Med-Surg Endocrine System, part 9: Growth Hormone Deficiency and Excess

by Cathy Parkes August 01, 2020

Full Transcript

Okay. In this video, we are going to talk about growth hormone deficiency as well as growth hormone excess. So growth hormone deficiency is where we have inadequate secretion of growth hormone from the anterior pituitary gland. This may be due to a congenital disorder. It may also be due to injury or damage to the pituitary gland, or it could be due to an issue with the hypothalamus. So if you recall, the hypothalamus produces growth hormone-releasing hormone, or GHRH, and this allows for secretion of growth hormone. If we are not producing GHRH due to some issue with the hypothalamus, then the pituitary gland is not getting the signal it needs to produce growth hormone.

So in terms of signs and symptoms of growth hormone deficiency, the primary thing we'll see is short stature in our patient but proportional height and weight. Other signs and symptoms may include reduced muscle mass, increased fat, and delayed puberty. So in terms of diagnosing this condition, we could do a growth hormone stimulation test as well as a bone age scan, and we could do a CT scan of the patient's head to take a look for abnormalities in the hypothalamus or the pituitary gland. In terms of treatment, we need to provide growth hormone replacement therapy. This is done with a drug called somatropin. We administer this through a subcutaneous route. So if you want more details about somatropin, you'll notice here, on the back of card 21 if you're following along with cards, there's a reference to Pharm card 109, and that card has information about somatropin. But some of the key points about administering somatropin, besides the fact that it's administered subcutaneously, is that we typically stop treatment with somatropin once X-rays show epiphyseal closure. So we would be doing X-rays throughout the therapy with the growth hormone replacement, and when we see that epiphyseal closure, that's typically when we terminate treatment with somatropin.

Alright. Now let's talk about growth hormone excess. This is where we have excess secretion of GH from the anterior pituitary gland, and this may be due to some kind of tumor or lesion in the pituitary gland. That is most likely. But it could also be due to some kind of dysfunction in the hypothalamus. So if the hypothalamus produces too much growth hormone-releasing hormone, that causes excess growth hormone to be produced in the pituitary gland. So when we have excess growth hormone, this causes increased growth of bone and cartilage as well as increased protein synthesis. Signs and symptoms will depend on when we had the onset of this disorder. So if we have growth hormone excess prior to epiphyseal growth plate closure, this results in gigantism. And key signs and symptoms of gigantism include excessive height and arthritis. However, if we have onset of growth hormone excess after growth plate closure, this results in acromegaly. And signs and symptoms of acromegaly include enlarged hands and feet, a protruding jaw, kyphosis, which is an abnormal curvature of the thoracic spine, arthritis, as well as an enlarged larynx. So this enlarged larynx can cause a deep and hollow voice. So one of my favorite movies of all time is Princess Bride. If you haven't seen it, I totally recommend it. But Andre the Giant is a key actor in this movie, and he has acromegaly. So he has that deep and hollow voice. He definitely has enlarged hands and feet and that kyphosis. So check it out, and that will help you to remember the signs and symptoms of acromegaly. So to diagnose this condition, we would do a CT or MRI of the pituitary gland to basically see if we have got some kind of lesion or tumor there. And then, for treatment, we would do a hypophysectomy to remove part of the pituitary gland or all of the pituitary gland, if necessary.

Alright. So that is it for this video. We will pick it up with diabetes insipidus and SIADH in my next video. Thanks so much for watching!

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