in such a place is just "bad" and causes "worsening conditions" that are unrelated to the actual cancer itself. When you think about it, the brain is the most protected organ we have. And the pituitary gland, the gland that Eli's tumor totally destroyed, it probably the best protected organ in the entire body.

Anatomy of the Pituitary - Beginning from the outside and moving in:
First, the pituitary is surrounded by the skull, which is made up of hard calcified bone as opposed to soft bone. Next it is surounded by brain tissue (undoubtable a vital organ) but provides cushion and sheilding to the pituitary. Finally the pituitary sits in a bony structure called the sella turcica or hypophyseal fossa. It is essentiall a little bowl that sits just between your eyes about 1/2-1 inch back in the head. The top of the bowl which holds the pituitary is finally not exposed to the air like a bowl of snap-krackly-pop, but protected again by a thick (relatively speaking) layer of dura mater akin to like a thousand layers of cellophane. With all these protective mechanisms, it becomes clear that a tumor in this location is a bad, bad thing.

So what does it mean to be pan-hypopit? It means that Eli does not have any pituitary function? So what? Well this is what he is missing, how it is replaced and how these deficiencies affect him.

1. ADH (Anti-diuretic hormone, also known as vasopressin): Without this hormone which is made in the hypothalymus and secreted by the posterior pituitary you cannot control your urine output and without replacement (or massive re-hydration) you will pee-yourself-to-death.
Replacement:
Eli take Desmopressin twice a day. It is a little pill that we crush up and mix with cherry syrup (yum! - aka Eli had to be brave!). It essentially decreases his urine output to very little. When the meds start to wear off we all know because he starts to drink massive amounts of water and ask to go "potty" every 30 minutes. As he grows older he will be able to compensate for his urine loss by drinking a lot, and will not necessarily have to be on the medication (if he so chooses). But right now his body cannot compensate for the loss.
2. Hydrocortisone (cortisone, glucocorticoids): Also secreted by the pituitary. This hormone is responsible for responding to stree: illnesses, falls, test-anxiety etc. I calls into action a whole array of other hormones and processes that I don't fully understand (we do Endocrin next year).
Replacement:
Again twice a day in the same manner. The only difference with this medication is that if he gets a bad cold, has a bad allergic reaction or a serious trauma, his body does not compensate by increasing its natural levels of hydrocortison, so we either augment this with aditional doses of his oral medication, or in severe cases we give his injections of cortisone. Thankfully, that has not happened yet.
3. Thyroid Stimulating Hormone (TSH). Replaced by Synthroid/thyroxine. Again I do not know what the details of this hormone, but it is responsibel for regulating metabolism, food intake, muscle building, fat metabolism etc. More importantly it is essential for normal growth of the brain, especially during the first 3 years of life, but also for later development. Deficiency can lead to growth delays and mental insufficiencies.
Replacement:
Once a day...and this is kinda cool, the dose is dependant on his body surface area (weight x hight essentially). Since his hight and weight has not really changed in the past year and will not change for about another year it is easy to regulate the dosing. Why????
4. Growth Hormone (GH): Release from the anterior pituitary, GH is responisble for, surprise, helping you to grow (not only taller which is the commonly understood affect, but it also helps your internal organs and brain grow and develop). It is also important for building muscle and regulating fat metabolism (ie preventing fat-ness). There are many other benefits to GH which is why it is the new rave in anti-aging. Hence while I thought that it was only really necessary during childhood and through adolesence, it is actually important for health throughout your life. Therefore Eli will need to be on GH replacement forever...just like all his other medications.
Replacement:
This cannot start until the tumor is more or less gone or on its way out! Because GH causes pretty much every cell in your body to grow. Therefore, we hope to start GH in 6-12 months. Until then he will remain my "little mouse" (currently he weights 26.4 lbs (he gained a whole pound over the past 3 months...huge deal) and is about 33 inches tall. When he was 18 month he was 33 inches tall and weight 24 lbs).
Beginning treatment will be exciting and a good thing, but also will be very hard and sad...it requires injection (very much like diabetic insulin injections) everyday for ever. So it will be analygous to being a little kid diagnosed with insulin-dependant diabetes.
5. FHS and LH --> Testosterone and Sperm: When the time comes for Eli to go through puberty, he will need a little help. Because his pituitary does not secrete LH (Leutinizing Hormone), there is no signal to tell his little testicles to make testosterone. Therefore, he will not develope male sexual characteristics and all that happens when adolescents go through puberty (like deepening voice and facial/body hair - hey maybe he won't be as hairy as his dad!!!).
Replacement:
Injections of testosterone...forever.

I think that is actually it. Clearly he has quite a regiment. He has become very compliant and does not even fuss when it is time for his meds, although the taste still makes him squirm! As with everything in life, he will become accustomed to the new treatments and they will become routine, like brushing his teeth. Hopefully, because he is so young, he will not know any different and in the long run that may make management easier.

Of couse we will keep you posted as to when new treatments start and how he is managing them. If you have any suggestions for teaching a child about giving themselves and receiving dailing injections we would love the advice (I am a little nervous). Also, I am sure as I learn more about his condition there will be more of these little anatomy and physiology sessions...hope I didn't bore you.